Download or read book Minimizing Background for the SuperCDMS SNOLAB Dark Matter Experiment written by Michael A. Bowles and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The sensitivity of future generations of dark-matter detectors are expected to be dominated by long-lived low-energy beta- and alpha-emitting radon daughters such as 210Pb on detector surfaces. I describe simulations indicating the detector could also be used to reduce background from material impurities plaguing rare-event searches, the commissioning of a prototype demonstration detector, and a gas handling system necessary to operate the detector. I demonstrated that the gas handling system reduces the otherwise dominant backgrounds by a factor of 62. This detector will therefore be able to detect [32Si and 210Pb] 100 times better than currently available screeners.
Download or read book Projected Sensitivity of the SuperCDMS SNOLAB Experiment written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: SuperCDMS SNOLAB will be a next-generation experiment aimed at directly detecting low-mass (10 GeV/c$^2$) particles that may constitute dark matter by using cryogenic detectors of two types (HV and iZIP) and two target materials (germanium and silicon). The experiment is being designed with an initial sensitivity to nuclear recoil cross sections ~ 1 x 10$^{-43}$ cm$^2$ for a dark matter particle mass of 1 GeV/c$^2$, and with capacity to continue exploration to both smaller masses and better sensitivities. The phonon sensitivity of the HV detectors will be sufficient to detect nuclear recoils from sub-GeV dark matter. A detailed calibration of the detector response to low energy recoils will be needed to optimize running conditions of the HV detectors and to interpret their data for dark matter searches. Low-activity shielding, and the depth of SNOLAB, will reduce most backgrounds, but cosmogenically produced $^{3}$H and naturally occurring $^{32}$Si will be present in the detectors at some level. Even if these backgrounds are x10 higher than expected, the science reach of the HV detectors would be over three orders of magnitude beyond current results for a dark matter mass of 1 GeV/c$^2$. The iZIP detectors are relatively insensitive to variations in detector response and backgrounds, and will provide better sensitivity for dark matter particle masses ( 5 GeV/c$^2$). The mix of detector types (HV and iZIP), and targets (germanium and silicon), planned for the experiment, as well as flexibility in how the detectors are operated, will allow us to maximize the low-mass reach, and understand the backgrounds that the experiment will encounter. Upgrades to the experiment, perhaps with a variety of ultra-low-background cryogenic detectors, will extend dark matter sensitivity down to the "neutrino floor", where coherent scatters of solar neutrinos become a limiting background.
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.
Download or read book The Limiting Background in a Detector Testing Facility for SuperCDMS at SNOLAB written by Shuo Liu and published by . This book was released on 2011 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: SuperCDMS is the next generation of the Cryogenic Dark Matter Search experiment (CDMS), aimed at the detection of the Weakly Interacting dark matter Particles (WIMPs) with the use of phonon and ionization signals in germanium detectors operated at about 40 mK. The current experiment is operating in the Soudan underground laboratory in northern Minnesota. However, due to limitation of cosmic ray muons, in the next stage of SuperCDMS, the whole experiment will be moved to a deeper site at SNOLAB. This could reduce the influence of extraterrestrial high energy particles to a negligible level, leaving the natural radioactivity locally existing in the laboratory wall rock as the dominating background source. Along with this relocation, newly designed detectors will be implemented to further increase the sensitivity. The prototype of this kind of detector has been manufactured, but it needs to be carefully tested prior to its formal application. To thoroughly examine its performance, especially in an environment that is less affected by cosmic rays, a new detector testing facility is to be built underground at SNOLAB (STF) surrounded by a water tank serving as the passive shield against the natural radioactivity. A series of Monte Carlo simulations have been performed to investigate the effectiveness of the water tank shield, the background level and also the energy spectra of events in the detectors. The goal of 1 neutron/day and 1 Hz of gammas for external sources can be achieved.
Download or read book The Limiting Background in a Detector Testing Facility for Supercdms written by Shuo Liu and published by LAP Lambert Academic Publishing. This book was released on 2011-05 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last few decades, numerous experiments have been operated to search for dark matter, the mysterious component of the universe. The dark matter is unseen and only known by its gravitational effect, but it greatly outnumbers the normal matter concluded from a wide variety of evidence. Since the dark matter only interacts weakly with normal substance, the experiment to search for it is preferred to be located deeply underground and surrounded by layers of shielding materials, which is to diminish the influence of background radiations. One has to have a quantitative idea of the radiation level and the effectiveness of the proposed shielding strategy in order to operate an experiment with a desired sensitivity. This work is to list the background radiations presented at SNOLAB and to examine the water tank shield of the detector testing facility for SuperCDMS experiment by means of Monte Carlo simulation. It is found that the goal of
Download or read book Dark Matter in Astro and Particle Physics written by Hans-Volker Klapdor-Kleingrothaus and published by Springer Science & Business Media. This book was released on 2006-02-23 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt: TheFifthHEIDELBERGInternationalConferenceonDarkMatterinAst- and Particle Physics, DARK 2004, took place at Texas A&M University, College Station Texas, USA, October 3–9, 2004. It was, after Cape Town 2002, the second conference of this series held outside Germany. The earlier meetings, starting in 1996, were held in Heidelberg. Dark Matter is still one of the most exciting and central ?elds of ast- physics, particle physics and cosmology. The conference covered, as usual for this series, a large range of topics, theoretical and experimental. Theoretical talks covered SUSY/SUGRA phenomenology, which provides at present a preferred theoretical framework for the existence of cold dark matter. Also included were other possible explanations of dark matter such as SUSY Q balls, exciting New Symmetries, etc. The most important experiments in the underground search for cold and hot dark matter were presented. Talks describing the current experimental dark matter bounds, what might be obtained in the near future, and the reach of future large (i.e. one ton) detectors were given. The potential of future colliders to correlate accelerator physics with dark matter searches was also outlined. Thus the reader will be able to see the present status and future prospects in the search for dark matter. The exciting astronomical evidence for dark matter and corresponding observations concerning the Milky Way’s black hole, high-redshift clusters, wakes in dark matter halos were other important topics at the conference.
Download or read book Background Simulations for a Large scale Cryogenic Dark Matter Experiment written by Vito Tomasello and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plastic Scintillators written by Matthieu Hamel and published by Springer Nature. This book was released on 2021-07-10 with total page 647 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the physics and chemistry of plastic scintillators (fluorescent polymers) that are able to emit light when exposed to ionizing radiation, discussing their chemical modification in the early 1950s and 1960s, as well as the renewed upsurge in interest in the 21st century. The book presents contributions from various researchers on broad aspects of plastic scintillators, from physics, chemistry, materials science and applications, covering topics such as the chemical nature of the polymer and/or the fluorophores, modification of the photophysical properties (decay time, emission wavelength) and loading of additives to make the material more sensitive to, e.g., fast neutrons, thermal neutrons or gamma rays. It also describes the benefits of recent technological advances for plastic scintillators, such as nanomaterials and quantum dots, which allow features that were previously not achievable with regular organic molecules or organometallics.
Download or read book Search for Low mass Dark Matter with SuperCDMS Soudan and Study of Shorted Electric Field Configurations in CDMS Detectors written by Kristiana E. Schneck and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The area of dark matter is one of the most interesting and exciting topics in physics today. Experiments such as SuperCDMS are built to detect dark matter in the lab by looking for low-energy nuclear recoils produced by collisions between dark matter particles and atoms in terrestrial detectors. SuperCDMS Soudan is particularly well-suited to follow up on possible hints of low-mass dark matter seen by other recent experiments because of its low thresholds and excellent background discrimination. Analyzing SuperCDMS Soudan data to look for low-mass dark matter comes with particular challenges because of the low signal-to-noise very near threshold. However, with a detailed background model developed by scaling high-energy events down into the low-energy signal region, SuperCDMS Soudan produced world-leading limits on the existence of low-mass dark matter. However, a few SuperCDMS Soudan detectors experienced cold hardware problems that can affect the data collected. Of particular interest is one detector considered for the low-mass WIMP search that has one of its charge electrodes shorted to chassis ground. The data collected by the shorted detector may have been compromised since an electrode shorted to ground will modify the electric field in the detector. A new model of the expected backgrounds in the low-mass WIMP search is developed using the SuperCDMS Detector Monte Carlo to try to explain how the short may have affected the data collected. Finally, the consequences of a new effective field theory of dark matter-nucleon scattering are examined in the context of current and future dark matter direct detection experiments.
Download or read book Search for Low Mass Dark Matter Wtih SuperCDMS Soudan and Study of Shorted Electric Field Configurations in CDMS Detectors written by and published by . This book was released on 2015 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: The area of dark matter is one of the most interesting and exciting topics in physics today. Existing at the intersection of particle physics and astrophysics, the existence of a new dark matter particle can be used to explain many astrophysical and cosmological observations, as well as to reconcile outstanding issues in the standard model of particle physics. Experiments such as SuperCDMS are built to detect dark matter in the lab by looking for low-energy nuclear recoils produced by collisions between dark matter particles and atoms in terrestrial detectors. SuperCDMS Soudan is particularly well-suited to follow up on possible hints of low-mass dark matter seen by other recent experiments because of its low thresholds and excellent background discrimination. Analyzing SuperCDMS Soudan data to look for low-mass dark matter comes with particular challenges because of the low signal-to-noise very near threshold. However, with a detailed background model developed by scaling high-energy events down into the low-energy signal region, SuperCDMS Soudan produced worldleading limits on the existence of low-mass dark matter. In addition, a few SuperCDMS Soudan detectors experienced cold hardware problems that can affect the data collected. Of particular interest is one detector considered for the low-mass WIMP search that has one of its charge electrodes shorted to chassis ground. Three events were observed in this detector upon unblinding the SuperCDMS Soudan low-energy data, even though
Download or read book Commissioning the Miner Experiment to Take the First Low background Data Using a Data Acquisition System from the SuperCDMS Dark Matter Search Experiment written by Joseph Mammo and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Intrinsic Background Reduction by Cryogenic Distillation for the XENON1T Dark Matter Experiment written by Michael Murra and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Modified Detector Concept for SuperCDMS written by Kedar Mohan Page and published by . This book was released on 2013 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: SuperCDMS is a leading direct dark matter search experiment which uses solid state detectors (Ge crystals) at milliKelvin temperatures to look for nuclear recoils caused by dark matter interactions in the detector. 'Weakly Interacting Massive Particles' (WIMPs) are the most favoured dark matter candidate particles. SuperCDMS, like many other direct dark matter search experiments, primarily looks for WIMPs. The measurement of both the ionization and the lattice vibration (phonon) signals from an interaction in the detector allow it to discriminate against electron recoils which are the main source of background for WIMP detection. SuperCDMS currently operates about 9 kgs worth of germanium detectors at the Soudan underground lab in northern Minnesota. In its next phase, SuperCDMS SNOLAB, it plans to use 100-200 kg of target mass (Ge) which would allow it to probe more of the interesting and unexplored parameter space for WIMPs predicted by theoretical models. The SuperCDMS Queen's Test Facility is a detector testing facility which is intended to serve detector testing and detector research and development purposes for the SuperCDMS experiment. A modified detector called the 'HiZIP' (Half-iZIP), which is reduced in complexity in comparison to the currently used iZIP (interleaved Z-sensitive Ionization and Phonon mediated) detectors, is studied in this thesis. The HiZIP detector design also serves to discriminate against background from multiple scatter events occurring close to the surfaces in a single detector. Studies carried out to compare the surface event leakage in the HiZIP detector using limited information from iZIP data taken at SuperCDMS test facility at UC Berkley produce a highly conservative upper limit of 5 out of 10,000 events at 90% confidence level. This upper limit is the best among many different HiZIP configurations that were investigated and is comparable to the upper limit calculated for an iZIP detector in the same way using the same data. A real HiZIP device operated at Queen's Test Facility produced an exposure limited 90% upper limit of about 1 in 100 events for surface event leakage. The data used in these studies contain true nuclear recoil events from cosmogenic and ambient neutrons. This background was not subtracted in the calculation of the upper limits stated above and hence they are highly conservative. A surface event source was produced by depositing lead-210 from radon exposure onto a copper plate. This source was then used to take data for a surface event discrimination study of the HiZIP detector operated at Queen's Test Facility. A study of the contribution of the noise from capacitive crosstalk between charge sensors in a HiZIP detector configuration was investigated, confirming the expectation that no significant drop in performance is to be expected due to this effect.
Download or read book Mitigation of Backgrounds for the Large Underground Xenon Dark Matter Experiment written by Chang Lee and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: While the existence of particle dark matter is widely accepted through multitude of astrophysics evidence, its exact nature remains mysterious. It is expected to comprise the local galactic halo, and one of the most favored candidates, weakly interacting massive particle (WIMP), is hypothesized to interact with baryonic matter. Such an interaction can be detected in a radio-quiet low-threshold detector such as the large underground xenon (LUX) detector. The LUX is a dual-phase xenon time projection chamber (TPC), and it operates at Sanford Underground Research Facility in Lead, SD. Analysis of the first science data with a 86.3 days live-time from LUX yielded the best spin-independent WIMP-nucleon cross-section exclusion limit to date, with the lower limit of $7.6\times10^{-46}$~cm$^2$ at 33~GeV/c$^2$ with a 90\% confidence level. This thesis consists the following chapters. The case for cold dark matter from the current cosmological observations is reviewed. The natures of the expected WIMP-nucleon scattering signal and the techniques to discriminate the background events are discussed. Principles of the dual-phase TPC are explained, with details of the LUX hardware. The original works for this thesis follows. A campaign to remove radioactive noble impurities from the target xenon is described in depth. A position reconstruction algorithm based on comparison of observed data to simulation is developed. Background events from the detector's internal walls are studied and modeled for the profile likelihood ratio test of the second analysis. Finally, the first published results are reviewed in detail.
Download or read book Simulating the XENONnT Dark Matter Experiment written by Diego Ramírez García and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Investigation of Backgrounds in the DEAP 3600 Dark Matter Direct Detection Experiment written by Laurelle Maria Veloce and published by . This book was released on 2013 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomical and cosmological observations reveal that the majority of the matter in our universe is made of an unknown, non-luminous substance called dark matter. Many experimental attempts are underway to directly detect particle dark matter, which is very difficult to measure due to the expected low interaction rate with normal matter. DEAP-3600 is a direct dark matter search experiment located two kilometres underground at SNOLAB, in Sudbury, Ontario. DEAP-3600 will make use of liquid argon as the detector material, which scintillates as charged particles pass through. The work presented here is an investigation of expected background sources in the DEAP detector. Because DEAP-3600 is a noble liquid-based experiment, a thin film of [1,1,4,4]-tetraphenyl-[1,3]-butadiene (TPB) is coated on the detector walls to shift the scintillation peak from the UV to visible regime for detection. However, alphas passing through TPB produce scintillation signals which can mimic recoil events. Because scintillation properties can change with temperature, we have conducted an investigation of alpha-induced TPB scintillation at temperatures ranging from 300 K to 3.4 K. We were able to characterize the light yield and decay times, and demonstrated that these background events should be distinguishable from true recoil events in liquid argon, thus enabling DEAP-3600 to achieve higher dark matter sensitivity. Additionally, we investigate the performance of the liquid argon purification systems, specifically the activated charcoal used for radon filtration. Previous measurements with the DEAP prototype experiment have demonstrated the necessity of removing radon from the argon prior to filling the detector, due to the release of contaminates from the argon storage systems. Charcoal radon filters are extremely efficient, however, if the emanation rate of the charcoal is too high, there is the possibility of re-contamination. We performed a measurement of the radon emanation rate of a charcoal sample using a radon emanation and extraction system at Queens University. We demonstrated that the emanation rate of the charcoal was consistent with zero. We also show that the number of residual radon atoms which reach the detector would not be an issue for DEAP-3600.
Download or read book The Low mass Limit written by Noah Kurinsky and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The SuperCDMS SNOLAB experiment will be a 20-kg scale Si and Ge direct dark matter detection experiment designed to probe down to 300 MeV in dark matter (DM) mass through DM-nucleus scattering and 500 keV in DM electron scattering. In order to reach these low masses with appreciable sensitivity to dark matter, it needs to achieve very low energy resolution (≤ 10 ev) for nuclear recoils in both detector materials, which will be achieved using a new detector design and operating mode, CDMS HV. This detector is designed to operate at a bias of 100V to convert charges liberated in our detector targets to into phonon energy in order to resolve individual electron-hole pairs. This has never before been achieved in a kg-scale detector. In this thesis, I cover three elements of the design of the CDMS HV detectors. I discuss the detector physics controlling how charges and phonons are generated in our detector crystals, com- paring theory to results of recent experiments carried out at Stanford. I move on to describe the operating principles of our phonon-mediated charge readout, as well as the design of the CDMS HV detector. I then describe the performance tests of early CDMS HV prototypes in conjunction with the SuperCDMS SNOLAB electronics, and discuss the path towards achieving single electron-hole pair resolving detectors at the kg-scale given the performance obtained thus far. As a result of these tests, we were able to refine our noise and sensor dynamics models, and develop new metrics for diagnosing non-ideal sources of noise to aid in reducing coupling of the external environment to our detectors. In order to study the microphysics of phonon and charge production in our target crystals, we fabricated a number of gram-scale devices with various sensor designs in order to separate sensor and environmental effects from intrinsic crystal properties. These devices provided the first successful demonstrating of using voltage to amplify charge energy by production of phonons (the Neganov-Trofimov-Luke effect) in order to resolve electron-hole pairs, and opened up a new regime of dark matter and photon science at the gram-scale that we are just beginning to explore. A first dark matter search was carried out with one of these gram-scale devices, producing world-leading limits on electron-recoiling dark matter between 0.5 and 5 MeV in dark matter mass for multiple form factors. This device achieved a phonon resolution of 10 eV, allowing a single gram-day of exposure to rival kg-days of exposure in the competing liquid-noble based electron-recoil search.
