GEM operation in helium and neon at low temperatures Buzulutskov, A.; Dodd, J.; Galea, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2005, Volume:
548, Issue:
3
Journal Article
Peer reviewed
Open access
We study the performance of Gas Electron Multipliers (GEMs) in gaseous He, Ne and Ne+H
2 at temperatures in the range of 2.6–293
K. In He, at temperatures between 62 and 293
K, the triple-GEM ...structures often operate at rather high gains, exceeding 1000. There is an indication that this high gain is achieved by the Penning effect in the gas impurities released by outgassing. At lower temperatures, the gain–voltage characteristics are significantly modified probably due to the freeze-out of impurities. In particular, the double- and single-GEM structures can operate down to 2.6
K at gains reaching only several tens at a gas density of about 0.5
g/l; at higher densities the maximum gain drops further. In Ne, the maximum gain also drops at cryogenic temperatures. The gain drop in Ne at low temperatures can be reestablished in Penning mixtures of Ne+H
2: very high gains, exceeding 10
4, have been obtained in these mixtures at 50–60
K, at a density of 9.2
g/l corresponding to that of saturated Ne vapor near 27
K. The results obtained are relevant in the fields of two-phase He and Ne detectors for solar neutrino detection and electron avalanching at low temperatures.
The performance of Gas Electron Multipliers (GEMs) in gaseous He, Ne, He+H 2 and Ne+H 2 was studied at temperatures in the range of 3-293 K. This paper reports on previously published measurements ...and additional studies on the effects of the purity of the gases in which the GEM performance is evaluated. In He, at temperatures between 77 and 293 K, triple-GEM structures operate at rather high gains, exceeding 1000. There is an indication that this high gain is achieved through the Penning effect as a result of impurities in the gas. At lower temperatures the gain-voltage characteristics are significantly modified probably due to the freeze-out of these impurities. Double-GEM and single-GEM structures can operate down to 3 K at gains reaching only several tens at a gas density of about 0.5 g/l; at higher densities the maximum gain drops further. In Ne, the maximum gain also drops at cryogenic temperatures. The gain drop in Ne at low temperatures can be re-established in Penning mixtures of Ne+H 2 : very high gains, exceeding 10 4 , have been obtained in these mixtures at 30-77K, at a density of 9.2 g/l which corresponds to saturated Ne vapor density at 27 K. The addition of small amounts of H 2 in He also re-establishes large GEM gains above 30 K but no gain was observed in He+H 2 at 4 K and a density of 1.7 g/l (corresponding to roughly one-tenth of the saturated vapor density). These studies are, in part, being pursued in the development of two-phase He and Ne detectors for solar neutrino detection
We are developing a new cryogenic neutrino detector: electron bubble chamber, using liquid helium as the detecting medium, for the detection of low energy p–p reaction neutrinos (<420
keV), from the ...Sun. The program focuses in particular on the interactions of neutrinos scattering off atomic electrons in the detecting medium of liquid helium, resulting in recoil electrons which can be measured. We designed and constructed a small test chamber with 1.5
L active volume to start the detector R&D, and performed experimental proofs of the operation principle. The test chamber is a stainless steel cylinder equipped with five optical windows and ten high voltage cables. To shield the liquid helium chamber against the external heat loads, the chamber is made of double-walled jacket cooled by a pumped helium bath and is built into a LN
2/LHe cryostat, equipped with 80
K and 4
K radiation shields. A needle valve for vapor helium cooling was used to provide a 1.7–4.5
K low temperature environments. The cryogenic test chamber has been successfully operated to test the performance of Gas Electron Multipliers (GEMs) in He and He
+
H
2 at temperatures in the range of 3–293
K. This paper will give an introduction on the cryogenic solar neutrino detector using electron bubbles in liquid helium, then present the cryogenic design and operation of liquid helium in the small test chamber. The general principles of a full-scale electron bubble detector for the detection of low energy solar neutrinos are also proposed.
The invariant cross section as a function of transverse momentum for antideuterons produced in 158A GeV/c per nucleon Pb+Pb central collisions has been measured by the NA44 experiment at CERN. This ...measurement, together with a measurement of antiprotons, allows for the determination of the antideuteron coalescence parameter. The extracted coalescence radius is found to agree with the deuteron coalescence radius and radii determined from two particle correlations.
The abundances of light nuclei probe the later stages of the evolution of a system formed in a relativistic heavy-ion collision. After the system has cooled and expanded, nucleons in close proximity ...and moving with small relative momenta coalesce to form nuclei. Light nuclei production enables the study of several topics, including the mechanism of composite particle production, freeze-out temperature, size of the interaction region, and entropy of the system. NA44 is the only relativistic heavy-ion experiment to have both deuteron and antideuteron results in both pA and AA collisions and the first CERN experiment to study the physics topics addressed by
d and
d
production.
Liquid ionization calorimetry with time-sampled signals
Nuclear instruments and methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment/Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/1994
Journal Article
Performance of an accordion electromagnetic calorimeter with liquid krypton and argon
Nuclear instruments and methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment/Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1994
Journal Article
An accordion liquid argon electromagnetic calorimeter with absorber in all electrodes
Nuclear instruments and methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment/Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/1994
Journal Article
We describe the electric circuits (electrodes) which polarize and read out the lead–liquid argon electromagnetic calorimeter for the ATLAS detector. The paper covers design and material choices of ...the circuits as well as their production in industry. We also show how the electrodes integrate into the calorimeter and conclude with results from groups of electrodes making up calorimeter modules.
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