Improved method to measure the electron drift velocity using the Frisch-grid ionization chamber

作者：Liu, Jie; Jiang, Haoyu; Cui, Zengqi; Hu, Yiwei; Chen, Jinxiang; Zhang, Guohui^*

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2021, 1004: 165363.

DOI：10.1016/j.nima.2021.165363

• Differentiated cathode signal
• Digital signals
• Electron diffusion
• Electron drift velocity
• Electron loss
• Frisch grids
• Frisch-grid ionization chamber
• Real time measurements
• Working gas

An improved method for processing digital signals of the Frisch-grid ionization chamber to measure the electron drift velocity is proposed, which is based on the analysis of the cathode signal and the differentiated cathode signal. This method allows the real-time measurement eliminating the influence of electron diffusion and it is suitable for working gases with electron loss from the electronegative impurities. The electron drift velocities in gas mixtures of Ar + 9.86% CH4, Ar + 3.45% CO2, (Ar + 3.45% CO2) + x% O2 (x is less than 0.33), (Ar + 3.45% CO2) + y% Air (y is less than 2.09) have been measured, and the results are compared with existing measurements and calculations using MAGBOLTZ-11.4 code. Meanwhile, the influences of the impurities of oxygen and nitrogen on the electron drift velocity are analyzed.