Digital FPGA-based processing of pulses of gas-filled gamma-radiation detector for acoustic noise suppression

Abstract

Gas-filled proportional detectors of ionizing radiation often contain such elements as thin anode wire, which make them sensitive to external acoustic or vibrational impact. This study investigates such sensitivity for the case of the proportional γ-radiation detectors filled with high-purity xenon gas. The detector demonstrates a dependence of its signal noise on the external acoustic wave frequency, the character of which most likely depends on the design of the detector, i.e. on such parameters as diameter and tension strength of the anode wire, etc. To suppress the negative impact of acoustic noise on the characteristics of the detector, the detector digital signal is processed in a Field-Programmable Gate Array board. The authors investigate the algorithm of «time windows», which allows separating (filtering) low-frequency noise in the output signal of a gas-filled detector, which arises due to the influence of external sound, from the useful signal, i.e. the ionization pulses. This approach allows performing spectral measurements of γ-radiation with a significant acoustic noise background, when detectors with a conventional analog spectrometric channel cannot handle the task.

Keywords

• gamma-radiation detectors
• xenon
• proportional counters
• fpga
• digital signal processing
• noise suppression