GaAs detectors with an ultra-thin Schottky contact for spectrometry of charged particles

This paper examines the feasibility of detecting strontium 90 in groundwater directly with photodiodes and considers the physical parameters which maximise radiation absorption within the detector. Geant4 simulations were used to draw comparisons between silicon, gallium arsenide and cadmium telluride detectors of varying surface area and thickness. Detectors were compared in their ability to absorb point and scattered sources of radiation. The results indicate that a detector, of 10 mm 2 surface area, and 1 mm thickness offered the highest detection efficiency in a contaminated groundwater simulation. 1 mm thick and 100 mm 2 detectors cadmium telluride and gallium arsenide detectors were modelled in a groundwater borehole scenario. Each material offered similar detection efficiency, but the greater backscattering effect in cadmium telluride resulted in a greater peak at lower energies compared to that observed in gallium arsenide. K: Detector design and construction technologies and materials; Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc); Interaction of radiation with matter; Solid state detectors 1Corresponding author.

Section: Jinst 14 P10018mentioning

confidence: 99%

Direct measurement of strontium 90 in groundwater: geometry optimisation of a photodiode based detector

Turkington¹,

Gamage²,

Graham³

2019

“…The spectrometric quality of the detectors was determined with a 238 Pu source. The measurements were carried out at room temperature and 1.33 Pa residual pressure using the measuring scheme shown in [19].…”

Section: Alpha-particle Characterizationmentioning

confidence: 99%

Characterization and simulation of fast neutron detectors based on surface-barrier VPE GaAs structures with polyethylene converter

Черных

Baryshnikov

et al. 2016

Self Cite

A: Fast neutron detectors with an active area of 80 mm 2 based on surface-barrier VPE GaAs structures were fabricated and tested. Polyethylene with density of 0.90 g/cm 3 was used as a converter layer. The recoil-proton surface-barrier sensor was fabricated on high purity VPE GaAs epilayers with a thickness of 50 µm. The neutron detection efficiency measured with a 241 Am-Be source was 1.30 • 10 −3 puls./neutr. for the PE converter thickness of 670 µm. The signal-togamma-background ratio was at the level of 50. Simulation of the detector characteristics with Geant4 toolkit has showed good correlation with the experimental data and allowed to estimate the maximal theoretical detection efficiency of the detector which is determined by the PE converter and equals to 1.37 • 10 −3 puls./neutr. The difference between the measured and simulated values of the detection efficiency is due to the fact that the events with energies below 0.5 MeV were not taken into account during the measurements. K: Neutron detectors (cold, thermal, fast neutrons); Solid state detectors; Instrumentation for neutron sources 1Corresponding author.

“…First, GaAs detectors were intensively studied in the 1990's, when their application in the Large Hadron Collider experiments was considered [1]. Three of its material forms, the bulk semi-insulating [1][2][3], the bulk Cr-doped [4] as well as the epitaxially grown [5,6] GaAs were used for detector preparation onwards. The bulk SI GaAs detectors are characterized by a developed material preparation technology but suffer from material inhomogeneity leading to poorer energy resolution than silicon detectors.…”

Section: Introductionmentioning

confidence: 99%

Spreading of an active region of semi-insulating GaAs detectors after radiation degradation

Sagatova,

Kurucova,

Necas

et al. 2024

The radiation hardness of GaAs detectors against high-energy electrons goes up to a few MGy. Their degradation is mainly connected to the decrease of the charge collection efficiency and the increase of the reverse current. On the other hand, an improvement in detection efficiency was observed at low degradation doses. The explanation that this could be caused by an enlargement of the detector active area due to spreading of the collecting electric field caused by radiation-induced defects is studied in this paper. We have used the alpha particles of 241Am, which interact in the GaAs surface layer, to study the enlargement of the detector active region after its degradation by 5 MeV electrons with doses ranging from 24 to 2000 kGy. The results show that the electric field spreads behind the Schottky contact metallization edges not only with increasing applied reverse bias but also with rising cumulative dose of radiation degradation in the dose range from 24 up to 100 kGy, followed by a slight reduction in area size. The electric collecting field keeps larger dimensions than before detector degradation for doses up to 600 kGy. For higher doses than 1000 kGy, the active area of the detector was reduced below its initial size before degradation. Moreover, the improvement of detection efficiency with increasing bias applied becomes weaker with increasing degradation dose. Radiation degradation affects the electric field distribution in semi-insulating GaAs detectors and the results obtained may provide useful knowledge to preparation of multi-pixel GaAs structures for imaging and particle tracking.