The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and ...proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of \(^{238}\)U\(_{e}\)~\(<\)1.6~mBq/kg, \(^{238}\)U\(_{l}\)~\(<\)0.09~mBq/kg, \(^{232}\)Th\(_{e}\)~\(=0.28\pm 0.03\)~mBq/kg, \(^{232}\)Th\(_{l}\)~\(=0.25\pm 0.02\)~mBq/kg, \(^{40}\)K~\(<\)0.54~mBq/kg, and \(^{60}\)Co~\(<\)0.02~mBq/kg (68\% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of \(0.160\pm0.001\)(stat)\(\pm0.030\)(sys) counts.
In this Technical Design Report (TDR) we describe the LZ detector to be built at the Sanford Underground Research Facility (SURF). The LZ dark matter experiment is designed to achieve sensitivity to ...a WIMP-nucleon spin-independent cross section of three times ten to the negative forty-eighth square centimeters.
The design and performance of the LUX-ZEPLIN (LZ) detector is described as of March 2015 in this Conceptual Design Report. LZ is a second-generation dark-matter detector with the potential for ...unprecedented sensitivity to weakly interacting massive particles (WIMPs) of masses from a few GeV/c2 to hundreds of TeV/c2. With total liquid xenon mass of about 10 tonnes, LZ will be the most sensitive experiment for WIMPs in this mass region by the end of the decade. This report describes in detail the design of the LZ technical systems. Expected backgrounds are quantified and the performance of the experiment is presented. The LZ detector will be located at the Sanford Underground Research Facility in South Dakota. The organization of the LZ Project and a summary of the expected cost and current schedule are given.
It is very difficult to remediate a 40-year old contamination site if there's no knowledge of the site's geology or extent of contamination and have limited resources. Researchers have addressed the ...decision-making part of this problem by developing a software package, 3D subsystem, that characterize the subsurface contamination of soil and groundwater based on collected data, creates 3D groundwater flow and solute transport models, provides input to a management decision process.
