Muon Capture on the Proton and Deuteron

By measuring the lifetime of the negative muon in pure protium (hydrogen-1), the MuCap experiment determines the rate of muon capture on the proton, from which the proton's pseudoscalar coupling g_p may be inferred. A precision of 15% for g_p has been published; this is a step along the way to a goal of 7%. This coupling can be calculated precisely from heavy baryon chiral perturbation theory and therefore permits a test of QCD's chiral symmetry. Meanwhile, the MuSun experiment is in its final design stage; it will measure the rate of muon capture on the deuteron using a similar technique. This process can be related through pionless effective field theory and chiral perturbation theory to other two-nucleon reactions of astrophysical interest, including proton-proton fusion and deuteron breakup.Comment: Submitted to the proceedings of the 2007 Advanced Studies Institute on Symmetries and Spin (SPIN-Praha-2007

Ein Nachweissystem aus ortsaufloesenden Halbleiterdetektoren fuer ( , ) - Reaktionen

SIGLETIB: RN 4852 (85-26) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Analysis of Cl-36 in atmospheric samples from Seville (Spain) by AMS

In this work, the time evolution of Cl-36 concentration and Cl- 36/Cl isotopic ratio has been studied in rainwater samples from Seville, Southern Spain. Cl-36 concentrations range between 10(5) - 10(7) at l(-1) and Cl-36/Cl ratios range between 10(- 15)-10(-13), in good agreement with other values found in literature. The time evolution of these values suggests that Cl-36 is more available in late spring due to the injection of stratospheric air into the troposphere. The arrival of stable chlorine coming from the Atlantic Ocean also seems to have an important influence on the Cl-36/Cl isotopic ratio. Finally, the values obtained for the Cl-36 deposition are noticeably higher than the values predicted by cosmogenic production models. This fact has been found by other authors

36Cl studies at the ETH/SIN-AMS facility

36Cl has been measured in polar ice from Dye 3 (65° 11 N, 43° 50 W) and Camp Century (77° 11 N, 82° 08W) in Greenland. In an exploratory study 4 series consisting of about 20 samples each have been selected covering approximately the following time periods: 12000-10000 BP (transition Wisconsin-Holocene), 1530–1730 a.d. (Maunder minimum), 1942–1977 a.d. (nuclear bomb pulse) and 1978 (seasonal variations). The results are compared with 10Be data of the same cores which were measured previously. The variations of the ratio 10Be36Cl are generally larger than expected from the experimental errors indicating that this ratio is not suitable for dating of old ice

Levels and temporal variability of I-129 concentrations and I- 129/I-127 isotopic ratios in atmospheric samples from southern Spain

The temporal variability of I-129 in atmospheric samples taken between 1993 and 1999 in Seville (Spain) has been studied. Results show a good agreement with the history of the I-129 gaseous emissions of the reprocessing plants at Sellafield and La Hague. This suggests that these emissions are the origin of the I-129 present in the atmosphere in southern Spain. Apart from this, the similarity between the time evolution of gaseous I-129 and I-129/I-127 in 1998 would imply a fast chemical equilibration between I-129 from the reprocessing plants and stable iodine

Relative influence of I-129 sources in a sediment core from the Kattegat area

The depth profiles of the I-129 concentration and the I-129/I- 127 ratio in a surface sediment core from the Kattegat area have been analyzed in order to obtain information about the different sources of I-129 in that core. Therefore, a mathematical model that relates the measured values to the available emission data from the nuclear fuel reprocessing plants and nuclear weapons tests has been applied. Results show that the reprocessing plants at La Hague and Sellafield are the main sources of I-129 in the sediment. Results about the transfer from the release points at the reprocessing plants to the sampling zone agree with other literature data. The model calculates quite fast the sedimentation of I-129 in the sampling place, probably attached to organic matter. Finally, an estimation of approximately 89 kg of I-129 released by Sellafield between 1952 and 1968 has been obtained from the model