We have studied, using cosmic rays, the influence of oxygen contamination on the performance of a test drift chamber filled with a CO
2:iso-C
4H
10 (90:10) gas mixture. The test chamber has the same ...mini-jet-cell structure as our proposed central tracker for JLC (JLC-CDC). We observed significant deterioration of its spatial resolution with oxygen contamination in the long drift region, though the wire efficiency stayed essentially 100% up to
50
ppm
of oxygen over the full drift length of
5
cm
. From the drift-time dependence of signal charge, we evaluated the electron attachment rates at different oxygen concentrations. The results were found to be consistent with a proposed empirical expression for the attachment of thermal electrons.
Gas gain study for CO2/isobutane mixtures Okuno, H; Khalatyan, N; Nakamura, Y ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2000, Letnik:
447, Številka:
3
Journal Article
Cosmic ray tests of a 4.6 m-long test drift chamber for JLC Kurihara, Y.; Yamaguchi, A.; Sudo, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2000, Letnik:
441, Številka:
3
Journal Article
Recenzirano
Performance of a 4.6 m-long drift chamber filled with a CO
2 iso-butane (90:10) mixture was studied using cosmic-ray data, in the course of detector R&D for JLC. After correcting the data for wire ...displacements due to gravitational and electrostatic forces, a spatical resolution of
100
μ
m per wire was achieved over the full length of the chamber. The relation between wire efficiency and oxygen remnant in the chamber gas is also discussed.
We present measurements of the differential cross section dσ/dργτ for the inclusive production of a photon in association with a b -quark jet for photons with rapidities |yγ| < 1.0 and 30 < ργτ < 300 ...GeV , as well as for photons with 1.5 <|yγ| < 2.5 and 30 < ργτ < 200 GeV, where ργτ is the photon transverse momentum. The b -quark jets are required to have pT > 15 GeV and rapidity |yjet| < 1.5. The results are based on data corresponding to an integrated luminosity of 8.7 fb-1, recorded with the D0 detector at the Fermilab Tevatron $p\bar{p}$ Collider at $\sqrt{s}$ =1.96 TeV. The measured cross sections are compared with next-to-leading order perturbative QCD calculations using different sets of parton distribution functions as well as to predictions based on the kT-factorization QCD approach, and those from the SHERPA and PYTHIA Monte Carlo event generators.
Measurements of wire tensions, gravitational and electrostatic sags for 4.6 m test chamber are described. A method to calculate the wire sags knowing the initial position of and tension and high ...voltage on each wire is developed. There is a good agreement between measurement and calculation.
Common problems in designing stereo-wire geometry for a long cylindrical drift chamber with small jet cells are described and possible ways to approach them are discussed in detail. Among these ...problems, special emphasis is put on the surface field variation along an anode wire due to the geometrical deformation of the cell structure. Also estimated is the surface field variation due to electrostatic and gravitational sags, based on the sags measured for a 4.6
m-long test chamber. These field variations are translated into gain variation along the stereo wires and used to constrain the stereo geometry.
Mini-tower beam tests were carried out at a test beam line of KEK-PS in order to study the performance of the prototype level-1 trigger system and drift tubes with field-shapers originally designed ...for the SDC barrel muon detector at the SSC. A mini-tower of 10 layers, 31 drift tubes in total, and a prototype level-1 trigger module were designed and fabricated for the tests. The spatial resolution of about 230 μm was obtained for the tubes. Relatively high rates of multi-pulse signals were observed for most of the tubes. The trigger module designed at KEK using a logic delta-T method was studied for various trigger logics and its performance was found to be very satisfactory.
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