Speaker
Summary
The quest for new “super” scintillators, with significantly better energy and timing characteristics to replace the workhorse crystals of past decades is a work in progress. While the recent advent of LaBr3:Ce is a positive development, the high cost of growing large crystals of LaBr3 provides justification for continued R&D in this arena. We report here on our studies of three new scintillators for nuclear physics applications: (i) CeBr3, (ii) Cs2LiYCl6 (CLYC), and (iii) Cs2LiLaBr6 (CLLB). The crystals (~1 cm X ~1 cm) were coupled to Hamamatsu H6610 fast phototubes. Energy and time resolutions were measured with standard gamma calibration sources, using a multi-channel analyzer, as well as a CAMAC-based multi-parameter data acquisition system for extracting energy-gated parameters. A time resolution of 120 ps was obtained for two CeBr3 scintillators detecting back-to-back 511-keV positron annihilation photons. Electronic timing measurements were carried out with a 152Eu source, with excellent results obtained for the 1.4 ns half-life of the 2+ state of 152Sm populated in the decay sequence. Sub-nanosecond measurements are in progress. For the CLYC and CLLB detectors, in addition to energy and time resolution, the capability of these detectors in distinguishing between neutron and gamma signals through pulse shape discrimination was studied. Raw waveforms were captured, with subsequent digital signal processing. Following initial tests with a PuBe source, thermal neutron tests at our on-campus 1-MW research reactor facility are in progress. Fast neutron tests, as well as tests in coincidence with Ge detectors are also planned.
*Work supported by the U.S. Department of Energy.
