93,332 research outputs found
Spatial Resolution of a Micromegas-TPC Using the Charge Dispersion Signal
The Time Projection Chamber (TPC) for the International Linear Collider will
need to measure about 200 track points with a resolution close to 100 m. A
Micro Pattern Gas Detector (MPGD) readout TPC could achieve the desired
resolution with existing techniques using sub-millimeter width pads at the
expense of a large increase in the detector cost and complexity. We have
recently applied a new MPGD readout concept of charge dispersion to a prototype
GEM-TPC and demonstrated the feasibility of achieving good resolution with pads
similar in width to the ones used for the proportional wire TPC. The charge
dispersion studies were repeated with a Micromegas TPC amplification stage. We
present here our first results on the Micromegas-TPC resolution with charge
dispersion. The TPC resolution with the Micromegas readout is compared to our
earlier GEM results and to the resolution expected from electron statistics and
transverse diffusion in a gaseous TPC.Comment: 5 pages, 8 figures, to appar in the Proceedings of the 2005
International Linear Collider Workshop (LCWS05), Stanford, 18-22 March 200
The STAR Time Projection Chamber: A Unique Tool for Studying High Multiplicity Events at RHIC
The STAR Time Projection Chamber (TPC) is used to record collisions at the
Relativistic Heavy Ion Collider (RHIC). The TPC is the central element in a
suite of detectors that surrounds the interaction vertex. The TPC provides
complete coverage around the beam-line, and provides complete tracking for
charged particles within +- 1.8 units of pseudo-rapidity of the center-of-mass
frame. Charged particles with momenta greater than 100 MeV/c are recorded.
Multiplicities in excess of 3,000 tracks per event are routinely reconstructed
in the software. The TPC measures 4 m in diameter by 4.2 m long, making it the
largest TPC in the world.Comment: 28 pages, 11 figure
Impact of different solvents on the recovery of bioactive compounds and antioxidant properties from lemon (Citrus limon L.) pomace waste
The effects of different solvents on the recovery of (i) extractable solids (ES), (ii) total phenolic compounds (TPC), (iii) total flavonoid content (TFC), (iv) vitamin C, and (v) antioxidant activity from lemon pomace waste were investigated. The results revealed that solvents significantly affected the recovery of ES, TPC, TFC, and antioxidant properties. Absolute methanol and 50% acetone resulted in the highest extraction yields of TPC, whereas absolute methanol resulted in the highest extraction of TFC, and water had the highest recovery of vitamin C. 50% ethanol, and 50% acetone had higher extraction yields for TPC, and TFC, as well as higher antioxidant activity compared with their absolute solvents and water. TPC and TFC were shown to be the major components contributing to the antioxidant activity of lemon pomace
The GAP-TPC
Several experiments have been conducted worldwide, with the goal of observing
low-energy nuclear recoils induced by WIMPs scattering off target nuclei in
ultra-sensitive, low-background detectors. In the last few decades noble liquid
detectors designed to search for dark matter in the form of WIMPs have been
extremely successful in improving their sensitivities and setting the best
limits. One of the crucial problems to be faced for the development of large
size (multi ton-scale) liquid argon experiments is the lack of reliable and low
background cryogenic PMTs: their intrinsic radioactivity, cost, and borderline
performance at 87 K rule them out as a possible candidate for photosensors. We
propose a brand new concept of liquid argon-based detector for direct dark
matter search: the Geiger-mode Avalanche Photodiode Time Projection Chamber
(GAP-TPC) optimized in terms of residual radioactivity of the photosensors,
energy and spatial resolution, light and charge collection efficiencyComment: 7 pages, 5 figures, Accepted for publication on JINS
A Large TPC Prototype with MPGD Readout: Status and Plans
The use of a TPC in future collider experiments needs significant research
and development. Within the EUDET program an infrastructure has been designed
and built to allow the efficient testing of TPC prototypes under realistic
conditions. The infrastructure consists of a test beam facility, located at
DESY Hamburg, and a multi-purpose TPC field cage.Comment: Conference LCES 2008, Chicag
Particle Identification Studies with an ALICE Test TPC
Using a test TPC, consisting of the ALICE TPC field cage prototype in
combination with the final ALICE TPC readout and electronics, the energy loss
distribution and resolution were measured for identified protons. The
measurements were compared to theoretical calculations and good quantitative
agreement was found when detector effects were taken into account. The
implications for particle identification are discussed.Comment: 6 pages, 4 figures, Quark Matter 06 poster proceedin
Performance of the TPC with Micro Pixel Chamber Readout: micro-TPC
Micro-TPC, a time projection chamber(TPC) with micro pixel chamber(-PIC)
readout was developed for the detection of the three-dimensional fine(sub-m
illimeter) tracks of charged particles. We developed a two-dimensional position
sensitive gaseous detector, or the -PIC, with the detection area of
1010 cm and 65536 anode electrodes of 400 m pitch. We
achieved the gas gain of over 10000 without any other multipliers. With the
pipe-line readout system specially developed for the -PIC, we detected
X-rays at the rate as high as 7.7 Mcps. We attached a drift cage with an 8 cm
drift length to the -PIC and developed a micro-TPC. We measured the basic
performances of the micro-TPC and took three-dimensional tracks of electrons.
We also developed a prototype of the MeV gamma-ray imaging detector which is a
hybrid of the micro-TPC and NaI(Tl) scintillators and confirmed its concept by
reconstructing the obtained data.Comment: 6 pages 16 figures, submitted for IEEE/TNS 200
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