A Modified Detector Concept for SuperCDMS: The HiZIP and Its Charge Performance

dc.contributor.authorPage, Kedar Mohanen
dc.contributor.departmentPhysics, Engineering Physics and Astronomyen
dc.contributor.supervisorRau, Wolfgangen
dc.date2013-09-30 23:48:49.375
dc.date.accessioned2013-10-03T19:23:03Z
dc.date.available2013-10-03T19:23:03Z
dc.date.issued2013-10-03
dc.degree.grantorQueen's University at Kingstonen
dc.descriptionThesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2013-09-30 23:48:49.375en
dc.description.abstractSuperCDMS is a leading direct dark matter search experiment which uses solid state detectors (Ge crystals) at milliKelvin temperatures to look for nuclear recoils caused by dark matter interactions in the detector. ‘Weakly Interacting Massive Particles’ (WIMPs) are the most favoured dark matter candidate particles. SuperCDMS, like many other direct dark matter search experiments, primarily looks for WIMPs. The measurement of both the ionization and the lattice vibration (phonon) signals from an interaction in the detector allow it to discriminate against electron recoils which are the main source of background for WIMP detection. SuperCDMS currently operates about 9 kgs worth of germanium detectors at the Soudan underground lab in northern Minnesota. In its next phase, SuperCDMS SNOLAB, it plans to use 100-200 kg of target mass (Ge) which would allow it to probe more of the interesting and unexplored parameter space for WIMPs predicted by theoretical models. The SuperCDMS Queen’s Test Facility is a detector testing facility which is intended to serve detector testing and detector research and development purposes for the SuperCDMS experiment. A modified detector called the ‘HiZIP’ (Half-iZIP), which is reduced in complexity in comparison to the currently used iZIP (interleaved Z-sensitive Ionization and Phonon mediated) detectors, is studied in this thesis. The HiZIP detector design also serves to discriminate against background from multiple scatter events occurring close to the surfaces in a single detector. Studies carried out to compare the surface event leakage in the HiZIP detector using limited information from iZIP data taken at SuperCDMS test facility at UC Berkley produce a highly conservative upper limit of 5 out of 10,000 events at 90% confidence level. This upper limit is the best among many different HiZIP configurations that were investigated and is comparable to the upper limit calculated for an iZIP detector in the same way using the same data. A real HiZIP device operated at Queen’s Test Facility produced an exposure limited 90% upper limit of about 1 in 100 events for surface event leakage. The data used in these studies contain true nuclear recoil events from cosmogenic and ambient neutrons. This background was not subtracted in the calculation of the upper limits stated above and hence they are highly conservative. A surface event source was produced by depositing lead-210 from radon exposure onto a copper plate. This source was then used to take data for a surface event discrimination study of the HiZIP detector operated at Queen’s Test Facility. A study of the contribution of the noise from capacitive crosstalk between charge sensors in a HiZIP detector configuration was investigated, confirming the expectation that no significant drop in performance is to be expected due to this effect.en
dc.description.degreeM.Sc.en
dc.identifier.urihttp://hdl.handle.net/1974/8394
dc.language.isoengen
dc.relation.ispartofseriesCanadian thesesen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectcryogenic detectoren
dc.subjectSuperCDMSen
dc.subjectparticle detectoren
dc.subjectdark matteren
dc.subjectWIMP searchen
dc.titleA Modified Detector Concept for SuperCDMS: The HiZIP and Its Charge Performanceen
dc.typethesisen
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