Download or read book Huguenot Society of America Membership Application of Joseph N Wright of Trenton New Jersey Descendant of Isaac Garnee written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Extending the Sensitivity to the Detection of WIMP Dark Matter with an Improved Understanding of the Limiting Neutron Backgrounds written by Sharmila Kamat and published by . This book was released on 2005 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Edge of Physics written by Anil Ananthaswamy and published by Houghton Mifflin Harcourt. This book was released on 2011 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: The story of modern cosmology told through a tour of the most extraordinary detectors and telescopes in the world.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2005 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deep Underground Science and Engineering Lab written by H. Nelson and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this report we have described the broad and compelling range of astrophysical and cosmological evidence that defines the dark matter problem, and the WIMP hypothesis, which offers a solution rooted in applying fundamental physics to the dynamics of the early universe. The WIMP hypothesis is being vigorously pursued, with a steady march of sensitivity improvements coming both from astrophysical searches and laboratory efforts. The connections between these approaches are profound and will reveal new information from physics at the smallest scales to the origin and workings of the entire universe. Direct searches for WIMP dark matter require sensitive detectors that have immunity to electromagnetic backgrounds, and are located in deep underground laboratories to reduce the flux from fast cosmic-ray-muon-induced neutrons which is a common background to all detection methods. With US leadership in dark matter searches and detector R & D, a new national laboratory will lay the foundation of technical support and facilities for the next generation of scientists and experiments in this field, and act as magnet for international cooperation and continued US leadership. The requirements of depth, space and technical support for the laboratory are fairly generic, regardless of the approach. Current experiments and upgraded versions that run within the next few years will probe cross sections on the 10{sup -45}-10{sup -44} cm{sup 2} scale, where depths of 3000-4000 m.w.e. are sufficient to suppress the neutron background. On the longer term, greater depths on the 5000-6000 level are desirable as cross sections down to 10{sup -46} cm{sup 2} are probed, and of course, if WIMPs are discovered then building up a statistical sample free of neutron backgrounds will be essential to extracting model parameters and providing a robust solution to the dark matter problem. While most of the detector technologies are of comparable physical scale, i.e., the various liquid and solid-state detector media under consideration have comparable density, a notable exception is the low-pressure gaseous detectors. These detectors are very likely to play a critical role in establishing the galactic origin of a signal, and so it is important to design the lab with this capability in mind. For example, for a WIMP-nucleon cross section of 10{sup -43} cm{sup 2} (just below the present limit [20]), 100 of the current DRIFT-II modules of 1 m{sup 3} at 40 torr CS{sub 2} [63] would require a two-year exposure [61] to get the approximately 200 events [64] required to establish the signal's galactic origin. While detector improvements are under investigation, a simple scaling for the bottom of the MSSM region at 10{sup -46} cm{sup 2} would require a 100,000 m{sup 3} detector volume. If a factor of 10 reduction in required volume is achieved (e.g., higher pressure operation, more detailed track reconstruction, etc.) then an experimental hall of (50 m){sup 3} could accommodate the experiment. Because the WIMP-nucleon cross section is unknown, it is impossible to make a definitive statement as to the ultimate requirements for a directional gaseous dark matter detector, or any other device, for that matter. What is clear, however, is that whatever confidence one gives to specific theoretical considerations, the foregoing discussion clearly indicates the high scientific priority of, broad intellectual interest in, and expanding technical capabilities for increasing the ultimate reach of direct searches for WIMP dark matter. Upcoming experiments will advance into the low-mass Supersymmetric region and explore the most favored models in a complementary way to the LHC, and on a similar time scale. The combination of astrophysical searches and accelerator experiments stands to check the consistency of the solution to the dark matter problem and provide powerful constraints on the model parameters. Knowledge of the particle properties from laboratory measurements will help to isolate and reduce the astrophysical uncertainties, which will allow a more complete picture of the galactic halo and could eventually differentiate between, say, infall versus isothermal models of galaxy formation. The scientific landscape of dark matter, which spans particle physics, astrophysics and cosmology, is very rich and interwoven. Exploring this exciting program following an initial detection will need many observables and hence a range of capabilities for followup experiments including different targets to sort out the mass and coupling of the WIMP, and directional sensitivity to confirm its galactic origin and open the age of WIMP astronomy. Clearly, this broad and fascinating program is ideally suited to the multi-decade span of DUSEL.

Download or read book Limits on Spin dependent WIMP proton Cross sections Using the DRIFT IId Directional Dark Matter Detector written by Mark Pipe and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book First 5 Tower WIMP search Results from the Cryogenic Dark Matter Search with Improved Understanding of Neutron Backgrounds and Benchmarking written by Raul Hennings-Yeomans and published by . This book was released on 2009 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improved Limits On The Existence Of Dark Matter written by and published by . This book was released on 2015 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: The final results of the PICASSO experiment, with 409 kg days of exposure collected from November 2012 to January 2014, have yielded new limits for Spin-Dependent and Spin-Independent Dark Matter interactions.\\ The data collected and the various backgrounds were assiduously studied using Monte Carlo simulations and a new set of sophisticated analysis techniques including the wavelet analysis presented in this thesis. In general, a good suppression of most backgrounds was attained. The neutron background event rate was reduced to about a factor of 10 compared to the previous phase of the experiment. Electronic and acoustic noise events were thoroughly suppressed. A new class of ``mystery events'' were removed as well. All that remained was the irreducible alpha background.\\ No signal consistent with a WIMP Dark Matter hypothesis was observed. Consequently, an exclusion curve was obtained with a minimum limit at ${90\%}$ C.L. of ${\sigma_{\chi p}^{SD} =0.0228}$ pb at a WIMP mass of 20 GeV/$c^2$ in the Spin-Dependent sector. By combining results from 2012 and the current results, an improved constraint of ${\sigma_{\chi p}^{SD}}$(90${\%}$ C.L.) ${=0.0188}$ pb at 20 GeV/$c^2$ was placed on the Dark Matter interaction with protons in the Fluorine nuclei used in the detectors.\\ In addition, the new limits on WIMP-proton interactions in the Spin Independent sector exclude the DAMA/LIBRA results (at ${90\%}$ C.L.) for low masses below 12 GeV/$c^2$ and further constrain the published CRESST and CDMS Si discovery regions at low WIMP masses.

Download or read book The DRIFT Dark Matter Project written by Steven James Sutherland Plank and published by . This book was released on 2008 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Heavy WIMP Effective Theory written by Mikhail P. Solon and published by Springer. This book was released on 2016-02-22 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is about dark matter’s particle nature and the implications of a new symmetry that appears when a hypothetical dark matter particle is heavy compared to known elementary particles. Dark matter exists and composes about 85% of the matter in the universe, but it cannot be explained in terms of the known elementary particles. Discovering dark matter's particle nature is one of the most pressing open problems in particle physics. This thesis derives the implications of a new symmetry that appears when the hypothetical dark matter particle is heavy compared to the known elementary particles, a situation which is well motivated by the null results of searches at the LHC and elsewhere. The new symmetry predicts a universal interaction between dark matter and ordinary matter, which in turn may be used to determine the event rate and detectable energy in dark matter direct detection experiments. The computation of heavy wino and higgsino dark matter presented in this work has become a benchmark for the field of direct detection. This thesis has also spawned a new field of investigation in dark matter indirect detection, determining heavy WIMP annihilation rates using effective field theory methods. It describes a new formalism for implementing Lorentz invariance constraints in nonrelativistic theories, with a surprising result at 1/M^4 order that contradicts the prevailing ansatz in the past 20 years of heavy quark literature. The author has also derived new perturbative QCD results to provide the definitive analysis of key Standard Model observables such as heavy quark scalar matrix elements of the nucleon. This is an influential thesis, with impacts in dark matter phenomenology, field theory formalism and precision hadronic physics.

Download or read book Production Yield of Muon Induced Neutrons in Lead written by Holger Kluck and published by Springer. This book was released on 2015-07-28 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this book is a major step towards understanding and eventually suppressing background in the direct search for dark matter particles scattering off germanium detectors. Although the flux of cosmic muons is reduced by many orders of magnitude in underground laboratories, the remaining energetic muons induce neutrons through various processes, neutrons that can potentially mimic a dark matter signal. This thesis describes the measurement of muon-induced neutrons over more than 3 years in the Modane underground laboratory. The data are complemented by a thorough modeling of the neutron signal using the GEANT4 simulation package, demonstrating the appropriateness of this tool to model these rare processes. As a result, a precise neutron production yield can be presented. Thus, future underground experiments will be able to reliably model the expected rate of muon-induced neutrons, making it possible to develop the necessary shielding concept to suppress this background component.

Download or read book Low Temperature Detectors for Neutrinos and Dark Matter II written by Luis Gonzalez-Mestres and published by Atlantica Séguier Frontières. This book was released on 1988 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Calibrations for the Improved Search for Dark Matter with the LZ LUX ZEPLIN Experiment written by Madan K. Sharma Timalsina and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A hypothetical non-luminous existence of matter is known as dark matter, inferred by the convincing collection of astrophysical and cosmological indirect evidence. In spite of compelling indirect observations, the physical nature of dark matter remains one of the most profound questions in the field of modern physics. A Weakly Interacting Massive Particle (WIMP) is historically the most favored candidate particle for dark matter, which could nicely explain the observed indirect measurements with the direct detection of WIMPs for the first time. The new second-generation direct detection dark matter experiment LZ (LUXZEPLIN), designed for direct detection of WIMP dark matter, has performed the most sensitive search for spin-independent WIMP-nucleon interactions. LZ is located 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. LZ is employing a two-phase xenon detector with an active mass of 7 tonnes. With LZ we have recently managed in the summer of 2022 to provide the most rigorous exclusion limit for spin-independent WIMP-nucleon scattering with an upper limit on the cross-section of 6.5×10−48 cm2 (90 % confidence level) for a WIMP mass of 30 GeV/c2 . The first WIMP search result of LZ utilizes a fiducial mass of 5.5 tonnes of liquid xenon and an exposure time of 60 live days. WIMPs could interact in the cryogenic liquid xenon of the detector’s core by scattering off xenon nuclei, which would then recoil and produce both scintillation light and electric charge. The ratio of the immediately detected scintillation light (S1) and the delayed charge detection (S2) is characteristic for such a nuclear recoil (NR) from hypothesized dark matter, e.g. a WIMP, and differs significantly from an electron recoil (ER) produced by undesired background reactions. However, the precise knowledge of the energy-dependent ratio S1/S2, for which the ER-dominated regime transitions into the NR-dominated regime, is key hereby to separate WIMP dark matter signals from unwanted background signals. We performed calibrations with neutron sources to map out the NR signal region for the WIMP search. Instead, gamma- and beta-ray calibration sources were utilized to map out the ER region, characteristic for background signals to be discriminated against. In this thesis, the calibration data to map out the NR signal region has been extensively studied and compared to the results of a full LZ detector simulation. In addition, another crucial detector calibration, for which all LZ data has to be corrected, is the purity monitoring of the liquid xenon. The chemical purity determines the lifetime of signal electrons against the absorption on impurities during their drift within the liquid xenon time projection chamber of the LZ detector. This electron lifetime analysis has been performed on a daily basis within the framework of this thesis and results have been applied by every data evaluator within the large LZ collaboration and for obtaining the current world’s best exclusion limit on WIMP dark matter.

Download or read book Characterizing the Peripheral Dynamics of Xenon Dark Matter Detectors written by Jacob Edward Cutter and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most important fundamental problems in physics today is to understand the nature of dark matter. The landscape of explanations for observed dark matter phenomena is vast and still expanding, and an impressive number of experiments have been built to probe the dark sector of the universe. A prominent class of detectors is aimed at discovering (or excluding) a particular kind of dark matter: the Weakly Interacting Massive Particle (WIMP). Searching for this popular dark matter candidate requires an ultra-sensitive, low-background target; xenon detectors serve as such a target for dark matter interactions. The Large Underground Xenon (LUX) detector is a dual-phase xenon time-projection chamber (TPC) which was operated underground at the Homestake Mine in Lead, South Dakota from 2013 to 2016, and was able to achieve the world's leading WIMP exclusion limit. However, successful reconstruction of WIMP-nucleus scatters in such detectors requires thorough understanding of the detection medium, which is made difficult by various confounding effects near the detector walls. Field-fringing is a major component of confusion in the periphery, and the large electric field non-uniformities in Run 4 of LUX provided a significant challenge in the dark matter analysis. Here is presented an algorithm to bijectively map between reconstructed event positions and true spatial coordinates, which serves as an important tool for studying field effects and fiducialization in LUX. Additionally, a successful dark matter search must model interfering background events in the WIMP search region which can't be directly vetoed. One class of unavoidable backgrounds comes from nuclear decay chain daughters in detector materials themselves, which may produce WIMP-like signals (an effect which is amplified due to various detector effects). The Davis Xenon (DAX) test bed system and a dual-phase TPC have been assembled and operated at UC Davis to characterize these common "wall backgrounds", as well as perform other R&D studies for the next-generation LUX-ZEPLIN (LZ) experiment. The DAX TPC specifically measures the xenon response to heavy nuclei produced by custom [alpha] decay sources created using novel chemical deposition procedures. In this thesis, results will be presented for the light and charge yields of immersed localized sources of 206Pb ions in liquid xenon, as well as a method for tagging such recoil events in situ by using PIN diodes as charged particle detectors to capture the correlated [alpha] particles. We also compare our isolated 206Pb events with previous WIMP search data from LUX, and discuss the significance of 206Pb as a WIMP background. Such information is most useful to future experiments if it can improve existing background models and simulations. The Noble Element Simulation Technique (NEST) is the ultimate software package for calculating expected signal yields in xenon detectors, but is an empirical framework that relies on experimental data to inform the models. We discuss the development of current NEST v2 models, specifically the heavy nuclear recoil models, as well as our current understanding of the xenon microphysics. We also show NEST predictions for mono-energetic 206Pb recoils, and discuss how our most recent DAX 206Pb measurements may inform NEST models in future work.

Download or read book Searching for Dark Matter with Superheated Liquid Detectors written by Arthur Plante and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dark Matter Limits From a 2L C3F8 Filled Bubble Chamber written by and published by . This book was released on 2015 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: The PICO-2L C3F8 bubble chamber search forWeakly Interacting Massive Particle (WIMP) dark matter was operated in the SNOLAB underground laboratory at the same location as the previous CF3I lled COUPP-4kg detector. Neutron calibrations using photoneutron sources in C3F8 and CF3I lled calibration bubble chambers were performed to verify the sensitivity of these target uids to dark matter scattering. This data was combined with similar measurements using a low-energy neutron beam at the University of Montreal and in situ calibrations of the PICO-2L and COUPP-4kg detectors. C3F8 provides much greater sensitivity to WIMP-proton scattering than CF3I in bubble chamber detectors. PICO-2L searched for dark matter recoils with energy thresholds below 10 keV. Radiopurity assays of detector materials were performed and the expected neutron recoil background was evaluated to be 1.6+0:3.

Download or read book Dark Matter Neutrinos and Our Solar System written by Nirmala Prakash and published by World Scientific. This book was released on 2013 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes these issues in terms of links, between cosmology, particle and nuclear physics, as well as between cosmology, atmospheric and terrestrial physics. It studies the constituents of dark matter (classified as hot warm and cold) first in terms of their individual structures, and second, in terms of facilities available to detect these structures. Neutrinos are treated as a separate entity. The last chapter details the real-time stories about the "regions" that were not explored thus far, for lack of advanced technology. Their untold stories (which span up to 2010) are illustrated here datewise in full. The book concludes with the latest news that the Large Hadron Collider team at CERN has finally succeeded in producing 7 trillion electronic Volts of energy by creating head-on-collisions of protons and more protons (in search of God-particle).