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21.
Trinczek M Gorelov A Melconian D Alford WP Asgeirsson D Ashery D Behr JA Bricault PG D'Auria JM Deutsch J Dilling J Dombsky M Dubé P Eaton S Fingler J Giesen U Gu S Häusser O Jackson KP Lee B Schmid JH Stocki TJ Swanson TB Wong W 《Physical review letters》2003,90(1):012501
A new technique, full neutrino momentum reconstruction, is used to set limits on the admixture of heavy neutrinos into the electron neutrino. We measure coincidences between nuclear recoils and positrons from the beta decay of trapped radioactive atoms and deduce the neutrino momentum. A search for peaks in the reconstructed recoil time-of-flight spectrum as a function of positron energy is performed. The admixture upper limits range from 4 x 10(-3) to 2 x 10(-2) and are the best direct limits for neutrinos (as opposed to antineutrinos) for the mass region of 0.7 to 3.5 MeV. 相似文献
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E. Man�� J. A. Behr J. Billowes T. Brunner M. Brodeur F. Buchinger J. E. Crawford J. Dilling S. Ettenauer C. D. P. Levy A. Voss M. R. Pearson 《Hyperfine Interactions》2011,199(1-3):357-363
Collinear laser spectroscopy with reverse-extracted cooled bunched beams was performed at TRIUMF with radioactive ion beams. Surface-ionized 78,78mRb ions were injected into TITAN??s cooler-buncher, and reverse-extracted to the laser beam line. There they were neutralised and excited with a counter-propagating laser beam. The fluorescence signal from the D 2 line was recorded with a photomultiplier tube. The cooler provided typically 50 ion bunches per second, with each bunch containing approximately 105 ions, temporally distributed with a 1.6 ??s width. A hardware gate was set on the signal, suppressing the background by four orders of magnitude. 相似文献
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A. Gorelov J.A. Behr D. Melconian M. Trinczek P. Dubé O. Häusser U. Giesen K.P. Jackson T. Swanson J.M. D'Auria M. Dombsky G. Ball L. Buchmann B. Jennings J. Dilling J. Schmid D. Ashery J. Deutsch W.P. Alford D. Asgeirsson W. Wong B. Lee 《Hyperfine Interactions》2000,127(1-4):373-380
Laser trapping and cooling techniques are now being applied to the study of nuclear β-decay at several labs. A magneto-optical
trap (MOT) provides a localized source of atoms suspended in space, so the low-energy recoiling nuclei can freely escape and
be detected in coincidence with the β. This allows reconstruction of the neutrino momentum, and the deduction of the β-v correlation in a more direct fashion than previously possible. In addition, the nuclei can be polarized by atomic techniques,
opening a new class of spin correlation measurements to test the degree to which parity is maximally violated in the weak
interaction. Our present experiment has detected several hundred thousand recoil-β+ coincidences from the 0+ → 0+ pure Fermi decay of 38mK, produced at the on-line isotope separators TISOL and ISAC at TRIUMF. Our goal is to set constraints on non-Standard Model
scalar bosons competitive with high-energy colliders and more conventional β-v correlation experiments.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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S. A. Waksman K. R. Stevens A. Rippel G. Behr H. Wiangke Pfeiffer R. R. Le G. Worsley und F. J. Nutman 《Fresenius' Journal of Analytical Chemistry》1934,96(3-4):151-155
Ohne Zusammenfassung 相似文献
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Malick Camara Nasser Gharbi Emmanuelle Cocco Cedric Guignard Marc Behr Daniele Evers Pierre Orlewski 《International Journal for Ion Mobility Spectrometry》2011,14(1):39-47
Rapid, hyphenated detection techniques involving a gas chromatograph (GC) coupled to a classical time-of-flight ion mobility
(IMS) spectrometer, or more recently, to a micro-machined, miniature differential ion mobility spectrometer (DMS) are quite
attractive for in-situ detection of many kinds of volatile organic compounds (VOCs) of concern and notably of natural contaminants appearing in
the headspaces of selected foodstuff. This work aims at a rapid detection, identification and quantification of geosmin in
the headspace of grape must and of wine. Samples of white and red wines have both been analyzed with a hyphenated GC/DMS and
by Solid Phase Micro-Extraction (SPME) coupled to GC/MS taken as a reference. The detection of geosmin at concentrations below
the human olfactory threshold of 50 ng/L has been demonstrated. 相似文献