A novel method to measure the dE/dx resolution of a TPC prototype using 266 nm UV laser

TL;DR

This paper introduces a new laser-based method to measure the dE/dx resolution in TPCs, offering a more convenient alternative to traditional particle beam techniques, validated on a prototype and applicable to CEPC TPCs.

Contribution

A novel UV laser technique for measuring dE/dx resolution in TPCs, validated experimentally and theoretically, enhancing flexibility over traditional methods.

Findings

Laser ionisation follows Gaussian distribution

Method is feasible with a TPC prototype

Extrapolated dE/dx resolution for CEPC TPC

Abstract

The specific energy loss (dE/dx) resolution is critical for particle identification and separation in TPC. In connection with the R&D for the TPC at the Circular Electron Positron Collider (CEPC), we find the laser ionisation obeys the Gaussian distribution theoretically and experimentally. Based on this, we develop a novel method using a 266 nm UV laser to measure the dE/dx resolution. Comparing to the traditional methods with particle beams or cosmic rays, the novel method with 266 nm UV laser is more convenient and flexible. We verify the method's feasibility with a TPC prototype and extrapolate the dE/dx resolution to the CEPC TPC. The estimation of the dE/dx resolution is without the magnetic field.