Monte-Carlo simulation of CdZnTe detectors

• Monte-Carlo simulation of the energy dependence of the sensitivity of planar CdZnTe gamma-ray detectors
• Monte-Carlo simulation of CdZnTe detector response to beta-radiation

Monte-Carlo simulation of the energy dependence of the sensitivity of planar CdZnTe gamma-ray detectors ↑

The sensitivity is the ratio of the number of pulses, N, produced by the detector to the value of exposure (X) or absorbed (D) radiation dose:

δ_X = N/X or δ_D = N/D.

It sharply depends on gamma-ray energy, δ_X,D(E_γ).

Monte-Carlo simulation of the sensitivity of 6×6×3 mm³ CdZnTe detector, δ_X(E_γ), at a zero noise discrimination threshold.

Exposure radiation dose is

X = N_T / δ = N_T (М×E_ph + C)

where М and C are constants, to be determined at detector calibration;
N_T is the total number of pulses;
E_ph is the averaged pulse height.

Monte-Carlo simulation of CdZnTe detector response to beta-radiation ↑

• The electron energy spectra of ⁹⁰Sr/⁹⁰Y radiation source were measured with a planar CdZnTe detector.
• A model of the wide gap semiconductor gamma-ray detector, developed earlier, was used for the simulation of CdZnTe detector response functions by Monte-Carlo method.
• Only two fitting parameters: products of mobility and lifetime for electrons and holes: (τμ)_e и (τμ)_h;
• Applied for the extraction of beta radiation spectrum from the mixed beta and gamma fields (i.e., in situ determination of ¹³⁷Cs and ⁹⁰Sr sources activity).

⁹⁰Sr/⁹⁰Y source spectrum measured with CdZnTe detector without any slowing-down filter.

⁹⁰Sr/⁹⁰Y source spectrum measured with CdZnTe detector with lead filter.