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Sturm M. Schl?sser M. Lewis R. J. Bornschein B. Drexlin G. Telle H. H. 《Laser Physics》2010,20(2):493-507
We have recorded Raman spectra for all hydrogen isotopologues, using a CW Nd:YVO4 laser (5 W output power at 532 nm) and a high-throughput (f/1.8) spectrograph coupled to a Peltier-cooled (200 K) CCD-array detector (512 × 2048 pixels). A (static) gas cell was used
in all measurements. We investigated (i) “pure” fillings of the homonuclear isotopologues H2, D2, and T2; (ii) equilibrated binary fillings of H2 + D2, H2 + T2, and D2 + T2, thus providing the heteronuclear isotopologues HD, HT, and DT in a controlled manner; and (iii) general mixtures containing
all isotopologues at varying concentration levels. Cell fillings within the total pressure range 13–985 mbar were studied,
in order to determine the dynamic range of the Raman system and the detection limits for all isotopologues. Spectra were recorded
for an accumulation period of 1000 s. The preliminary data evaluation was based on simple peak-height analysis of the ro-vibrational
Q1-branches, yielding 3σ measurement sensitivities of 5 × 10−3, 7 × 10−3, and 25 × 10−3 mbar for the tritium-containing isotopologues T2, DT, and HT, respectively. These three isotopologues are the relevant ones for the KATRIN experiment and in the ITER fusion
fuel cycle. While the measurement reported here were carried out with static-gas fillings, the cells are also ready for use
with flowing-gas samples. 相似文献
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Armbruster B Drexlin G Eitel K Jannakos T Kleinfeller J Maschuw R Oehler C Plischke P Reichenbacher J Steidl M Zeitnitz B Gemmeke H Kleifges M Eichner C Ruf C Bodmann BA Finckh E Hössl J Jünger P Kretschmer W Wolf J Booth NE Blair IM Edgington JA 《Physical review letters》2003,90(18):181804
We investigated mu(+) decays at rest produced at the ISIS beam stop target. Lepton flavor (LF) conservation has been tested by searching for nu(e) via the detection reaction p(nu(e),e(+))n. No nu(e) signal from LF violating mu(+) decays was identified. We extract upper limits of the branching ratio (BR) for the LF violating decay mu(+)-->e(+)+nu(e)+nu(-) compared to the standard model (SM) mu(+)-->e(+)+nu(e)+nu(mu) decay: BR<0.9(1.7) x 10(-3) (90% C.L.) depending on the spectral distribution of nu(e) characterized by the Michel parameter rho=0.75(0.0). These results improve earlier limits by one order of magnitude and restrict extensions of the SM in which nu(e) emission from mu(+) decay is allowed with considerable strength. The decay mu(+)-->e(+)+nu(e)+nu(mu) often proposed as a potential source for the nu(e) signal observed in the LSND experiment can be excluded. 相似文献
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