The 32nd World Conference of the International Nuclear Target Development Society (INTDS2026)

30 Aug 2026, 08:30 → 4 Sept 2026, 17:00 Asia/Tokyo

RIKEN Wako Campus

Hiroki Okuno (RIKEN Nishina center for accelerator-based science)

1st announcement INTDS2026.pdf

2nd announcement INTDS2026.pdf

Financial-support-form_2026.pdf

INTDS2026_Abstract.docx

INTDS2026_Poster.pdf

Monday 31 August

Registration

Openning session

MOA1

1 CHALLENGES, STATUS AND PLAN OF FRIB HIGH POWER BEAM INTERCEPT-ING DEVICES TOWARD 400 KW OPERATION

The Facility for Rare Isotope Beams (FRIB) is a U.S. Department of Energy (DOE) Office of Science user facility for rare isotope research supporting the mission of the Office of Nuclear Physics. FRIB houses a continuous wave superconducting radiofrequency (SRF) linear accelerator to accelerate all ions with atomic numbers 1 through 92 to energies of 200 MeV/u or higher. FRIB currently operates at a beam power of 20 kW, steadily ramping up toward the goal of 400 kW. Like any other high-intensity heavy-ion accelerators, FRIB faces technical challenges in the beam intercepting devices that originate from the extremely high energy loss per distance travelled by heavy ions traversing the materials. The challenges are twofold: extremely high thermal density (~60 kW/cm³ [1]) and radiation damage rate (~1000 dpa/day [2]), which require unique solutions in beam intercepting devices. In this paper, the challenges faced by FRIB beam intercepting devices for power ramp up to 400 kW and our approach to address them are discussed.

[1] T. Kanemura et al., Phys. Rev. Lett., vol. 128, p. 212301, May. 2022.
[2] T. Kanemura et al., in Proc. HIAT’25, East Lansing, USA, June 2025, paper MOZ03, p. 20-25.

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This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics and used resources of the Facility for Rare Isotope Beams (FRIB) Operations, which is a DOE Office of Science User Facility under Award Number DE-SC0023633.

Speaker: Takuji Kanemura (Facility for Rare Isotope Beams, Michigan State University)

2 Charge-state distributions of uranium and lead beams in RI-beam production at BigRIPS

The superconducting in-flight RI-beam separator BigRIPS produces RI beams by bombarding a beryllium target with heavy-ion beams such as uranium and lead at 345 MeV/nucleon. In recent years, the production of heavy RI beams in the Z>70 region by projectile fragmentation has been actively studied.
Heavy ions change their charge states when passing through materials in the separator and are distributed among multiple charge states. Ions of the same nuclide but with different charge states have different magnetic rigidities and follow different trajectories in the spectrometer. Therefore, understanding the charge-state distributions is essential for interpreting and predicting the yields of heavy RI beams.
In this study, uranium and lead beams were passed through several materials, including a beryllium target, and the charge-state distributions were measured with a downstream spectrometer. In this presentation, we report the measured charge-state distributions, compare the results with charge-state calculations, and discuss their impact on RI-beam production.

Speaker: Masahiro Yoshimoto (RIKEN Nishina Center)

3 Latest news and projects from the GANIL Targets Laboratory

The growing number of experiments at GANIL has led to a significant increase in target demand—from approximately 50 units annually to an anticipated 500+. Moreover, the materials required for these targets have grown more complex, now including rare earth elements and natural uranium. This shift necessitates not only a larger quantity of targets but also enhanced quality, with stringent standards for homogeneity and purity. To meet these challenges, advanced equipment, controlled working environments, and rigorous validation protocols are essential to ensure reproducibility and precision.
In response to these evolving needs, GANIL has established PALAIS (Plateforme cibles pour GANIL/SPIRAL2), a dedicated target fabrication platform designed to serve an international user community. This platform, PALAIS specializes in producing a diverse range of high-quality targets in large quantities.
This report will provide an update on the GANIL Target Laboratory, which has recently undergone extensive renovation and modernization, including the acquisition of state-of-the-art equipment.

Speaker: Christelle Stodel (GANIL)

4 CERN-ISOLDE targets for radioactive ion beam production

For more than 50 years CERN-ISOLDE has been producing a wide range of radioactive ion beams (RIBs) using the isotope separation on-line (ISOL) method. Central to ISOLDE’s beam portfolio is its diverse selection of thick target materials and the high energy proton beam (1.4-1.7 GeV) both driving the radionuclide production. Isotopes are generated via spallation, fission and fragmentation reactions and released by heating the target material to ultra-high temperatures (> 2000 °C) in vacuum. Via a transfer line isotopes effuse to the ion source, where they are ionised, formed into an ion beam and send to experimental stations. Ever increasing user demands in terms of yield and beam purity drive the development of target and structural materials. With this contribution, we will give an overview of ISOLDE’s target systems and highlight recent developments, tailored to provide diverse, high-intensity, high-purity RIBs.

Speaker: Simon Stegemann (CERN)

10:40 Coffee Break

Joint Sesstion: INTDS: Ntombi / HPTW: Stodel / WWTC: Francisco Facilitator: Bettina Summary Etienne

12:00 Lunch Break

MOB1

5 METALLIC HAFNIUM TARGETS

Hafnium isotopes are interesting candidates in experiments studying shell effects and nuclear reaction mech-anisms. The general availability and price of enriched isotopes determines if producing targets from the want-ed isotope is realistically feasible.
For future applications, we investigated the yields achievable when producing metallic hafnium targets with the methods available at the GSI target laboratory, such as electron-gun evaporation and DC magnetron sput-tering, on different backing materials.

Speaker: Birgit Kindler (GSI Helmholtzzentrum fuer Schwerionenforschung)

6 Tailoring ligand design for adjacent lanthanide separations

Lanthanide isotopes such as Pm-147, Gd-153, Tb-161, and Lu-177 are indispensable for nuclear medicine and materials research. Their domestic supply, however, is constrained by one of the toughest challenges: separating neighboring lanthanides whose chemical properties are nearly identical. Conventional cation‑exchange processes with α‑hydroxyisobutyric acid offer only modest separation factors and produce large volumes of acidic waste, while extraction‑chromatography resins containing di‑2‑ethylhexyl phosphoric acid (HDEHP) improve selectivity but are costly and have limited capacity. These limitations underscore the need for better separation strategies.
One promising approach is rational ligand design that takes advantage of the subtle size differences produced by the lanthanide contraction. We have developed a tetradentate “chemical chameleon” ligand that can switch its preference from heavy to light lanthanides based on medium acidity and contact time. This adaptability means the same ligand can perform multiple separations, reducing the number of stages and the amount of solvent required without compromising purity. Another approach pairs hydrophilic ligands with lipophilic extractants in a two‑phase “tug‑of‑war,” pulling light and heavy lanthanides into opposite phases. These strategies include diglycolamide complexes that harness the lanthanide contraction, rigid ligand architectures that enforce size selectivity, and stimuli‑responsive ligands that adapt to changing conditions. Collectively, these approaches demonstrate that high‑purity radiolanthanides can be produced more efficiently, with fewer stages and lower solvent volumes.

Speaker: Prof. Ilja Popovs (University of Tennessee, Knoxville)

7 RUTHENIUM TARGET PRODUCTION OF DIFFERENT THICKNESSES

Natural ruthenium targets were needed for a measurement of the excitation function and cross sections using a high energetic proton beam. The experiment aims for a stacked target setup with monitor foils and offline counting of the activation using high purity germanium detectors. The optimal thickness and size of the target of 2 - 2.5centimeters in diameter and 20 – 100 micrometers (at maximal density) required tests of several methods. We will inform about failed approaches and our final solution to the problem in this presentation.

Speaker: Claus Mueller Gatermann (Argonne National Laboratory)

8 INTERFERENCE COLOR ANALYSIS FOR THICKNESS ESTIMATION OF MOLEC-ULAR-PLATED GADOLINIUM FILMS

Molecular plating (MP) is a widely used technique for preparing thin targets for nuclear physics applications, including cross-section measurements [1-3] and muon spectroscopy [4]. Target characterization typically relies on areal density (mg/cm²), which gives the total amount of material but not its spatial distribution. In non-uniform films, the same total mass can correspond to different local thicknesses, affecting energy loss and energy straggling of charged parti-cles in cross-section measurements, as well as interaction probabilities in muon spectroscopy. Therefore, reliable esti-mation of the film thickness and its spatial variation is required for a more complete characterization of molecular-plated targets.
Thickness determination by indirect methods, such as mass-based or optical approaches, relies on key parameters such as density and refractive index. These parameters are not well defined for molecular-plated films, and must therefore be treated as effective values.
In this work, we explore optical interference as a simple and robust approach to estimate the thickness of molecular-plated gadolinium films. Thin films were deposited galvanostatically on carbon substrates from dimethyl acetamide-based solutions. Deposition yields were quantified by ICP-OES, and film thickness was independently verified by SEM. For films in the 50–200 nm thickness range, distinct interference colors were observed, originating from light reflected at the film surface and at the film–substrate interface.
Film thickness was determined by mapping experimentally observed colors to simulated interference color charts, using a hue-based comparison to minimize sensitivity to illumination conditions. The thickness values obtained from this optical analysis are in good agreement with those derived from deposition yields and SEM measurements. In this comparison, yield-based thicknesses were calculated assuming a representative density for an amorphous hydrox-ide/carbonate matrix, while the interference analysis relied on an effective refractive index. Although these assump-tions introduce systematic uncertainty, the agreement with independent measurements indicates that their impact is limited under the investigated conditions.
The smooth and monotonic evolution of interference colors with deposition time further suggests that the effective optical properties remain approximately constant during film growth. Overall, interference color analysis provides a rapid, non-destructive, and spatially resolved tool for thickness estimation of molecular-plated films. The method is well suited for routine target preparation and process monitoring, and offers indirect insight into the consistency of film growth under typical MP conditions.

Speaker: Dr emilio andrea maugeri (Paul Scherrer Institut)

9 MICROSCOPIC AND SPECTROSCOPIC ANALYSIS OF HEAVY-ION BEAM IRRADIATED F-ELEMENT TARGETS

The synthesis of the heaviest known elements is mostly based on irradiation of actinide targets [1,2] with intense heavy-ion beams at energies around the Coulomb barrier, with Ca-48 being a key projectile [3]. Target production relies generally on the molecular plating technique, which was invented five decades ago [4] and is based on the electrochemical deposition of actinides from alcoholic solution at voltages of several hundred volts. Despite the long experience with the method, even basic aspects remain poorly understood [5] and the elucidation of the process [6] and of the composition and structure of MP produced films, as well as the parameters that govern film properties is still ongoing. Given the breadth of superheavy element research at GSI [7] and the importance of actinide targets for many of these studies, we have performed systematic studies of MP produced thin films (e.g., [8]), which shall serve as a basis towards actinide targets with improved properties, including i) higher beam resistance as is needed in light of ever more powerful heavy-ion accelerators coming online in the major superheavy element laboratories, and ii) thicker target layers that allow covering the whole width of excitation functions of the useful fusion-evaporation channels [1].
In my contribution, I will first discuss the production of lanthanide films by MP, which were characterized by a variety of microscopic, spectroscopic, and ion-beam techniques. Combining the results of several methods, MP thin films were shown to consist of a mixture of carbonates and formates. Under irradiation, these films transform into amorphous oxides with embedded carbon clusters [9]. In the second part I will discuss our studies of advance elec-trochemical procedures based on anhydrous electrochemical routes, which allow producing thicker films than MP does [10]. Also these films were characterized before and after irradiation using microscopic [10] as well as spectro-scopic [11] methods.

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[1] Ch.E. Düllmann et al., J. Radioanal. Nucl. Chem. 332, 1505 (2023).
[2] B. Lommel et al., Eur. Phys. J. A 59, 14 (2023).
[3] Yu.Ts. Oganessian, V.K. Utyonkov, Nucl. Phys. A 944, 62 (2015).
[4] W. Parker, R. Falk, Nucl. Instrum. Meth. 16, 355 (1962).
[5] E. Artes, Ch.E. Düllmann, C.-C. Meyer, D. Renisch, EPJ Web Conf. 285, 03001 (2023).
[6] A. Vascon et al., Nucl. Instrum. Meth. A 696, 180 (2012).
[7] Ch.E. Düllmann et al., Radiochim. Acta 110, 417 (2022).
[8] E. Artes et al., Radiochim. Acta 113, 779 (2025).
[9] C.-C. Meyer et al., Nucl. Instrum. Meth. A 1075, 170361 (2025).
[10] C.-C. Meyer et al., Radiochim. Acta 111, 801 (2023).
[11] E. Artes et al., Nucl. Instrum. Meth. A 1075, 170403 (2025).

Speaker: Christoph Düllmann (JGU Mainz / GSI Darmstadt / HIM Mainz)

15:00 Coffee Break

MOB2

10 Preparation and Detection of “Mock” Debris Targets for Isotope Analysis of Debris from the Fukushima Daiichi Nuclear Power Plant toward Its Decommissioning

It has been 15 years since the Fukushima Daiichi nuclear power plant accident, and we are still working
toward our mission of achieving safe decommissioning, which is expected to require approximately 40 years. One of
the most difficult challenges is the presence of approximately 880 tons of nuclear fuel debris in the reactors that melted
during the accident. Key questions include: (1) how can the debris be safely removed, (2) how can nuclear fuel be
separated from alpha-contaminated waste within the debris, and (3) how can long-term storage of the debris be man-
aged? The answers depend strongly on the actual composition of the debris.
Japan Atomic Energy Agency (JAEA) has successfully obtained two debris samples, which were transported
to the JAEA campus in November 2024 and April 2025. From isotopic and elemental analyses using ICP-MS and
SEM, majority of the components, such as uranium and iron, have been identified. However, trace components (<1%),
including ²⁴³Am, ²⁴³Cm, ²⁴⁸Cm, ²³⁸Pu, ²³⁹Pu, and ¹⁰B, are difficult to identify due to interfering nuclides, even though
these nuclei are critical for controlling criticality and ensuring safe decommissioning.
To analyze such trace components using advanced nuclear physics and chemistry techniques, we employ
(1) Coulomb excitation activation analysis coupled with a Ge detector array and (2) alpha–gamma coincidence meas-
urement techniques. As a validation experiment for method (1), “mock” debris targets were prepared using electrodep-
osition techniques and irradiated with a ⁵⁸Ni beam from the JAEA-Tokai tandem accelerator. The mock debris targets
were prepared by mixing ^natZr, ^natFe, ^natCr, ^natNi, and ^natPb to reproduce the composition of actual debris samples. In
addition, ²⁴⁸Cm was intentionally added as a trace component at approximately the 1% level. Rotational band peaks
from ²⁴⁸Cm were clearly observed, demonstrating the feasibility of the method.
Actual debris samples will be provided to our research group in 2026. We will then perform both alpha–
gamma coincidence measurements and Coulomb excitation activation analysis using real debris samples.

Speaker: Taiki Tanaka (Japan Atomic Energy Agency)

11 NONDESTRUCTIVE EVALUATION TESTING FOR SELENIUM-75 PRODUCTION TARGETS IN THE HIGH FLUX ISOTOPE REACTOR

Selenium-75 (⁷⁵Se) is one of dozens of radioisotopes produced at Oak Ridge National Laboratory (ORNL) to support the US Department of Energy’s Office of Isotope R&D and Production. The isotope is produced by irradiating enriched ⁷⁴Se target material in the High Flux Isotope Reactor (HFIR). ⁷⁵Se has a half-life of 120 days and is used as an industrial gamma radiography source in remote locations where standard x-ray generators cannot go due to size, weight, and power limitations [1].
Before being loaded into HFIR irradiation capsules, the ⁷⁴Se subcapsules undergo x-ray fluorescence spectroscopy (XRF) to identify any Se contamination on the subcapsule surfaces. Any subcapsules identified with Se surface contamination are excluded from the assembly. Recently, two ⁷⁵Se contamination events occurred in the hot cell during routine processing following HFIR irradiation cycles 510 (November 2024) and 511 (March 2025) in which evidence of surface contamination via XRF analysis was not identified prior to irradiation. In both events, elevated ⁷⁵Se contamination levels were identified via smears taken by radiation control technicians on the subcapsules and various hot cell surfaces. No personnel were contaminated with ⁷⁵Se during these events; however, the additional efforts that were required to decontaminate the hot cell and identify the leaking Se subcapsule added significant unforeseen time, cost, and complexity to the standard processing schedule. An effort began to conduct a thorough review of the XRF testing process and evaluate other nondestructive examination (NDE) methods to improve the effectiveness in identifying leaking Se subcapsules prior to irradiation.
Four additional NDE/spectroscopy techniques were selected to investigate further: helium (He) bombing/mass spectrometer leak testing (MSLT), bubble leak testing (BLT), x-ray computed tomography (XCT), and laser-induced breakdown spectroscopy (LIBS). Several Se subcapsules that failed MSLT and/or BLT were analyzed via XCT. Figs. 1 and 2 show a 3D rendition and cross-sectional view of the weld surface of one Se subcapsule, respectively. Although obvious leaks were not identified, XCT confirmed significant porosity in these welds that could lead to the release of ⁷⁵Se during the harsh HFIR irradiation environment.
This investigation determined that XRF is valuable for identifying Se surface contamination on the subcapsules, but additional NDE testing should be performed to evaluate the weld integrity prior to irradiation. Given the small size and large quantity of the Se subcapsules, He bombing/MSLT and BLT are readily available methods at ORNL and appropriate complement XRF to cover a greater range of possible leak rates, thereby reducing the likelihood of future Se hot cell contamination events.

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[1] QSA Global Inc., Selenium-75 Sealed Sources for Gamma Radiography (2026).

Speaker: Mikayla Duggan (Oak Ridge National Laboratory)

12 TARGETRY FOR LASER DRIVEN INERTIAL FUSION ENERGY (IFE)

Focused Energy is developing laser-driven Inertial Fusion Energy (IFE) technology aimed at enabling commercially viable fusion power generation. Our approach combines high-efficiency lasers, advanced target design, and scalable reactor engineering to address the key challenges on the path toward continuous, high-repetition-rate fusion energy production. This presentation will outline the Focused Energy roadmap toward a future power plant and highlight the central role of targetry in achieving reactor-relevant performance.
A major focus will be the requirements and specifications for IFE targets in a deuterium-tritium-based fusion demon-stration reactor to be built in Germany. These include target gain, dimensional tolerances, fuel-layer quality, cryogen-ic stability, survivability during handling and transport, compatibility with high-repetition-rate operation, and eco-nomically scalable production. In addition, target design must account for reactor integration, safety requirements, tritium handling, regulatory constraints, and the need for reliable operation in an industrial power-plant environment.
We will also present an update on the commissioning of the Focused Energy Laboratory Darmstadt (FELD), a dedi-cated facility for target production development and target deployment technologies for High Energy Density (HED) physics experiments and Inertial Fusion Energy (IFE). FELD supports the development of automated target fabrica-tion, cryogenic handling, target insertion, and high-speed injection systems. Emphasis will be placed on progress toward precise and stable target delivery at repetition rates up to 10 Hz. These developments are essential building blocks for demonstrating reactor-compatible target supply and for enabling practical laser-driven fusion energy.

Speaker: Dr Gabriel Schaumann (Technische Universität Darmstadt)

Tuesday 1 September

Registration

TUA1

13 Preparation of Isotopically Enriched Oxygen Targets (Ta218O5) for Nuclear Reactions in Inverse Kinematics and Nuclear Astrophysics Studies

The IFIN-HH Target Laboratory team has successfully produced high-quality targets for a wide range of experiments conducted at the 9 MV Tandem accelerator facility, using the laboratory’s existing infrastructure.
Recently, for the preparation of isotopically enriched solid oxygen targets (Ta₂¹⁸O₅) which are used in nuclear physics experiments, a dedicated anodization system inspired by the set-up from Laboratory Nationali del Gran Sasso - INFN (Italy). The system is based on an electrolyte consisting of 18O isotopically enriched water. By varying the applied voltage within the 200–550 V range, Ta₂¹⁸O₅ layers of different thicknesses and similar elemental composition were obtained. The anodization method proved to be efficient, cost-effective and reproducible, allowing the reuse of isotopically enriched water and the production of high-purity targets, which are essential for nuclear physics experiments [1-3].
The obtained targets were characterized using various techniques (such as RBS, SEM/EDS, XRD) in order to determine properties such as thickness, surface morphology, uniformity, and crystal structure.

[1] A. Caciolli et al, “Preparation and characterisation of isotopically enriched Ta2O5 targets for nuclear astrophysics studies” European Physical Journal A, 48, 144 (2012), DOI 10.1140/epja/i2012-12144-0.
[2] D. A. Yermilyea, “The kinetics of formation and structure of anodic oxide films on tantalum”, Acta Metallurgica, Volume 1, Issue 3 (1953), 282-291, 293-294
[3] M.P. Seah, M.W. Holbourn, C. Ortega, and J.A. Davies, “An intercomparison of tantalum pentoxide reference studies”, Nuclear Instruments and Methods in Physics Research B 30 (1988) 128-139

Speaker: Andreea Radu (IFIN-HH)

14 Novel Production Mechanism for Air Stabilization of Enriched Lithium Targets

Lithium targets are used in many nuclear experiments, such as alpha transfer experiments with enriched lithium-6 targets. Lithium, however, is difficult to work with. In its pure metallic elemental form, lithium is extraordinarily chemically sensitive, reacting with oxygen, water vapor, and even nitrogen. Lithium salts can be used as more stable targets for experiments, but can create additional backgrounds and reduced yields. Our innovation is a complete encapsulation of the lithium in a thin layer of gold to prevent it from coming in contact with the atmosphere through careful physical vapor deposition. The use of a hijacked shutter to serve as a mask for our multilayer deposition allowed for the lithium target core to have no direct contact with air. Our targets were subsequently used in a successful alpha transfer experiment.

Speaker: Robert Bartsch (Texas A&M University)

15 TARGETS OF PRASEODYMIUM AND ITS COMPOUNDS

Praseodymium is an interesting element for nuclear physics experiments investigating the structure of matter. Because of the chemical similarity to other lanthanides and its natural abundance, praseodymium, as a monois-totope, is a suitable material for initial tests. Once the method is established, it can be expanded to other (en-riched) rare earth elements. So far, targets can be either produced by rolling metallic praseodymium with anti-oxidation protection [1] or, as shown more recently, using different PVD processes [2-4].
In this work, we report on the preparation of targets made from metallic praseodymium, praseodymium fluo-ride, PrF₃, and praseodymium oxide, Pr₆O₁₁, on various backings and target frames.

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[1] Helmut, Folger and Josef Klemm, Book, Ed.: J. Jaklovsky, Plenum Press, NY (1981) 171-179
[2] John P. Greene and George E. Thomas, Nucl. Inst. Meth. B 61 (1991) 575-579
[3] V. Kumar, S.R. Abhilash, D. Kabiraj, P. Thakur, A.K. Bhati, Nucl. Inst. Meth. A 613 (2010), 404-406
[4] Connor Mohs, Claus Müller-Gatermann, and John P. Greene, EPJ Web of Conferences 327 (2025) 01007

Speaker: Bettina Lommel (GSI Targetlaboratory)

16 Electron Beam Physical Vapor Deposition of Germanium-70 for targets manufacturing

Here, we report the manufacturing process of ⁷⁰Ge targets used in a nuclear physics experiment conducted at iThemba LABS (Laboratory for Accelerator-Based Sciences). The objective of this experiment was to gather information on the lowest excited states of ⁷²Se, ⁷²Ge, and ⁷²As through alpha-induced reactions on a ⁷⁰Ge target, specifically the reaction ⁷⁰Ge (α, X) Y. The targets for this experiment were physically deposited under vacuum using an electron beam deposition (EBEAM) procedure. Atomic layers of ⁷⁰Ge were collected on the polished stainless-steel substrates, which were previously coated with barium chloride, which acted as a parting agent. The thickness of the deposited targets was subsequently measured using X-ray fluorescence.
Key words: Ge, ⁷⁰Ge, e-beam, parting agent

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[1] Á. Barna et al. Nucl. Instr. and Meth. 102 (1972) 549-552.
[2] D.N. Braski. Nucl. Instr. and Meth. 102 (1972) 549-552.

Speaker: ntombizonke kheswa (iThemba LABS)

17 PREPARATION OF CARBON BACKING FOIL

At the RIKEN Nishina Center, multilayer graphene (MG) and graphite sheets (GS) manufactured by Kaneka Corporation [1] are employed as charge strippers, enabling the stable delivery of high-intensity beams [2]. Thin carbon foils are also utilized as backing foils for targets in superheavy element search experiments, where they are typically fabricated by arc discharge or magnetron sputtering methods.
In recent years, target materials for superheavy element searches have become extremely costly, available only in limited quantities. The electrodeposition method [3,4] offers an effective means of bonding expensive target material onto metal backing foils. However, this method involves aqueous solutions, rendering it incompatible with conventional carbon foils, which are prone to cracking when dry, deforming upon absorbing water, and disintegrating in organic solvents.
It is well established that carbon backing foils extend target lifetimes compared to their metallic counterparts. We therefore pursued the development of MG-based backing foils capable of withstanding the solutions used in electrodeposition, much like metal foils. This effort posed a significant challenge due to the inherently low surface wettability of MG and GS, which results in poor adhesion to other materials. Nonetheless, we have successfully fabricated MG backing foils exhibiting good adhesion to the target material. In this contribution, we present the development process.

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[1] A. Tatami et al., AIP Conference Proceedings 1962, 030005 (2018).
[2] H. Hasebe et al., EPJ Web Conf. 229 (2020) 01004.
[3] W. Parker, R. Falk, Nucl. Instr. And Meth. 16, 355-357 (1962)
[4] Y. Kudou et al., RIKEN Accel. Prog. Rep. 42, 265 (2009).

Speaker: Hiroo Hasebe (RIKEN)

10:40 Coffee Break

TUA2

18 Production of self-supported thin Tin film for a high resolution measurement of two nucleon transfer reaction

The overall objective of this study is to reveal the proton-neutron pair correlation in neutron-rich nuclei to measure proton-neutron pair transfer. For this purpose, we are aiming at the evaluation of the transition strength of proton-neutron transfer between the ground states of tin and indium via proton-neutron pair transfer reactions such as (p,3He), (d,4He), and (4He,6Li) measured with Grand Raiden magnetic spectrometer. For instance, to resolve the ground state of 114In from its first excited state (190 keV), an energy resolution of approximately 75 keV (FWHM) is required. Furthermore, our ultimate goal is to resolve the ground and first excited states (separated by 60 keV) in the 120Sn(4He,6Li)118In reaction. Energy resolution is primarily determined by the beam spread and energy loss difference relative to the reaction position within the target. The required target thickness for 116Sn(p,3He)114In reaction is less than 2 \mu\mathrm{m}. For the ultimate goal of 60 keV resolution, a target thickness of approximately 0.5 \mu\mathrm{m} is required. Since rolling methods have thickness limitations, vacuum deposition method was adopted. While standard deposition typically maintains a source-to-substrate distance of 10–30 cm to ensure uniformity, the high cost of enriched isotopes poses a financial challenge. Therefore, we adopted a "short-distance deposition" technique to improve collection efficiency, subsequently measuring thickness at multiple points to evaluate the thickness distribution. In practical, the target thickness can be simultaneously measured by using energy loss difference in the physics measurement. To eliminate the background events, the target should be self-supported without any backing. In this paper, we discuss the fabrication method of self-supported thin-film tin targets and the results of the high-resolution measurements obtained using them. Tin has a low melting point and is prone to structural changes, requiring sophisticated techniques for high-quality film formation [1]. We utilized a tungsten boat as the evaporation stage and glass slides as the substrate. The process began by evacuating the chamber, followed by the deposition of a NaCl thin layer. Subsequently, tin metal was deposited onto the NaCl layer. The NaCl layer served as a sacrificial layer. After deposition, it was dissolved in water. The tin foil was carefully scooped up from the water surface using a target holder.
The parameters for 116Sn deposition were: a source-to-substrate distance of 4.5 cm, 100 mg of 116Sn source material, 30 mg of NaCl, a deposition time of 11 min, an initial current of 37.5 A, and a vacuum level of 5\times{10}^{-3}\ Pa. We observed that using approximately 0.9 g of NaCl caused the metallic luster to disappear on both sides, whereas 30 mg of NaCl successfully preserved the luster on the substrate side. In March 2026, we performed the 116Sn(p,3He)114In reaction measurement using this target. To evaluate the target thickness, we utilized the energy loss difference observed in the two-nucleon transfer reaction. The resulting resolution was approximately 57 keV, successfully meeting our goal and allowing for the clear separation of the ground state peak from the first excited state. Our results indicate that excessive thickness of the NaCl sacrificial layer negatively impacts the quality of tin deposition. Through energy loss analysis, a thickness of 1.6 \mu\mathrm{m} is measured, achieving our target of a thickness below 2 \mu\mathrm{m}. This study successfully established a cost-effective, short-distance vacuum deposition method for enriched isotope targets, enabling high-resolution nuclear spectroscopy measurements.

Reference
[1] V. Borra et al., Thin Solid Films, 616, 311 (2016).

Speaker: 香穂理 平松 (大阪大学)

19 Increasing Availability for Polyethylene (CH2) and Deuterated Polyethylene (CD2) Thin-Films

Hydrogen- and deuterium-containing thin films are widely used across the nuclear physics community as
accelerator targets for studying a variety of nuclear reactions involving protons and neutrons, which can
often provide great insight into numerous astrophysical processes. Polyethylene (C₂H₄)_n or CH₂ for short,
and deuterated polyethylene (C₂D₄)_n or CD₂ are typically utilized for these studies as they have a relatively
high hydrogen density, while still providing the advantages of a solid target. Although production methods
for these targets have been well-studied [1], there is a lack of commercial availability of these targets,
leaving researchers on their own to develop their own targets. CH2 also notably does not behave identically
to CD₂ when produced via the same methods, leading to frustrating difficulties when attempting to produce
CH₂ targets. CH₂ and CD₂ targets are also known for having relatively short lifetimes in beam, resulting in
the need for numerous replacement targets. To this end, researchers at The Arizona Carbon Foil Company
have been making advancements in both the efficiency and production volume of the previously established
solvent casting techniques for both CH₂ and CD₂, demonstrated here, in an effort to make both of these foils
commercially available and overall more accessible for the community.

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[1] M. Febbraro, et. al. NIM B. 410, 53-59 (2017).

Speaker: Laura Bills

20 Development of a thin self-supporting Boron target

The proton–boron fusion reaction (p + $^{11}$B) is one of the candidate reactions for aneutronic nuclear fusion energy. Two resonances have been reported at laboratory energies of 160 and 600 keV; however, the reported cross sections show significant discrepancies among previous measurements.

We plan to perform new measurements of the reaction cross sections using state-of-the-art detector systems and digital electronics, providing nearly $2\pi$ geometrical coverage. A key requirement for this experiment is a thin, self-supporting, highly enriched $^{11}$B target.
To meet this requirement, we have been developing such targets using evaporation and sputtering techniques. In this contribution, we present the current status of the target development and outline the experimental plan for the forthcoming cross-section measurements.

Speaker: Nobuaki IMAI (CNS, Univ. of Tokyo)

12:00 Lunch Break

TUB1

21 METALLOTHERMIC REDUCTION EVAPORATION OF LANTHANIDES

A self-supporting target of monoisotopic, metallic lanthanide can be considered ideal due to the absence of interfer-ing elements that could disturb a nuclear physics experiment. Unfortunately, the majority of elements in the lantha-nide series are not monoisotopic. Experiments rely therefore on enriched lanthanides, typically available in the form of oxides. The enriched oxide material must therefore be reduced in order to produce metallic lanthanide thin films. For this purpose, the metallothermic reduction evaporation is the method of choice, having been proven by target makers worldwide over the past six decades [1-4].

This work focuses on the implementation of the metallothermic reduction evaporation method at GSI for the produc-tion of thin, metallic lanthanide targets on different backings. Different lanthanide oxides were tested and their reduc-tion yields compared, applying hafnium as the reducing agent. In addition, the effect of the amount of reducing met-al on the yield is discussed for the case of samarium.

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[1] L. Westgaard et al., Nucl. Instrum. Methods, 42, 77-80 (1966).
[2] E. H. Kobisk et al., Nucl. Instrum. Methods, 167, 153-160 (1979).
[3] R. Pengo et al., Nucl. Instrum. Methods, A303, 146-151 (1991).
[4] J. P. Greene et al., Nucl. Instrum. Methods, B61, 575-579 (1991).

Speaker: Noemi Cerboni (GSI)

22 Facility Expansion and Community-Driven Development of Nuclear Target Materials at ACF-Metals

Over the last few years, The Arizona Carbon Foil Co., Inc. has been taking a community-informed approach to manufacturing. We are asking a simple question to the global nuclear target community: What basic materials are you struggling to acquire, and how can we help?
We are excited to announce that the answers to those questions have guided the direction of our current expansion.
Our first action was to acquire a new department head for our Materials Chemistry and Target Development Division. Next, we expanded our facility to include a chemical laboratory enabling us to produce additional types of targets, including CD₂ and CH₂. Simultaneously, we brought in target specialists to examine potential new product ideas and shorten the gap between idea and end-product.
While all of this was underway, we installed additional PVD systems, specifically for carbon-13, and are currently re-establishing our thin-film metals capability, (Au, Al, Ag, Ti, Cu, etc.). On top of that our website was entirely updated to help reflect the many changes, including our new Consultants page and the new products we are making available. Now, the best for last - we are also testing new carbon stripper foils that we are very excited about and hope will demonstrate significantly longer life-times.
This talk provides the facility update from listening and investing, to delivering. We also extend an invitation to the community to please continue providing the essential feedback that will help shape our path and ensure that together we meet the challenges ahead.

Keywords: accelerator targets, Carbon extraction foils, polyethylene (CH₂), deuterated polyethylene (CD₂), commercial availability

Speaker: Ms Constance Stoner (The Arizona Carbon Foil Co., Inc.)

Sponsor company presentations

Poster-style session

15:00 Coffee Break

Facility Tour: RIKEN RIBF

Wednesday 2 September

Registration

WEA1

23 RECENT DEVELOPMENTS IN THE PRODUCTION OF ACTINIDE TARGETS AND SOURCES IN MAINZ

Actinide isotopes play a crucial role in various scientific research initiatives, serving as targets for accelerator-based irradiation experiments, as targets for laser spectroscopic investigations aimed at exploring atomic and nuclear properties, as laser ablation sources or as recoil ion sources for alpha-decay daughter nuclides. Each experiment demands specific parameters such as sample thickness, geometry, (radio)chemical purity, and backing material. Consequently, tailored targets are essential for each experiment.
At the Joahnnes Gutenberg University Mainz, Germany, various production techniques are employed, such as elec-trochemical deposition, Drop-on-Demand printing or spin-coating. All these methods are constantly being further developed and refined to improve the yield and quality of the desired samples and to adapt to new requirements. The development process often commences with preparatory work using inactive lanthanides as chemical homologs for the actinides. Subsequently, neutron activation of the lanthanides in the TRIGA Mainz research reactor is often performed, resulting in radioactive lanthanide tracers (e.g. Tb-160). This enables the application of radiochemical characterization methods, including gamma spectroscopy and radiographic imaging. The optimized procedure is then applied to the desired actinide isotopes, some of which are highly valuable due to their limited availability. Additional characterization methods for the finished samples include alpha spectroscopy, conventional weighing with a µg balance, optical microscopy as well as scanning electron microscopy with energy dispersive x-ray spec-troscopy.
To expand the range of available actinide isotopes, tailored irradiation of suitable isotopes is performed, e.g. in the high-flux reactor of Institute Laue Langevin (ILL) in Grenoble, France. This way the nuclides Cm-242 and Bk-249 were made available recently.
This presentation provides an overview of diverse production and characterization methods, accompanied by a detailed discussion of specific examples from ongoing projects.

Speaker: Dennis Renisch (Johannes Gutenberg University Mainz)

24 Purification of plutonium from americium, neptunium, and uranium using anion exchange chromatography for the production of plutonium-241 targets

The isolation of plutonium from complex actinide matrices represents a critical stage in the preparation of high-purity targets for nuclear data measurements. This process is inherently challenging due to the closely related chemical behaviours of actinide elements and the coexistence of multiple oxidation states. In this study, an anion-exchange chromatography method is used to achieve the requisite purity. By employing a controlled redox pre-treatment cycle, plutonium is stabilised in the +IV oxidation state to maximise retention on the resin, while other actinides, namely americium, neptunium, and uranium, are selectively eluted. The purified plutonium is subsequently recovered from the column using an ascorbic acid solution as eluent. Alpha-particle and gamma-ray spectroscopic analyses confirmed a plutonium recovery yield exceeding 98 %, with residual americium contamination suppressed to below 1.6 %. Additionally, thermal ionisation mass spectrometry (TIMS) verified the effective removal of neptunium and uranium, thereby demonstrating the method’s efficacy for producing high-purity plutonium targets suitable for nuclear physics experiments.

Speaker: Mr David Vanleeuw (EC-JRC-GEEL)

25 HIGHLY ENRICHED URANIUM FOILS FOR RADIOACTIVE BEAM PRODUC-TION

The Californium Rare Isotope Breeder Upgrade (CARIBU) at the Argonne Tandem Linac Accelerator System (ATLAS) was used previously to provide beam of neutron-rich isotopes from spontaneous fission of ²⁵²Cf to experiments. The beams were either used in low energy experiments for mass measurements, beta decay or laser manipulation , or for injection into the ATLAS accelerator after charge breeding.
The system has been upgraded to nuCARIBU, where fission products are now obtained from neutron-induced fission on ²³⁵U. The facility allows for fast, efficient and essentially chemistry-free extraction of fission frag-ments. nuCARIBU, like its predecessor CARIBU, uses a gas catcher and various isotope separation techniques.
A proton cyclotron produces neutrons using a (p,n) reaction on a thick ⁷Li target. The neutrons are moderated before hitting the ²³⁵U target sitting inside the gas catcher. To get the required yield, the minimum require-ments on the uranium foil were 5mg/cm² thickness over 4 inch diameter.
The presentation will cover the production of the uranium foil.

Speaker: Claus Mueller Gatermann (Argonne National Laboratory)

26 RADIOACTIVE TARGETS FOR NEUTRON-INDUCED REACTION MEASUREMENTS AT LANL

Computational modeling of environments with neutron fluxes, such as stellar nucleosynthesis and validations in nuclear applications, requires high fidelity nuclear data to be reliable. So far, such highly accurate data has been acquired primarily for stable nuclei. As a result, higher quality experimental nuclear data is needed for other nuclei, which includes nearly all radionuclides, because theoretical data is currently used to predict their nuclear properties and these data can vary significantly from their true values [1]. Directly measuring nuclear reactions on solid targets provides the highest quality experimental data [2]. These kinds of measurements have been performed at the Los Alamos Neutron Science CEnter (LANSCE) using a variety of radioactive targets produced in house utilizing recently expanded radioactive target fabrication capabilities and leveraging production capabilities for production of radioactive isotopes at Los Alamos National Laboratory (LANL). Recently, a microliter-sized liquid source containing tens of mCi of $^{88}$Zr and an $^{26}$Al molecular plated target were fabricated and measured utilizing Device for Indirect Neutron Capture Experiments on Radionuclides (DICER) and Low Energy NZ (LENZ) instruments, respectively [3-5]. This talk will cover the more recent efforts at LANL to manufacture and characterize solid radioactive targets to enable the acquisition of high-quality nuclear reaction data.

This work is supported by the U.S. Department of Energy under Contract No. 89233218CNA000001 at Los Alamos National Laboratory.

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[1] J. A. Shusterman et al., Nature, 565, 328–330 (2019).
[2] P. Schillebeeckx et al., Nucl. Instrum. Methods Phys. Res. A, 613, 378-385 (2010).
[3] A. Stamatopoulos et al., Phys. Rev. Lett., 134, 112702 (2025).
[4] A. Stamatopoulos et al., Phys. Rev. C, 111, 034613 (2025).
[5] S. D. Essenmacher et al., Sci. Rep. (in press).

LA-UR-26-23426

Speaker: Scott Essenmacher (Los Alamos National Laboratory)

27 FABRICATION OF CALIFORNIUM-249 TARGETS TO ENABLE THE SEARCH FOR ELEMENT 120 AND OTHER SUPERHEAVY NUCLIDES

The discovery of new elements proceeded at a breakneck pace between 1935 and 2010. Twenty-two elements were discovered during that time, with an average discovery rate of every 3 years. Although many exciting developments have occurred in the field of superheavy elements since then, a new element continues to elude the community. The most recently discovered elements used 48Ca beams on actinide (U through Cf) targets with great success. The 48Ca nucleus is special and referred to as doubly magic because it has filled nuclear shells. This unique nuclear structure has been found to greatly increase the likelihood that a compound nucleus reaction will yield an intermediate nucleus that prefers to eject a few neutrons and form a heavier nucleus rather than spontaneously fission. To continue using this successful approach and push beyond Og, the heaviest known element, the actinide target would need to be made of Es or Fm. This requirement creates a currently impassable roadblock. The typical quantity of actinide material needed for a target is tens of milligrams, but both Es and Fm are produced at only microgram and picogram quantities, respectively. Approaches to producing larger quantities of both, especially Es, can be envisioned but would require extraordinary irradiation campaigns in a nuclear reactor with a high neutron flux to produce. An alternative approach is to increase the mass of the ion beam beyond 48Ca, which the community has undertaken. Experiments in recent years have shown that this approach is viable. Currently, Lawrence Berkeley National Laboratory is on a path to explore the possible formation of element 120 using a 50Ti beam with a 249Cf target. Oak Ridge National Laboratory is fabricating the 249Cf target for the experiment using the lab’s unique radiochemical processing facilities. This paper will focus on the process being used to fabricate the 249Cf targets.

Speaker: Kristian Myhre (Oak Ridge National Laboratory)

10:40 Coffee Break

Invited talk: Experiments on Three-Nucleon Forces: Recent Achievements and Target Innovations

Convener: Kimiko Sekiguchi (Tokyo Institute of Technology)

12:00 Lunch / Bus transfer

Excursion to near Omiya Station Museums visits etc.

18:00 Reception dinner Japanese cuisine

Thursday 3 September

Registration

THA1

28 High power targets at J-PARC

J-PARC has three proton accelerators and three research facilities with using MW-class high power proton beams. Each experimental facility is equipped with beam-intercepting devices, such as targets and beam windows, to generate secondary particles; the survivability of beam-intercepting devices, such as target and beam window under intense beam irradiation is a key factor limiting the achievement of higher beam power.
In April 2026, the Beam Technology Development Section was established to address the development of common technologies across all facilities. This presentation reports on the high power targets at J-PARC and the activities of the newly established Beam Technology Development Section.

Speaker: Shunsuke Makimura (J-PARC/KEK)

29 TOWARD RADIATION-TOLERANT TITANIUM ALLOY BEAM WINDOWS FOR MW-CLASS PROTON ACCELERATORS

Beam windows used in MW-class proton accelerator facilities are subjected to severe thermal shock, cyclic stress, and radiation damage under intense pulsed beam operation. In the J-PARC neutrino beamline, a 0.4-mm-thick double-dome Ti-6Al-4V (Ti-64) beam window structure with He gas cooling between the two layers has been successfully operated; however, future higher-power operation toward the Hyper-Kamiokande era will require improved irradiation tolerance and structural reliability[1].

To address this issue, metastable β-Ti alloys are being investigated as candidate beam window materials. In particular, Ti-15V-3Cr-3Sn-3Al (Ti-15-3) alloy with a specially designed two-step aging treatment (ST2A) has shown promising indications of reduced irradiation hardening and enhanced defect recovery behavior under high-energy proton irradiation compared with conventional Ti-64 alloys. These characteristics are considered to be related to the unique defect dynamics and lattice instability inherent in metastable β-Ti systems[2].

Based on these findings, a practical beam window upgrade concept for future MW-class operation is being studied using a hybrid structure consisting of Ti-15-3 ST2A on the accelerator side and Ti-64 on the downstream target-vessel side, in order to reduce the fracture risk of the upstream window region, which could lead to severe contamination of the accelerator vacuum system.

Post-irradiation examination (PIE) of actual irradiated Ti-64 beam window materials and Ti-15-3 OTR beam monitor foils recovered from the J-PARC neutrino facility is also planned, including small punch testing and gas production measurements such as thermal desorption spectroscopy (TDS). Furthermore, dual-ion irradiation experiments at Japanese facilities (HIT/TIARA) are planned to investigate spallation-induced He production effects, together with meso-scale ultrasonic fatigue testing using the proton cyclotron facility at the University of Birmingham.

This presentation will discuss current irradiation issues of high-power proton beam windows at J-PARC, recent progress in β-Ti alloy development, and future prospects toward radiation-tolerant beam-intercepting components for next-generation accelerator facilities.

[1] T. Ishida, E.Wakai, S.Makimura et al., JPS Conf. Proc., 28, 041001 (2020).
[2] T.Ishida, S.Kano, E.Wakai et al., J. Alloys Compd., 995, 174701 (2024).

Speaker: Taku Ishida (High Energy Accelerator Research Organization (KEK)／J-PARC Center)

30 CONCEPTUAL DESIGN STUDY OF A BERYLLIUM TARGET FOR A FUSION NEU-TRON SOURCE FOR THE DEMO REACTOR

Design and development activities are currently underway with the aim of demonstrating power generation using a Fusion DEMO reactor in Japan in the 2030s. At QST Rokkasho, feasibility studies are being conducted on a fusion neutron source required for qualifying blanket performance for the Fusion DEMO reactor (hereafter referred to as DEMO-FNS).
Unlike A-FNS [1], DEMO-FNS is planned to operate in a pulsed mode with a duty cycle of several tens of percent, rather than in continuous-wave operation for the deuteron beam current. The nominal beam energy and beam cur-rent are assumed to be approximately 40 MeV and 50 mA, respectively.
In A-FNS, liquid lithium was adopted as the target material from the viewpoint of heat removal. In contrast, DEMO-FNS is investigating high–melting-point metals, with beryllium currently considered a promising candidate. In this presentation, we report on studies of a beryllium target for DEMO-FNS, including neutron yield evaluation, thermal analysis, structural strength assessment, and mitigation strategies for blistering.

Speaker: Kohki Kumagai (National Institutes for Quantum Science and Technology)

31 - Design and offline qualification of a high-temperature niobium bent-foil target for SPIRAL1

The SPIRAL1 facility (Système de Production d'Ions Radioactifs Accélérés en Ligne) at GANIL (Grand Accélérateur National d'Ions Lourds) produces radioactive ion beams via the Isotope Separation On-Line (ISOL) method. Primary heavy-ion beams from ¹²C to ²³⁸U at up to 95 MeV/u currently impinge on graphite targets to induce projectile fragmentation. To extend and enhance isotope production, a new target based on fragmentation of a heavier target material is under development at SPIRAL1. Using a high-power ¹²C beam (up to 3 kW) on higher-Z materials, the long-term objective is to deliver a wider range of exotic beams for nuclear physics and interdisciplinary research, including future experiments at the SPIRAL2–DESIR low-energy facility.

The design of these new ISOL targets must reconcile enhanced isotope production, a high operating temperature to favour isotope release, and management of the thermal load. Target material selection was guided by EPAX-estimated in-target production and material properties (melting point, vapour pressure, manufacturability, diffusion). Niobium and the composite oxides ZrO₂ and Y₂O₃ emerged as the most promising candidates within the Z ≤ 41 regulatory limit at GANIL.

Unlike proton-driven ISOL facilities, where energy is deposited over several hundred millimeters, the ¹²C beam stops within ~4.7 mm in niobium. The volumetric energy density is several orders of magnitude higher, shifting design priorities from global heat dissipation towards local heat spreading, while preserving short diffusion paths.

To address this, a bent-foil geometry has been developed: foils mounted at an inclined angle provide a larger apparent beam thickness, an enlarged radiative surface and self-supporting stacking with minimal inter-foil contact, mitigating large-area sticking that would impede release. A first preliminary design comprises: each 50 µm-thick foil is bent with a 45° included angle, repeated periodically to form a corrugated profile, providing an apparent beam thickness of 130 µm; 34 such foils are then stacked into the final assembly. Energy deposition profiles calculated with TRIM (Transport of Ions in Matter) coupled with steady-state ANSYS simulations code show that this configuration, within an enclosure held at 2000 °C, keeps the maximum foil temperature within the operational limits of niobium and below that of a flat-foil equivalent.

The geometrical parameters of the stack (foil angle, height, inter-foil spacing) directly influence both the temperature distribution and isotope release. A parametric optimisation is therefore being implemented to identify configurations that combine improved temperature homogeneity with favourable release rates.

In support of this design effort, niobium bent-foil samples have been tested offline inside a graphite resistance furnace, maintained at nominal operating temperature without observable damage, providing a first offline qualification of the mechanical and thermal behaviour. The next steps include the fabrication of a complete target prototype, full-scale heating tests on a dedicated offline platform, and ultimately online irradiation tests under the high-power ¹²C beam.

Speaker: Sophie Hurier (CNRS-GANIL)

32 ANALYSIS OF IRRADIATION DAMAGE AND HIGH-HEAT LOAD IN THE BEAM DUMP MATERIALS TOWARD HIGH-POWER OPERATION

High-energy particles in accelerator facilities and nuclear research reactors utilize for the basic science, materials science, and engineering application and analysis in the world. In many facilities it is required to increase the operation power level and beam intensity for the requirements for them. In such facilities the beam intercept device such as beam dump and components of structure of the system are receiving particles with the high-energy and high-intensity, and the materials are gradually degraded by the irradiation damage and high-heat loaded damage. To improve and develop the system and components it is necessary to examine and analysis these effects on materials properties. The Facility for Rare Isotope Beams (FRIB) is a U.S. Department of Energy (DOE) Office of Science user facility for rare isotope research supporting the mission of the Office of Nuclear Physics. FRIB houses a continuous wave superconducting radiofrequency (SRF) linear accelerator to accelerate all ions with atomic numbers from 1 to 92 to energies of 200 MeV/u or higher. FRIB currently operates at a beam power of 20 kW, steadily ramping up toward high-power operation. For high-power operation, a water-cooled rotating shell structure has been proposed as the design for the beam dump. The objective of this study is to evaluate these effects on the materials and material selection suitable for high-power operation of FRIB beam dump, and it will discuss and present the results of high-temperature load experiments and the radiation damage behaviour.

• This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nu-clear Physics and used resources of the Facility for Rare Isotope Beams (FRIB) Operations, which is a DOE Of-fice of Science User Facility under Award Number DE-SC0023633.

Speaker: Dr Eiichi Wakai (Facility for Rare Isotope Beams, Michigan State University)

10:40 Coffee Break

THA2

33 Upgrade of Gaseous Active Target CAT-M for High-Intensity heavy-ion beam experiments using AN Embedded Permanent Magnet Delta-Electron Sweeper

Gaseous active targets are a key technology for nuclear physics experiments requiring full kinematic reconstruction of beam and low-energy reaction products. However, their application to high-intensity heavy-ion beams is limited by severe background from delta-electrons, which significantly degrade the signal-to-noise ratio and trigger performance in conventional readout systems. In experiments with heavy-ion beams exceeding $10^5$ counts per second at $\sim 100$~MeV/nucleon, such as tin isotopes, a large number of energetic delta-electrons reach the sensitive region of the gaseous active target CAT-M. The accumulation of ionization electrons from these backgrounds leads to severe signal degradation, making stable operation with standard electronics difficult.

Suppression of delta-electrons is therefore essential for extending active target techniques to high-intensity environments. Electrons produced in these reactions are light particles with a maximum energy of about $300$~keV, corresponding to a magnetic rigidity of about $0.002$~Tm. To confine these electrons within $10$~mm of the beam path, a magnetic field of approximately $0.2$~T is required. While traditional coils are impractical for an active volume of $28 \times 32 \times 20$~cm$^3$, recent high-remanence permanent magnets enable a compact and efficient solution.

To address this issue, we developed an ``embedded permanent magnet delta-electron sweeper'' integrated directly inside CAT-M to sweep delta-electrons away from the active region. The magnet is coupled with grading strip electrodes to maintain a uniform electric field. Since the dipole field prevents direct beam tracking in the main TPC, auxiliary small-scale TPCs are installed at the entrance and exit to recover precise beam trajectory information.

The system was commissioned at HIMAC using a $^{132}$Xe beam at $\sim 100$~MeV/u (21H445). The implementation of this magnetic suppression system improved the signal-to-noise ratio by more than a factor of 450. The dead region, which was caused by setting the higher threshold and was 40% of the active area for the high energy particles, is recovered. The system was successfully applied to deuteron scattering on $^{86}$Kr in inverse kinematics (21H445). These results demonstrate that a compact permanent-magnet-based approach enables gaseous active targets to operate under high-intensity heavy-ion beams, achieving stable operation that was previously not feasible. This development opens a path toward experiments that were previously limited by severe background conditions.

Speaker: Dr Shinsuke Ota (RCNP, Osaka University)

34 Thermal-hydraulic characteristics of an IFMIF-type liquid lithium target for a higher-current deuteron accelerator

In Moonshot program 10, a novel high-power neutron source based on deuteron accelerator is being developed for fusion materials irradiation experiments. This project aims to achieve higher neutron yields than the International Fusion Materials Irradiation Facility (IFMIF) through the same mechanism—stripping reactions between deuterium and a liquid-lithium target. While IFMIF accelerates deuterium up to 250 mA, this project targets an unprecedented 1 A. Due to the significantly increased heat load associated with this high-current operation, precise control of the liquid lithium target is essential to ensure safe and stable operation.
In this study, thermal–hydraulic analyses were performed to assess target soundness under the 1 A operation scenario. A simplified two-dimensional model of the lithium target was constructed, and numerical simulations were carried out using OpenFOAM version 2512 to evaluate temperature distributions and flow velocity fields. Based on the simulation results, the optimal lithium flow velocity required to maintain the target temperature below its boiling point was also investigated.

Speaker: Yu Fujiwara (Nagoya University)

35 Diagnostics & Characterization of Cluster-Jet Targets for Accelerator Experiments

Cluster-jet targets provide compelling advantages for a wide array of experimental investigations owing to their unique windowless configuration and internal design. A powerful state-of-the-art cluster target source, specifically designed and constructed for the future PANDA experiment at FAIR, has been successfully assembled and inte-grated with a dedicated target setup at COSY/Jülich [1,2]. This target system will play a decisive role in the up-coming KOALA experiment at the GSI in Darmstadt over the next years.

The target properties – including target thickness, width, cluster sizes [3], and cluster velocities – can be precisely specified and thoroughly characterized using several diagnostic tools designed for Münster-type jet targets. These diagnostic tools allow for detailed optimization of the target conditions to meet the requirements of the respective experiment, e.g., for high precision experiments in nuclear and particle physics.

Advanced shadowgraphy measurements were employed to determine both the size and velocity distributions of the clusters. A commercial laser emitting a wavelength of 450 nm with a pulse duration of 129 ns is utilized, ensuring the clusters move during laser illumination. This allows not only to resolve the cluster size but also to extract key characteristics – including cluster diameter, velocity and flight direction – from the observed shadow patterns. The measured cluster size distribution is deconvolved using data acquired from a series of static particles with known sizes. This correction process addresses the dependence of the observed size on the distance from the objective-camera system’s focal plane.
These measurements were conducted across several different target stagnation conditions and nozzle designs to explore variations in cluster characteristics.

Additional beam diagnostic tools are positioned within the cluster-jet target’s beam dump, which efficiently re-moves clusters and residual gas not interacting with an accelerator beam. To optimize the beam dump perfor-mance, a dedicated setup was designed and commissioned with a newly implemented orifice system. A compre-hensive study was then conducted investigating vacuum pressure distributions along the target beam line and clus-ter-jet thicknesses under various stagnation conditions.
This presentation highlights key findings, including detailed characterization of individual clusters and their prop-erties. Furthermore, the optimization of high target thicknesses of more than $5\cdot10^{14}$ atoms/cm² at the interaction point which is 2.25 m downstream from the jet nozzle was carried out while maintaining minimal residual back-ground pressure through careful adjustment of the orifice system within the beam dump.

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[1] S. Vestrick et al., EPJ Web Conf., 285 02002 (2023).
[2] P. Brand et al., Phys. Rev. Accel. Beams 29, 023001 (2026).
[3] H. Eick et al., Nucl. Instrum. Methods Phys. Res. A, 1085, 171245 (2026).

Speaker: Hanna Eick

12:00 Lunch Break

THB1

36 NEW NOZZLE PRODUCTION METHOD AND VACUUM STUDIES ON THE PANDA CLUSTER-JET TARGET

In the upcoming PANDA experiment at FAIR in Darmstadt (Germany) the annihilation of antiprotons with protons will be investigated in order to study the QCD, i.e., the theory explaining the strong interaction [1]. The antiprotons will be produced with a series of linear and ring accelerators and reach a momentum of up to 15 GeV/c in the storage ring HESR. The protons for the annihilation experiment will be provided by a cluster-jet target operated with hydrogen. Around the interaction point a 4π detector will be mounted; hence the cluster source and the beam dump will be located in more than 2 m away from the interaction point (Fig. 1). Narrow pipes will connect the interaction point with the source and the beam dump. To achieve the desired luminosities high target thicknesses are required which have never been realized before in such large distances to the cluster source. Thus, a new state-of-the-art cluster-jet target is under development at the University of Münster.

The core piece of the cluster-jet target is a convergent-divergent Laval nozzle with a narrowest cross-section of 30 μm that produces clusters, i.e., hydrogen spheres with diameters of <20 μm [2]. At temperatures between 20 to 50 K and pressures of up to 20 bar hydrogen is pressed through the Laval nozzle. Via different cluster building processes that depend on the operating parameters and the phase of the hydrogen upstream of the nozzle, clusters are produced. The resulting cluster jet is separated from the residual gas and tailored by two orifices, the skimmer and the collimator. By using movable orifices and a nozzle tilting system, the cluster jet can be aligned to pass through narrow pipes to the IP and the beam dump.

At the Institute of Nuclear Physics at the University of Münster, a new nozzle design is developed, that allows precise control of the beam shape (Fig. 2). It also allows for target densities that exceed the needs of the PANDA experi-ment. Nozzles with even smaller narrowest cross-sections of 10 μm and 20 μm are currently in production, and the latest results will be presented.

As the accelerator facilities at FAIR are still under construction, the PANDA cluster-jet target was operated at the accelerator facility COSY in Jülich (Germany) until the last beam time in 2023 [3]. The provided proton beam with a beam momentum of up to 3.7 GeV/c was utilized to perform studies on the ion beam induced evaporation of the clusters during their interaction with the accelerator beam by measuring the increase of the residual gas background [4]. Combined with calculations on flash evaporation, vacuum simulations are conducted on cluster-jet targets to predict the vacuum conditions in the PANDA experiment or in any other cluster-jet setup.

[1] G. Barucca et al., “PANDA Phase One”, European Physics Journal A57, 44, arXiv: 2101.11877 (2021).
[2] H. Eick et al., “Determination of hydrogen cluster size distributions of a cluster-jet target using shadowgraphy”, Nuclear Instruments and Methods in Physics Research Section A, DOI: 10.1016/j.nima.2025.171245 (2026).
[3] P. Brand et al., “Operation of the PANDA cluster-jet target with the HESR stochastic cooling at COSY”, Phys. Rev. Accel. Beams, DOI: 10.1103/3g6s-qm12 (2026).
[4] U. Bechstedt et al., “Progress and developments at the cooler Synchrotron Cosy”, Proceedings of EPAC (2002).

Speaker: Michael Weide

37 THE WINDOWLESS JET TARGET FOR E-P SCATTERING EXPERIMENTS AT MAGIX AT MESA

In order to address some still open questions in physics, a new accelerator, MESA (Mainz Energy-Recovery Superconducting Accelerator), is currently under construction in Mainz, Germany. MESA will be the world's first accelerator to use superconducting energy-recovery technology. This will allow for an electron beam with high intensity, up to 10 mA, and low energy, up to 105 MeV, enabling a next phase of high-precision experiments.
MAGIX (MAinz Gas Injection target eXperiment) will be one of the key experiments at MESA and will use the Energy-Recovery Linac (ERL) mode of operation. With this cutting-edge technology, MAGIX will offer a versatile physics program ranging from studies of baryonic matter to searches for dark-sector particles.
To fulfill the experimental requirements of MAGIX, a state-of-the-art target is needed. For the ERL to operate, the target must be thin enough to minimize the beam energy loss. On the other hand, a high target density is required to achieve the necessary luminosity for the experiments. Additionally, the target must be windowless to avoid an irreducible background and beam energy loss in the window material. It should also be operable with different gases, depending on the experimental requirements.
To meet these challenging requirements, MAGIX will use a cryogenic windowless jet target that can be operated with various gases, including hydrogen, helium, and almost all heavier gases. When operated with hydrogen, the MAGIX jet target can deliver a high-density jet of up to $10^{18}$ atoms/cm$^2$ at the interaction point. Achieving such a high target density requires a large gas flow rate at cryogenic temperatures. To reach the desired temperature, the gas is first precooled with liquid nitrogen and then further cooled using a powerful dual-stage cold head. The cooled gas is then pressed through a specially designed convergent-divergent nozzle. This produces a supersonic jet with a very small divergence and a well-defined structure.
The nozzle geometry defines how the jet target expands into vacuum. Therefore, numerical simulations of the jet formation and propagation are performed to understand and optimize target performance. In this contribution, the setup and optimization of the MAGIX jet target will be presented, with a focus on numerical simulations for different gases. In addition, frozen filament jets can be generated in Münster. Plans and activities toward adapting the MAGIX jet target for the generation of a frozen filament jet structure will be described and presented.

Speaker: Liridon Deda (University of Münster)

38 Thin 128Te Sandwiched target for Plunger measurements

The nuclear level lifetimes in the range of picoseconds to femtoseconds cannot be measured directly with any conventional technique available to us. For such small lifetimes, the methods based on the Doppler’s effect of light have been used historically. The excited states for which the level lifetimes are of the order of a few 10s to a few 100s picoseconds, the recoil distance Doppler shift method (RDM) [1, 2] is used. In order to perform the RDM measurements, a special device, called the plunger setup is used. The success of an RDM lifetime measurement heavily depends on the quality of the target and the stopper foils used in the experiment and therefore the fabrication of a quality target in such an experiment becomes challenging. In plunger measurements always a smooth, wrinkle-free, surface target and stopper foils are required. Also, in such measurements, as the target and the stop-per foils need to be mounted and then carefully stretched on the target holder cones (to ensure smoothness of the surface), so the target and stopper foils needs to satisfy some more properties, like they should have good mechanical strength (to sustain the stretching), uniform thickness (to keep distance between the target and stopper same at all points), and good thermal conductivity (to avoid burnout of the target due excessive deposition of energy imparted by the heavy ion beam). Preparing such a high-quality target is a real challenge, and therefore, some special care is required during every step in the fabrication process of the target. In one such activity, an isotopically pure thin 128Te sandwiched target has been made at the Inter-University Accelerator Center (IUAC), New Delhi. For this purpose, a thin layer (thickness ∼ 1.1 mg/cm2) of isotopically enriched 128Te material was sandwiched be-tween an ultra-thin (thickness ∼ 0.073 mg/cm2) and a relatively thick (thickness ∼ 3.4 mg/cm2) layers of highly pure gold via the evaporation technique. The isotopic purity of the target material has been verified with material characterization techniques such as Energy Dispersive X-ray Fluorescence (EDXRF) and the Rutherford Back Scattering (RBS) techniques. The prepared target has been used successfully in a recent lifetime measurement experiment with the plunger technique to extract the level lifetimes of the excited nuclear states in the 151Dy nuclei. The results of the experiment are encouraging and indicate the overall success of the RDM lifetime measurements with the fabricated sandwiched target.

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[1] T.K. Alexander and A. Bell, Nuclear Instruments and Methods 81, 22 (1970).
[2] A. Dewald et al., Progress in Particle and Nuclear Physics 67 (3) (2012) 786.

Speaker: Sanjay Kumar Chamoli (Department of Physics and Astrophysics, University of Delhi, Delhi, India)

39 Gd-doped Pd alloys targets for radiolanthanides production in a pressurized water power reactor’s core

This project focuses on the development of suitable metallic targets for the in-core neutron irradiation of enriched lanthanide materials (e.g., Yb-176 and Gd-160) in a commercial nuclear power plant in Switzerland, enabling a reliable supply of medical-use of radiolanthanides (i.e., Lu-177 and Tb-161, both applied in Targeted Radionuclide Therapy). To achieve this, the project proposes to exploit the existing Aeroball core monitoring system (AMS; used for routine neutron flux measurements inside the reactor) as an insertion pathway for specially designed Gd and Yb target spheres.

Target materials were developed as Pd-based alloys doped with the selected lanthanoid element (Pd-Gd alloys were the first ones investigated). These are synthesized via hydrogen-mediated high temperature treatment [1] and must comply with the dimensional and mechanical specifications required by the AMS. Optimization efforts focused on key processing parameters, including composition, temperature, and heat treatment conditions, with the aim of enhancing both mechanical integrity and irradiation stability. Structural and microstructural characterization using X-ray diffraction and electron microscopy revealed the formation of a single, stable Pd-rich phase at a Pd-to-Gd ratio of 5:1, along with a homogeneous elemental distribution throughout the bulk volume. Mechanical testing through indentation and punch experiments suggested sufficient robustness to withstand stresses associated with the insertion into the AMS pipelines. Based on these results, spherical targets were successfully fabricated by arc melting under an Ar atmosphere, while preserving the optimized material features.

The produced spheres will then undergo neutron irradiation tests at the Swiss Spallation Neutron Source (SINQ) at PSI to evaluate the radiation hardness and to quantify radionuclide production yields. In a final step, a suitable chemical separation and purification strategy will be devised in order to obtain high-purity, non-carrier-added 177Lu and 161Tb suitable for radiopharmaceutical applications. This contribution outlines the current progress of the RAPIC project, which aims to establish a scalable and sustainable production route for key radiolanthanides in commercial nuclear power plants, ultimately improving their availability in Switzerland and internationally.

[1] H. Schulz et al., Z. anorg. allg. Chem. 357 (1968) 299-313

Speaker: Sofia Pasolini (PSI, ETHZ)

40 ADVANCED MANUFACTURING OF CERMET TARGETS FOR RADIOISOTOPE PRODUCTION

Aluminum has long served as the primary choice of filler material for the production of critical radioisotopes such as actinium-227, barium-133, californium-252, thorium-228, thorium-229, and plutonium-238 in the High Flux Iso-tope Reactor at the US Department of Energy’s (DOE’s) Oak Ridge National Laboratory (ORNL). Aluminum’s high thermal conductivity and ease of use in fabricating ceramic–metallic (cermet) targets make it an ideal material. How-ever, the high charge density of the aluminum cation and the thermal instability of its nitrate salt can be major hin-drances during ion exchange purification and matrix exchange operations, respectively. Carbon powder is proposed as an alternative due to its comparable thermal conductivity and desirable chemical properties. The relative chemical inertness of carbon means it will not interfere with the ion exchange and heating techniques commonly employed in radioisotope production. Furthermore, by eliminating the necessity of solvating aluminum, process solution vol-umes and ion exchange resin volumes could be significantly reduced, resulting in a reduction in waste and overall process complexity.
The recovery of radium-226 and its irradiation products, actinium-227 and thorium-228, serves as a useful example of the difficulties that could be solved by this proposed substitution. Currently, a small quantity of irradiated radi-um-226 is unrecoverable by ion exchange due to the large quantity of cosolvated aluminum. Additionally, the purifi-cation process incurs a risk of trapping actinium-227 and thorium-228 within the chemically inert thermal degrada-tion products of aluminum nitrate. The substitution of aluminum with carbon would eliminate these issues, allow-ing for a closed loop in the recovery of these isotopes and a reduction in waste, process volumes, and overall com-plexity.
The benefits allowed by this substitution could be generalized to any process that uses aluminum as a filler material for irradiation. This work supports the DOE Office of Isotope R&D and Production and ORNL Radioisotope Pro-gram mission to strengthen the domestic isotope supply chain by improving target performance and downstream chemical processing. We evaluate replacing aluminum powder in carbonate cermet targets with graphite to reduce ion-exchange resin demand and elution volumes, decrease acid/base consumption and waste generation, prevent radi-oisotope trapping in inert alumina residues during heat-to-dryness steps, and improve thermal conductivity by avoid-ing aluminum oxidation. Because handling radium directly is challenging, BaCO₃ was used as a surrogate for RaCO₃. Graphite/BaCO₃ composite pellets (10–30 vol % BaCO₃) were fabricated via uniaxial pressing, vacuum hot pressing, graphite matrix overcoating, and spark plasma sintering, followed by heat treatments from 750°C to 1650°C guided by thermodynamic expectations for carbonate decomposition and potential carbide formation. Pellets were characterized by laser flash analysis, scanning electron microscopy/energy-dispersive X-ray spectroscopy, and X-ray diffraction to assess microstructure, phase evolution, and barium distribution. Initial results showed good barium dispersion in graphite and the highest thermal diffusivity for uniaxial-pressed and vacuum hot-pressed pellets. Time-of-flight secondary ion mass spectrometry indicated surface BaO and subsurface BaC₂ in some cases. Preliminary barium recovery tests using 1 M HCl demonstrated strong dependence on thermal history: pellets heat-treated above 1600°C showed low recovery (≤33%), but a graphite matrix overcoat pellet heat-treated at 750°C achieved essentially complete recovery (~103%). Ongoing work will tune heat treatment conditions (e.g., ~1500°C) to balance thermal performance with chemical recoverability and enable scalable graphite/RaCO₃ target fabrication and closed-loop iso-tope recovery.

Speaker: Victor Bautista (Oak Ridge National Laboratory)

15:00 Coffee Break

THB2

41 NUMERICAL ANALYSIS OF NEUTRON IRRADIATION FIELDS FOR A HIGH-EFFICIENCY NEUTRON SOURCE BASED ON DEUTERON CARA

NUMERICAL ANALYSIS OF NEUTRON IRRADIATION FIELDS
FOR A HIGH-EFFICIENCY NEUTRON SOURCE BASED ON DEUTERON CARA
K. ARAI, M. Cuvelier, T. Itagaki, J. Hasegawa (Institute of Science Tokyo, Japan), Y. Miyake, H. Okuno (Riken Nishina Center for Accelerator-Based Science, Japan)

1. INTRODUCTION
   In the development of fusion reactor materials, establishing high-intensity and high-energy neutron sources capable of simulating actual reactor environments is an urgent priority. As a promis-ing candidate, an accelerator-based neutron source utilizing the Cyclotron Auto-Resonance Accelera-tion (CARA) [1] principle has been proposed and is currently under development. CARA enables continuous acceleration within a remarkably compact cavity of approximately 1.8 m through syn-chronization between particle cyclotron motion and a rotating electric field. Historically, matching the cyclotron frequency with standard radio-frequency (RF) bands required magnetic fields exceeding 1 T, limiting its application to electron acceleration. However, with the technological advancements in high magnetic field generation following extensive research on MRI scanners, the application of CARA to light ions such as deuterons has become feasible. This deuteron CARA (dCARA) neutron source aims to generate a neutron flux with a peak at 10–20 MeV by accelerating a DC deuteron beam to 40 MeV and directing it onto a liquid lithium target to induce reactions such as the 7Li(d,n)8Be stripping reaction. The purpose of this study is to evaluate the performance and charac-teristics of the neutron irradiation field through numerical simulations toward the practical imple-mentation of this system.

2. SIMULATION METHOD
   In this study, a comprehensive computational model including the dCARA, beam transport system, liquid lithium target, and shielding is constructed in PHITS (Particle and Heavy Ion Transport code System) [2] to evaluate the irradiation field. A distinctive feature of the dCARA sys-tem is that the extracted deuteron beam possesses a gyration motion with a diameter of approximate-ly 10 cm. This motion is a characteristic resulting from the interaction between the static magnetic field and the radio-frequency electromagnetic field within the acceleration cavity, resulting in a spa-tial spread distinct from conventional linear beams. Since the angular and energy distributions of the generated neutrons are highly sensitive to the beam's incident conditions on the target, precise design of the transport is essential. Specifically, it is necessary to achieve both uniformity of the neutron flux and dispersion of the thermal load on the target by controlling the pitch angle and incident posi-tion distribution of the beam just before the target. The computational procedure involves first devis-ing the design of the deuteron beam transport system using Particle-in-Cell (PIC) simulations. In this step, the evolution of the beam's phase-space distribution is analyzed in detail, taking into account space-charge effects within the high magnetic field. Next, the obtained three-dimensional phase-space distribution is implemented as the source term in PHITS to calculate the spatial distribution and energy spectra of the neutron flux. These results are fed back into the design of the transport and shielding systems to investigate a more efficient neutron source configuration.

3. CONCLUSION
   This report describes a coupled simulation framework integrating PIC and PHITS to analyze the irradiation field characteristics of the dCARA neutron source. While the interaction be-tween a 40 MeV deuteron beam and a lithium target is effective for simulating D-T fusion environ-ments, the transport control of the gyrating beam remains a primary technical challenge. Currently, the impact of these complex beam dynamics on the incident angle and the neutron flux distribution is being evaluated using this simulation. The findings discussed in this report are expected to serve as crucial design guidelines for determining the optimal configuration of the dCARA system to meet the stringent requirements of fusion material testing, such as achieving high displacement-per-atom (dpa) rates in specimen volumes.

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[1] C. Wang et al., Phys. Rev. E. 51(3), 2456 (1995).
[2] T. Sato et al., Recent improvements of the Particle and Heavy Ion Transport code System - PHITS version 3.33, J. Nucl. Sci. Technol, 61(1), 127-135 (2024).

Speaker: Koshiro Arai (Institute of Science Tokyo)

42 IMPROVING BISMUTH TARGETRY FOR ENHANCED ASTATINE-211 PRODUCTION

Astatine‑211 (211At) is a high‑value alpha‑emitting radionuclide with significant potential for targeted alpha therapy. However, current production capacity remains insufficient to meet research and pre-clinical demand, limiting progress toward broader medical adoption. The dominant production route for 211At (t₁/₂ = 7.2 h) is the 209Bi (α,2n) 211At reaction using 28-29 MeV alpha irradiation of high‑purity bismuth targets. Metallic bismuth is commonly employed due to its favorable chemical properties, monoisotopic nature, and ability to be readily melted and cast into targets. The standard geometry is 90 microns thick and 25.4 mm diameter. Despite this, challenges in target robustness, thermal performance under high‑current irradiation, and efficient post‑irradiation recovery remain key barriers to in-creasing the production scale.

This work investigates improved bismuth target fabrication methods with an emphasis on the interface between the bismuth and aluminium target backing, which has been identified through experimentally benchmarked computational modeling and simulation to be a critical limiting factor for target performance. In addition to conventional melt‑casting, new approaches are being evaluated, including electrodeposition of bismuth layers to achieve enhanced uniformity, substrate compatibility, and performance under high‑power irradiation conditions. These advancements aim to support more efficient, scalable, and reliable 211At production for the nuclear medicine research community.

Speaker: Kristian Myhre (Oak Ridge National Laboratory)

43 Mesurement of the lifetime of carbon stripper foils based on the LEAF facility

To achieve higher acceleration efficiency, carbon foils will be utilized to strip the pre-accelerated ions from iLinac and then the stripped ions will be injected into the Booster Ring (BRing) at the High Intensity heavy ion Accelera-tor Facility (HIAF) [1]. Considering the impacts of high energy deposition of heavy ions and extremely high beam intensity, the foils face severe lifetime challenges. Previous studies identified two types of radiation resistant multi-layer graphite (MLG) foils, those prepared by the methods of vacuum-assisted self-assembly (VASA) and graphitization of polyimide (PI), through irradiation experiments conducted at the Sector-Focused Cyclotron (SFC) of the Heavy Ion Research Facility in Lanzhou (HIRFL), but did not determine their lifetime limits [2]. In this study, lifetime measurement experiments were carried out using high-intensity Xe26+ and Bi35+ beams with varying beam duty cycles at the Low Energy High Intensity Heavy Ion Accelerator Facility (LEAF). Real-time monitoring of foil appearance, effective thickness, and stripped beam intensity was achieved by employing charge-coupled device (CCD) imaging, post-stripping charge-state distribution spectrum analysis, and time-of-flight measurements. Monitoring results reveal the failure mechanism of MLG foils originates from an elastic-to-plastic deformation transition, during which radial wrinkles radiating from the bombardment center cause cracking, increasing effective thickness and reducing the beam intensity after stripping. Moreover, the estimations of foil lifetimes based on the theory proposed by Lebedev [3], using measured elongation at break and lateral lattice size, aligned closely with experimental results, validating this estimation approach for guiding the lifetime assessments and process improvements of MLG foils under HIAF conditions. Consistent with previous studies, the experiments verified that the determinants of foil lifetime shift from radiation damage to evaporation effects at an average target temperature of approximately 2500 K. Finally, characterization results from X-ray diffraction (XRD) and Raman spectroscopy indicate that despite exhibiting macroscopic failure and reaching stripping performance limits, the MLG foils retain their fundamental internal microstructures and a high degree of graphitization.

Speaker: Mr Zhiyou Xu (Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China; School of Nuclear Science and Tech-nology, University of Chinese Academy of Sciences, Beijing, China)

44 Toward In-situ Temperature Diagnostics of Charge-Exchange Stripping Foils under High-Power Operation: Feasibility Study Based on Offline Experiments and Operational Experience at the J-PARC RCS.

The J-PARC RCS has achieved 1 MW beam operation using pure carbon stripping foils instead of hybrid boron-doped carbon (HBC) foils. Although the temperature rise is estimated to be on the order of 1000 K under current conditions and does not yet limit operation, it is expected to become a critical factor for future higher-power upgrades.
　This study presents a feasibility study of temperature diagnostics using near-infrared (NIR) cameras, together with operational foil experience and temperature-rise simulations. For in-situ measurement, the existing foil observation system with quartz optics will be upgraded to integrate an NIR camera, since conventional mid-infrared diagnostics are not applicable. An offline test stand has also been developed to evaluate the performance of the NIR system. The test stand includes a carbon block heating device (~300°C) and a foil heating system via electron-beam irradiation (~50°C).
　The results demonstrate that NIR diagnostics provide a viable pathway toward in-situ temperature measurement under high-power operation.

Speaker: Masahiro Yoshimoto (Japan Atomic Energy Agency / J-PARC center)

16:40 Coffee Break

INTDS membership meeting and election

Friday 4 September

Registration

FRA1

45 POLYMER-ASSISTED DEPOSITION (PAD) FOR THE FABRICATION OF GADOLIN-IUM TARGETS

The development of high-quality gadolinium (Gd) targets is of significant interest for nuclear physics exper-iments and radioisotope production [1,2], where precise control over thickness, uniformity, and chemical composi-tion is essential. Conventional fabrication techniques often face limitations related to cost, scalability, and composi-tional homogeneity. In this work, we investigate polymer-assisted deposition (PAD) as a versatile and cost-effective method for producing Gd-based thin film targets with controlled properties.
The PAD approach [3] relies on the complexation of Gd³⁺ ions with a water-soluble polymer such as poly-ethylenimine (PEI) to form a stable precursor solution. This strategy enables homogeneous distribution of metal ions at the molecular level while preventing premature precipitation. The resulting solution is deposited onto graphite substrates, using a spin-coating technique. Graphite substrates are particularly attractive for nuclear applications due to their low atomic number and excellent thermal conductivity, allowing efficient heat dissipation under high irradia-tion fluxes. Subsequent thermal treatment leads to the decomposition of the polymer matrix and the formation of dense, uniform gadolinium oxide (Gd₂O₃) films.
Key parameters influencing the quality of the deposited targets were systematically investigated, including the PEI-to-metal ratio, solution pH (adjusted using mild buffering systems such as acetate buffers), and thermal processing conditions. Control of pH was found to be critical in balancing the protonation state of the polymer and the stability of Gd(III) complexes, directly impacting film homogeneity and reproducibility. Thermal treatment pro-tocols were optimized to ensure complete removal of organic residues while minimizing film cracking and preserving adhesion to the substrate.
The resulting films were characterized using complementary techniques, including scanning electron microscopy (SEM) and Rutherford backscattering spectroscopy (RBS). These analyses indicate the formation of Gd₂O₃ layers with relatively uniform thickness and good adhesion, with no significant cracking observed under the investigated conditions. The PAD method shows acceptable reproducibility and scalability, suggesting its potential as an alternative to conventional target fabrication techniques.
This study explores the application of PAD to the preparation of gadolinium-based targets on graphite sub-strates for nuclear applications. Future work will focus on extending this approach to enriched isotopic materials and further evaluating target performance under irradiation conditions.

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[1] J. M. Pyles et al., ACS Omega, 10(28), 30335 (2025).
[2] M. Bouteculet et al., Applied Radiation and Isotopes, 213, 111485 (2024).
[3] Q. X. Jia et al., Nature Materials, 3(8), 529 (2004).

Speaker: Vladimir Sladkov (IJCLab/CNRS)

46 OPTIMIZING THE PRODUCTION OF ENRICHED ROLLED MOLYBDENUM FOILS

Technetium-99m is the most used medical radioisotope and has historically been produced in nuclear reactor facilities around the globe but supply chain disruptions have resulted in critical shortages of 99mTc. [1]. Due to continued demand for this radioisotope, interest in 98Mo and 100Mo has grown since the early 2000s as accelerator-based production of 99mTc replaces the reactor-based 235U spallation pathway [2] [3]. Neutron activation of 98Mo and cyclotron based 100Mo(p,2n) production pathways are actively under development and are increasing demand for enriched molybdenum targets in the form of thin foils for nuclear data studies. Foil targets must be free of pinholes and near-uniform in areal density to produce accurate data during beamline experiments. High-quality molybdenum foils are notoriously difficult to make due both to a high melting point and a propensity to shatter during the cold rolling process [4]. Prior literature has demonstrated different pathways of producing rolled molybdenum foils [5-7], but materials characterization of the produced material is lacking. An individual study that applies different production pathways and characterizes the produced material does not exist. This study directly examines the influence of vacuum hot-pressing vs. vacuum sintering as well as electron-beam melting vs. arc melting on the final purity, uniformity, and continuity of the rolled molybdenum foils. Impurity analysis was conducted using ONH analysis and ICP-OES to determine the trace metal and oxygen contamination picked up throughout the fabrication process. Metallography was conducted on the arc/electron beam-melted material to examine for potential voids and harmful oxide/carbide inclusions that limit the final thickness a foil can be rolled to. The outcome of this work is a detailed methodology illustrating an optimal production pathway for pinhole-free rolled molybdenum foils with thicknesses of below 1mg/cm2.

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[1] International Atomic Energy Agency. Non-HEU Production Technologies for Molybdenum-99 and Technetium-99m. Technical Report Series No. NF-T-5.4, 3-16 (2013).
[2] Nuclear Energy Agency. Review of Potential Molybdenum-99/Technetium-99m Production Technologies. The Supply of Medical Radioisotopes 13-18 (2010).
[3] J. Ballinger. Short- and long term responses to molybdenum-99 shortages in nuclear medicine. The British Journal of RadiologyVol. 83899-901 (2010).
[4] A. Pandley et al. Fabrication of thin Molybdenum backed target using rolling method. Applied Radiation and IsotopesVol 199 (2023).
[5] F. J. Karasek. Fabrication of Target Foils by Rolling Techniques. Nuclear Instruments and MethodsVol. 102457-458 (1972).
[6] J. P. Greene et al. The production of molybdenum targets for heavy-ion experiments by electron beam evaporation. Nuclear Instruments and Methods in Physics ResearchVol. A303 165-167 (1991).
[7] A. Stolarz et al. Molybdenum targets produced by mechanical reshaping. Journal of Radioanalytical and Nuclear Chemistry Vol 203. 947-952 (2015).

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Isotope R&D and Production.

Speaker: Jon Norman

47 Development of thick Yb$_2$O$_3$ targets using the spray method for multinucleon transfer reaction experiments

The origin of heavy elements such as gold and uranium is one of the most important questions in nuclear astrophysics. Approximately half of the abundances of elements heavier than iron are considered to originate from the rapid neutron-capture process (r-process) in astrophysical environments [1]. To understand the r-process path and the resulting elemental abundances, precise experimental mass data for neutron-rich nuclei along the path are essential. In particular, neutron-rich lanthanoid isotopes are expected to play a crucial role in the formation of the rare-earth peak, although experimental data in this region remain extremely scarce.

We plan to perform precise mass measurements of neutron-rich lanthanoid nuclei produced via the $^{136}$Xe+$^{176}$Yb multinucleon transfer (MNT) reaction at the KEK Isotope Separation System (KISS) [2] using a multi-reflection time-of-flight mass spectrograph (MRTOF-MS) [3]. To obtain sufficient production yields in MNT reactions, a high-intensity heavy-ion beam and a thick target of approximately 10 mg/cm$^2$ are required. However, metallic ytterbium has a relatively low melting point of 824$^\circ$C and is therefore susceptible to thermal damage under high-intensity beam irradiation. Furthermore, fabricating such a thick target layer is difficult using conventional methods such as vacuum evaporation. Thus, the development of a thick ytterbium-based target that can withstand intense beam irradiation is a key technical challenge for MNT experiments.

To address this issue, we focus on ytterbium oxide (Yb$_2$O$_3$), which has a high melting point (approximately 2400$^\circ$C). Using this material, we are developing thick targets using the spray coating method [4]. By suspending Yb$_2$O$_3$ powder in a solvent and spraying the suspension onto a metal backing, we aim to form a thick target layer. In this presentation, we will report on the preparation of thick Yb$_2$O$_3$ targets by the spray coating method and discuss the results of their performance evaluation.

[1] E. M. Burbidge et al., Rev. Mod. Phys. 29, 547 (1957).
[2] Y. Hirayama et al., Nucl. Instrum. and Methods B 353, 4 (2015).
[3] J. Y. Moon et al., RIKEN Accel. Prog. Rep. 52, 138, (2018).
[4] J. P. Greene & C. J. Lister, Nucl. Instrum. Methods A 482, 79 (2002).

Speaker: Yuki Yamanouchi (Kyushu University)

48 FABRICATION OF SELF-SUPPORTING ISOTOPIC MAGNESIUM FOIL TARGETS

In astrophysics, isotopically enriched magnesium is studied to better understand each isotope’s individual role in stellar fusion reactions. To fully understand the modes by which these reactions occur, accurate calculations of nuclear cross sections for each isotope are necessary [1–3]. Accurate nuclear cross sections are reliant on uniformity of the magnesium foil, high isotopic purity of the sample, and two inversely proportional parameters—either a long beam capture volume (or thick foil) or an extended time in beam.
Magnesium metal is infamous, even in commercial production environments [4], for its low sublimation temperature under high vacuum, poor workability, high reactivity with air, and low density. These characteristics make it a challenging candidate for thick, self-supporting foils. Most magnesium foils produced for use in beamlines are made via evaporation. Unfortunately, this process results in high loss of the extremely expensive starting material [4]. The targets also have an upper limit of thickness at ~200 µg/cm2 [5], after which the metal deforms and begins flaking during deposition. If a user requests material thicker than this limit, then multiple foils must be fabricated and stacked which compounds uncertainty due to each individual foil’s inherent defects.
The production of thick (i.e., <3 mm thick and >500 µg/cm2) magnesium foils are described herein (Figure 1), beginning with the initial distillation of the metal, through melting, hot rolling, and final cold rolling to illustrate the niche techniques needed to overcome its challenging material properties.

[1] O. Straniero, G. Imbriani, F. Strieder, et. al. Impact of a Revised 25Mg(p, γ)26Al Reaction Rate on the Operation of the Mg-Al Cycle. The Astrophysical Journal 763:100 1-10 (2013).
[2] C. Massimi, P. Koehler, S. Bisterzo, et. al. Resonance Neutron-Capture Cross Sections of Stable Magnesium Isotopes and Their Astrophysical Implications. Physical Review 85 044615 (2012).
[3] C. Chen, Y.J. Li, H. Zhang, Z. H. Li. Preparation of Large-Area Isotopic Magnesium Targets for the 25Mg(p, γ)26Al Experiment at JUNA. Nuclear Science and Techniques 31 (2020).
[4] Q. Shen, Y. Ba, P. Zhang, J, Song, F. Pan. Recent progress in the research on magnesium and magnesium alloy foils: A short review. International Journal of Minerals, Metallurgy and Materials 5, 842-854 (2024).
[5] G.E. Thomas. Isotope Targets Preparation By Vapor Deposition. Nuclear Instruments and Methods 200 (1982) 27-31.

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Isotope R&D and Production

Speaker: J. Conner (Oak Ridge National Laboratory)

49 DEVELOPMENT OF METALLIC TARGETS AT GANIL

The fabrication of nuclear targets is a crucial and active field of study that advances research in nuclear physics and related disciplines. The effectiveness of measurements and the results of various nuclear experiments depend directly on the isotopic purity, surface homogeneity, and thickness consistency of these targets. These characteristics ensure the reliability of experimental data.
In this context, to meet the needs of nuclear physics experiments, GANIL has developed different types of targets, each with specific characteristics. This optimization involves studying various deposition techniques to precisely control the thickness and uniformity of thin films. In this framework, we propose to present fabrication methods for thin targets made of isotopic chromium, nickel, and ytterbium, as well as the analyses conducted on these targets, demonstrating an approach based on a systematic study of fabrication parameters to develop protocols for synthesizing homogeneous and pure targets.

Speaker: Radia Rahali (GANIL)

10:40 Coffee Break

Closing session / wrap-up