Geant4 modeling of spectral performance and parameter effects in CdZnTe detectors

Area of Science:

• Nuclear instrumentation and detectors
• Semiconductor physics
• Radiation detection technology

Background:

• Cadmium Zinc Telluride (CdZnTe, CZT) detectors are crucial for nuclear radiation detection, offering high efficiency and resolution.
• Understanding spectral response is key to optimizing CZT detector performance.

Purpose of the Study:

• To systematically investigate the energy spectrum response of planar CZT detectors.
• To explore the impact of key parameters on energy resolution and photopeak tailing.
• To establish a theoretical framework for CZT detector performance optimization.

Main Methods:

• Utilized GEANT4 Monte Carlo simulations to model γ-ray interactions and energy deposition.
• Applied the Shockley-Ramo theorem and Hecht equation to analyze charge carrier transport.
• Coupled simulation and theoretical analysis to study detector parameter effects.

Main Results:

• Energy resolution is sensitive to the electron to hole mobility-lifetime product ratio ((μτ)e/(μτ)h), with lower ratios improving resolution.
• Increased bias voltage enhances charge collection and energy resolution.
• Thicker detectors reduce hole contribution, mitigating tailing and improving energy resolution.

Conclusions:

• A theoretical framework was established for understanding CZT spectral response mechanisms.
• The study provides guidance for optimizing CZT detector performance through parameter tuning.
• Charge carrier transport properties significantly influence detector spectral characteristics.