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The Cryogenic Dark Matter Search Cdms
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Book Synopsis The Cryogenic Dark Matter Search (CDMS-II) Experiment - First Results from the Soudan Mine by : Clarence Leeder Chang
Download or read book The Cryogenic Dark Matter Search (CDMS-II) Experiment - First Results from the Soudan Mine written by Clarence Leeder Chang and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis First Results from the Cryogenic Dark Matter Search Experiment at the Deep Site by :
Download or read book First Results from the Cryogenic Dark Matter Search Experiment at the Deep Site written by and published by . This book was released on 2004 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cryogenic Dark Matter Search (CDMS) experiment is designed to search for dark matter in the form of the Weakly Interacting Massive Particles (WIMPs). For this purpose, CDMS uses detectors based on crystals of Ge and Si, operated at the temperature of 20 mK, and providing a two-fold signature of an interaction: the ionization and the athermal phonon signals. The two signals, along with the passive and active shielding of the experimental setup, and with the underground experimental sites, allow very effective suppression and rejection of different types of backgrounds. This dissertation presents the commissioning and the results of the first WIMP-search run performed by the CDMS collaboration at the deep underground site at the Soudan mine in Minnesota. We develop different methods of suppressing the dominant background due to the electron-recoil events taking place at the detector surface and we apply these algorithms to the data set. These results place the world's most sensitive limits on the WIMP-nucleon spin-independent elastic-scattering cross-section. Finally, they examine the compatibility of the supersymmetric WIMP-models with the direct-detection experiments (such as CDMS) and discuss the implications of the new CDMS result on these models.
Book Synopsis Cryogenic Dark Matter Search (CDMS) by :
Download or read book Cryogenic Dark Matter Search (CDMS) written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Deciphering the nature of dark matter has great scientific importance. A leading hypothesis is that dark matter is made of Weakly Interactive Massive Particles (WIMPs), which may result from supersymmetry or additional spatial dimensions. The underground search for elastic scattering of WIMPs on suitable targets (the so-called 'direct detection') is currently led by the Cryogenic Dark Matter Search II (CDMS II) experiment. Its sensitivity is ten times better than any other experiment and we hope to obtain another factor ten in the coming two years. After a brief recall of our recent results, I will describe the complementarity between direct detection experiments, the LHC and the ILC and I will outline the role that SLAC could play in this SuperCDMS program.
Book Synopsis The Cryogenic Dark Matter Search (CDMS) by : Peter David Barnes
Download or read book The Cryogenic Dark Matter Search (CDMS) written by Peter David Barnes and published by . This book was released on 1996 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Cryogenic Dark Matter Search by :
Download or read book The Cryogenic Dark Matter Search written by and published by . This book was released on 2010 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cryogenic Dark Matter Search (CDMS) is searching for Weakly Interacting Massive Particles (WIMPs) with cryogenic particle detectors. These detectors have the ability to discriminate between nuclear recoil candidate and electron recoil background events by collecting both phonon and ionization energy from recoils in the detector crystals. The CDMS-II experiment has completed analysis of the first data runs with 30 semiconductor detectors at the Soudan Underground Laboratory, resulting in a world leading WIMP-nucleon spin-independent cross section limit for WIMP masses above 44 GeV/c2. As CDMS aims to achieve greater WIMP sensitivity, it is necessary to increase the detector mass and discrimination between signal and background events. Incomplete ionization collection results in the largest background in the CDMS detectors as this causes electron recoil background interactions to appear as false candidate events. Two primary causes of incomplete ionization collection are surface and bulk trapping. Recent work has been focused on reducing surface trapping through the modification of fabrication methods for future detectors. Analyzing data taken with test devices has shown that hydrogen passivation of the amorphous silicon blocking layer worsens surface trapping. Additional data has shown that the iron-ion implantation used to lower the critical temperature of the tungsten transition-edge sensors causes a degradation of the ionization collection. Using selective implantation on future detectors may improve ionization collection for events near the phonon side detector surface. Bulk trapping is minimized by neutralizing ionized lattice impurities. Detector investigations at testing facilities and in situ at the experimental site have provided methods to optimize the neutralization process and monitor running conditions to maintain full ionization collection. This work details my contribution to the 5-tower data taking, monitoring, and analysis effort as well as the SuperCDMS detector development with the focus on monitoring and improving ionization collection in the detectors.
Book Synopsis Low-Mass Dark Matter Search Results and Radiogenic Backgrounds for the Cryogenic Dark Matter Search by :
Download or read book Low-Mass Dark Matter Search Results and Radiogenic Backgrounds for the Cryogenic Dark Matter Search written by and published by . This book was released on 2016 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: An ever-increasing amount of evidence suggests that approximately one quarter of the energy in the universe is composed of some non-luminous, and hitherto unknown, "dark matter". Physicists from numerous sub-fields have been working on and trying to solve the dark matter problem for decades. The common solution is the existence of some new type of elementary particle with particular focus on weakly interacting massive particles (WIMPs). One avenue of dark matter research is to create an extremely sensitive particle detector with the goal of directly observing the interaction of WIMPs with standard matter. The Cryogenic Dark Matter Search (CDMS) project operated at the Soudan Underground Laboratory from 2003-2015, under the CDMS II and SuperCDMS Soudan experiments, with this goal of directly detecting dark matter. The next installation, SuperCDMS SNOLAB, is planned for near-future operation. The reason the dark-matter particle has not yet been observed in traditional particle physics experiments is that it must have very small cross sections, thus making such interactions extremely rare. In order to identify these rare events in the presence of a background of known particles and interactions, direct detection experiments employ various types and amounts of shielding to prevent known backgrounds from reaching the instrumented detector(s). CDMS utilized various gamma and neutron shielding to such an effect that the shielding, and other experimental components, themselves were sources of background. These radiogenic backgrounds must be understood to have confidence in any WIMP-search result. For this dissertation, radiogenic background studies and estimates were performed for various analyses covering CDMS II, SuperCDMS Soudan, and SuperCDMS SNOLAB. Lower-mass dark matter t c2 inent in the past few years. The CDMS detectors can be operated in an alternative, higher-biased, mode v to decrease their energy thresholds and correspondingly increase their sensitivity to low-mass WIMPs. This is the CDMS low ionization threshold experiment (CDMSlite), which has pushed the frontier at lower WIMP masses. This dissertation describes the second run of CDMSlite at Soudan: its hardware, operations, analysis, and results. The results include new WIMP mass-cross section upper limits on the spin-independent and spin-dependent WIMP-nucleon interactions. Thanks to the lower background and threshold in this run compared to the first CDMSlite run, these limits are the most sensitive in the world below WIMP masses of ~4 GeV/c2. This demonstrates also the great promise and utility of the high-voltage operating mode in the SuperCDMS SNOLAB experiment.
Book Synopsis The Cryogenic Dark Matter Search: First 5-Tower Data and Improved Understanding of Ionization Collection by : Catherine N. Bailey
Download or read book The Cryogenic Dark Matter Search: First 5-Tower Data and Improved Understanding of Ionization Collection written by Catherine N. Bailey and published by . This book was released on 2010 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cryogenic Dark Matter Search (CDMS) is searching for Weakly Interacting Massive Particles (WIMPs) with cryogenic particle detectors. These detectors have the ability to discriminate between nuclear recoil candidate and electron recoil background events by collecting both phonon and ionization energy from recoils in the detector crystals. The CDMS-II experiment has completed analysis of the Ơ̐1rst data runs with 30 semiconductor detectors at the Soudan Underground Laboratory, resulting in a world leading WIMP-nucleon spin-independent cross section limit for WIMP masses above 44 GeV/c^2. As CDMS aims to achieve greater WIMP sensitivity, it is necessary to increase the detector mass and discrimination between signal and background events. Incomplete ionization collection results in the largest background in the CDMS detectors as this causes electron recoil background interactions to appear as false candidate events. Two primary causes of incomplete ionization collection are surface and bulk trapping. Recent work has been focused on reducing surface trapping through the modiƠ̐1cation of fabrication methods for future detectors. Analyzing data taken with test devices has shown that hydrogen passivation of the amorphous silicon blocking layer worsens surface trapping. Additional data has shown that the iron-ion implantation used to lower the critical temperature of the tungsten transition-edge sensors causes a degradation of the ionization collection. Using selective implantation on future detectors may improve ionization collection for events near the phonon side detector surface. Bulk trapping is minimized by neutralizing ionized lattice impurities. Detector investigations at testing facilities and in situ at the experimental site have provided methods to optimize the neutralization process and monitor running conditions to maintain full ionization collection. This work details my contribution to the 5-tower data taking, monitoring, and analysis eƠ̐0ort as well as the SuperCDMS detector development with the focus on monitoring and improving ionization collection in the detectors.
Book Synopsis Cryogenic Dark Matter Search (CDMS II) by : Michael J. Attisha
Download or read book Cryogenic Dark Matter Search (CDMS II) written by Michael J. Attisha and published by . This book was released on 2006 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Background Characterization and Discrimination in the Final Analysis of the CDMS II Phase of the Cryogenic Dark Matter Search by :
Download or read book Background Characterization and Discrimination in the Final Analysis of the CDMS II Phase of the Cryogenic Dark Matter Search written by and published by . This book was released on 2011 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cryogenic Dark Matter Search (CDMS) is designed to detectWeakly-Interacting Massive Particles (WIMPs) in the Milky Way halo. The phase known as CDMS II was performed in the Soudan Underground Laboratory. The final set of CDMS II data, collected in 2007-8 and referred to as Runs 125-8, represents the largest exposure to date for the experiment. We seek collisions between WIMPs and atomic nuclei in disk-shaped germanium and silicon detectors. A key design feature is to keep the rate of collisions from known particles producing WIMP-like signals very small. The largest category of such background is interactions with electrons in the detectors that occur very close to one of the faces of the detector. The next largest category is collisions between energetic neutrons that bypass the experimental shielding and nuclei in the detectors. Analytical efforts to discriminate these backgrounds and to estimate the rate at which such discrimination fails have been refined and improved throughout each phase of CDMS. Next-generation detectors for future phases of CDMS require testing at cryogenic test facilities. One such facility was developed at the University of Minnesota in 2007 and has been used continuously since then to test detectors for the next phase of the experiment, known as SuperCDMS.
Download or read book CDMS written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Deciphering the nature of dark matter has great scientific importance. A leading hypothesis is that dark matter is made of Weakly Interactive Massive Particles (WIMPs), which may result from supersymmetry or additional spatial dimensions. The underground search for elastic scattering of WIMPs on suitable targets (the so-called "direct detection") is currently led by the Cryogenic Dark Matter Search II (CDMS II) experiment. Its sensitivity is ten times better than any other experiment and we hope to obtain another factor ten in the coming two years. After a brief recall of our recent results, I will describe the complementarity between direct detection experiments, the LHC and the ILC and I will outline the role that SLAC could play in this SuperCDMS program.
Download or read book CDMS Experiment written by and published by . This book was released on 2007 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the current status of the Cryogenic Dark Matter Search (CDMS). The five tower detector array, total 30 detectors, are running stable since October 2006. We have accumulated more than 900 kg-days of low background data. We also summarize the prospect of SuperCDMS project.
Book Synopsis Background Reduction in Cryogenic Detectors by : Daniel A. Bauer
Download or read book Background Reduction in Cryogenic Detectors written by Daniel A. Bauer and published by . This book was released on 2005 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper discusses the background reduction and rejection strategy of the Cryogenic Dark Matter Search (CDMS) experiment. Recent measurements of background levels from CDMS II at Soudan are presented, along with estimates for future improvements in sensitivity expected for a proposed SuperCDMS experiment at SNOLAB.
Book Synopsis The Cryogenic Dark Matter Search Low Ionization-threshold Experiment by :
Download or read book The Cryogenic Dark Matter Search Low Ionization-threshold Experiment written by and published by . This book was released on 2014 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over 80 years ago we discovered the presence of Dark Matter in our universe. Endeavors in astronomy and cosmology are in consensus with ever improving precision that Dark Matter constitutes an essential 27% of our universe. The Standard Model of Particle Physics does not provide any answers to the Dark Matter problem. It is imperative that we understand Dark Matter and discover its fundamental nature. This is because, alongside other important factors, Dark Matter is responsible for formation of structure in our universe. The very construct in which we sit is defined by its abundance. The Milky Way galaxy, hence life, wouldn't have formed if small over densities of Dark Matter had not caused sufficient accretion of stellar material. Marvelous experiments have been designed based on basic notions to directly and in-directly study Dark Matter, and the Cryogenic Dark Matter Search (CDMS) experiment has been a pioneer and forerunner in the direct detection field. Generations of the CDMS experiment were designed with advanced scientific upgrades to detect Dark Matter particles of mass O(100) GeV/c2. This mass-scale was set primarily by predictions from Super Symmetry. Around 2013 the canonical SUSY predictions were losing some ground and several observations (rather hints of signals) from various experiments indicated to the possibility of lighter Dark Matter of mass O(10) GeV/c2. While the SuperCDMS experiment was probing the regular parameter space, the CDMSlite experiment was conceived to dedicatedly search for light Dark Matter using a novel technology. "CDMSlite" stands for CDMS - low ionization threshold experiment. Here we utilize a unique electron phonon coupling mechanism to measure ionization generated by scattering of light particles. Typically signals from such low energy recoils would be washed under instrumental noise. In CDMSlite via generation of Luke-Neganov phonons we can detect the small ionization energies, amplified in phonon modes during charge transport. This technology allows us to reach very low thresholds and reliably measure and investigate low energy recoils from light Dark Matter particles. This thesis describes the physics behind CDMSlite, the experimental design and the first science results from CDMSlite operated at the Soudan Underground Laboratory.
Book Synopsis Ionization Collection in Detectors of the Cryogenic Dark Matter Search by : Arran Thomas James Phipps
Download or read book Ionization Collection in Detectors of the Cryogenic Dark Matter Search written by Arran Thomas James Phipps and published by . This book was released on 2016 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Determining the composition of dark matter is at the forefront of modern scientific research. There is compelling evidence for the existence of vast quantities of dark matter throughout the universe, however it has so-far eluded all direct detection efforts and its identity remains a mystery. Weakly interacting massive particles (WIMPs) are a favored dark matter candidate and have been the primary focus of direct detection for several decades. The Cryogenic Dark Matter Search (CDMS) has developed the Z-dependent Ionization and Phonon (ZIP) detector to search for such particles. Typically made from germanium, these detectors are capable of distinguishing between electromagnetic background and a putative WIMP signal through the simultaneous measurement of ionization and phonons produced by scattering events. CDMS has operated several arrays of these detectors at the Soudan Underground Laboratory (Soudan, MN, USA) resulting in many competitive (often world-leading) WIMP exclusion limits. This dissertation focuses on ionization collection in these detectors under the sub-Kelvin, low electric field, and high crystal purity conditions unique to CDMS. The design and performance of a fully cryogenic HEMT-based amplifier capable of achieving the SuperCDMS SNOLAB ionization energy resolution goal of 100 eVee is presented. The experimental apparatus which has been used to record electron and hole properties under CDMS conditions is described. Measurements of charge transport, trapping, and impact ionization as a function of electric field in two CDMS detectors are shown, and the ionization collection efficiency is determined. The data is used to predict the error in the nuclear recoil energy scale under both CDMSlite and iZIP operating modes. A two species, two state model is developed to describe how ionization collection and space charge generation in CDMS detectors are controlled by the presence of ``overcharged'' $D^-$ donor and $A^+$ acceptor impurity states. The thermal stability of these states is exclusive to sub-Kelvin operation, explaining why ionization collection in CDMS detectors differs from similar semiconductor detectors operating at higher temperature. This work represents a solid foundation for the understanding ionization collection in CDMS detectors.
Book Synopsis Detector Simulation and WIMP Search Analysis for the Cryogenic Dark Matter Search Experiment by : Kevin Ahmad McCarthy
Download or read book Detector Simulation and WIMP Search Analysis for the Cryogenic Dark Matter Search Experiment written by Kevin Ahmad McCarthy and published by . This book was released on 2013 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astrophysical and cosmological measurements on the scales of galaxies, galaxy clusters, and the universe indicate that ~85% of the matter in the universe is composed of dark matter, made up of non-baryonic particles that interact with cross-sections on the weak scale or lower. Hypothetical Weakly Interacting Massive Particles, or WIMPs, represent a potential solution to the dark matter problem, and naturally arise in certain Standard Model extensions. The Cryogenic Dark Matter Search (CDMS) collaboration aims to detect the scattering of WIMP particles from nuclei in terrestrial detectors. Germanium and silicon particle detectors are deployed in the Soudan Underground Laboratory in Minnesota. These detectors are instrumented with phonon and ionization sensors, which allows for discrimination against electromagnetic backgrounds, which strike the detector at rates orders of magnitude higher than the expected WIMP signal. This dissertation presents the development of numerical models of the physics of the CDMS detectors, implemented in a computational package collectively known as the CDMS Detector Monte Carlo (DMC). After substantial validation of the models against data, the DMC is used to investigate potential backgrounds to the next iteration of the CDMS experiment, known as SuperCDMS. Finally, an investigation of using the DMC in a reverse Monte Carlo analysis of WIMP search data is presented. 140.23 kg-days of WIMP search data from the silicon detectors in the CDMSII experiment is also analyzed. The resulting upper limits on the WIMP-nucleon crosssection are higher than those published by other experiments at all WIMP masses, and the lowest limit on the WIMP-nucleon cross-section is 1.07*10-42 cm2 at a mass of 60 GeV/c2. These results do provide new and interesting constraints at WIMP masses
Book Synopsis First Results from the Cryogenic Dark Matter Search Experiment at the Deep Site by : Vuk Mandic
Download or read book First Results from the Cryogenic Dark Matter Search Experiment at the Deep Site written by Vuk Mandic and published by . This book was released on 2004 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Detector Simulation and WIMP Search Analysis for the Cryogenic Dark Matter Search Experiment by :
Download or read book Detector Simulation and WIMP Search Analysis for the Cryogenic Dark Matter Search Experiment written by and published by . This book was released on 2013 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astrophysical and cosmological measurements on the scales of galaxies, galaxy clusters, and the universe indicate that 85% of the matter in the universe is composed of dark matter, made up of non-baryonic particles that interact with cross-sections on the weak scale or lower. Hypothetical Weakly Interacting Massive Particles, or WIMPs, represent a potential solution to the dark matter problem, and naturally arise in certain Standard Model extensions. The Cryogenic Dark Matter Search (CDMS) collaboration aims to detect the scattering of WIMP particles from nuclei in terrestrial detectors. Germanium and silicon particle detectors are deployed in the Soudan Underground Laboratory in Minnesota. These detectors are instrumented with phonon and ionization sensors, which allows for discrimination against electromagnetic backgrounds, which strike the detector at rates orders of magnitude higher than the expected WIMP signal. This dissertation presents the development of numerical models of the physics of the CDMS detectors, implemented in a computational package collectively known as the CDMS Detector Monte Carlo (DMC). After substantial validation of the models against data, the DMC is used to investigate potential backgrounds to the next iteration of the CDMS experiment, known as SuperCDMS. Finally, an investigation of using the DMC in a reverse Monte Carlo analysis of WIMP search data is presented.
