Results for "J. I. Collar"

total 222084took 0.20s
Comments on "Final Analysis and Results of the Phase II SIMPLE Dark Matter Search"Jun 17 2011The SIMPLE collaboration has recently claimed improved limits on WIMP-nucleus couplings (arXiv:1106.3014). The limited shelf-life of SIMPLE detectors and apparent deficiencies in the acoustic background discrimination method employed severely affect the ... More
A Realistic Assessment of the Sensitivity of XENON10 and XENON100 to Light-Mass WIMPsJun 03 2011Jun 14 2011The underlaying assumptions and uncertainties involved in the derivation of WIMP exclusion limits from XENON10 and XENON100 detectors are examined. In view of these, recent claims of sensitivity to light-mass Weakly Interacting Massive Particles (WIMPs) ... More
Comments on "A Dark Matter Search with MALBEK"Jul 09 2014Jul 10 2014CoGeNT and MALBEK use p-type point contact germanium detectors to search for low-mass dark matter particles. Both detectors enjoy identical intrinsic noise characteristics. However, MALBEK's data acquisition electronics severely degrade the ability to ... More
Biological Effects of Stellar Collapse NeutrinosMay 05 1995Dec 01 1995Massive stars in their final stages of collapse radiate most of their binding energy in the form of MeV neutrinos. The recoil atoms that they produce in elastic scattering off nuclei in organic tissue create radiation damage which is highly effective ... More
Comments on "Limits on Dark Matter Using Ancient Mica"Nov 13 1995To appear in Phys. Rev. Lett. together with the author's Reply.
Clumpy Cold Dark Matter and Biological ExtinctionsDec 10 1995Cosmological models with cosmic string and texture seeded universes predict a present abundance of very dense clumps of Cold Dark Matter particles. Their crossing through the solar system would induce a non-negligible amount of radiation damage to all ... More
A comparison between the low-energy spectra from CoGeNT and CDMSMar 17 2011A side-to-side comparison is established between the nuclear recoil energy spectrum from CDMS germanium bolometers and its low-energy equivalent for events in the inner bulk volume of a CoGeNT germanium diode. Acknowledging the orthogonality of the background ... More
A new approach to neutrino and WIMP detection using telecom-grade electrooptic and fiber-optic componentsMay 10 2001The dense energy deposition from a low-energy nuclear recoil produces, via the thermoacoustic effect, a brief yet intense pressure pulse that can be used for WIMP or neutrino detection in some fiber-optic devices sensitive to acoustooptic disturbances. ... More
Applications of an Y-88/Be photo-neutron calibration source to Dark Matter and Neutrino ExperimentsMar 11 2013Mar 18 2013The low-energy monochromatic neutron emission from an Y-88/Be source can be exploited to mimic the few keVnr nuclear recoils expected from low-mass Weakly Interacting Massive Particles (WIMPs) and coherent scattering of neutrinos off nuclei. Using this ... More
Superheated Microdrops as Cold Dark Matter DetectorsJul 29 1996It is shown that under realistic background considerations, an improvement in Cold Dark Matter sensitivity of several orders of magnitude is expected from a detector based on superheated liquid droplets. Such devices are totally insensitive to minimum ... More
Light WIMP Searches: The Effect of the Uncertainty in Recoil Energy Scale and Quenching FactorOct 25 2010Taking liquid xenon detectors as a case study, the importance of a robust recoil energy calibration as a prerequisite to a search for light-mass Weakly Interacting Massive Particles (WIMPs) is emphasized. Important shortfalls in the analysis of existing ... More
Comments on arXiv:1006.0972 "XENON10/100 dark matter constraints in comparison with CoGeNT and DAMA: examining the Leff dependence"Jun 09 2010Savage et al. have recently put forward the claim that results from the XENON10 experiment are incompatible with the totality of both DAMA/LIBRA and CoGeNT experimental regions. In this brief note the source of this erroneous conclusion is identified ... More
Quenching and Channeling of Nuclear Recoils in NaI[Tl]: Implications for Dark Matter SearchesFeb 04 2013Mar 18 2013A new experimental evaluation of the quenching factor for nuclear recoils in NaI[Tl] is described. Systematics affecting previous measurements are addressed by careful characterization of the emission spectrum of the neutron source, use of a small scintillator ... More
CAST: A search for solar axions at CERNApr 15 2003The new axion helioscope at CERN started acquiring data during September of 2002: CAST (Cern Axion Solar Telescope) employs a decommissioned LHC dipole magnet to convert putative solar axions or axion-like particles into detectable photons. The unprecedented ... More
Endpoint Structure in Beta Decay from Coherent Weak-Interaction of the NeutrinoNov 25 1996Jul 09 1999Recent tritium beta decay experiments yield unphysical negative best-fit values for the square of the neutrino mass. An unidentified bump-like excess of counts few eV below the endpoint in the electron energy spectrum has been tentatively recognized as ... More
Search for a Non-Relativistic Component in the Spectrum of Cosmic Rays at EarthMay 07 2018May 09 2018Dark matter particles gravitationally bound to our galaxy should exhibit a characteristic speed distribution limited by their escape velocity at the position of the Earth ($v_{esc}\simeq$ 550 km/s). An ongoing search for anomalous cosmic rays at Earth, ... More
Constraints on Exotic Heavily Ionizing Particles from the Geological Abundance of FullerenesFeb 22 1999Aug 31 1999The C_{60} molecule exhibits a remarkable stability and inertness that leads to its survival in ancient carbonaceous rocks initially subject to the high temperatures requisite for its formation. Elementary particles having very high electronic stopping ... More
Low-background applications of MICROMEGAS detector technologySep 28 2000Jan 17 2001The MICROMEGAS detector concept, generally optimized for use in accelerator experiments, displays a peculiar combination of features that can be advantageous in several astroparticle and neutrino physics applications. Their sub-keV ionization energy threshold, ... More
Recent Results from the SIMPLE Dark Matter SearchApr 12 2005SIMPLE is an experimental search for evidence of spin-dependent dark matter, based on superheated droplet detectors using C$_{2}$ClF$_{5}$. We report preliminary results of a 0.6 kgdy exposure of five one liter devices, each containing $\sim$10 g active ... More
A Maximum Likelihood Analysis of Low-Energy CDMS DataApr 16 2012Apr 22 2012An unbinned maximum likelihood analysis of CDMS low-energy data reveals a strong preference (5.7 sigma C.L.) for a model containing an exponential excess of events in the nuclear recoil band, when compared to the null hypothesis. We comment on the possible ... More
Surface Sputtering from Cold Dark Matter Interactions: Proposed Search for its Diurnal ModulationMay 12 1995Nuclear recoil cascades induced by Cold Dark Matter (CDM) elastic scattering can produce the ejection of target atoms from solid surfaces. We calculate the yield and energy distribution of these sputtered atoms in a variety of materials. These parameters ... More
Response to arXiv:1005.2615May 20 2010Brief response to a Reply [arXiv:1005.2615] on our Comments [arXiv:1005.0838] on XENON100 recent results [arXiv:1005.0380].
Comments on "First Dark Matter Results from the XENON100 Experiment"May 05 2010May 12 2010The XENON100 collaboration has recently released new dark matter limits, placing particular emphasis on their impact on searches known to be sensitive to light-mass (below 10 GeV/c^2) Weakly Interacting Massive Particles (WIMPs), such as DAMA and CoGeNT. ... More
Comments on arXiv:0902.4693v1 "Search for Axions with the CDMS Experiment"Mar 29 2009We offer a few remarks that should help clarify the relative sensitivity of CoGeNT, CDMS and DAMA to dark pseudoscalars. An alternative dark matter origin for the DAMA modulation is briefly mentioned within this context.
Nuclear Tracks from Cold Dark Matter Interactions in Mineral Crystals: A Computational StudyMay 11 1995May 12 1995Recoiling nuclei from Cold Dark Matter (CDM) elastic scattering interactions with the constituent elements of some minerals may produce etchable damage tracks in the crystal structure. Present calculations show that in muscovite mica, CDM tracks from ... More
Towards Coherent Neutrino Detection Using Low-Background Micropattern Gas DetectorsDec 13 2002Dec 14 2002The detection of low energy neutrinos ($<$ few tens of MeV) via coherent nuclear scattering remains a holy grail of sorts in neutrino physics. This uncontroversial mode of interaction is expected to profit from a sizeable increase in cross section proportional ... More
Superheated Droplet Detectors as CDM Detectors: The SIMPLE ExperimentOct 31 1996Superheated Droplet Detectors (SDDs) are becoming commonplace in neutron personnel dosimetry. Their total insensitivity to minimum ionizing radiation (while responsive to nuclear recoils of energies ~ few keV), together with their low cost, ease of production, ... More
Design and Characterization of a Neutron Calibration Facility for the Study of sub-keV Nuclear RecoilsJan 06 2007As part of an experimental effort to demonstrate sensitivity in a large-mass detector to the ultra-low energy recoils expected from coherent neutrino-nucleus elastic scattering, we have designed and built a highly monochromatic 24 keV neutron beam at ... More
Comment on "Fitting the annual modulation in DAMA with neutrons from muons and neutrinos''Sep 10 2014We estimate rates of solar neutrino-induced neutrons in a DAMA/LIBRA-like detector setup, and find that the needed contribution to explain the annual modulation would require neutrino-induced neutron cross sections several orders of magnitude larger than ... More
Large-Mass Ultra-Low Noise Germanium Detectors: Performance and Applications in Neutrino and Astroparticle PhysicsJan 07 2007A new type of radiation detector, a p-type modified electrode germanium diode, is presented. The prototype displays, for the first time, a combination of features (mass, energy threshold and background expectation) required for a measurement of coherent ... More
Response of CsI[Na] to Nuclear Recoils: Impact on Coherent Elastic Neutrino-Nucleus Scattering (CE$ν$NS)Jul 10 2019A new measurement of the quenching factor for low-energy nuclear recoils in CsI[Na] is presented. Past measurements are revisited, identifying and correcting several systematic effects. The resulting global data are well-described by a physics-based model ... More
WIMP identification through a combined measurement of axial and scalar couplingsMay 17 2007Jul 23 2007We study the prospects for detecting Weakly Interacting Massive Particles (WIMPs), in a number of phenomenological scenarios, with a detector composed of a target simultaneously sensitive to both spin-dependent and spin-independent couplings, as is the ... More
Additional Comments on "New Limits on Spin-Independent Couplings of Low-Mass WIMP Dark Matter with a Germanium Detector at a Threshold of 200 eV"Jun 08 2008Aug 09 2008In a previous comment (arXiv:0806.1341v1) we criticized purely technical aspects of arXiv:0712.1645 but pointed out that many other inconsistencies were readily apparent. In view of the imminent posting of another version of arXiv:0712.1645, still containing ... More
Solar-bound weakly interacting massive particles: a no-frills phenomenologyAug 07 1998Jan 22 1999The case for a stable population of solar-bound Earth-crossing Weakly Interacting Massive Particles (WIMPs) is reviewed. A practical general expression for their speed distribution in the laboratory frame is derived under basic assumptions. If such a ... More
Response of CsI[Na] to Nuclear Recoils: Impact on Coherent Elastic Neutrino-Nucleus Scattering (CE$ν$NS)Jul 10 2019Jul 13 2019A new measurement of the quenching factor for low-energy nuclear recoils in CsI[Na] is presented. Past measurements are revisited, identifying and correcting several systematic effects. The resulting global data are well-described by a physics-based model ... More
A First Mass Production of Gas Electron MultipliersApr 07 2003We report on the manufacture of a first batch of approximately 2,000 Gas Electron Multipliers (GEMs) using 3M's fully automated roll to roll flexible circuit production line. This process allows low-cost, reproducible fabrication of a high volume of GEMs ... More
First Characterization of the Ultra-Shielded Chamber in the Low-noise Underground Laboratory (LSBB) of Rustrel Pays d'AptOct 11 1999Oct 13 1999In compliance with international agreements on nuclear weapons limitation, the French ground-based nuclear arsenal has been decommissioned in its totality. One of its former underground missile control centers, located in Rustrel, 60 km east of Avignon ... More
Measurement of the low-energy quenching factor in germanium using an $^{88}$Y/Be photoneutron sourceAug 11 2016We employ an $^{88}$Y/Be photoneutron source to derive the quenching factor for neutron-induced nuclear recoils in germanium, probing recoil energies from a few hundred eV$_{nr}$ to 8.5keV$_{nr}$. A comprehensive Monte Carlo simulation of our setup is ... More
First Dark Matter Limits from a Large-Mass, Low-Background Superheated Droplet DetectorJan 28 2000Sep 29 2000We report on the fabrication aspects and calibration of the first large active mass ($\sim15$ g) modules of SIMPLE, a search for particle dark matter using Superheated Droplet Detectors (SDDs). While still limited by the statistical uncertainty of the ... More
A Consistent Dark Matter Interpretation For CoGeNT and DAMA/LIBRAJul 06 2010Oct 27 2010In this paper, we study the recent excess of low energy events observed by the CoGeNT collaboration and the annual modulation reported by the DAMA/LIBRA collaboration, and discuss whether these signals could both be the result of the same elastically ... More
Beta Irradiation of a Geometrically Metastable Superconducting Strip Detector with a Magnetic Flux Penetration Read-OutDec 10 1995Geometrical metastability, observed in superconducting type I tin flat strips, has been previously proposed as a principle for particle detection. The energy deposition of an incoming beta-particle induces the rupture of the metastability and consequently ... More
S-35 Beta Irradiation of a Tin Strip in a State of Superconducting Geometrical MetastabilityNov 30 1995We report the first energy loss spectrum obtained with a geometrically metastable type I superconducting tin strip irradiated by the beta-emission of S-35. (Nucl. Instr. Meth. A, in press)
Liquid Scintillator Response to Proton Recoils in the 10-100 keV RangeApr 17 2018May 08 2018We study the response of EJ-301 liquid scintillator to monochromatic 244.6 $\pm$ 8.4 keV neutrons, targeting the 10-100 keV proton recoil energy interval. Limited experimental information exists for proton light yield in this range, for this or any other ... More
Prospects for SIMPLE 2000: A large-mass, low-background Superheated Droplet Detector for WIMP searchesMay 03 2000SIMPLE 2000 (Superheated Instrument for Massive ParticLE searches) will consist of an array of eight to sixteen large active mass ($\sim15$ g) Superheated Droplet Detectors(SDDs) to be installed in the new underground laboratory of Rustrel-Pays d'Apt. ... More
Cold dark matter identification: Diurnal modulation reexaminedFeb 19 1997Jul 29 1997We report on new estimates of the modulation expected in semiconductor detectors due to eclipsing of dark matter particles in the Earth. We reevaluate the theoretical modulation significances and discuss the differences found with previous calculations. ... More
Coherent neutrino-nucleus scattering detection with a CsI[Na] scintillator at the SNS spallation sourceJul 28 2014Aug 20 2014We study the possibility of using CsI[Na] scintillators as an advantageous target for the detection of coherent elastic neutrino-nucleus scattering (CENNS), using the neutrino emissions from the SNS spallation source at Oak Ridge National Laboratory. ... More
Theory for the Direct Detection of Solar Axions by Coherent Primakoff Conversion in Germanium DetectorsAug 01 1997It is assumed that axions exist and are created in the Sun by Primakoff conversion of photons in the Coulomb fields of nuclei. Detection rates are calculated in germanium detectors due to the coherent conversion of axions to photons in the lattice when ... More
WIMP searches with superheated droplet detectors: Status and ProspectsJan 11 2001Jan 14 2001SIMPLE (Superheated Instrument for Massive ParticLE searches) employs superheated droplet detectors (SDDs) to search for Weakly Interacting Massive Particle (WIMP) dark matter. As a result of the intrinsic SDD insensitivity to minimum ionizing particles ... More
Improved Limits on Spin-Dependent WIMP-Proton Interactions from a Two Liter CF$_3$I Bubble ChamberAug 20 2010Mar 07 2011Data from the operation of a bubble chamber filled with 3.5 kg of CF$_{3}$I in a shallow underground site are reported. An analysis of ultrasound signals accompanying bubble nucleations confirms that alpha decays generate a significantly louder acoustic ... More
Measurement of the ionization produced by sub-keV silicon nuclear recoils in a CCD dark matter detectorAug 02 2016We report a measurement of the ionization efficiency of silicon nuclei recoiling with sub-keV kinetic energy in the bulk silicon of a charge-coupled device (CCD). Nuclear recoils were produced by low-energy neutrons ($<$24 keV) from a $^{124}$Sb-$^{9}$Be ... More
Measurement of the ionization produced by sub-keV silicon nuclear recoils in a CCD dark matter detectorAug 02 2016Nov 10 2016We report a measurement of the ionization efficiency of silicon nuclei recoiling with sub-keV kinetic energy in the bulk silicon of a charge-coupled device (CCD). Nuclear recoils are produced by low-energy neutrons ($<$24 keV) from a $^{124}$Sb-$^{9}$Be ... More
Development of Bubble Chambers With Enhanced Stability and Sensitivity to Low-Energy Nuclear RecoilsMar 17 2005The viability of using a Bubble Chamber for rare event searches and in particular for the detection of dark matter particle candidates is considered. Techniques leading to the deactivation of inhomogeneous nucleation centers and subsequent enhanced stability ... More
Improved Spin-Dependent WIMP Limits from a Bubble ChamberApr 17 2008Bubble Chambers provided the dominant particle detection technology in accelerator experiments for several decades, eventually falling into disuse with the advent of other techniques. We report here on the first period of operation of an ultra-clean, ... More
CSL Collapse Model And Spontaneous Radiation: An UpdateJan 12 2000A brief review is given of the Continuous Spontaneous Localization (CSL) model in which a classical field interacts with quantized particles to cause dynamical wavefunction collapse. One of the model's predictions is that particles "spontaneously" gain ... More
First dark matter search results from a 4-kg CF$_3$I bubble chamber operated in a deep underground siteApr 13 2012Sep 19 2012New data are reported from the operation of a 4.0 kg CF$_{3}$I bubble chamber in the 6800-foot-deep SNOLAB underground laboratory. The effectiveness of ultrasound analysis in discriminating alpha-decay background events from single nuclear recoils has ... More
Search for an annual modulation of dark-matter signals with a germanium spectrometer at the Sierra Grande LaboratorySep 02 1998Sep 14 1998Data collected during three years with a germanium spectrometer at the Sierra Grande underground laboratory have been analyzed for distinctive features of annual modulation of the signal induced by WIMP dark matter candidates. The main motivation for ... More
Experimental Search for Solar AxionsDec 23 1997Dec 26 1997A new technique has been used to search for solar axions using a single crystal germanium detector. It exploits the coherent conversion of axions into photons when their angle of incidence satisfies a Bragg condition with a crystalline plane. The analysis ... More
Search for an Annual Modulation in a P-type Point Contact Germanium Dark Matter DetectorJun 03 2011Oct 04 2011Fifteen months of cumulative CoGeNT data are examined for indications of an annual modulation, a predicted signature of Weakly Interacting Massive Particle (WIMP) interactions. Presently available data support the presence of a modulated component of ... More
The C-4 Dark Matter ExperimentOct 23 2012Feb 07 2013We describe the experimental design of C-4, an expansion of the CoGeNT dark matter search to four identical detectors each approximately three times the mass of the p-type point contact germanium diode presently taking data at the Soudan Underground Laboratory. ... More
Direct Measurement of the Bubble Nucleation Energy Threshold in a CF3I Bubble ChamberApr 22 2013Jan 31 2014We have directly measured the energy threshold and efficiency for bubble nucleation from iodine recoils in a CF3I bubble chamber in the energy range of interest for a dark matter search. These interactions cannot be probed by standard neutron calibration ... More
Experimental constraints on a dark matter origin for the DAMA annual modulation effectJul 05 2008Jul 31 2008A claim for evidence of dark matter interactions in the DAMA experiment has been recently reinforced. We employ a new type of germanium detector to conclusively rule out a standard isothermal galactic halo of Weakly Interacting Massive Particles (WIMPs) ... More
Search for An Annual Modulation in Three Years of CoGeNT Dark Matter Detector DataJan 14 2014Weakly Interacting Massive Particles (WIMPs) are well-established dark matter candidates. WIMP interactions with sensitive detectors are expected to display a characteristic annual modulation in rate. We release a dataset spanning 3.4 years of operation ... More
CoGeNT: A Search for Low-Mass Dark Matter using p-type Point Contact Germanium DetectorsAug 28 2012Apr 29 2013CoGeNT employs p-type point-contact (PPC) germanium detectors to search for Weakly Interacting Massive Particles (WIMPs). By virtue of its low energy threshold and ability to reject surface backgrounds, this type of device allows an emphasis on low-mass ... More
Experimental Search for Solar Axions via Coherent Primakoff Conversion in a Germanium SpectrometerAug 01 1997Results are reported of an experimental search for the unique, rapidly varying temporal pattern of solar axions coherently converting into photons via the Primakoff effect in a single crystal germanium detector. This conversion is predicted when axions ... More
SIMPLE Dark Matter Search ResultsMay 17 2005We report an improved SIMPLE experiment comprising four superheated droplet detectors with a total exposure of 0.42 kgd. The result yields ~ factor 10 improvement in the previously-reported results, and -- despite the low exposure -- is seen to provide ... More
A Decommissioned LHC Model Magnet as an Axion TelescopeJan 18 1998Jan 22 1999The 8.4 Tesla, 10 m long transverse magnetic field of a twin aperture LHC bending magnet can be utilized as a macroscopic coherent solar axion-to-photon converter. Numerical calculations show that the integrated time of alignment with the Sun would be ... More
ORB5: a global electromagnetic gyrokinetic code using the PIC approach in toroidal geometryMay 06 2019This paper presents the current state of the global gyrokinetic code ORB5 as an update of the previous reference [Jolliet et al., Comp. Phys. Commun. 177 409 (2007)]. The ORB5 code solves the electromagnetic Vlasov-Maxwell system of equations using a ... More
Effects of Diurnal Modulation in Direct Cold Dark Matter Searches. the Experiment in Sierra GrandeNov 18 1993Contains a summary, current status and prospects for the direct detection of cold dark matter using diurnal modulation effects as presented at the ELAF 93, Mar del Plata Argentina. The potential advantages of using the Earth as an absorber to produce ... More
Results from a Search for Light-Mass Dark Matter with a P-type Point Contact Germanium DetectorFeb 25 2010Mar 16 2010We report on several features present in the energy spectrum from an ultra low-noise germanium detector operated at 2,100 m.w.e. By implementing a new technique able to reject surface events, a number of cosmogenic peaks can be observed for the first ... More
Comment on "Evidence for Neutrinoless Double Beta Decay"Feb 07 2002May 22 2002We comment on the recent claim for the experimental observation of neutrinoless double-beta decay. We discuss several limitations in the analysis provided in that paper and conclude that there is no basis for the presented claim.
A Low-noise Germanium Ionization Spectrometer for Low-background ScienceMar 04 2016Recent progress on the development of very low noise high purity germanium ionization spectrometers has produced an instrument of 1.2 kg mass and excellent noise performance. The detector was installed in a low-background cryostat intended for use in ... More
The Majorana Ge-76 Double-Beta Decay ProjectJan 11 2002The Majorana Experiment is a next-generation Ge-76 double-beta decay search. It will employ 500 kg of Ge, isotopically enriched to 86% in Ge-76, in the form of 200 detectors in a close-packed array for high granularity. Each crystal will be electronically ... More
Search for chameleons with CASTMar 16 2015Mar 18 2016In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter ($\beta_{\rm m}$) and to photons ... More
New solar axion search in CAST with $^4$He fillingMar 02 2015Jun 11 2015The CERN Axion Solar Telescope (CAST) searches for $a\to\gamma$ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. Two parallel magnet bores can be filled with helium of adjustable pressure to match ... More
New CAST Limit on the Axion-Photon InteractionMay 05 2017Dec 20 2017During 2003--2015, the CERN Axion Solar Telescope (CAST) has searched for $a\to\gamma$ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. In its final phase of solar axion searches (2013--2015), ... More
Improved dark matter search results from PICO-2L Run 2Jan 14 2016Mar 25 2016New data are reported from a second run of the 2-liter PICO-2L C$_3$F$_8$ bubble chamber with a total exposure of 129$\,$kg-days at a thermodynamic threshold energy of 3.3$\,$keV. These data show that measures taken to control particulate contamination ... More
CAST constraints on the axion-electron couplingFeb 26 2013Apr 19 2013In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axio-recombination, the "BCA processes." Based on a new calculation of this flux, including ... More
Results and perspectives of the solar axion search with the CAST experimentSep 27 2012Oct 30 2012The status of the solar axion search with the CERN Axion Solar Telescope (CAST) will be presented. Recent results obtained by the use of $^3$He as a buffer gas has allowed us to extend our sensitivity to higher axion masses than our previous measurements ... More
Probing eV-scale axions with CASTOct 24 2008Jan 09 2009We have searched for solar axions or other pseudoscalar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup. Whereas we previously have reported results from CAST with evacuated magnet bores (Phase I), setting limits ... More
Dark Matter Search Results from the PICO-60 CF$_3$I Bubble ChamberOct 27 2015Mar 03 2016New data are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 36.8 kg of CF$_3$I and located in the SNOLAB underground laboratory. PICO-60 is the largest bubble chamber to search for dark matter to date. With ... More
Developing a Bubble Chamber Particle Discriminator Using Semi-Supervised LearningNov 27 2018The identification of non-signal events is a major hurdle to overcome for bubble chamber dark matter experiments such as PICO-60. The current practice of manually developing a discriminator function to eliminate background events is difficult when available ... More
Dark Matter Search Results from the PICO-60 C$_3$F$_8$ Bubble ChamberFeb 24 2017Aug 02 2017New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C$_3$F$_8$ located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60 C$_3$F$_8$ exhibits excellent ... More
Dark Matter Search Results from the PICO-2L C$_3$F$_8$ Bubble ChamberFeb 27 2015Jun 29 2015New data are reported from the operation of a 2-liter C$_3$F$_8$ bubble chamber in the 2100 meter deep SNOLAB underground laboratory, with a total exposure of 211.5 kg-days at four different recoil energy thresholds ranging from 3.2 keV to 8.1 keV. These ... More
Dark Matter Search Results from the Complete Exposure of the PICO-60 C$_3$F$_8$ Bubble ChamberFeb 11 2019Final results are reported from operation of the PICO-60 C$_3$F$_8$ dark matter detector, a bubble chamber filled with 52 kg of C$_3$F$_8$ located in the SNOLAB underground laboratory. The chamber was operated at thermodynamic thresholds as low as 1.2 ... More
Search for solar axion emission from 7Li and D(p,gamma)3He nuclear decays with the CAST gamma-ray calorimeterApr 14 2009Mar 06 2010We present the results of a search for a high-energy axion emission signal from 7Li (0.478 MeV) and D(p,gamma)3He (5.5 MeV) nuclear transitions using a low-background gamma-ray calorimeter during Phase I of the CAST experiment. These so-called "hadronic ... More
Search for 14.4 keV solar axions emitted in the M1-transition of 57Fe nuclei with CASTJun 24 2009Dec 04 2009We have searched for 14.4 keV solar axions or more general axion-like particles (ALPs), that may be emitted in the M1 nuclear transition of 57Fe, by using the axion-to-photon conversion in the CERN Axion Solar Telescope (CAST) with evacuated magnet bores ... More
CAST search for sub-eV mass solar axions with 3He buffer gasJun 20 2011Oct 04 2012The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using 3He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with 4He. With ... More
Fermi Surface of Alpha-Uranium at Ambient PressureMay 21 2009We have performed de Haas-van Alphen measurements of the Fermi surface of alpha-uranium single crystals at ambient pressure within the alpha-3 charge density wave (CDW) state from 0.020 K - 10 K and magnetic fields to 35 T using torque magnetometry. The ... More
Coherent Scattering Investigations at the Spallation Neutron Source: a Snowmass White PaperOct 01 2013The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Tennessee, provides an intense flux of neutrinos in the few tens-of-MeV range, with a sharply-pulsed timing structure that is beneficial for background rejection. In this white paper, ... More
Physics at a Fermilab Proton DriverSep 16 2005This report documents the physics case for building a 2 MW, 8 GeV superconducting linac proton driver at Fermilab.
The COHERENT Experiment at the Spallation Neutron SourceSep 29 2015Apr 04 2016The COHERENT collaboration's primary objective is to measure coherent elastic neutrino-nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory ... More
CAST solar axion search with 3^He buffer gas: Closing the hot dark matter gapJul 08 2013Sep 15 2014The CERN Axion Solar Telescope (CAST) has finished its search for solar axions with 3^He buffer gas, covering the search range 0.64 eV < m_a <1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the ... More
The Majorana DemonstratorSep 30 2011A 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 ... More
The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay of Germanium-76Sep 07 2011The 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 ... More
Depth Requirements for a Tonne-scale 76Ge Neutrinoless Double-beta Decay ExperimentSep 19 2011Apr 18 2013Neutrinoless 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 ... More
Data-Driven Modeling of Electron Recoil Nucleation in PICO C$_3$F$_8$ Bubble ChambersMay 29 2019The primary advantage of moderately superheated bubble chamber detectors is their simultaneous sensitivity to nuclear recoils from WIMP dark matter and insensitivity to electron recoil backgrounds. A comprehensive analysis of PICO gamma calibration data ... More
Data-Driven Modeling of Electron Recoil Nucleation in PICO C$_3$F$_8$ Bubble ChambersMay 29 2019Jul 01 2019The primary advantage of moderately superheated bubble chamber detectors is their simultaneous sensitivity to nuclear recoils from WIMP dark matter and insensitivity to electron recoil backgrounds. A comprehensive analysis of PICO gamma calibration data ... More
Search for low Energy solar Axions with CASTSep 26 2008Sep 29 2008We have started the development of a detector system, sensitive to single photons in the eV energy range, to be suitably coupled to one of the CAST magnet ports. This system should open to CAST a window on possible detection of low energy Axion Like Particles ... More
Solar axion search with the CAST experimentOct 10 2008The CAST (CERN Axion Solar Telescope) experiment is searching for solar axions by their conversion into photons inside the magnet pipe of an LHC dipole. The analysis of the data recorded during the first phase of the experiment with vacuum in the magnet ... More