Speaker
Description
A new generation of instruments dedicated to the study of superheavy elements has just been com- missioned in several laboratories around the world. One can cite the SPIRAL2 accelerator in GANIL, the SHE-Factory in FLNR and the new RILAC2 in RIKEN which are designed to reach beam intensities up to 10 pμA with heavy ions as 48Ca, 50Ti, 51V or 54Cr. Under these conditions, with more than 6.1013 ions per second interacting with the target, the beam spot power will be unsustainable for the usual Titanium backings that we are using for decades. The development of a new generation of materials especially designed for these specific conditions becomes of paramount importance for the future of SHE studies.
With the support of an USIAS (University of Strasbourg Institute for Advanced Study) grant, we are exploring the current possibilities at IPHC. For these developments, we face two major problematics : the heat dissipation and the structural defaults induced by high dose effects. Moreover, we are still constrained by the target backing thickness (μm order of magnitude) and by the mass of the chosen material (as low Z as possible).
These requirements have pushed us to consider Carbon-based foils as very promising leads, and especially graphite, diamond-like carbon and multilayer-graphene. We worked on different materials with a special interest for the graphene structure. This pure Carbon material consisting of single layers of atoms arranged in a two-dimensional honeycomb lattice nanostructure shows amazing thermal and mechanical properties. Although this innovative material seems to be very promising, the production of foils with a few μm thickness requires a state-of-the-art collaboration between chemistry, material physics and nuclear physics. We produced three types of graphene foils which are currently under study to measure their mechanical properties. Nevertheless, it will be mandatory to test these foils under real conditions to measure the dose effects induced by irradiation.
In parallel, we are also considering to test different Titanium-based alloys, which are well-know and widely used in the aerospace industry. In this context, we are building a laboratory fully dedicated to these studies in IPHC with the ambition to produce and to characterize μm foils of these alloys with different compositions, crystalline phases and cooking methods. Indeed, the design of an alloy especially dedicated to our studies could allow us to customize it on purpose. Complementary, we are developing multilayer materials in order to take the benefit of the specific properties (tensile strength, flexibility, thermal conductivity...) associated to different materials in the same backing foil.
The first part of this talk will be dedicated to the characterization of the extreme conditions these materials will encounter at the target plane. Then, our first materials and some preliminary results will be presented and we will finish by a discussion on the possibility to test these innovative foils under real conditions; as close as possible to the operational conditions of the future experiments performed with such intense beams.
| Themes for the contribution | 1 R&D to support concepts |
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