Publications
152 results found
Akerib DS, Akerlof CW, Akimov DY, et al., 2020, The LUX-ZEPLIN (LZ) experiment, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment, Vol: 953, Pages: 1-22, ISSN: 0168-9002
We describe the design and assembly of the LUX-ZEPLIN experiment, a direct detection search for cosmic WIMP dark matter particles. The centerpiece of the experiment is a large liquid xenon time projection chamber sensitive to low energy nuclear recoils. Rejection of backgrounds is enhanced by a Xe skin veto detector and by a liquid scintillator Outer Detector loaded with gadolinium for efficient neutron capture and tagging. LZ is located in the Davis Cavern at the 4850’ level of the Sanford Underground Research Facility in Lead, South Dakota, USA. We describe the major subsystems of the experiment and its key design features and requirements.
Akimov DY, Araújo HM, Barnes EJ, et al., 2012, WIMP-nucleon cross-section results from the second science run of ZEPLIN-III, Physics Letters B, Vol: 709, Pages: 14-20, ISSN: 0370-2693
Akimov DY, Araujo HM, Barnes EJ, et al., 2010, Limits on inelastic dark matter from ZEPLIN-III, Physics Letters B, Vol: 692, Pages: 180-183, ISSN: 0370-2693
We present limits on the WIMP–nucleon cross section for inelastic dark matter from a reanalysis of the2008 run of ZEPLIN-III. Cuts, notably on scintillation pulse shape and scintillation-to-ionisation ratio, givea net exposure of 63 kg day in the range 20–80 keV nuclear recoil energy, in which 6 events are observed.Upper limits on signal rate are derived from the maximum empty patch in the data. Under standard haloassumptions a small region of parameter space consistent, at 99% CL, with causing the 1.17 ton yr DAMAmodulation signal is allowed at 90% CL: it is in the mass range 45–60 GeVc−2 with a minimum CLof 87%, again derived from the maximum patch. This is the tightest constraint yet presented using xenon,a target nucleus whose similarity to iodine mitigiates systematic error from the assumed halo.
Lebedenko VN, Araujo HM, Barnes EJ, et al., 2009, Limits on the Spin-Dependent WIMP-Nucleon Cross Sections from the First Science Run of the ZEPLIN-III Experiment, PHYSICAL REVIEW LETTERS, Vol: 103, ISSN: 0031-9007
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- Citations: 48
Lebedenko VN, Araujo HM, Barnes EJ, et al., 2009, Results from the first science run of the ZEPLIN-III dark matter search experiment, Physical Review D- particles, fields, gravitation, and cosmology, Vol: 80, ISSN: 1550-7998
The ZEPLIN-III experiment in the Palmer Underground Laboratory at Boulby uses a 12 kg two-phasexenon time-projection chamber to search for the weakly interacting massive particles (WIMPs) that mayaccount for the dark matter of our Galaxy. The detector measures both scintillation and ionizationproduced by radiation interacting in the liquid to differentiate between the nuclear recoils expected fromWIMPs and the electron-recoil background signals down to 10 keV nuclear-recoil energy. An analysisof 847 kg days of data acquired between February 27, 2008, and May 20, 2008, has excluded a WIMPnucleonelastic scattering spin-independent cross section above 8:1 10 8 pb at 60 GeVc 2 with a 90%confidence limit. It has also demonstrated that the two-phase xenon technique is capable of betterdiscrimination between electron and nuclear recoils at low-energy than previously achieved by otherxenon-based experiments.
Alner GJ, Araujo HM, Bewick A, et al., 2009, ZEPLIN-II limits on WIMP-nucelon interactions, 8th UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, Publisher: AMER INST PHYSICS, Pages: 218-+, ISSN: 0094-243X
Alner GJ, Araujo HM, Bewick A, et al., 2008, The ZEPLIN II dark matter detector: Data acquisition system and data reduction, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 587, Pages: 101-109, ISSN: 0168-9002
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- Citations: 6
Sumneri TJ, Araujo HM, Bewick A, et al., 2007, The zeplin III detector: Results from surface calibrations, Pages: 288-295
ZEPLIN-I11 is a direct dark-matter search instrument using liquid xenon as a target. Both scintillation light and ionisation charge are measured. The instrument has been built and tested in a surface laboratory, and we present some of the results here, including design thermal control system verification, photomultiplier calibration and two-phase operation showing simultaneous measurement of scintillation and charge and position reconstruction.
Sumner TJ, Akimov DY, Alner GJ, et al., 2007, The ZEPLIN III detector; Results from surface calibrations, 7th UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, Publisher: ELSEVIER, Pages: 108-112, ISSN: 0920-5632
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- Citations: 1
Alner GJ, Araujo HM, Bewick A, et al., 2007, Limits on spin-dependent WIMP-nucleon cross-sections from the first ZEPLIN-II data, PHYSICS LETTERS B, Vol: 653, Pages: 161-166, ISSN: 0370-2693
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- Citations: 32
Alner GJ, Araujo HM, Bewick A, et al., 2007, First limits on WIMP nuclear recoil signals in ZEPLIN-II: A two-phase xenon detector for dark matter detection, Astroparticle Physics, Vol: 28, Pages: 287-302, ISSN: 1873-2852
Results are presented from the first underground data run of ZEPLIN-II, a 31 kg two-phase xenon detector developed to observe nuclear recoils from hypothetical weakly interacting massive dark matter particles. Discrimination between nuclear recoils and background electron recoils is afforded by recording both the scintillation and ionisation signals generated within the liquid xenon, with the ratio of these signals being different for the two classes of event. This ratio is calibrated for different incident species using an AmBe neutron source and 60Co γ-ray sources. From our first 31 live days of running ZEPLIN-II, the total exposure following the application of fiducial and stability cuts was 225 kg × days. A background population of radon progeny events was observed in this run, arising from radon emission in the gas purification getters, due to radon daughter ion decays on the surfaces of the walls of the chamber. An acceptance window, defined by the neutron calibration data, of 50% nuclear recoil acceptance between 5 keVee and 20 keVee, had an observed count of 29 events, with a summed expectation of 28.6 ± 4.3 γ-ray and radon progeny induced background events. These figures provide a 90% c.l. upper limit to the number of nuclear recoils of 10.4 events in this acceptance window, which converts to a WIMP–nucleon spin-independent cross-section with a minimum of 6.6×10−7 pb following the inclusion of an energy-dependent, calibrated, efficiency. A second run is currently underway in which the radon progeny will be eliminated, thereby removing the background population, with a projected sensitivity of 2×10−7 pb for similar exposures as the first run.
Akimov DY, Alner GJ, Araujo HM, et al., 2007, The ZEPLIN-III dark matter detector: Instrument design, manufacture and commissioning, Astroparticle Physics, Vol: 27, Pages: 46-60, ISSN: 1873-2852
We present details of the technical design, manufacture and testing of the ZEPLIN-III dark matter experiment. ZEPLIN-III is a twophasexenon detector which measures both the scintillation light and the ionisation charge generated in the liquid by interacting particlesand radiation. The instrument design is driven by both the physics requirements and by the technology requirements surrounding the useof liquid xenon. These include considerations of key performance parameters, such as the efficiency of scintillation light collection, restrictionsplaced on the use of materials to control the inherent radioactivity levels, attainment of high vacuum levels and chemical contaminationcontrol. The successful solution has involved a number of novel design and manufacturing features which will be of specific use tofuture generations of direct dark matter search experiments as they struggle with similar and progressively more demanding requirements.
Araujo HM, Akimov DY, Alner GJ, et al., 2006, The ZEPLIN-III dark matter detector: Performance study using an end-to-end simulation tool, Astroparticle Physics, Vol: 26, Pages: 140-153, ISSN: 1873-2852
We present results from a GEANT4-based Monte Carlo tool for end-to-end simulations of the ZEPLIN-III dark matter experiment.ZEPLIN-III is a two-phase detector which measures both the scintillation light and the ionisation charge generated in liquid xenon byinteracting particles and radiation. The software models the instrument response to radioactive backgrounds and calibration sources,including the generation, ray-tracing and detection of the primary and secondary scintillations in liquid and gaseous xenon, and subsequentprocessing by data acquisition electronics. A flexible user interface allows easy modification of detector parameters at run time.Realistic datasets can be produced to help with data analysis, an example of which is the position reconstruction algorithm developedfrom simulated data. We present a range of simulation results confirming the original design sensitivity of a few times 108 pb to theWIMP-nucleon cross-section.
Dawson JV, Howard AS, Akimov D, et al., 2005, A study of the scintillation induced by alpha particles and gamma rays in liquid xenon in an electric field, Nuclear Instruments & Methods in Physics Research Section A - Accelerators Spectrometers Detectors and Associated Equipment, Vol: 545, Pages: 690-698, ISSN: 0168-9002
Scintillation produced in liquid xenon by alpha particles and gamma rays has been studied as a function of applied electric field. For back scattered gamma rays with energy of about 200 keV, the number of scintillation photons was found to decrease by 64±2% with increasing field strength. Consequently, the pulse shape discrimination power between alpha particles and gamma rays is found to reduce with increasing field, but remaining non-zero at higher fields.
Alner GJ, Araujo HM, Arnison GJ, et al., 2005, Limits on WIMP cross-sections from the NAIAD experiment at the boulby underground laboratory, PHYS LETT B, Vol: 616, Pages: 17-24, ISSN: 0370-2693
The NAIAD experiment (NaI Advanced Detector) for WIMP dark matter searches at the Boulby Underground Laboratory (North Yorkshire, UK) ran from 2000 until 2003. A total of 44.9 kg x years of data collected with 2 encapsulated and 4 unencapsulated NaI(Tl) crystals with high light yield were included in the analysis. We present final results of this analysis carried out using pulse shape discrimination. No signal associated with nuclear recoils from WIMP interactions was observed in any run with any crystal. This allowed us to set upper limits on the WIMP-nucleon spin-independent and WIMP-proton spin-dependent cross-sections. The NAIAD experiment has so far imposed the most stringent constraints on the spin-dependent WIMP-proton cross-section. (c) 2005 Elsevier B.V. All rights reserved.
Alner GJ, Araujo H, Arnison GJ, et al., 2005, First limits on nuclear recoil events from the ZEPLIN I galactic dark matter detector, ASTROPARTICLE PHYSICS, Vol: 23, Pages: 444-462, ISSN: 0927-6505
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- Citations: 99
Alner GJ, Atac M, Bewick A, et al., 2005, Status of the ZEPLIN II experiment, 6th UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, Publisher: ELSEVIER SCI LTD, Pages: 259-263, ISSN: 1387-6473
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- Citations: 12
Alner GJ, Araujo H, Arnison GJ, et al., 2005, Nuclear recoil limits from the ZEPLIN I liquid xenon WIMP dark matter detector, 6th UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, Publisher: ELSEVIER SCI LTD, Pages: 245-249, ISSN: 1387-6473
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- Citations: 2
Alner GJ, Araujo HM, Arnison GJ, et al., 2005, Limits on wimp cross-sections from the NAIAD experiment at Boulby, Singapore, 5th international workshop on the identification of dark matter, 6 - 10 September 2004, Edinburgh, SCOTLAND, Publisher: World Scientific Publ Co Pte Ltd, Pages: 224-229
Alner GJ, Araujo HM, Arnison GJ, et al., 2005, Zeplin I: first limits on nuclear recoil rate, Singapore, 5th international workshop on the identification of dark matter, 6 - 10 September 2004, Edinburgh, SCOTLAND, Publisher: World Scientific Publ Co Pte Ltd, Pages: 218-223
Alner GJ, Araujo H, Ayad R, et al., 2004, The DRIFT-I dark matter detector at Boulby: design, installation and operation, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 535, Pages: 644-655, ISSN: 0168-9002
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- Citations: 35
Alner GJ, Araujo H, Ayad R, et al., 2004, The DRIFT-I dark matter detector at Boulby: Design, installation and operation, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol: 535, Pages: 644-655, ISSN: 0168-9002
DRIFT-I, the first full-scale gaseous dark matter detector, has recently been installed at ∼1100 m depth at the Boulby Underground Laboratory, UK. The DRIFT concept offers high background discrimination and sensitivity to the direction of WIMP-induced nuclear recoils, the latter being of particular importance in the search for evidence of WIMPs in our galaxy, In this paper we discuss the design of the DRIFT-I detector and its installation and operation at Boulby. We also present results of early engineering runs and outline plans for the future. © 2004 Elsevier B.V. All rights reserved.
Araujo HM, Bewick A, Davidge D, et al., 2004, Low-temperature study of 35 photomultiplier tubes for the ZEPLIN III experiment, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 521, Pages: 407-415, ISSN: 0168-9002
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- Citations: 21
Ahmed B, Alner GJ, Araujo H, et al., 2003, The NAIAD experiment for WIMP searches at Boulby mine and recent results, Astroparticle Physics, Vol: 19, Pages: 691-702, ISSN: 1873-2852
The NAIAD experiment (NaI Advanced Detector) for weakly interacting massive particle (WIMP) dark mattersearches at Boulby mine (UK) is described. The detector consists of an array of encapsulated and unencapsulatedNaI(Tl) crystals with high light yield. Six crystals are collecting data at present. Data accumulated by four of them (10.6kg year exposure) have been used to set upper limits on the WIMP–nucleon spin-independent and WIMP–protonspin-dependent cross-sections. Pulse shape analysis has been applied to discriminate between nuclear recoils, as may becaused by WIMP interactions, and electron recoils due to gamma background. Various calibrations of crystals arepresented.
Ahmed B, Alner GJ, Barton JC, et al., 2003, Recent results of the dark matter search with NaI(Tl) detectors at Boulby Mine, 5th International UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, Publisher: ELSEVIER SCIENCE BV, Pages: 193-196, ISSN: 0920-5632
Cline DB, Seo Y, Sergiampietri F, et al., 2003, Status of ZEPLIN II and ZEPLIN IV study, 5th International UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe, Publisher: ELSEVIER SCIENCE BV, Pages: 229-232, ISSN: 0920-5632
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- Citations: 19
Akimov DY, Bewick A, Danilov MV, et al., 2003, Development of a two-phase xenon dark matter detector, 3rd International Conference on Nonaccelerator New Physics, Publisher: MAIK NAUKA/INTERPERIODICA PUBL, Pages: 497-499, ISSN: 1063-7788
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- Citations: 2
Carson MJ, Davies JC, Gamble T, et al., 2003, NaIAD experiment for WIMP Search at Boulby mine and recent results, Proceedings of the fourth international workshop on the identification of dark matter, York, UK, 2 - 6 September 2002, Editors: Spooner, Kudryavtsev, Spooner, Kudryavtsev, Spooner, Kudryavtsev, Spooner, Kudryavtsev, River Edge, NJ, Publisher: World Scientific, Pages: 284-289, ISBN: 9789812382375
Akimov DY, Batyaev VF, Borovlev SP, et al., 2003, Liquid Xenon for WIMP searches: measurement with a two-phase prototype, River Edge, NJ, Proceedings of the fourth international workshop on the identification of dark matter, York, UK, 2 - 6 September 2002, Publisher: World Scientific, Pages: 371-376
Ditlov VA, Akimov DY, Danilov MV, et al., 2003, Three-dimensional reconstruction of event space coordinates in Xenon chamber, River Edge, NJ, 4th international workshop on the identification of dark matter, York, England, September 2002, Publisher: World Scientific, Pages: 383-389
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