Optical and scintillation properties of CsI:In crystals

The work is dedicated to study of optical and scintillation properties of CsI:In crystals. Using the Bridgeman method a concentration row of CsI:In single crystals was grown with the dopant content from 10⁻⁴ to 10⁻¹ mol. %. The segregation coefficient of In in CsI was estimated to be ~0.15. In CsI:In luminescence spectra one symmetric band is observed, peaking around 545 nm, with FWHM of 0.46 eV. Under intracenter excitation 1.9 μ s exponential decay was observed. The light yield under gamma excitation of ¹³⁷Cs isotope (662 keV), measured with a shaping time of 10 μ s, was 27 000 photons/MeV. The radio-luminescence yield of CsI:In , measured by the current mode method, approached to that of CsI:Tl . Probably, this difference is connected with the presence of a stronger afterglow in CsI:In crystals

Comparison of prompt and delayed photofission neutron detection techniques using different types of radiation detectors

Conference of 2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop, NSS/MIC/RTSD 2016 ; Conference Code:131365International audienceFor several years, detection of various threats on country borders plays a significant role in the frame of Homeland Security applications. One of this threat is the illicit trafficking of nuclear materials (especially including Special Nuclear Material - SNM - 235U, 233U or 239Pu), which can be potentially used for production of nuclear weapon as well as radiological dispersal device (RDD) - known also as a "dirty bomb". In order to detect the potentially hidden nuclear material, systems using linear accelerators and a group of detectors are developed by several scientific groups around the world. Besides solutions focusing on detection of delayed γ-rays or neutrons, also the systems dedicated for prompt neutron detection were proposed. One of the possible prompt neutron detection technique is known as Threshold Activation Detection (TAD). This technique relies on activation of 19F nuclei in the scintillator medium by fast neutrons and registration of high-energy particles and γ-rays from the decay of reaction products (for example, 19F(n,α)16N or 19F(n,p)19O). Recent studies in the frame of the European Horizon 2020 C-BORD project showed that, despite the low 19F(n,α)16N or 19F(n,p)19O reaction cross-section, the method could be a good solution for detection of shielded nuclear material. A benchmark of the TAD technique based on fluorine detectors with reference method focused on delayed neutron detection with 3He detectors will be presented in this paper. These experimental results were obtained using 9 MeV Varian Linatron M9 linear accelerator (LINAC)

Temperature Dependence of CsI:Tl Scintillation Pulse Shapes from -183°C to +90°C Measured with a SiPM Readout

A custom designed cryostat was constructed to measure the response of a CsI:Tl scintillator in temperature range from -183°C up to +90°C. The light readout was realized using a SiPM developed by FBK in near ultraviolet high density (NUV-HD) technology. The crystal and the SiPM were installed on separated copper frames. The crystal was cooled down by liquid nitrogen, while the SiPM was kept at temperature close to room temperature. A separation of 1 mm was kept between the crystal and the photodetector to ensure thermal isolation. The temperature of the crystal could be varied by heaters on the scintillator frame and was continuously monitored using a coil shaped resistance thermometer. The CsI:Tl scintillation decay profiles were recorded in the entire temperature range provided by the cryostat