Lorentz Angle Measurement for CO2/Isobutane Gas Mixtures

TL;DR

This paper presents a new laser-based system for measuring Lorentz angles in CO2/isobutane gas mixtures, providing experimental data that aligns well with simulation predictions, aiding the development of drift chambers.

Contribution

Introduces a novel laser and flash ADC-based measurement system for Lorentz angles in gas mixtures, validated through experimental results and simulations.

Findings

Measured Lorentz angles for various gas mixtures and fields

Results agree with GARFIELD/MAGBOLTZ simulations

Demonstrated system's effectiveness for drift chamber research

Abstract

We have developed a Lorentz angle measurement system for cool gas mixtures in the course of our R&D for a proposed JLC central drift chamber (JLC-CDC). The measurement system is characterized by the use of two laser beams to produce primary electrons and flash ADCs to read their signals simultaneously. With this new system, we have measured Lorentz angles for CO2/isobutane gas mixtures with different proportions (95:5, 90:10, and 85:15), varying drift field from 0.6 to 2.0 kV/cm and magnetic field up to 1.5 T. The results of the measurement are in good agreement with GARFIELD/MAGBOLTZ simulations.