High efficiency neutron sensitive amorphous silicon pixel detectors

• Published in: IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States) 1994-08, Vol.41 (4), p.915-921
• Main Authors: Mireshghi, A., Cho, G., Drewery, J.S., Hong, W.S., Jing, T., Lee, H., Kaplan, S.N., Perez-Mendez, V.
• Format: Article
• Language: English
• Subjects: Amorphous silicon; COMPUTERIZED SIMULATION; DESIGN; DETECTION; EFFICIENCY; Electrons; ELEMENTS; Exact sciences and technology; Experimental methods and instrumentation for elementary-particle and nuclear physics; FABRICATION; GADOLINIUM; Gamma ray detection; Gamma ray detectors; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; MEASURING INSTRUMENTS; METALS; NEUTRON DETECTION; NEUTRON DETECTORS; Neutrons; Nuclear physics; Physics; Plasma chemistry; Plasma simulation; POSITION SENSITIVE DETECTORS; Position sensitive particle detectors; QUANTUM EFFICIENCY; RADIATION DETECTION; RADIATION DETECTORS; Radiation detectors, dosimeters; RARE EARTHS; SEMICONDUCTOR DETECTORS; SI SEMICONDUCTOR DETECTORS; SIMULATION 440101 > Radiation Instrumentation-- General Detectors or Monitors & Radiometric Instruments; Solid-state detectors; Spatial resolution
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/23.322831

A multi-layer a-Si:H based thermal neutron detector was designed, fabricated and simulated by Monte Carlo method. The detector consists of two a-Si:H pin detectors prepared by plasma enhanced chemical vapor deposition (PECVD) and interfaced with coated layers of Gd, as a thermal neutron converter. Simulation results indicate that a detector consisting of 2 Gd films with thicknesses of 2 and 4 /spl mu/m, sandwiched properly with two layers of sufficiently thick (/spl sim/30 /spl mu/m) amorphous silicon diodes, has the optimum parameters. The detectors have an intrinsic efficiency of about 42% at a threshold setting of 7000 electrons, with an expected average signal size of /spl sim/12000 electrons which is well above the noise. This efficiency will be further increased to nearly 63%, if we use Gd with 50% enrichment in /sup 157/Gd. We can fabricate position sensitive detectors with spatial resolution of 300 /spl mu/m with gamma sensitivity of /spl sim/1/spl times/10/sup -5/. These detectors are highly radiation resistant and are good candidates for use in various application, where high efficiency, high resolution, gamma insensitive position sensitive neutron detectors are needed.< >