9,519 research outputs found
The CAST Time Projection Chamber
One of the three X-ray detectors of the CAST experiment searching for solar
axions is a Time Projection Chamber (TPC) with a multi-wire proportional
counter (MWPC) as a readout structure. Its design has been optimized to provide
high sensitivity to the detection of the low intensity X-ray signal expected in
the CAST experiment. A low hardware threshold of 0.8 keV is safely set during
normal data taking periods, and the overall efficiency for the detection of
photons coming from conversion of solar axions is 62 %. Shielding has been
installed around the detector, lowering the background level to 4.10 x 10^-5
counts/cm^2/s/keV between 1 and 10 keV. During phase I of the CAST experiment
the TPC has provided robust and stable operation, thus contributing with a
competitive result to the overall CAST limit on axion-photon coupling and mass.Comment: 19 pages, 11 figures and images, submitted to New Journal of Physic
The TESLA Time Projection Chamber
A large Time Projection Chamber is proposed as part of the tracking system
for a detector at the TESLA electron positron linear collider. Different
ongoing R&D studies are reviewed, stressing progress made on a new type readout
technique based on Micro-Pattern Gas Detectors.Comment: 5 pages, 8 figures; Proceeding for the topical Seminar on Innovative
Particle and Radiation Detectors Siena, 21-24 October 2002; to appear in
Nucl.Phys. B (Proceedings Supplement
Liquid Scintillator Time Projection Chamber Concept
Results are presented from a small-scale experiment to investigate the use of
room temperature organic liquid scintillators as the active medium for a time
projection chamber (TPC). The optical properties of liquid scintillators have
long been known, but their ability to transport charge has remained, until now,
largely untested. The idea of using room temperature liquids as an active
medium for an ionisation chamber was first presented in \cite{EnglerTMS}. Since
then the range of liquid scintillators available has been greatly developed. We
present successful transport of ionization charges in a selection of both, pure
organic liquid solvents and liquid scintillator cocktails over 20mm using a
variety of electric drift field strengths. The target of this research is to
offer a cost effective alternative to liquid noble gas detectors in neutrino
physics.Comment: 6 pages, 5 figures, submitted to Proceedings 12th Pisa Meeting on
Advanced Detectors, La Biodola, Isola d'Elba, Ital
The Laser of the ALICE Time Projection Chamber
The large TPC () of the ALICE detector at the CERN LHC was
commissioned in summer 2006. The first tracks were observed both from the
cosmic ray muons and from the laser rays injected into the TPC. In this article
the basic principles of operating the lasers are presented,
showing the installation and adjustment of the optical system and describing
the control system. To generate the laser tracks, a wide laser beam is split
into several hundred narrow beams by fixed micro-mirrors at stable and known
positions throughout the TPC. In the drift volume, these narrow beams generate
straight tracks at many angles. Here we describe the generation of the first
tracks and compare them with simulations.Comment: QM06 poster proceedings, 6 pages, 4 figure
A Time Projection Chamber with GEM-Based Readout
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.Comment: 22 pages, 19 figure
The ALICE time projection chamber
The ALICE TPC is a conventional TPC based on experience with previous TPCs used in heavy ion beams. However, the unpreceeded high particle multiplicities at LHC Pb+Pb collision has led in detail to many innovations in its design and construction
Laser calibration system for the CERES Time Projection Chamber
A Nd:YAG laser was used to simulate charged particle tracks at known
positions in the CERES Time Projection Chamber at the CERN SPS. The system was
primarily developed to study the response of the readout electronics and to
calibrate the electron drift velocity. Further applications were the
determination of the gating grid transparency, the chamber position
calibration, and long-term monitoring of drift properties of the gas in the
detector.Comment: 28 pages, 26 figures; reference to the TPC preprint update
A Readout System for the STAR Time Projection Chamber
We describe the readout electronics for the STAR Time Projection Chamber. The
system is made up of 136,608 channels of waveform digitizer, each sampling 512
time samples at 6-12 Mega-samples per second. The noise level is about 1000
electrons, and the dynamic range is 800:1, allowing for good energy loss
() measurement for particles with energy losses up to 40 times minimum
ionizing. The system is functioning well, with more than 99% of the channels
working within specifications.Comment: 22 pages + 8 separate figures; 2 figures are .jpg photos to appear in
Nuclear Instruments and Method
MicroBooNE: A New Liquid Argon Time Projection Chamber Experiment
Liquid Argon Time Projection Chamber detectors are well suited to study
neutrino interactions, and are an intriguing option for future massive
detectors capable of measuring the parameters that characterize neutrino
oscillations. These detectors combine fine-grained tracking with calorimetry,
allowing for excellent imaging and particle identification ability. In this
talk the details of the MicroBooNE experiment, a 175 ton LArTPC which will be
exposed to Fermilab's Booster Neutrino Beamline starting in 2011, will be
presented. The ability of MicroBooNE to differentiate electrons from photons
gives the experiment unique capabilities in low energy neutrino interaction
measurements.Comment: Proceedings of the 6th International Workshop on Neutrino-Nucleus
Interactions in the Few-GeV Region (NuInt09
Continuous Monitoring of STAR\u27s Main Time Projection Chamber
STAR refers to the Solenoidal Tracking instrument At RHIC (the Relativistic Heavy Ion Collider). For momenta above 500 MeV/c charged kaons are not separated from pions within STAR\u27s Main TPC (Time Projection Chamber) by track density alone and they are poorly separated below 500 MeV/c, even when using information from other sources like the vertex tracker. Within the TPC large numbers of kaons and pions decay into muons (and undetected neutrinos). Earlier work has shown parent pions and kaons whose decays are detected within a TPC may be distinguished uniquely from each other in a two-dimensional plot of muon-emission angle versus momentum difference (between each parent meson and its decay muon). Since pions and kaons have zero spin, each muon decay-product emerges isotropically in its parent meson\u27s rest frame. Identification of particle type provides the parent meson\u27s rest mass and, thus, its total energy. This means the measurement of each decay event is kinematically complete. Thus, Lorentz Transformations may be used to transform each component of the decaying muon\u27s laboratory four-momentum into the rest frame of its parent meson, where the muon decay is isotropic. An aggregated plot of muon directions from many parent rest frames will be isotropic in each (selected) sub-volume of the TPC unless there is a problem within the TPC or in its tracking algorithms. Continuous monitoring of a TPC is possible using this subset of detected charged particles
- …