@article{f541d43850484851800dc70cffd2cbd0,
title = "Performance of the veto detector incorporated into the ZEPLIN-III experiment",
abstract = "The ZEPLIN-III experiment is operating in its second phase at the Boulby Underground Laboratory in search of dark matter WIMPs. The major upgrades to the instrument over its first science run include lower background photomultiplier tubes and installation of a plastic scintillator veto system. Performance results from the veto detector using calibration and science data in its first six months of operation in coincidence with ZEPLIN-III are presented. With fully automated operation and calibration, the veto system has maintained high stability and achieves near unity live time relative to ZEPLIN-III. Calibrations with a neutron source demonstrate a rejection of 60% of neutron-induced nuclear recoils in ZEPLIN-III that might otherwise be misidentified as WIMPs. This tagging efficiency reduces the expected untagged nuclear recoil background from neutrons during science data taking to a very low rate of ≃0.2 events per year in the WIMP acceptance region. Additionally, the veto detector provides rejection of 28% of γ-ray induced background events, allowing the sampling of the dominant source of background in ZEPLIN-III - multiple scatter γ-rays with rare topologies. Since WIMPs will not be tagged by the veto detector, and tags due to γ-rays and neutrons are separable, this population of multiple scatter events may be characterised without biasing the analysis of candidate WIMP signals in the data.",
author = "C. Ghag and Akimov, {D. Yu} and Ara{\'u}jo, {H. M.} and Barnes, {E. J.} and Belov, {V. A.} and Burenkov, {A. A.} and V. Chepel and A. Currie and L. Deviveiros and B. Edwards and V. Francis and A. Hollingsworth and M. Horn and Kalmus, {G. E.} and Kobyakin, {A. S.} and Kovalenko, {A. G.} and Lebedenko, {V. N.} and A. Lindote and Lopes, {M. I.} and R. L{\"u}scher and K. Lyons and P. Majewski and Murphy, {A. St J.} and F. Neves and Paling, {S. M.} and {Pinto Da Cunha}, J. and R. Preece and Quenby, {J. J.} and L. Reichhart and Scovell, {P. R.} and C. Silva and Solovov, {V. N.} and Smith, {N. J.T.} and Smith, {P. F.} and Stekhanov, {V. N.} and Sumner, {T. J.} and C. Thorne and Walker, {R. J.}",
note = "Funding Information: The UK groups acknowledge the support of the Science & Technology Facilities Council (STFC) for the ZEPLIN-III project and for maintenance and operation of the underground Palmer laboratory which is hosted by Cleveland Potash Ltd. (CPL) at Boulby Mine, near Whitby on the North-East coast of England. The project would not be possible without the co-operation of the management and staff of CPL. We also acknowledge support from a Joint International Project award, held at ITEP and Imperial College, from the Russian Foundation of Basic Research (08-02-91851 KO_a) and the Royal Society. LIP–Coimbra acknowledges financial support from Funda{\c c}{\~a}o para a Ci{\^e}ncia e Tecnologia (FCT) through the project-grants CERN/FP/109320/2009 and CERN/FP/116374/2010, as well as the postdoctoral grants SFRH/BPD/27054/2006, SFRH/BPD/47320/2008 and SFRH/BPD/63096/2009. This work was supported in part by SC Rosatom , contract #H.4e.45.90.10.1053 from 03.02.2010. The University of Edinburgh is a charitable body, registered in Scotland, with the registration number SC005336.",
year = "2011",
month = sep,
doi = "10.1016/j.astropartphys.2011.06.006",
language = "English (US)",
volume = "35",
pages = "76--86",
journal = "Astroparticle Physics",
issn = "0927-6505",
publisher = "Elsevier B.V.",
number = "2",
}