No Arabic abstract
We report the design, construction, and initial commissioning results of a large high pressure gaseous Time Projection Chamber (TPC) with Micromegas modules for charge readout. The detector vessel has an inner volume of about 600 L and an active volume of 270 L. At 10 bar operating pressure, the active volume contains about 20 kg of xenon gas and can image charged particle tracks. Drift electrons are collected by the charge readout plane, which accommodates a tessellation of seven Micromegas modules. Each of the Micromegas covers a square of 20 cm by 20 cm. A new type of Microbulk Micromegas is chosen for this application due to its good gain uniformity and low radioactive contamination. Initial commissioning results with 1 Micromegas module running with 1 bar argon and isobutane gas mixture and 5 bar xenon and trimethylamine (TMA) gas mixture are reported. We also recorded extended background tracks from cosmic ray events and highlighted the unique tracking feature of this gaseous TPC.
This document illustrates the technical layout and the expected performance of a Time Projection Chamber as the central tracking system of the PANDA experiment. The detector is based on a continuously operating TPC with Gas Electron Multiplier (GEM) amplification.
For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1 T solenoidal field and read out with three independent GEM-based readout modules, are reported. The TPC was exposed to a 6 GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.
A new Micromegas manufacturing technique, based on kapton etching technology, has been recently developed, improving the uniformity and stability of this kind of readouts. Excellent energy resolutions have been obtained, reaching 11% FWHM for the 5.9 keV photon peak of 55Fe source and 1.8% FWHM for the 5.5 MeV alpha peak of the 241Am source. The new detector has other advantages like its flexible structure, low material and high radio-purity. The two actual approaches of this technique will be described and the features of these readouts in argon-isobutane mixtures will be presented. Moreover, the low material present in the amplification gap makes these detectors approximate the Rose and Korff model for the avalanche amplification, which will be discussed for the same type of mixtures. Finally, we will present several applications of the microbulk technique.
Dark Matter experiments are recently focusing their detection techniques in low-mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we describe the TREX-DM experiment, a low background Micromegas-based Time Projection Chamber for low-mass WIMP detection. Its main goal is the operation of an active detection mass $sim$0.3 kg, with an energy threshold below 0.4~keVee and fully built with previously selected radiopure materials. This work focuses on the commissioning of the actual setup situated in a laboratory on surface. A preliminary background model of the experiment is also presented, based on Geant4 simulations and two discrimination methods: a conservative muon/electron and one based on a $^{252}$Cf source. Based on this model, TREX-DM could be competitive in the search for low mass WIMPs and, in particular, it could be sensitive to the WIMP interpretation of the DAMA/LIBRA hint.
A micro time-projection-chamber (micro-TPC) with a detection volume of 23*28*31 cm^3 was developed, and its fundamental performance was examined. The micro-TPC consists of a micro pixel chamber with a detection area of 31*31 cm^2 as a two-dimensional imaging device and a gas electron multiplier with an effective area of 23*28 cm^2 as a pre-gas-multiplier. The micro-TPC was operated at a gas gain of 50,000, and energy resolutions and spatial resolutions were measured.