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.
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 by interacting 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 subsequent processing 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 developed from simulated data. We present a range of simulation results confirming the original design sensitivity of a few times 10
−8
pb to the WIMP-nucleon cross-section.
We report the first results of the AMANDA detector. During the antarctic summer 1993-94 four strings were deployed between 0.8 an 1 km depth, each equipped with 20 photomultiplier tubes (PMTs). A ...laser source was used to investigate the optical properties of the ice
in situ. We find that the ice is intrinsically extremely transparent. The measured absorption length is 59 ± 3 m, i.e. comparable with the quality of the ultra-pure water used in the IMB and Kamiokande proton-decay and neutrino experiments 1,2 and more than two times longer than the best value reported for laboratory ice 3. Due to a residual density of air bubbles at these depths, the motion of photons in the medium is randomized. For spherical, smooth bubbles we find that, at 1 km depth, the average distance between collisions is about 25 cm. The measured inverse scattering length on bubbles decreases linearly with increasing depth in the volume of ice investigated.
Re-analysis of published data from the UKDMC NaI(Tl) dark matter experiment is presented using latest spin factors and comparison is made with the sensitivity predicted for NAIAD, a 100 kg NaI ...detector concept based on unencapsulated NaI(Tl). We present experimental results and Monte Carlo simulations for NAIAD and show that a factor of 1.5–2 improvement in energy threshold is achievable over conventional NaI dark matter detectors with consequent ∼50% improvement in nuclear recoil discrimination at 10 keV. An overall improvement in sensitivity to spin dependent WIMP interactions of factor 50, based on 100 kg×yrs of data, is predicted relative to previous UKDMC limits.
Preliminary results on position reconstruction for ZEPLIN III Lindote, A.; Araujo, H.M.; Pinto da Cunha, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2007, Letnik:
573, Številka:
1
Journal Article
Recenzirano
Odprti dostop
ZEPLIN III is a two-phase xenon detector for direct dark matter search that will look for rare nuclear recoils from elastic scattering of Weakly Interacting Massive Particles off xenon atoms. ZEPLIN ...III measures both the scintillation and ionisation signals produced in the liquid by the interacting particle. The prompt scintillation is detected by an array of 31 photomultipliers (PM) immersed in the liquid, and a strong electric field extracts the ionisation electrons to the vapour phase. Electroluminescence photons are produced in the gas and detected by the same PM array. In this paper we describe position reconstruction methods that use both these signals to achieve a position accuracy of a few millimetres in the horizontal plane and sub-millimetre in the vertical coordinate.
The first four strings of phototubes for the AMANDA high-energy neutrino observatory are now frozen in place at a depth of 800-1000 m in ice at the South Pole, During the 1995-96 season, as many as ...six more strings will be deployed at greater depths. Provided absorption, scattering and refraction of visible light are sufficiently small, the trajectory of a muon into which a neutrino converts can be determined by using the array of phototubes to measure the arrival times of Cherenkov light emitted by the muon. To help in deciding on the depth for implantation of the six new strings, we discuss models of age vs depth for South Pole ice, we estimate mean free paths for scattering from bubbles and dust as a function of depth and we assess distortion of light paths due to refraction at crystal boundaries and interfaces between air-hydrate inclusions and normal ice. We conclude that the interval 1600-2100 m will be suitably transparent for a future 1 km3 observatory except possibly in a region a few tens of meters thick at a depth corresponding to a peak in the dust concentration at 60 k year BP.
Measurements of cosmic-ray muon rates and energy deposition spectra in a
1
t
liquid scintillator detector at
1070
m
vertical depth in the Boulby underground laboratory are discussed. In addition, the ...simulations used to model the detector are described. The results of the simulations are compared to the experimental data and conclusions given. The muon flux in the laboratory is found to be
(4.09±0.15)×10
−8
cm
−2
s
−1
.
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