An improved measurement of electron-ion recombination in high-pressure xenon gas

Abstract

We report on results obtained with the NEXT-DEMO prototype of the NEXT-100 high-pressure xenon gas time projection chamber (TPC), exposed to an alpha decay calibration source. Compared to our previous measurements with alpha particles, an upgraded detector and improved analysis techniques have been used. We measure event-by-event correlated fluctuations between ionization and scintillation due to electron-ion recombination in the gas, with correlation coeffcients between -0.80 and -0.56 depending on the drift field conditions. By combining the two signals, we obtain a 2.8 % FWHM energy resolution for 5.49 MeV alpha particles and a measurement of the optical gain of the electroluminescent TPC. The improved energy resolution also allows us to measure the specific activity of the radon in the gas due to natural impurities. Finally, we measure the average ratio of excited to ionized atoms produced in the xenon gas by alpha particles to be $0.561\pm 0.045$, translating into an average energy to produce a primary scintillation photon of $W_{\mathrm{ex}}=(39.2\pm 3.2)$ eV.

arXiv comment22 pages, 11 figures, 1 table

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• Dark Matter Results from 225 Live Days of XENON100 Data
• The XENON100 Dark Matter Experiment
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• Compton Imaging of MeV Gamma-Rays with the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)
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Cited by in corpus (9)

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• Neutral Bremsstrahlung emission in xenon unveiled
• Microscopic simulation of xenon-based optical TPCs in the presence of molecular additives
• Radiopurity assessment of the energy readout for the NEXT double beta decay experiment
• Modelling the behaviour of microbulk Micromegas in Xenon/trimethylamine gas
• FAT-GEMs: (Field Assisted) Transparent Gaseous-Electroluminescence Multipliers
• Double Beta Decay Experiments at Canfranc Underground Laboratory
• Design and performance of a high-pressure xenon gas TPC as a prototype for a large-scale neutrinoless double-beta decay search