Development of a time projection chamber with micro pixel electrodes

TL;DR

This paper presents a novel time projection chamber using micro pixel electrodes that accurately reconstructs 3D charged particle tracks at high event rates, demonstrating stable operation and successful gamma-ray tracking.

Contribution

The development of a micro pixel electrode-based TPC with a synchronized FPGA readout system for high-rate 3D particle tracking is a new advancement.

Findings

Stable operation over three days with cosmic muons.

Successful 3D tracking of Compton scattered electrons.

Achieved uniform electric field and precise 2D position measurement.

Abstract

A time projection chamber (TPC) based on a gaseous chamber with micro pixel electrodes (micro-PIC) has been developed for measuring three-dimensional tracks of charged particles. The micro-PIC with a detection area of 10 cm square consists of a double-sided printing circuit board. Anode pixels are formed with 0.4 mm pitch on strips aligned perpendicular to the cathode strips in order to obtain a two-dimensional position. In the TPC with drift length of 8 cm, 4 mm wide field cage electrodes are aligned at 1mm spaces and a uniform electric field of about 0.4 kV/cm is produced. For encoding of the three-dimensional position a synchronous readout system has been developed using Field Programmable Gate Arrays with 40 MHz clock. This system enables us to reconstruct the three-dimensional track of the particle at successive points like a cloud chamber even at high event rate. The drift velocity of electrons in the TPC was measured with the tracks of cosmic muons for three days, during which the TPC worked stably with the gas gain of 3000. With a radioisotope of gamma-ray source the three-dimensional track of a Compton scattered electron was taken successfully.