M. A. Howe - University of North Carolina

M. A. Howe
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Name
M. A. Howe
Affiliation
University of North Carolina
City
Wilmington
Country
United States

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Nuclear Experiment (37)
 
Physics - Instrumentation and Detectors (31)
 
High Energy Physics - Experiment (10)
 
Astrophysics (1)
 
Solar and Stellar Astrophysics (1)
 
High Energy Astrophysical Phenomena (1)
 
High Energy Physics - Phenomenology (1)

Publications Authored By M. A. Howe

We present new limits on exotic keV-scale physics based on 478 kg d of MAJORANA DEMONSTRATOR commissioning data. Constraints at the 90% confidence level are derived on bosonic dark matter (DM) and solar axion couplings, Pauli exclusion principle violating (PEPV) decay, and electron decay using monoenergetic peak signal-limits above our background. Our most stringent DM constraints are set for 11. Read More

A search for Pauli-exclusion-principle-violating K-alpha electron transitions was performed using 89.5 kg-d of data collected with a p-type point contact high-purity germanium detector operated at the Kimballton Underground Research Facility. A lower limit on the transition lifetime of 5. Read More

The Majorana Demonstrator searches for neutrinoless double-beta decay of $^{76}$Ge using arrays of high-purity germanium detectors. If observed, this process would demonstrate that lepton number is not a conserved quantity in nature, with implications for grand-unification and for explaining the predominance of matter over antimatter in the universe. A problematic background in such large granular detector arrays is posed by alpha particles. Read More

Neutrinoless double-beta decay searches seek to determine the nature of neutrinos, the existence of a lepton violating process, and the effective Majorana neutrino mass. The {\sc Majorana} Collaboration is assembling an array of high purity Ge detectors to search for neutrinoless double-beta decay in $^{76}$Ge. The {\sc Majorana Demonstrator} is composed of 44. Read More

The MAJORANA Collaboration is constructing a system containing 44 kg of high-purity Ge (HPGe) detectors to demonstrate the feasibility and potential of a future tonne-scale experiment capable of probing the neutrino mass scale to ~15 meV. To realize this, a major goal of the MAJORANA DEMONSTRATOR is to demonstrate a path forward to achieving a background rate at or below 1 count/(ROI-t-y) in the 4 keV region of interest (ROI) around the Q-value at 2039 keV. This goal is pursued through a combination of a significant reduction of radioactive impurities in construction materials and analytical methods for background rejection, for example using powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. Read More

The MAJORANA Collaboration is constructing the MAJORANA Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in Ge-76. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the MAJORANA Demonstrator. This effect can damage the front-end electronics or mimic detector signals. Read More

2016Mar
Authors: M. Arenz, M. Babutzka, M. Bahr, J. P. Barrett, S. Bauer, M. Beck, A. Beglarian, J. Behrens, T. Bergmann, U. Besserer, J. Blümer, L. I. Bodine, K. Bokeloh, J. Bonn, B. Bornschein, L. Bornschein, S. Büsch, T. H. Burritt, S. Chilingaryan, T. J. Corona, L. De Viveiros, P. J. Doe, O. Dragoun, G. Drexlin, S. Dyba, S. Ebenhöch, K. Eitel, E. Ellinger, S. Enomoto, M. Erhard, D. Eversheim, M. Fedkevych, A. Felden, S. Fischer, J. A. Formaggio, F. Fränkle, D. Furse, M. Ghilea, W. Gil, F. Glück, A. Gonzalez Urena, S. Görhardt, S. Groh, S. Grohmann, R. Grössle, R. Gumbsheimer, M. Hackenjos, V. Hannen, F. Harms, N. Hauÿmann, F. Heizmann, K. Helbing, W. Herz, S. Hickford, D. Hilk, B. Hillen, T. Höhn, B. Holzapfel, M. Hötzel, M. A. Howe, A. Huber, A. Jansen, N. Kernert, L. Kippenbrock, M. Kleesiek, M. Klein, A. Kopmann, A. Kosmider, A. Kovalík, B. Krasch, M. Kraus, H. Krause, M. Krause, L. Kuckert, B. Kuffner, L. La Cascio, O. Lebeda, B. Leiber, J. Letnev, V. M. Lobashev, A. Lokhov, E. Malcherek, M. Mark, E. L. Martin, S. Mertens, S. Mirz, B. Monreal, K. Müller, M. Neuberger, H. Neumann, S. Niemes, M. Noe, N. S. Oblath, A. Off, H. -W. Ortjohann, A. Osipowicz, E. Otten, D. S. Parno, P. Plischke, A. W. P. Poon, M. Prall, F. Priester, P. C. -O. Ranitzsch, J. Reich, O. Rest, R. G. H. Robertson, M. Röllig, S. Rosendahl, S. Rupp, M. Rysavy, K. Schlösser, M. Schlösser, K. Schönung, M. Schrank, J. Schwarz, W. Seiler, H. Seitz-Moskaliuk, J. Sentkerestiova, A. Skasyrskaya, M. Slezak, A. Spalek, M. Steidl, N. Steinbrink, M. Sturm, M. Suesser, H. H. Telle, T. Thümmler, N. Titov, I. Tkachev, N. Trost, A. Unru, K. Valerius, D. Venos, R. Vianden, S. Vöcking, B. L. Wall, N. Wandkowsky, M. Weber, C. Weinheimer, C. Weiss, S. Welte, J. Wendel, K. L. Wierman, J. F. Wilkerson, D. Winzen, J. Wolf, S. Wüstling, M. Zacher, S. Zadoroghny, M. Zboril

The KATRIN experiment will probe the neutrino mass by measuring the beta-electron energy spectrum near the endpoint of tritium beta-decay. An integral energy analysis will be performed by an electro-static spectrometer (Main Spectrometer), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m^3, and a complex inner electrode system with about 120000 individual parts. Read More

2016Feb
Affiliations: 1The Majorana Collaboration, 2The Majorana Collaboration, 3The Majorana Collaboration, 4The Majorana Collaboration, 5The Majorana Collaboration, 6The Majorana Collaboration, 7The Majorana Collaboration, 8The Majorana Collaboration, 9The Majorana Collaboration, 10The Majorana Collaboration, 11The Majorana Collaboration, 12The Majorana Collaboration, 13The Majorana Collaboration, 14The Majorana Collaboration, 15The Majorana Collaboration, 16The Majorana Collaboration, 17The Majorana Collaboration, 18The Majorana Collaboration, 19The Majorana Collaboration, 20The Majorana Collaboration, 21The Majorana Collaboration, 22The Majorana Collaboration, 23The Majorana Collaboration, 24The Majorana Collaboration, 25The Majorana Collaboration, 26The Majorana Collaboration, 27The Majorana Collaboration, 28The Majorana Collaboration, 29The Majorana Collaboration, 30The Majorana Collaboration, 31The Majorana Collaboration, 32The Majorana Collaboration, 33The Majorana Collaboration, 34The Majorana Collaboration, 35The Majorana Collaboration, 36The Majorana Collaboration, 37The Majorana Collaboration, 38The Majorana Collaboration, 39The Majorana Collaboration, 40The Majorana Collaboration, 41The Majorana Collaboration, 42The Majorana Collaboration, 43The Majorana Collaboration, 44The Majorana Collaboration, 45The Majorana Collaboration, 46The Majorana Collaboration, 47The Majorana Collaboration, 48The Majorana Collaboration, 49The Majorana Collaboration, 50The Majorana Collaboration, 51The Majorana Collaboration, 52The Majorana Collaboration, 53The Majorana Collaboration, 54The Majorana Collaboration, 55The Majorana Collaboration, 56The Majorana Collaboration, 57The Majorana Collaboration, 58The Majorana Collaboration, 59The Majorana Collaboration, 60The Majorana Collaboration, 61The Majorana Collaboration, 62The Majorana Collaboration, 63The Majorana Collaboration, 64The Majorana Collaboration, 65The Majorana Collaboration, 66The Majorana Collaboration, 67The Majorana Collaboration, 68The Majorana Collaboration, 69The Majorana Collaboration, 70The Majorana Collaboration, 71The Majorana Collaboration, 72The Majorana Collaboration, 73The Majorana Collaboration, 74The Majorana Collaboration

We report the first measurement of the total MUON flux underground at the Davis Campus of the Sanford Underground Research Facility at the 4850 ft level. Measurements were done with the Majorana Demonstrator veto system arranged in two different configurations. The measured total flux is (5. Read More

The MAJORANA collaboration is constructing the MAJORANA DEMONSTATOR at the Sanford Underground Research Facility at the Homestake gold mine, in Lead, SD. The apparatus will use Ge detectors, enriched in isotope \nuc{76}{Ge}, to demonstrate the feasibility of a large-scale Ge detector experiment to search for neutrinoless double beta decay. The long half-life of this postulated process requires that the apparatus be extremely low in radioactive isotopes whose decays may produce backgrounds to the search. Read More

Neutrinoless double beta decay searches play a major role in determining neutrino properties, in particular the Majorana or Dirac nature of the neutrino and the absolute scale of the neutrino mass. The consequences of these searches go beyond neutrino physics, with implications for Grand Unification and leptogenesis. The \textsc{Majorana} Collaboration is assembling a low-background array of high purity Germanium (HPGe) detectors to search for neutrinoless double-beta decay in $^{76}$Ge. Read More

The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, modular, HPGe detector array with a mass of 44-kg (29 kg 76Ge and 15 kg natGe) to search for neutrinoless double beta decay in Ge-76. The next generation of tonne-scale Ge-based neutrinoless double beta decay searches will probe the neutrino mass scale in the inverted-hierarchy region. The MAJORANA DEMONSTRATOR is envisioned to demonstrate a path forward to achieve a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value of 2039 keV. Read More

The MAJORANA Collaboration will seek neutrinoless double beta decay (0nbb) in 76Ge using isotopically enriched p-type point contact (PPC) high purity Germanium (HPGe) detectors. A tonne-scale array of HPGe detectors would require background levels below 1 count/ROI-tonne-year in the 4 keV region of interest (ROI) around the 2039 keV Q-value of the decay. In order to demonstrate the feasibility of such an experiment, the MAJORANA DEMONSTRATOR, a 40 kg HPGe detector array, is being constructed with a background goal of <3 counts/ROI-tonne-year, which is expected to scale down to <1 count/ROI-tonne-year for a tonne-scale experiment. Read More

The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, 40-kg modular HPGe detector array to search for neutrinoless double beta decay in 76Ge. In view of the next generation of tonne-scale Ge-based 0nbb-decay searches that will probe the neutrino mass scale in the inverted-hierarchy region, a major goal of the MAJORANA DEMONSTRATOR is to demonstrate a path forward to achieving a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value at 2039 keV. The background rejection techniques to be applied to the data include cuts based on data reduction, pulse shape analysis, event coincidences, and time correlations. Read More

The MAJORANA DEMONSTRATOR is a planned 40 kg array of Germanium detectors intended to demonstrate the feasibility of constructing a tonne-scale experiment that will seek neutrinoless double beta decay ($0\nu\beta\beta$) in $^{76}\mathrm{Ge}$. Such an experiment would require backgrounds of less than 1 count/tonne-year in the 4 keV region of interest around the 2039 keV Q-value of the $\beta\beta$ decay. Designing low-noise electronics, which must be placed in close proximity to the detectors, presents a challenge to reaching this background target. Read More

The goal of the \textsc{Majorana} \textsc{Demonstrator} project is to search for 0$\nu\beta\beta$ decay in $^{76}\mathrm{Ge}$. Of all candidate isotopes for 0$\nu\beta\beta$, $^{76}\mathrm{Ge}$ has some of the most favorable characteristics. Germanium detectors are a well established technology, and in searches for 0$\nu\beta\beta$, the high purity germanium crystal acts simultaneously as source and detector. Read More

2015Feb
Affiliations: 1Lawrence Berkeley National Laboratory, 2Pacific Northwest National Laboratory, 3University of South Carolina, 4Institute for Theoretical and Experimental Physics, 5Oak Ridge National Laboratory, 6Joint Institute for Nuclear Research, 7Duke University, 8University of South Dakota, 9South Dakota School of Mines and Technology, 10Lawrence Berkeley National Laboratory, 11South Dakota School of Mines and Technology, 12North Carolina State University, 13Center for Experimental Nuclear Physics and Astrophysics and University of Washington, 14Center for Experimental Nuclear Physics and Astrophysics and University of Washington, 15Center for Experimental Nuclear Physics and Astrophysics and University of Washington, 16University of Tennessee, 17Joint Institute for Nuclear Research, 18Osaka University, 19Los Alamos National Laboratory, 20Duke University, 21Pacific Northwest National Laboratory, 22University of North Carolina, 23University of North Carolina, 24Oak Ridge National Laboratory, 25University of North Carolina, 26Los Alamos National Laboratory, 27Oak Ridge National Laboratory, 28Center for Experimental Nuclear Physics and Astrophysics and University of Washington, 29University of South Carolina, 30Joint Institute for Nuclear Research, 31University of Alberta, 32Osaka University, 33Lawrence Berkeley National Laboratory, 34University of North Carolina, 35Pacific Northwest National Laboratory, 36South Dakota School of Mines and Technology, 37University of North Carolina, 38Black Hills State University, 39Tennessee Tech University, 40Joint Institute for Nuclear Research, 41Institute for Theoretical and Experimental Physics, 42Pacific Northwest National Laboratory, 43Osaka University, 44Center for Experimental Nuclear Physics and Astrophysics and University of Washington, 45North Carolina State University, 46Shanghai Jiao Tong University, 47University of North Carolina, 48University of South Dakota, 49University of North Carolina, 50Lawrence Berkeley National Laboratory, 51Center for Experimental Nuclear Physics and Astrophysics and University of Washington, 52University of South Carolina, 53Osaka University, 54Pacific Northwest National Laboratory, 55University of North Carolina, 56Pacific Northwest National Laboratory, 57University of North Carolina, 58North Carolina State University, 59Lawrence Berkeley National Laboratory, 60University of South Dakota, 61Oak Ridge National Laboratory, 62University of North Carolina, 63Los Alamos National Laboratory, 64Center for Experimental Nuclear Physics and Astrophysics and University of Washington, 65Oak Ridge National Laboratory, 66Los Alamos National Laboratory, 67University of North Carolina, 68Osaka University, 69Joint Institute for Nuclear Research, 70University of North Carolina, 71University of South Dakota, 72Pacific Northwest National Laboratory, 73South Dakota School of Mines and Technology, 74University of South Carolina, 75Black Hills State University, 76Joint Institute for Nuclear Research, 77Duke University, 78University of North Carolina, 79Oak Ridge National Laboratory, 80University of Tennessee, 81Lawrence Berkeley National Laboratory, 82University of North Carolina, 83Oak Ridge National Laboratory, 84University of North Carolina, 85University of South Carolina, 86Los Alamos National Laboratory, 87Joint Institute for Nuclear Research, 88North Carolina State University, 89Oak Ridge National Laboratory, 90Institute for Theoretical and Experimental Physics, 91Joint Institute for Nuclear Research

The Majorana Demonstrator is an ultra-low background physics experiment searching for the neutrinoless double beta decay of $^{76}$Ge. The Majorana Parts Tracking Database is used to record the history of components used in the construction of the Demonstrator. The tracking implementation takes a novel approach based on the schema-free database technology CouchDB. Read More

The MAJORANA Collaboration is constructing the MAJORANA Demonstrator, an ultra-low background, 40-kg modular high purity Ge detector array to search for neutrinoless double-beta decay in Ge. In view of the next generation of tonne-scale Ge-based neutrinoless double-beta decay searches that will probe the neutrino mass scale in the inverted-hierarchy region, a major goal of the Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value at 2039 keV. The current status of the Demonstrator is discussed, as are plans for its completion. Read More

The MAJORANA DEMONSTRATOR is an array of natural and enriched high purity germanium detectors that will search for the neutrinoless double-beta decay of 76-Ge and perform a search for weakly interacting massive particles (WIMPs) with masses below 10 GeV. As part of the MAJORANA research and development efforts, we have deployed a modified, low-background broad energy germanium detector at the Kimballton Underground Research Facility. With its sub-keV energy threshold, this detector is sensitive to potential non-Standard Model physics, including interactions with WIMPs. Read More

The Majorana Collaboration is constructing a system containing 40 kg of HPGe detectors to demonstrate the feasibility and potential of a future tonne-scale experiment capable of probing the neutrino mass scale in the inverted-hierarchy region. To realize this, a major goal of the Majorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest around the Q-value at 2039 keV. This goal is pursued through a combination of a significant reduction of radioactive impurities in construction materials with analytical methods for background rejection, for example using powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. Read More

High purity germanium (HPGe) crystals will be used for the MAJORANA DEMONSTRATOR, where they serve as both the source and the detector for neutrinoless double beta decay. It is crucial for the experiment to understand the performance of the HPGe crystals. A variety of crystal properties are being investigated, including basic properties such as energy resolution, efficiency, uniformity, capacitance, leakage current and crystal axis orientation, as well as more sophisticated properties, e. Read More

The focal-plane detector system for the KArlsruhe TRItium Neutrino (KATRIN) experiment consists of a multi-pixel silicon p-i-n-diode array, custom readout electronics, two superconducting solenoid magnets, an ultra high-vacuum system, a high-vacuum system, calibration and monitoring devices, a scintillating veto, and a custom data-acquisition system. It is designed to detect the low-energy electrons selected by the KATRIN main spectrometer. We describe the system and summarize its performance after its final installation. Read More

A low-background, high-purity germanium detector has been used to search for evidence of low-energy, bremsstrahlung-generated solar axions. An upper bound of $1.36\times 10^{-11}$ $(95% CL)$ is placed on the direct coupling of DFSZ model axions to electrons. Read More

The MAJORANA DEMONSTRATOR neutrinoless double beta-decay experiment is currently under construction at the Sanford Underground Research Facility in South Dakota, USA. An overview and status of the experiment are given. Read More

Semiconductor detectors in general have a dead layer at their surfaces that is either a result of natural or induced passivation, or is formed during the process of making a contact. Charged particles passing through this region produce ionization that is incompletely collected and recorded, which leads to departures from the ideal in both energy deposition and resolution. The silicon \textit{p-i-n} diode used in the KATRIN neutrino-mass experiment has such a dead layer. Read More

The {\sc Majorana Demonstrator will search for the neutrinoless double-beta decay of the isotope Ge-76 with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate the neutrino is its own antiparticle, demonstrate that lepton number is not conserved, and provide information on the absolute mass scale of the neutrino. The {\sc Demonstrator} is being assembled at the 4850-foot level of the Sanford Underground Research Facility in Lead, South Dakota. Read More

The {\sc Majorana} collaboration is searching for neutrinoless double beta decay using $^{76}$Ge, which has been shown to have a number of advantages in terms of sensitivities and backgrounds. The observation of neutrinoless double-beta decay would show that lepton number is violated and that neutrinos are Majorana particles and would simultaneously provide information on neutrino mass. Attaining sensitivities for neutrino masses in the inverted hierarchy region, $15 - 50$ meV, will require large, tonne-scale detectors with extremely low backgrounds, at the level of $\sim$1 count/t-y or lower in the region of the signal. Read More

2012Oct
Affiliations: 1The. MAJORANA. Collaboration, 2The. MAJORANA. Collaboration, 3The. MAJORANA. Collaboration, 4The. MAJORANA. Collaboration, 5The. MAJORANA. Collaboration, 6The. MAJORANA. Collaboration, 7The. MAJORANA. Collaboration, 8The. MAJORANA. Collaboration, 9The. MAJORANA. Collaboration, 10The. MAJORANA. Collaboration, 11The. MAJORANA. Collaboration, 12The. MAJORANA. Collaboration, 13The. MAJORANA. Collaboration, 14The. MAJORANA. Collaboration, 15The. MAJORANA. Collaboration, 16The. MAJORANA. Collaboration, 17The. MAJORANA. Collaboration, 18The. MAJORANA. Collaboration, 19The. MAJORANA. Collaboration, 20The. MAJORANA. Collaboration, 21The. MAJORANA. Collaboration, 22The. MAJORANA. Collaboration, 23The. MAJORANA. Collaboration, 24The. MAJORANA. Collaboration, 25The. MAJORANA. Collaboration, 26The. MAJORANA. Collaboration, 27The. MAJORANA. Collaboration, 28The. MAJORANA. Collaboration, 29The. MAJORANA. Collaboration, 30The. MAJORANA. Collaboration, 31The. MAJORANA. Collaboration, 32The. MAJORANA. Collaboration, 33The. MAJORANA. Collaboration, 34The. MAJORANA. Collaboration, 35The. MAJORANA. Collaboration, 36The. MAJORANA. Collaboration, 37The. MAJORANA. Collaboration, 38The. MAJORANA. Collaboration, 39The. MAJORANA. Collaboration, 40The. MAJORANA. Collaboration, 41The. MAJORANA. Collaboration, 42The. MAJORANA. Collaboration, 43The. MAJORANA. Collaboration, 44The. MAJORANA. Collaboration, 45The. MAJORANA. Collaboration, 46The. MAJORANA. Collaboration, 47The. MAJORANA. Collaboration, 48The. MAJORANA. Collaboration, 49The. MAJORANA. Collaboration, 50The. MAJORANA. Collaboration, 51The. MAJORANA. Collaboration, 52The. MAJORANA. Collaboration, 53The. MAJORANA. Collaboration, 54The. MAJORANA. Collaboration, 55The. MAJORANA. Collaboration, 56The. MAJORANA. Collaboration, 57The. MAJORANA. Collaboration, 58The. MAJORANA. Collaboration, 59The. MAJORANA. Collaboration, 60The. MAJORANA. Collaboration, 61The. MAJORANA. Collaboration, 62The. MAJORANA. Collaboration, 63The. MAJORANA. Collaboration, 64The. MAJORANA. Collaboration, 65The. MAJORANA. Collaboration, 66The. MAJORANA. Collaboration, 67The. MAJORANA. Collaboration, 68The. MAJORANA. Collaboration, 69The. MAJORANA. Collaboration, 70The. MAJORANA. Collaboration, 71The. MAJORANA. Collaboration, 72The. MAJORANA. Collaboration, 73The. MAJORANA. Collaboration, 74The. MAJORANA. Collaboration, 75The. MAJORANA. Collaboration, 76The. MAJORANA. Collaboration, 77The. MAJORANA. Collaboration, 78The. MAJORANA. Collaboration, 79The. MAJORANA. Collaboration, 80The. MAJORANA. Collaboration, 81The. MAJORANA. Collaboration, 82The. MAJORANA. Collaboration, 83The. MAJORANA. Collaboration

The MAJORANA DEMONSTRATOR will search for the neutrinoless double-beta decay of the 76Ge isotope with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate the neutrino is its own anti-particle, demonstrate that lepton number is not conserved, and provide information on the absolute mass-scale of the neutrino. The DEMONSTRATOR is being assembled at the 4850 foot level of the Sanford Underground Research Facility in Lead, South Dakota. Read More

A study of signals originating near the lithium-diffused n+ contact of p-type point contact (PPC) high purity germanium detectors (HPGe) is presented. The transition region between the active germanium and the fully dead layer of the n+ contact is examined. Energy depositions in this transition region are shown to result in partial charge collection. Read More

The Karlsruhe Tritium Neutrino Experiment (KATRIN) will detect tritium beta- decay electrons that pass through its electromagnetic spectrometer with a highly- segmented monolithic silicon pin-diode focal-plane detector (FPD). This pin-diode array will be on a single piece of 500-{\mu}m-thick silicon, with contact between titanium nitride (TiN) coated detector pixels and front-end electronics made by spring-loaded pogo pins. The pogo pins will exert a total force of up to 50N on the detector, deforming it and resulting in mechanical stress up to 50 MPa in the silicon bulk. Read More

The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the Majorana experiment, known as the Demonstrator, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the Demonstrator is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak. Read More

A brief review of the history and neutrino physics of double beta decay is given. A description of the MAJORANA DEMONSTRATOR research and development program including background reduction techniques is presented in some detail. The application of point contact (PC) detectors to the experiment is discussed, including the effectiveness of pulse shape analysis. Read More

Neutrinoless double-beta decay experiments can potentially determine the Majorana or Dirac nature of the neutrino, and aid in understanding the neutrino absolute mass scale and hierarchy. Future 76Ge-based searches target a half-life sensitivity of >10^27 y to explore the inverted neutrino mass hierarchy. Reaching this sensitivity will require a background rate of <1 count tonne^-1 y^-1 in a 4-keV-wide spectral region of interest surrounding the Q value of the decay. Read More

The observation of neutrinoless double-beta decay would determine whether the neutrino is a Majorana particle and provide information on the absolute scale of neutrino mass. The MAJORANA Collaboration is constructing the DEMONSTRATOR, an array of germanium detectors, to search for neutrinoless double-beta decay of 76-Ge. The DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76-Ge. Read More

2011Jul
Authors: B. Aharmim, S. N. Ahmed, J. F. Amsbaugh, J. M. Anaya, A. E. Anthony, J. Banar, N. Barros, E. W. Beier, A. Bellerive, B. Beltran, M. Bergevin, S. D. Biller, K. Boudjemline, M. G. Boulay, T. J. Bowles, M. C. Browne, T. V. Bullard, T. H. Burritt, B. Cai, Y. D. Chan, D. Chauhan, M. Chen, B. T. Cleveland, G. A. Cox, C. A. Currat, X. Dai, H. Deng, J. A. Detwiler, M. DiMarco, P. J. Doe, G. Doucas, M. R. Dragowsky, P. -L. Drouin, C. A. Duba, F. A. Duncan, M. Dunford, E. D. Earle, S. R. Elliott, H. C. Evans, G. T. Ewan, J. Farine, H. Fergani, F. Fleurot, R. J. Ford, J. A. Formaggio, M. M. Fowler, N. Gagnon, J. V. Germani, A. Goldschmidt, J. TM. Goon, K. Graham, E. Guillian, S. Habib, R. L. Hahn, A. L. Hallin, E. D. Hallman, A. A. Hamian, G. C. Harper, P. J. Harvey, R. Hazama, K. M. Heeger, W. J. Heintzelman, J. Heise, R. L. Helmer, R. Henning, A. Hime, C. Howard, M. A. Howe, M. Huang, P. Jagam, B. Jamieson, N. A. Jelley, K. J. Keeter, J. R. Klein, L. L. Kormos, M. Kos, A. Krueger, C. Kraus, C. B. Krauss, T. Kutter, C. C. M. Kyba, R. Lange, J. Law, I. T. Lawson, K. T. Lesko, J. R. Leslie, J. C. Loach, R. MacLellan, S. Majerus, H. B. Mak, J. Maneira, R. Martin, N. McCauley, A. B. McDonald, S. R. McGee, C. Mifflin, G. G. Miller, M. L. Miller, B. Monreal, J. Monroe, B. Morissette, A. W. Myers, B. G. Nickel, A. J. Noble, H. M. O'Keeffe, N. S. Oblath, R. W. Ollerhead, G. D. Orebi Gann, S. M. Oser, R. A. Ott, S. J. M. Peeters, A. W. P. Poon, G. Prior, S. D. Reitzner, K. Rielage, B. C. Robertson, R. G. H. Robertson, E. Rollin, M. H. Schwendener, J. A. Secrest, S. R. Seibert, O. Simard, J. J. Simpson, P. Skensved, M. W. E. Smith, T. J. Sonley, T. D. Steiger, L. C. Stonehill, G. Tesic, P. M. Thornewell, N. Tolich, T. Tsui, C. D. Tunnell, T. Van Wechel, R. Van Berg, B. A. VanDevender, C. J. Virtue, B. L. Wall, D. Waller, H. Wan Chan Tseung, J. Wendland, N. West, J. B. Wilhelmy, J. F. Wilkerson, J. R. Wilson, J. M. Wouters, A. Wright, M. Yeh, F. Zhang, K. Zuber

This paper details the solar neutrino analysis of the 385.17-day Phase-III data set acquired by the Sudbury Neutrino Observatory (SNO). An array of $^3$He proportional counters was installed in the heavy-water target to measure precisely the rate of neutrino-deuteron neutral-current interactions. Read More

The MAJORANA Collaboration is building the MAJORANA DEMONSTRATOR, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The MAJORANA DEMONSTRATOR will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c^2 mass range. Read More

An array of Neutral-Current Detectors (NCDs) has been built in order to make a unique measurement of the total active flux of solar neutrinos in the Sudbury Neutrino Observatory (SNO). Data in the third phase of the SNO experiment were collected between November 2004 and November 2006, after the NCD array was added to improve the neutral-current sensitivity of the SNO detector. This array consisted of 36 strings of proportional counters filled with a mixture of $^3$He and CF$_4$ gas capable of detecting the neutrons liberated by the neutrino-deuteron neutral current reaction in the D$_2$O, and four strings filled with a mixture of $^4$He and CF$_4$ gas for background measurements. Read More

Observations show that 1612 MHz masers of OH/IR stars can fade on a timescale of a decade. This fading is probably associated with the switch from rapid mass loss, which is ultimately linked with an internal He-shell flash, to the much slower mass loss supported by more quiescent conditions. We study the observed maser decay with a composite computational model, comprising a time-dependent chemical model of the envelope, and a radiation transfer model which provides the maser pumping. Read More

We describe an apparatus used to measure the triple-correlation term (\D \hat{\sigma}_n\cdot p_e\times p_\nu) in the beta-decay of polarized neutrons. The \D-coefficient is sensitive to possible violations of time reversal invariance. The detector has an octagonal symmetry that optimizes electron-proton coincidence rates and reduces systematic effects. Read More