157 research outputs found
Direct comparison of high voltage breakdown measurements in liquid argon and liquid xenon
As noble liquid time projection chambers grow in size their high voltage requirements increase, and detailed, reproducible studies of dielectric breakdown and the onset of electroluminescence are needed to inform their design. The Xenon Breakdown Apparatus (XeBrA) is a 5-liter cryogenic chamber built to characterize the DC high voltage breakdown behavior of liquid xenon and liquid argon. Electrodes with areas up to 33 cm2 were tested while varying the cathode-anode separation from 1 to 6 mm with a voltage difference up to 75 kV. A power-law relationship between breakdown field and electrode area was observed. The breakdown behavior of liquid argon and liquid xenon within the same experimental apparatus was comparable
Extraction efficiency of drifting electrons in a two-phase xenon time projection chamber
We present a measurement of the extraction efficiency of quasi-free electrons
from the liquid into the gas phase in a two-phase xenon time-projection
chamber. The measurements span a range of electric fields from 2.4 to 7.1 kV/cm
in the liquid xenon, corresponding to 4.5 to 13.1 kV/cm in the gaseous xenon.
Extraction efficiency continues to increase at the highest extraction fields,
implying that additional charge signal may be attained in two-phase xenon
detectors through careful high-voltage engineering of the gate-anode region
Observation of activity prior to dielectric breakdown in liquid xenon with the XeBrA experiment
Maintaining the electric fields necessary for the current generation of noble
liquid time projection chambers (TPCs), with drift lengths exceeding one meter,
requires a large negative voltage applied to their cathode. Delivering such
high voltage is associated with an elevated risk of electrostatic discharge and
electroluminescence, which would be detrimental to the performance of the TPC.
The Xenon Breakdown Apparatus (XeBrA) is a five-liter high-voltage test chamber
built to investigate the factors contributing to high voltage breakdown in
noble liquids. Area scaling and surface finish were observed to be the dominant
factors affecting breakdown. In addition, small electrical activity was
frequently observed during high voltage ramps prior to electrostatic discharge.
The position of breakdowns was reconstructed with a system of high-speed
cameras and good agreement with electric field simulations was found. Based on
the results presented in this work, we recommend that the next generation of
TPCs should not withstand fields larger than 20 kV/cm on the electrode
surfaces.Comment: 29 pages, 13 figures; typo in the author list correcte
Signal yields, energy resolution, and recombination fluctuations in liquid xenon
This work presents an analysis of monoenergetic electronic recoil peaks in
the dark-matter-search and calibration data from the first underground science
run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and
light yields for electronic recoil energies between 5.2 and 661.7 keV are
measured, as well as the energy resolution for the LUX detector at those same
energies. Additionally, there is an interpretation of existing measurements and
descriptions of electron-ion recombination fluctuations in liquid xenon as
limiting cases of a more general liquid xenon re- combination fluctuation
model. Measurements of the standard deviation of these fluctuations at
monoenergetic electronic recoil peaks exhibit a linear dependence on the number
of ions for energy deposits up to 661.7 keV, consistent with previous LUX
measurements between 2-16 keV with H. We highlight similarities in liquid
xenon recombination for electronic and nuclear recoils with a comparison of
recombination fluctuations measured with low-energy calibration data.Comment: 11 pages, 12 figures, 3 table
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