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Author: Shuo Liu
Publisher: LAP Lambert Academic Publishing
ISBN: 9783844380439
Category :
Languages : en
Pages : 116
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Book Description
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
Author: Shuo Liu
Publisher: LAP Lambert Academic Publishing
ISBN: 9783844380439
Category :
Languages : en
Pages : 116
Get Book Here
Book Description
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
Author: Shuo Liu
Publisher:
ISBN:
Category :
Languages : en
Pages : 282
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Book Description
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.
Author: Kedar Mohan Page
Publisher:
ISBN:
Category :
Languages : en
Pages : 324
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Book Description
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.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
SuperCDMS (Super Cryogenic Dark Matter Search) is a leading direct dark mat-ter search experiment which uses solid state detectors (Ge crystals) at milliKelvintemperatures to look for nuclear recoils caused by dark matter interactions in the de-tector. `Weakly Interacting Massive Particles' (WIMPs) are the most favoured darkmatter candidate particles. SuperCDMS, like many other direct dark matter searchexperiments, primarily looks for WIMPs. The measurement of both the ionizationand the lattice vibration (phonon) signals from an interaction in the detector allow itto discriminate against electron recoils which are the main source of background forWIMP detection. SuperCDMS currently operates about 9 kg of Ge detectors at the Soudan under-ground lab in northern Minnesota. In its next phase, SuperCDMS SNOLAB plansto use 100-200 kg of target mass (Ge) which would allow it to probe more of theinteresting and and as of yet unexplored parameter space for WIMPs predicted bytheoretical models. The SuperCDMS Queen's Test Facility is a detector test facilitywhich is intended to serve as detector testing and detector research and developmentpurposes for the SuperCDMS experiment. A modifed detector called the HiZIP (Half-iZIP), which is reduced in complex-ity in comparison to the currently used iZIP (interleaved Z-sensitive Ionization and Phonon mediated) detectors, is studied in this thesis. The HiZIP detector designalso serves to discriminate against background from multiple scatter events occurringclose to the surfaces in a single detector. Studies carried out to compare the surfaceevent leakage in the HiZIP detector using limited information from iZIP data takenat SuperCDMS test facility at UC Berkley produce a highly conservative upper limitof 5 out of 10,000 events at 90% condence level. This upper limit is the best amongmany different HiZIP congurations that were investigated and is comparable to theupper limit calculated for an HiZIP detector in the same way using the same data. Areal HiZIP device operated at the Queen's Test Facility produced an exposure lim-ited 90% upper limit of about 1 in 100 events for surface event leakage. The dataused in these studies contain true nuclear recoil events from cosmogenic and ambientneutrons. This background was not subtracted in the calculation of the upper limitsstated above and hence they are highly conservative. A surface event source was produced by depositing210Pbfrom radon exposureonto a copper plate. This source was then used to take data for a surface eventdiscrimination study of the HiZIP detector operated at the Queen's Test Facility. A study of the contribution of the noise from capacitive crosstalk between chargesensors in a HiZIP detector configuration was investigated, conrming the expectationthat no signicant drop in performance compared to an HiZIP is to be expected dueto this effect.
Author: Joseph Fox
Publisher:
ISBN:
Category :
Languages : en
Pages : 322
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Book Description
SuperCDMS, the next stage of the Cryogenic Dark Matter Search (CDMS), uses cylindrical germa- nium crystals as particle detectors to measure phonon and ionization signals resulting from particle interactions. The aim of CDMS is to identify and measure interactions from dark matter particles (WIMPs). Phonons produced during a particle interaction are absorbed by sensors on the detector surface and are measured through the change in the sensors' temperature dependent resistance. Electrodes on the detector surface create an electric eld causing charges released during an inter- action to drift through the detector and produce an ionization signal. Surface events, which are interactions that occur within a few m from the electrodes, cause a reduced ionization signal due to di usion of some of the initially hot charge carriers into the electrode. Because the ability of CDMS to discriminate between a WIMP interaction and background radiation is based on the ratio of phonon to ionization energies, surface events cause a signal similar to a WIMP interaction and are currently the largest source of background. A detector test facility at Queen's University has been commissioned to characterize detectors and test new detector technology. Multiple detectors have been characterized and many tungsten samples have been measured. Two sets of experiments were performed to test new detector designs. To possibly reduce surface events, an insulating layer was deposited on a germanium detector be- neath the electrode to prevent back di usion of charge into the electrode. To possibly simplify the phonon sensor production process, di erent cryogenic glues were used to attach silicon wafers with a tungsten lm to the crystal surface and phonon propagation through these glues was measured. The most e ective cryogenic glue for coupling tungsten samples to CDMS detectors was found to be Araldite epoxy. Both experiments were successful at measuring interactions. Energy calibrations were performed on both charge and phonon sensors. Further research is required to determine the success of reducing surface events with an insulating layer.
Author: Holger Kluck
Publisher: Springer
ISBN: 3319185276
Category : Science
Languages : en
Pages : 402
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Book Description
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.
Author: Geraint F. Lewis
Publisher: World Scientific
ISBN: 9812814353
Category : Science
Languages : en
Pages : 654
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Book Description
Dark matter remains one of the central mysteries in modern physics, although modern astronomical observations and particle physics experiments are providing vital clues in uncovering its true nature. The Dark2007 Conference brought together world-leading researchers in both astrophysics and particle physics, providing them with an opportunity to present their latest results and engage in discussion on their meaning and future direction. This book is important in its field, as it provides a vital snapshot of the seemingly disparate areas of dark matter research and provides an overview of current ideas and future directions.
Author: Elena Aprile
Publisher: John Wiley & Sons
ISBN: 3527609636
Category : Science
Languages : en
Pages : 362
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Book Description
This book discusses the physical properties of noble fluids, operational principles of detectors based on these media, and the best technical solutions to the design of these detectors. Essential attention is given to detector technology: purification methods and monitoring of purity, information readout methods, electronics, detection of hard ultra-violet light emission, selection of materials, cryogenics etc. The book is mostly addressed to physicists and graduate students involved in the preparation of fundamental next generation experiments, nuclear engineers developing instrumentation for national nuclear security and for monitoring nuclear materials.
Author: Hans-Christian Stahl
Publisher: Springer Science & Business Media
ISBN: 9783540201137
Category : Science
Languages : en
Pages : 538
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Book Description
The development of cryogenic devices for particle detection has reached a stage at which many interesting applications are conceivable and already have been demonstrated. The book provides a comprehensive review of the field of cryogenic particle detection. It introduces the different detection techniques and gives an overview of the important areas in which these detectors are successfully applied.
Author: Jonathan L. Feng
Publisher: American Institute of Physics
ISBN:
Category : Science
Languages : en
Pages : 750
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Book Description
This book contains the proceedings of the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, SUSY06, held in Irvine, California, in June 2006. This conference took place just before the start of the Large Hadron Collider, widely anticipated to yield profound new results, and provided a focus for the growing excitement in high energy physics through over 250 plenary and parallel talks.
