The TPC is operated with ArCO2 mixture (70/30), covering an active volume of 10x10x8 cm^3 and can register ionizing particle tracks in 3D. The uniform electric field is achieved by a field cage composed of printed circuit boards with 5 mm parallel strips at regular distances, interconnected by a voltage divider that provides a uniformly increasing potential. The field cage is fixed in the plastic 3D printed gaseous chamber that also holds the copper clad kapton cathode and the high voltage feedthrough. The readout plane is composed of a triple 10x10 cm^2 GEM stack, that can operate at charge gains up to 10 000 and has an intrinsic 2D position resolution around 350 um for this gas mixture, when imaging X-rays. The readout electrode has 10x12 pads (8x10 mm^2) that are read by 4 SAMPA chips using CERN's Scalable Readout System.
FIG. 1: CAD of the TPC prototype, where the triple GEM stack and the field cage PCB are visible.
FIG. 2: The TPC setup with the SAMPA chip board connected to the readout board.
Fig. 3: The testing of the GEM 2D readout with a produced X-ray imag
The accelerator and the laboratory are operated and upgraded in frame of the research funding grant "VdG Research infrastructure" by the Ministry of Education, Youth and Sports of the Czech Republic (Contract No. LM2015077).
Last update: January 2022