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[en] The GERDA experiment is attempting to measure neutrinoless double beta decay by using Germanium semiconductor detectors which are deployed naked in a volume of liquid Argon (LAr), which acts both as cryogenic cooling and background shield. The experiment recently started its first phase with eight enriched 76Ge detectors and is aiming to test the claims from parts of the Heidelberg Moscow Collaboration. The experiment is now exploring the possibility for instrumenting the LAr as an active veto using the scintillation light produced from energy deposition of background events. In order to optimize the veto design, an accurate knowledge of the LAr optical properties has to be achieved for the specific composition used in GERDA, as these are strongly affected by impurities. This talk covers the steps taken in the design of a method to perform the measurement of the LAr properties in GERDA, with particular emphasis on the in-situ measurement of the LAr attenuation length and light yield.
[en] The characteristics of the first excimer laser and the history of its creation are presented. The threshold lasing conditions and the modern theory of active media are considered, and the prospects for the development of excimer lasers operating on condensed inert gases are discussed. It is shown that in experiments on pumping liquid xenon, lasing was obtained simultaneously on excimers of several types, including excimers in liquid and gas phases. (special issue devoted to the 80th anniversary of academician n g basov's birth)
[en] We report the long term performance of the photosensors, 143 one-inch R8520-406 and 37 three-inch R11410-MOD photomultipliers from Hamamatsu, in the first phase of the PandaX dual-phase xenon dark matter experiment. This is the first time that a significant number of R11410 photomultiplier tubes were operated in liquid xenon for an extended period, providing important guidance to the future large xenon-based dark matter experiments
[en] We present an open source slow control system for small and medium scale projects. Thanks to its modular and flexible design, where the various instruments are read and controlled by independent plugins, Doberman (Detector OBsERving and Monitoring ApplicatioN) can be quickly adapted for many applications, also making use of existing code or proprietary components. The system uses a SQL database to store the data from the instruments and provides an online application to display and browse through the data. It allows the modification of device settings while the program is running and features a protocol to handle exceptions, including the automated distribution of alarm messages. We present two case studies from astroparticle physics, on which Doberman is successfully deployed: a low-background screening facility installed in a remote underground laboratory and a detector R and D platform using cryogenic liquid xenon.
[en] An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of "2"2"2Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of >or similar 4 for the "2"2"2Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based α-detector and miniaturized proportional counters are used to detect the radon. As the radon depletion in the boil-off gas is understood as a single-stage distillation process, this result establishes the suitability of cryogenic distillation to separate radon from xenon down to the 10"-"1"5 mol/mol level. (orig.)
[en] We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employed a cryostat cooled by liquid nitrogen combined with a xenon purification and chiller system. A modified Bridgeman's technique reproduces a large scale optically transparent solid xenon
[en] The Department of Energy (DOE) proposes to continue the capability to conduct Spill testing at the Nevada Test Site for the purpose of generating data needed to assess risks from accidental releases of hazardous and toxic materials. The testing would be conducted at the existing Liquefied Gaseous Fuels Spill Test Facility located on Frenchman Flat. The Liquefied Gaseous Fuels Spill Test Facility is located in Area 5, along the eastern edge of the Nevada Test Site, Nye County, Nevada, on the western edge of the desert playa, Frenchman Lake. The establishment of an equivalent facility at another location is not an alternative being considered by the DOE; a comprehensive site selection process in 1983 found Frenchman Flat to be the most suitable site for spill testing of relatively large quantities of hazardous materials. Spill tests were conducted at the site in 1986, 1987, 1988, 1990, 1991, and 1992. The experience gained from these tests, coupled with the documented results of no measurable or noticeable impact to the environment, provides the basis for this assessment. The procedural controls that limit downwind concentrations to predetermined values for each test would allow testing of a wide variety of hazardous materials to continue with the safety and negligible impacts experienced in previous tests. This environmental assessment draws heavily on the very thorough environmental assessment prepared by Lawrence Livermore National Laboratories in 1986, especially for the description of the affected environment. New information has been added regarding the existing environment and current land use