Thermal Neutron Dosimetry with Cadmium Telluride Detectors

Abstract

Cadmium telluride, a semiconductor compound with high Z is presently used at room temperature as a gamma ray detector. We have used this material to detect thermal neutrons by making use of the very high cross section of 113Cd to absorb thermal neutrons and emit gamma rays. Two CdTe detectors were exposed to a known thermal neutron beam at the CRN reactor, in order to analyse the performance of this device and a Monte Carlo code was developed to determine the expected response spectrum. For the two devices considered here under a series of experimental conditions, satisfactory agreement was observed between calculations and experimental data. Some of the 113Cd(n,?) radiative capture lines were identified by calibrating the detector with 57Co source. Since the atomic density of CdTe is much higher than in gas detectors, the efficiency under a small volume is very high, even if the total volume is presently limited to 10 x 10 x 2 mm3. In using CdTe as a thermal neutron dosemeter, it is best to use for calibration the line at 560 keV emitted and detected in the same device.

Gadolinium for neutron detection in current nuclear instrumentation research: A review

“…Aside from Si semiconductors, the intrinsic properties of sizeable, cadmium telluride (CdTe) crystals for neutron detection have been highlighted by Fasasi et al [62]. On this basis, Miyake et al [63] described an efficient scheme, in the form of pixelated Gd-covered CdTe diodes, with the purpose of taking advantage of both Gd and Cd neutron captures.…”

The physics of solid-state neutron detector materials and geometries

“…Advances in materials and device architectures toward passive or active high-efficiency charged-particle-based solid-state neutron detection, building from the foundation provided by Bell [1], Knoll [2], Leroy [3], Lutz [4], McGregor [5,6], Petrillo [7], Peurrung [8,9], Spieler [10] and references therein are reviewed. Processes or mechanisms that utilize phonon [11,12] or photon transduction [1,[13][14][15][16][17][18][19][20][21] are not reviewed. The following assumes that the reader has a working knowledge of the electronic structure of solids in the bulk and at heterostructure interfaces including the description of electronic band structure [22], space charge formation and electrical carrier transport [23,24], as well as moderateenergy ion loss processes in the solid state [25,26].…”

“…core-to-bound) electron transitions via absorption [78], wherein a next-order process can result in the emission of a photon [79] or low-energy Auger electron [80]. Here, only moderate-energy electrons converted from the gamma-ray primary reaction products of neutron capture by isotopes such as 72 Ge, 113 Cd, 155 Gd, 157 Gd or 199 Hg are considered a significant means through which to cause a sufficient energy transfer (enough generation of charge) for detection [13][14][15][16][17][18][19][20][21][81][82][83]. However, discussion of this gamma-ray transduction mechanism is outside the scope of this review.…”

Investigation of thermal neutron detection capability of a CdZnTe detector in a mixed gamma-neutron radiation field

“…To develop portable detectors addressing personal neutron dosimetry, semiconductor technologies are also Investigation of thermal neutron detection capability of a CdZnTe detector in a mixed gamma-neutron radiation fi eld preferable due to the high photon-stopping power. Initially, the intrinsic properties of CdTe for neutron detection have been studied [4]. A Gd-covered CdTe diode has been developed and tested using both 113 Cd and 157 Gd isotopes [5].…”