High Efficiency Neutron Sensitive Amorphous Silicon Pixel Detectors


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 µm, sandwiched properly with two layers of sufficiently thick (approx.30µm) 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 approx.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 157Gd. We can fabricate position sensitive detectors with spatial resolution of 300 ?m with gamma sensitivity of approx.1×10ˉ⁵. 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.

Meeting Name

Proceedings of the 1993 Nuclear Science Symposium and Medical Imaging Conference (NSS-MIC'93). Part 1 (of 2)


Nuclear Engineering and Radiation Science

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Article - Conference proceedings

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© 1994 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jan 1994