| Autor: |
Akimov, D. Yu., Araujo, H. M., Barnes, E. J., Belov, V. A., Burenkov, A. A., Chepel, V., Currie, A., Edwards, B., Francis, V., Ghag, C., Hollingsworth, A., Horn, M., Kalmus, G. E., Kobyakin, A. S., Kovalenko, A. G., Lebedenko, V. N., Lindote, A., Lopes, M. I., Luscher, R., Lyons, K., Majewski, P., Murphy, A. StJ., Neves, F., Paling, S. M., da Cunha, J. Pinto, Preece, R., Quenby, J. J., Reichhart, L., Scovell, P. R., Solovov, V. N., Smith, N. J. T., Smith, P. F., Stekhanov, V. N., Sumner, T. J., Taylor, R., Thorne, C., Walker, R. J. |
| Rok vydání: |
2010 |
| Předmět: |
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| Zdroj: |
Astroparticle Physics 34 (2010), pp. 151-163 |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1016/j.astropartphys.2010.06.010 |
| Popis: |
The design, optimisation and construction of an anti-coincidence veto detector to complement the ZEPLIN-III direct dark matter search instrument is described. One tonne of plastic scintillator is arranged into 52 bars individually read out by photomultipliers and coupled to a gadolinium-loaded passive polypropylene shield. Particular attention has been paid to radiological content. The overall aim has been to achieve a veto detector of low threshold and high efficiency without the creation of additional background in ZEPLIN-III, all at a reasonable cost. Extensive experimental measurements of the components have been made, including radioactivity levels and performance characteristics. These have been used to inform a complete end-to-end Monte Carlo simulation that has then been used to calculate the expected performance of the new instrument, both operating alone and as an anti-coincidence detector for ZEPLIN-III. The veto device will be capable of rejecting over 65% of coincident nuclear recoil events from neutron background in the energy range of interest in ZEPLIN-III. This will reduce the background in ZEPLIN-III from ~0.4 to ~0.14 events per year in the WIMP acceptance region, a significant factor in the event of a non-zero observation. Furthermore, in addition to providing valuable diagnostic capabilities, the veto is capable of tagging over 15% for gamma-ray rejection, all whilst contributing no significant additional background. In conjunction with the replacement of the internal ZEPLIN-III photomultiplier array, the new veto is expected to improve significantly the sensitivity of the ZEPLIN-III instrument to dark matter, allowing spin independent WIMP-nucleon cross sections below 1E-8 pb to be probed. |
| Databáze: |
arXiv |
| Externí odkaz: |
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