Scintillation neutron detector on the basis of boron-containing plastics

Main parameters are presented for plastic scintillators containing boron. These scintillators were obtained by the block polymerization method of polystyrene with luminescent dopants and allyldodecaborane. Sample dimensions: diameter 25 mm, height 25 mm. Parameters studied included light output, sensitivity to neutrons and time characteristics.У роботі представлені основні параметри пластмасових сцинтиляторів, які містять бор. Ці сцинтилятори одержані за допомогою методу блочної полімеризації полістиролу з домішками, що випромінюють люмінесценцію та алилдодекабораном. Розміри зразків: Ø25х25 мм. Досліджені світловий вихід, чутливість до нейтронів та компоненти висвічування.В работе представлены основные параметры пластмассовых сцинтилляторов, содержащих бор. Эти сцинтилляторы получены методом блочной полимеризации полистирола с люминесцирующими добавками и аллилдодекабораном. Размеры образцов: диаметр 25 мм и высота 25 мм. Исследованы световой выход, чувствительность к нейтронам и времен- ные характеристики

Multi-layer fast neutron detectors based on composite heavy-oxide scintillators for detection of illegal nuclear materials

The article of record as published may be found at https://doi.org/10.1016/j.nima.2018.06.074We developed and characterized a new type (designated ZEBRA) of multi-layer composite heavy-oxide scintillator detectors for fast neutron detection for homeland security and nuclear safeguards applications. In this heterogeneous detector medium, composite layers comprised of micro-granules of heavy-oxide scintillators (ZWO, CWO, PWO, BGO, GSO(Ce), GOS(Ce) and others) dispersed in transparent plastic are alternated with layers of clear plastic that serve as scintillation light guides and as a neutron moderator material. The physical peculiarities of the neutron interactions and the principal mechanisms of fast neutron registration in these detectors are discussed in detail. The fast neutron intrinsic detection efficiencies and sensitivities of ZEBRA-detectors based on BGO, ZWO and GSO(Ce) composite scintillators in response to neutrons from 239Pu–Be and 252Cf sources were measured. These detectors had cross-sectional areas ranging from 16 to 100 cm2. The sensitivities of such detectors of size 100 × 100 × 41 mm3 were found to be 40–51 cps/(nps × cm−2), a level that is comparable to the sensitivity of a typical 3He counter of 1600 cm2 area. The intrinsic efficiencies and sensitivities of the ZEBRA-detectors also compare favorably with those of fast neutron detectors based on large-size heavy-oxide single crystals, but the multi-layer composite ZEBRA structures are much less expensive and can be easily manufactured in much larger dimensions. This work represents a significant advance from earlier single-crystal detector types as part of our effort to explore alternatives and improvements to conventional 3He counters

The highly efficient gamma-neutron detector for control of fissionable radioactive materials

Comparative measurements and analysis of detection efficiency of fast and thermal neutrons from ²³⁹Pu-Be source by heavy oxide scintillators (Z≥50) confirmed high detection efficiency (∼ 40-50 %). The most probable mechanism determining the fast neutron detection efficiency is the reaction of inelastic scattering (n, n ′ γ ) as the main mechanism of interaction of neutrons with nuclei of oxide scintillators. The fast neutron detection efficiency was determined by the method of internal counting of gamma-quanta emerging in the scintillator under (n, n ′ γ ) reaction. It has been shown that the use of heavy oxide scintillators (which are also efficient gamma-detectors) in inspection systems can allow detection of fissionable radioactive materials