BEFS can be used for the study of microcrystalline structure by means of microcalorimetric detectors. To evaluate the precision and the reliability of this new method, we performed a comparison with ...EXAFS analysis. For this purpose the K-edge EXAFS measurement on rhenium metal have been done at the European Synchrotron Facility. The preliminary results indicate that BEFS analysis allows measurement of the interatomic distances with resolution of hundredths of Angstroms, comparable to EXAFS. (Author)
Precision measurements of solar neutrinos emitted by specific nuclear reaction chains in the Sun are of great interest for developing an improved understanding of star formation and evolution. Given ...the expected neutrino fluxes and known detection reactions, such measurements require detectors capable of collecting neutrino-electron scattering data in exposures on the order of 1 ktonne yr, with good energy resolution and extremely low background. Two-phase liquid argon time projection chambers (LAr TPCs) are under development for direct Dark Matter WIMP searches, which possess very large sensitive mass, high scintillation light yield, good energy resolution, and good spatial resolution in all three cartesian directions. While enabling Dark Matter searches with sensitivity extending to the "neutrino floor" (given by the rate of nuclear recoil events from solar neutrino coherent scattering), such detectors could also enable precision measurements of solar neutrino fluxes using the neutrino-electron elastic scattering events. Modeling results are presented for the cosmogenic and radiogenic backgrounds affecting solar neutrino detection in a 300 tonne (100 tonne fiducial) LAr TPC operating at LNGS depth (3,800 meters of water equivalent). The results show that such a detector could measure the CNO neutrino rate with ~15% precision, and significantly improve the precision of the 7Be and pep neutrino rates compared to the currently available results from the Borexino organic liquid scintillator detector.
The IMXS (Interstellar and intergalactic Medium X-ray Survey) - BOSS (gamma-ray Burst Observatory and Spectroscopy Survey) is an experiment proposed to fly on the ISS (International Space Station), ...in order to perform an all-sky survey to study the diffuse X-ray emission and to measure the spectra of Gamma-Ray Bursts (GRB) with high energy resolution in the 0.1-10 keV energy range. In a 3 years lifetime mission, the experiment will detect about 20 to 40 GRBs. In several events, we can perform high resolution spectroscopy of the iron emission lines and absorption edges. Such components have been observed by BeppoSAX and Chandra. The measurements of these features would provide a direct diagnostic of the physical and kinematical state of the medium surrounding a GRB. Furthermore, they would supply information about the origin of the progenitors of the GRBs (probably a supernova explosion of massive stars) and their site formation (possibly a star-forming region). (Author)
The natural {alpha}-decay of {sup 180}W has been unambiguously detected for the first time. The {alpha} peak is found in a ({gamma}, {beta}, and neutron)-free background spectrum. This has been ...achieved by the simultaneous measurement of phonon and light signals with the CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) cryogenic detectors. A half-life of T{sub 1/2}=(1.8{+-}0.2)x10{sup 18} years and an energy release of Q=2516.4{+-}1.1(stat.){+-}1.2(sys.) keV have been measured. New limits are also set on the half-lives of the other naturally occurring tungsten isotopes.
Results are presented from a reanalysis of the entire five-tower data set acquired with the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory, with an exposure of ...969 kg-days. The analysis window was extended to a recoil energy of 150 keV, and an improved surface-event background-rejection cut was defined to increase the sensitivity of the experiment to the inelastic dark matter (iDM) model. Three dark matter candidates were found between 25 keV and 150 keV. The probability to observe three or more background events in this energy range is 11%. Because of the occurrence of these events the constraints on the iDM parameter space are slightly less stringent than those from our previous analysis, which used an energy window of 10-100 keV.
CRESST – status and future Kraus, H.; Angloher, G.; Bauer, M. ...
Nuclear physics. Section B, Proceedings supplement,
11/2007, Letnik:
173
Journal Article
We present results on WIMP dark matter interaction, obtained using cryogenic phonon-scintillation detectors. The targets are CaWO
4 scintillating crystals with phonon sensors, while scintillation is ...detected with an associated cryogenic light detector. The combination of phonon and light signals leads to a strong suppression of nonnuclear recoil backgrounds. Results obtained before the upgrade of CRESST are presented and a status report on the upgrade itself is given.
We present first competitive results on WIMP dark matter using the
phonon-light-detection technique. A particularly strong limit for WIMPs with
coherent scattering results from selecting a region of ...the phonon-light plane
corresponding to tungsten recoils. The observed count rate in the neutron band
is compatible with the rate expected from neutron background. CRESST is
presently being upgraded with a 66 channel SQUID readout system, a neutron
shield and a muon veto system. This results in a significant improvement in
sensitivity.
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