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1.
A. Werthmüller A. Adamczak R. Jacot‐Guillarmod F. Mulhauser L.A. Schaller L. Schellenberg H. Schneuwly Y.‐A. Thalmann S. Tresch 《Hyperfine Interactions》1998,116(1-4):1-16
The charge exchange reaction of negative muons from the
atom to oxygen has been measured in gaseous mixtures of H2 + O2. The measurements were performed at three different relative oxygen concentrations ranging from 0.2% to 0.8% and total pressures 3.5–15 bar. A mean transfer rate of
, describing the transfer from the ground state of thermalized
atoms to oxygen, was determined. In order to investigate the energy dependence of the transfer rate, Monte Carlo simulations of the
thermalization and the muon transfer were carried out. The comparison of measured and simulated time spectra yielded an epithermal transfer rate
=3.9
1011 s-1 in the energy interval 0.12–0.22 eV. The analysis with the model of Two components shows that all measured time spectra can be reproduced with the same set of parameters. 相似文献
2.
B. Gartner P. Ackerbauer M. Augsburger W.H. Breunlich M. Cargnelli D. Chatellard J.-P. Egger T. von Egidy F.J. Hartmann R. Jacot-Guillarmod E. Jeannet P. Kammel R.C. King A. Kosak B. Lauss J. Marton M. Mühlbauer F. Mulhauser C. Petitjean C. Piller W. Prymas L.A. Schaller L. Schellenberg H. Schneuwly W. Schott Y.A. Thalmann S. Tresch A. Werthmüller J. Zmeskal 《Hyperfine Interactions》1999,119(1-4):103-108
The energy and time distributions of the decay X-rays of excited, metastable, molecular (dμHe)*-resonances were measured. The comparison of the observed energy spectra with calculated ones suggests that decay from
the rotational state J = 1 dominates at the investigated conditions. The muon transfer rates from ground state deuterium to the helium isotopes
3He and 4He at low temperatures were determined from the time distributions of these spectra. Additionally, the temperature dependence
of the muon transfer rate was clearly established in deuterium / 4He mixtures.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Gartner B. Ackerbauer P. Breunlich W. H. Cargnelli M. Fischer A. Kammel P. King R. Kminek G. Lauss B. Marton J. Prymas W. Steininger E. Zmeskal J. Petitjean C. Chatellard D. Egger J. -P. Jeannet E. Hartmann F. J. Kosak A. Mühlbauer M. von Egidy T. Piller C. Schaller L. A. Schellenberg L. Schneuwly H. Thalmann Y. -A. Tresch S. Werthmüller A. 《Hyperfine Interactions》1996,101(1):249-255
Muon transfer from the ground state of muonic deuterium to a helium atom proceeds mainly via the formation of a muonic molecule in an excited state. A large number of decay X rays ( 6.8 keV) from these (dµHe)* molecules were observed for the4He as well as for the3He case. The time distributions of these X rays allow the determination of the ground state transfer rate. The simultaneous employment of Ge/Si-detectors and CCDs for the same target conditions allows the determination of the branching ratio of radiative to nonradiative decay for the first time. 相似文献
4.
S. Tresch P. Ackerbauer M. Augsburger W.H. Breunlich M. Cargnelli D. Chatellard J.-P. Egger T. von Egidy B. Gartner F.J. Hartmann R. Jacot-Guillarmod E. Jeannet R. King B. Lauss J. Marton M. Mühlbauer F. Mulhauser C. Petitjean C. Piller W. Prymas L.A. Schaller L. Schellenberg H. Schneuwly W. Schott Y.-A. Thalmann A. Werthmüller J. Zmeskal 《Hyperfine Interactions》1999,119(1-4):109-114
The transfer reaction of negative muons from muonic protium to 3 and 4 in binary and triple gas mixtures was studied. In the binary mixtures the transfer rates to the two helium isotopes were
determined from the time distribution of the 7-keV X-rays of the intermediate muonic molecule (pμHe)*. The experimental transfer rate to 4 is in good agreement with theoretical predictions, whereas the rate to 3 is a factor 2 to 3 smaller than the predicted ones. Radiative branching ratios of the (pμHe)8 molecular decay were obtained. Muon transfer from excited states of muonic protium gives the main contribution to the
total intensity of the μHe Lyman series in the binary mixtures. Values of q
1s
He
are determined.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
6.
A. Werthmüller A. Adamczak R. Jacot-Guillarmod F. Mulhauser C. Piller L. A. Schaller L. Schellenberg H. Schneuwly Y. -A. Thalmann S. Tresch 《Hyperfine Interactions》1996,103(1):147-155
Negative muons were trapped in gaseous mixtures of hydrogen and oxygen. The time distributions of the muonic oxygen X-rays
showed a clear deviation from a single exponential structure. From these time distributions we evaluated the transfer rate
from thermalized muonic hydrogen atoms to oxygen. In order to test the hypothesis of an energy-dependent transfer rate to
oxygen we performed Monte Carlo simulations of the thermalization and the transfer process. We report on the present status
of our investigations. 相似文献
7.
S. Tresch R. Jacot-Guillarmod F. Mulhauser L.A. Schaller L. Schellenberg H. Schneuwly Y.-A. Thalmann A. Werthmüller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,2(2):93-97
The present status of research of muon transfer from the ground state of muonic protium to 4He is reviewed. The analysis of a recent measurement in a triple gas mixture of H2+4He+Ne at 15 bar and room temperature is presented and the result is compared to the existing experimental and theoretical
rates. The average muon transfer rate from protium to 4He determined from all lifetime measurements is .
Received: 22 January 1998 / Revised: 4 March 1998 / Accepted: 31 March 1998 相似文献
8.
Werthmüller A. Adamczak A. Jacot-Guillarmod R. Mulhauser F. Piller C. Schaller L. A. Schellenberg L. Schneuwly H. Thalmann Y. -A. Tresch S. 《Hyperfine Interactions》1996,101(1):271-275
To investigate the energy dependence of muon transfer to oxygen, we performed measurements in gaseous mixtures of hydrogen and oxygen. The time distributions of the muonic oxygen X-rays showed the same structure as the one observed earlier in H2+SO2 mixtures. In the delayed part of these distributions, one can distinguish a short-time and a long-time component. From the latter, we deduced the transfer rates from thermalized muonic protium, respectively deuterium, to oxygen. The short-time component can be interpreted as being due to muon transfer from epithermal muonic hydrogen atoms. The time parameters are characteristic for the deceleration process as well as for energy-dependent transfer rates. With results of recent research on the formation and the thermalization of muonic hydrogen, we performed Monte Carlo simulations in order to test the hypothesis of an energy-dependent transfer rate. 相似文献
9.
Y. -A. Thalmann R. Jacot-Guillarmod F. Mulhauser C. Piller L. A. Schaller L. Schellenberg H. Schneuwly S. Tresch A. Werthmüller 《Zeitschrift für Physik A Hadrons and Nuclei》1997,359(2):219-224
The yields of muonic x rays of the Lyman series of nitrogen, neon and argon have been analysed to determine capture ratios A(Z1,Z2) in about thirty gaseous mixtures under different experimental conditions. In addition, capture ratios A(Z,H) have been determined in hydrogen mixtures by taking into account transfer processes from muonic hydrogen to elements Z. The influence of the spectral flux density of the muons on capture ratios has been analysed. Our per-atom ratios form a coherent set and confirm the value A(Ar,Ne) = 1. 262(10). 相似文献
10.
A. Del Rosso M. Augsburger V.F. Boreiko V.M. Bystritsky M. Filipowicz O. Huot R. Jacot-Guillarmod P.E. Knowles F. Mulhauser V.N. Pavlov C. Petitjean N.P. Popov V.G. Sandukovsky L.A. Schaller H. Schneuwly V.A. Stolupin Y.-A. Thalmann S. Tresch J. Woźniak 《Hyperfine Interactions》1999,118(1-4):177-182
Many atomic and molecular processes may occur after a muon has been stopped in a mixture of hydrogen and helium isotopes.
In particular, the muonic molecule μd3He can be formed. This molecule either decays or undergoes muon catalyzed fusion. Theory predicts a fusion rate much lower
than the decay rate; moreover, the various theoretical predictions differ from each other by several orders of magnitude.
With the experiment presented here we intend to measure the effective fusion rate via the detection of the 14.7 MeV fusion
proton. A new target and gas mixing system, designed at JINR, were used in a ten-day test run at PSI. The fusion protons and
products from other transfer and background reactions were measured with several different detectors (plastic scintillators,
BGO, Germanium, neutron, and Silicon detectors).
The formation rate of the μd
3He molecule and an upper limit for the effective fusion rate have been measured and are presented here.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献