Author: Timothy Beresford LawsonPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Development of a WIMP Dark Matter Detector with Direction Sensitivity
Author: Timothy Beresford LawsonPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Detector Development for Direction-sensitive Dark Matter Research
Author: Hidefumi TomitaPublisher:
ISBN:
Category :
Languages : en
Pages : 384
Book Description
Abstract: The existence of Dark Matter was first proposed by Fritz Zwicky in 1933, based on the observed velocity distribution of galaxies in the Coma Cluster. Subsequent studies of visible mass and velocity distributions in other galaxies have confirmed Zwicky's original observation; there is now little doubt that Dark Matter exists. However, due to the fact that Dark Matter interacts very weakly through non-gravitational forces, nothing is known about the nature of Dark Matter. It is believed that Dark Matter particles are streaming toward the Earth, in the Earth's rest frame, from the direction of the constellation Cygnus. Observation of this so-called Dark Matter 'wind' with a direction-sensitive dark matter particle detector would be compelling evidence that Dark Matter does consist of a gas of discrete particles as a new form of matter. The DMTPC collaboration is developing such a detector, and this thesis describes R&D work in support of that project. The DMTPC technique for looking for Dark Matter relies on Dark Matter particles interacting with atomic nuclei, causing the nuclei to recoil and to leave optical signals that can be detected. Since neutrons are electrically neutral and collide with nuclei, they can mimic Dark Matter signals. Therefore, the reduction of neutron background is critical to the successful detection and identification of Dark Matter particles. One important aspect of this thesis is to fully understand and quantify neutron interactions with our detector. In addition to providing information for understanding Dark Matter experiments, this work also allows us to understand how our device can be used as a neutron detector. We have been able to measure a number of neutron events in a variety of experimental runs both with and without neutron sources such as a neutron generator and 252 Cf. From these runs, we have obtained data for both elastic and inelastic interactions of neutrons of various energy ranges with detector gas nuclei. In this thesis, I will also discuss our current background data taking for the Dark Matter research and our plan for scaling up the detector to 100 m 3 for a competitive Dark Matter search.
Limits on Spin-dependent WIMP-proton Cross-sections Using the DRIFT-IId Directional Dark Matter Detector
Author: Mark PipePublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The nature of dark matter remains one of the biggest questions in physics today. Weakly Interacting Massive Particles (WIMPs) are a particularly well motivated candidate for the missing matter that makes up 85% of the mass of the Universe. The most promising method for an unambiguous proof of the existence of WIMPs is via detection of the predicted directional anisotropy. The DRIFT detector at the Boulby Underground Laboratory in the UK is the world's first large scale directionally sensitive dark matter detector. This thesis presents work focussing on the ability of DRIFT to be competitive with non-directional detectors in exploring new spin-dependent WIMP interaction phase-space. Experimental efforts towards this are discussed, including the first calibration measurements of spin-dependent target gases in DRIFT, and development and implementation of an automated gas mixing system required for spin-dependent gas mixture operation. This thesis presents the first long-term study of backgrounds in DRIFT in which current limiting backgrounds are identified and studied, providing information crucial to future background reduction strategies. Developments of the WIMP analysis procedure are presented that result in an improved sensitivity to WIMP-mimicking neutron-induced nuclear recoils by a factor of 2.4. Data from the first runs with spin-dependent sensitive CS2-CF4 gas mixtures are presented with improved analysis methods. This thesis presents the first blind analysis results from a directionally sensitive dark matter detector with upper limits on the SD WIMP-proton interaction cross-section with a minimum of 0.93 pb for a 100 GeV WIMP.
Directional Dark Matter Searches
Author: Chamkaur GhagPublisher: LAP Lambert Academic Publishing
ISBN: 9783843380607
Category :
Languages : en
Pages : 272
Book Description
Cold Dark Matter is believed to constitute almost a quarter of the Universe, most likely in the form of Weakly Interacting Massive Particles (WIMPs), predicted by supersymmetry. This thesis describes the simulation methods, analysis techniques, and results for the calibration of the DRIFT-IIA directional dark matter detector. This is the first module in an array of gas time projection chambers capable of searching for WIMPs with directional sensitivity, located in the Boulby mine. Future operation, development and expansion of the DRIFT-II array will lead to increased potential for directional dark matter detection.
Prototype Direction Sensitive, Solid-state Dark Matter Detector
Author: Misganaw GetanehPublisher:
ISBN:
Category : Physics
Languages : en
Pages : 306
Book Description
Particle Dark Matter
Author: Gianfranco BertonePublisher: Cambridge University Press
ISBN: 0521763681
Category : Science
Languages : en
Pages : 763
Book Description
Describes the dark matter problem in particle physics, astrophysics and cosmology for graduate students and researchers.
The DRIFT Dark Matter Project
Author: Steven James Sutherland PlankPublisher:
ISBN:
Category : Dark matter (Astronomy)
Languages : en
Pages : 211
Book Description
It is now largely accepted that dark matter, and more specifically, Weakly Interacting Massive Particles (WIMPs), constitute the majority of the mass in our Universe. Within this thesis are presented: (i) an overview of the motivation and evidence for the existence of dark matter; (ii) a detailed discussion of direct detection techniques and a worldwide review of WIMP search experiments; and (iii) new experimental measurements and complementary detailed numerical simulations, carried out by the author, to determine the performance of DRIFT experimental technology. Collectively, this work explores the capability of DRIFT technology to detect dark matter, and in doing so, to resolve one of the key open questions of contemporary science. The DRIFT programme consists of an array of direct dark matter search detectors located in the Boulby mine. An important limitation to the experiment is the neutron and gamma-ray background. Experimental work presented here has determined the U and Th content of the cavern rock to be 66±6 ppb and 145±13 ppb respectively, clarifying ambiguities in previous estimations. Through the use of a Monte Carlo simulation the neutron and gamma-ray background experienced by DRIFT has been determined and the experimental implications assessed. In addition, the activity of the main neutron calibration source used to calibrate DRIFT modules has been measured and was found to be 11600 n s-1±5% on the date of exposure, resolving an earlier discrepancy. Analysis of experimental data has confirmed that the technology employed by DRIFT detectors has the capability to provide directional information of recoiling nuclei at the low energies of interest to dark matter searches. A Monte Carlo simulation has then been employed to determine the WIMP-nucleon sensitivity achievable using DRIFT detectors of the present performance, also examining what would be achievable if this was supplemented by a realistic active neutron veto detector. It is found that a CS2-filled DRIFT type detector running at a 500 NIP threshold ( 16 keV and 27 keV for C and S recoils respectively) for 300 kg years, and surrounded by the proposed veto scheme, would expect to observe a background of six un-vetoed events. The minimum positive signal above this background (90% C.L.) would correspond to a WIMP-nucleon sensitivity limit of 1.75×10-9 pb. This identifies the realistic limit of what can be achieved using gaseous CS2 as a target medium. An investigation into the limits achievable using a similar array in which DRIFT modules act as self-vetoing detectors is also examined providing insight into the future development and operation of the DRIFT programme.
Neutrino Oscillations And Their Origin - Proceedings Of The Fifth International Workshop
Author: Yoichiro SuzukiPublisher: World Scientific
ISBN: 9814480215
Category : Science
Languages : en
Pages : 522
Book Description
This volume brings together international experts in diverse areas of physics to discuss recent progress in the experimental and theoretical study of neutrino oscillations.Readers are brought up to date with the latest developments in important neutrino experiments, and the associated progress in theory is summarized. The principal projects worldwide, such as Super-Kamiokande, SNO, KamLAND, are considered, and contributions also report on future experiments, including JPARC, OPERA, and MINOS.Several other related topics, such as dark matter, double beta decay, lepton flavor violation, and cosmology, are discussed, reflecting the wide-ranging specializations of many contributors outside of pure neutrino physics.
Identification Of Dark Matter, The - Proceedings Of The Fifth International Workshop
Author: Neil J C SpoonerPublisher: World Scientific
ISBN: 9814480304
Category : Science
Languages : en
Pages : 685
Book Description
The prestigious Identification of Dark Matter workshop series was initiated to assess the status of work that attempts to identify the constitution of dark matter. In particular, it aims to review the success of current methods that are used in the search for dark matter, as well as the new techniques that are likely to improve prospects for detecting possible dark matter candidates in the future. In the 5th International Workshop, special emphasis was placed on the recent results obtained in experiments searching for baryonic and non-baryonic dark matter. This volume comprises the high-quality review articles and papers contributed by leaders and promising young physicists who attended the conference. It provides the most recent updates on dark matter searches from both experimental and theoretical points of view.The proceedings have been selected for coverage in:• Index to Scientific & Technical Proceedings® (ISTP® / ISI Proceedings)• Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)• CC Proceedings — Engineering & Physical Sciences
Development and Performance of Detectors for the Cryogenic Dark Matter Search Experiment with an Increased Sensitivity Based on a Maximum Likelihood Analysis of BetaContamination
Author: Donald D. DriscollPublisher:
ISBN:
Category :
Languages : en
Pages : 175
Book Description
The Cryogenic Dark Matter Search (CDMS) uses cryogenically-cooled detectors made of germanium and silicon in an attempt to detect dark matter in the form of Weakly-Interacting Massive Particles (WIMPs). The expected interaction rate of these particles is on the order of 1/kg/day, far below the 200/kg/day expected rate of background interactions after passive shielding and an active cosmic ray muon veto. Our detectors are instrumented to make a simultaneous measurement of both the ionization energy and thermal energy deposited by the interaction of a particle with the crystal substrate. A comparison of these two quantities allows for the rejection of a background of electromagnetically-interacting particles at a level of better than 99.9%. The dominant remaining background at a depth of {approx} 11 m below the surface comes from fast neutrons produced by cosmic ray muons interacting in the rock surrounding the experiment. Contamination of our detectors by a beta emitter can add an unknown source of unrejected background. In the energy range of interest for a WIMP study, electrons will have a short penetration depth and preferentially interact near the surface. Some of the ionization signal can be lost to the charge contacts there and a decreased ionization signal relative to the thermal signal will cause a background event which interacts at the surface to be misidentified as a signal event. We can use information about the shape of the thermal signal pulse to discriminate against these surface events. Using a subset of our calibration set which contains a large fraction of electron events, we can characterize the expected behavior of surface events and construct a cut to remove them from our candidate signal events. This thesis describes the development of the 6 detectors (4 x 250 g Ge and 2 x 100 g Si) used in the 2001-2002 CDMS data run at the Stanford Underground Facility with a total of 119 livedays of data. The preliminary results presented are based on the first use of a beta-eliminating cut based on a maximum-likelihood characterization described above.