GAMBE: Thermal neutron detection system based on a sandwich configuration of silicon semiconductor detector coupled with neutron reactive material. (March 2019)

• Record Type: Journal Article
• Authors: Omar, A.; Burdin, S.; Casse, G.; van Zalinge, H.; Powel, S.; Rees, J.; Smith, A.; Tsurin, I.
• Is Part Of: Radiation measurements. Volume 122(2019:Mar.)
• Page Start: 121
• Page End: 125
• Publication Date: 2019-03
• Subjects: Neutron detector -- Semiconductor detector -- Coated semiconductor detector -- Neutron detection -- Neutron conversion; Nuclear emulsions -- Periodicals; Particle tracks (Nuclear physics) -- Periodicals; Thermoluminescence -- Periodicals; Cosmic rays -- Periodicals; Radiation -- Measurement -- Periodicals; Radiometry -- Periodicals; Radiation Monitoring -- Periodicals; Émulsions nucléaires -- Périodiques; Particules (Physique nucléaire) -- Traces -- Périodiques; Thermoluminescence -- Périodiques; Rayonnement cosmique -- Périodiques; Radiométrie -- Périodiques; 539.77
• DOI: 10.1016/j.radmeas.2019.01.019
• Languages: English
• ISSNs: 1350-4487

Abstract

Abstract: Silicon semiconductor detectors are used efficiently for neutron detection when coated with a suitable material. They detect secondary reaction products resulting from the interaction of thermal neutrons with a neutron sensitive material such as 6 LiF. In the present work, the efficiency of the thermal neutron detector system, GAMBE, is discussed. This detector system based on two silicon sensors of 1 cm 2 active area and a layer of 6 LiF ( 1.5 ± 0.6 ) mg/cm 2 thick in a sandwich configuration. This arrangement achieves total and coincidence detection efficiency of ( 4.1 ± 0.5 )% and ( 0.9 ± 0.3 )% respectively. The coincidence method defines a true neutron hit by the simultaneous signal recorded by the two sensors facing the conversion film. This coincidence methodology is applied to enhance the rejection factor of fake hits due to high gamma background conditions up to 10 8 as discussed in previous work. Geant simulation indicates that total and coincidence detection efficiency up to 55% and 18% are possible using an advanced design of stacked detectors. Highlights: Detection of thermal neutrons using Si semiconductor material coated with neutron converter layer has been studied. The research started with a series of GEANT4 simulations to predict the converter thickness corresponding to optimal total and coincidence detection efficiencies. The results have shown that a single sandwich detector was able to achieve a highest total detection efficiency of 7.5\%. It has also been found that the highest coincidence detection efficiencies that can be achieved by a single sandwich detector is 1.1\%. To validate the coincidence detection capability of the single sandwich design, the detector was tested experimentally in front of an isotropic neutron source. Such detector was able to achieve a coincidence detection efficiency of (0.9 ± 0.3) % and a total detection efficiency of (4.1 ± 0.5) %. Detector stacking technique shows a dramatic increases in the thermal neutron detection efficiency.