Time projection chambers

Abstract

The Time Projection Chamber (TPC) had originally been proposed to permit full reconstruction of events of up to 20 particles at an electron-positron collider. It was to provide 3-D information for tracking and momentum measurement together with particle identification by multiple ionization sampling, in a compact detector. This powerful combination soon found applications in other fields: at one end, for studies of rare events of simple structure; at the other extreme, for heavy ion collisions, handling ever higher particle densities, finally up to several thousand tracks in a single event, still providing information on a track-to-track basis.Basic physics, performance and limitations of drift chambers in general will be discussed first. Then the characteristics of TPCs will be introduced, as well as their practical realization and performance. The development from the first TPC, 30 years ago, to the present day will be covered and followed by a few final comments on the ongoing studies for future applications.

Three-dimensional photograph of electron tracks through a plastic scintillator

“…The dark rate of the HPD was 2,000 counts per second, which corresponds to the intrinsic dark rate of the detector. The maximum digital counter value in the Timepix ToA mode is 11,810 and as we used a clock of 10 MHz (100 ns per clock cycle), the maximum frame integration time that could be used to avoid events with a maximum ToA value of 11,810 (and therefore with no useful) was 1 ms. 4 Since the read-out speed of the data acquisition system is limited, we could only start a frame every 0.1 s. To avoid dead-time in-between and increase statistics (the number of measured events), we used the trigger signal from the beam monitor (two crossed scintillator panels with a PMT attached) for the frame-stop signal in order to have a higher probability to see one electron during one frame. However, as turned out later during the data analysis, our trigger system had a malfunction during the experiment and a large part of the data has to be rejected since the ToA value of the triggered pixels was 11,810.…”

“…With technological progress ongoing the cloud chamber was replaced with the bubble chamber [1] and the spark or wire chamber [3] which allowed higher event rates, better position resolution and an automated electrical data read-out. This technology was developed further to the gas-filled multi-wire proportional chamber [3] and the gas-filled time-projection chamber [4], which made reconstruction of trajectories in three dimensions possible.…”

Particle and nuclear physics instrumentation and its broad connections

“…At one extreme, TPCs are being used for studies of rare events of simple structure; at the other, they are used for heavy ion collisions, handling ever higher particle densities, up to many thousands of tracks in a single event, still providing information on a track-by-track basis. The largest TPC currently in operation is the central detector of the ALICE experiment at CERN, which studies the creation of the quark-gluon plasma (Hilke, 2010). The TPC technology is now also being used with liquid argon as the active medium for the study of neutrino interactions.…”

Test of MPGD modules with a large prototype Time Projection Chamber

“…The International Large Detector (ILD) [2] is one of the two detector concepts for the ILC. The central tracking at ILD is based on a Time Projection Chamber (TPC) [3]. The ILD-TPC, which is planned to run in a 3.5 T magnetic field, will be 4.6 m in length and 3.6 m in diameter.…”