Characterization of Different Types of Micro-Fission and Micro-Ionization Chambers Under X-Ray Beams

Area of Science:

• Nuclear Engineering
• Radiation Detection and Measurement
• Materials Science

Background:

• Ionizing radiation detection is crucial for applications in fusion reactors and particle accelerators.
• Harsh operational environments necessitate robust and reliable radiation detectors.
• Existing detector models require thorough characterization for performance optimization.

Purpose of the Study:

• To experimentally and numerically evaluate various ionization and fission chamber models for ionizing radiation detection.
• To determine the optimal operating parameters and sensitivities of these detectors.
• To understand the factors influencing detector response variations.

Main Methods:

• Experimental characterization of micro-ionization and micro-fission chambers under X-ray irradiation.
• Numerical simulations using Monte Carlo methods to analyze detector physics.
• Calibration of detectors using a photon beam at varying dose rates (0.05–2.28 Gy/min).

Main Results:

• Photon sensitivities were measured for different chamber models, with values ranging from 29.8 ± 0.3 to 96.0 ± 0.9 pA/(Gy/h).
• Monte Carlo simulations identified the uranium layer's photoelectric absorption as key to higher fission chamber sensitivity.
• Detector response was linear with dose rate and demonstrated high reproducibility.

Conclusions:

• The characterized ionization and fission chambers are suitable for ionizing radiation detection in demanding conditions.
• Detector sensitivity is influenced by filling gas pressure and the presence of specific materials like uranium.
• These detectors offer reliable performance for accurate ionizing photon beam determination.