303 research outputs found
Electron transfer efficiency in liquid xenon across THGEM holes
Dual-phase liquid-xenon time projection chambers (LXe TPCs) deploying a few
tonnes of liquid are presently leading the search for WIMP dark matter. Scaling
these detectors to 10-fold larger fiducial masses, while improving their
sensitivity to low-mass WIMPs presents difficult challenges in detector design.
Several groups are considering a departure from current schemes, towards either
single-phase liquid-only TPCs, or dual-phase detectors where the
electroluminescence region consists of patterned electrodes. Here, we discuss
the possible use of Thick Gaseous Electron Multipliers (THGEMs) coated with a
VUV photocathode and immersed in LXe as a building block in such designs. We
focus on the transfer efficiencies of ionization electrons and photoelectrons
emitted from the photocathode through the electrode holes, and show
experimentally that efficiencies approaching 100 % can be achieved with
realistic voltage settings. The observed voltage dependence of the transfer
efficiencies is consistent with electron transport simulations once diffusion
and charging-up effects are included
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