Araújo, HM;
Akimov, DY;
Barnes, EJ;
Belov, VA;
Bewick, A;
Burenkov, AA;
Chepel, V;
... Walker, RJ; + view all
(2012)
Radioactivity backgrounds in ZEPLIN-III.
Astroparticle Physics
, 35
(8)
pp. 495-502.
10.1016/j.astropartphys.2011.11.001.
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Abstract
We examine electron and nuclear recoil backgrounds from radioactivity in the ZEPLIN-III dark matter experiment at Boulby. The rate of low-energy electron recoils in the liquid xenon WIMP target is 0.75 ± 0.05 events/kg/day/keV, which represents a 20-fold improvement over the rate observed during the first science run. Energy and spatial distributions agree with those predicted by component-level Monte Carlo simulations propagating the effects of the radiological contamination measured for materials employed in the experiment. Neutron elastic scattering is predicted to yield 3.05 ± 0.5 nuclear recoils with energy 5-50 keV per year, which translates to an expectation of 0.4 events in a 1 yr dataset in anticoincidence with the veto detector for realistic signal acceptance. Less obvious background sources are discussed, especially in the context of future experiments. These include contamination of scintillation pulses with Cherenkov light from Compton electrons and from β activity internal to photomultipliers, which can increase the size and lower the apparent time constant of the scintillation response. Another challenge is posed by multiple-scatter γ-rays with one or more vertices in regions that yield no ionisation. If the discrimination power achieved in the first run can be replicated, ZEPLIN-III should reach a sensitivity of ~1 × 10 -8pb · yr to the scalar WIMP-nucleon elastic cross-section, as originally conceived. © 2011 Elsevier B.V. All rights reserved.
| Type: | Article |
|---|---|
| Title: | Radioactivity backgrounds in ZEPLIN-III |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.astropartphys.2011.11.001 |
| Publisher version: | https://doi.org/10.1016/j.astropartphys.2011.11.00... |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Liquid xenon detectors, Dark matter searches, ZEPLIN-III, Radioactivity, Background studies |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1352125 |
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