共查询到20条相似文献,搜索用时 46 毫秒
1.
T. Matsuzaki K. Nagamine K. Ishida N. Kawamura S. N. Nakamura M. Kato H. Sugai M. Tanase K. Kudo N. Takeda G. H. Eaton 《Hyperfine Interactions》2001,138(1-4):295-305
We have measured X-rays and neutrons associated with the muon catalyzed t–t fusion process at the RIKEN-RAL Muon facility.
In the X-ray measurement, we observed Kα and Kβ X-rays originating from the muon sticking process in muon catalyzed t–t fusion, and obtained the Kα X-ray yield and the Kβ/Kα intensity ratio. An average recoil energy of the (μ−α) atoms in a solid T2 medium was determined from the observed Doppler broadening width of the Kα X-ray line. The obtained t–t fusion neutron has shown an exponential time spectrum with a single component and a continuous
energy spectrum with a maximum energy of 9 MeV. We have determined the t–t fusion neutron yield, the t–t fusion cycling rate
and the muon sticking probability from the neutron data. The obtained maximum neutron energy is a very peculiar value from
the view point of the reaction Q value (11.33 MeV) with the three-particle decay mode at the exit channel: t + t → α + n + n + Q. The obtained neutron energy distribution was analyzed by a simple model with two neutron energy components; reasonable agreement
has been obtained, suggesting a strong (n–α) correlation in the exit channel of the t–t muon catalyzed fusion reaction.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
T. Matsuzaki K. Nagamine K. Ishida S.N. Nakamura N. Kawamura M. Tanase M. Kato K. Kurosawa M. Hashimoto H. Sugai K. Kudo N. Takeda G.H. Eaton 《Hyperfine Interactions》1999,118(1-4):229-234
X-ray and neutron measurements were carried out for muon catalyzed fusion and related phenomena in solid T2. The X-ray originated from the μ- to α sticking in muon catalyzed fusion; t + t + μ
-
→ (μ
-
α) + 2n was measured for the first time, yielding K
α
X-ray intensity of (μα) atom and the intensity ratio of K
β
to K
α
. Utilizing the phenomena of 3He accumulation in solid T2, the X-ray in the μ- transfer process from (tμ) to 3He was detected, providing a formation rate and radiative decay branching-ratio of (t
3Heμ) molecule. From fusion neutron measurements, estimated values were obtained for (ttμ) molecular formation rate as well as sticking probability ωt in ttμ fusion. A possible new insight in t + t fusion reaction process at a low energy limit is also obtained.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
The influence of resonances on the muon transfer processes from muonic hydrogen to oxygen and neon (pμ)1s + O8+ → p + (μO)nl7+ and (pμ)1s + Ne10+ → p + (μNe)nl9+ is considered using the Smith lifetime matrix formalism. It is shown that the existence of a long lived resonance in the
case of Ne induces a stronger dependence on collision energy of the muon transfer cross-section for this system.
Present address: Chemistry Department, Vancouver University, Vancouver, BC V6T 1Z3, Canada 相似文献
4.
In a recent paper [1], we applied the methods of quantum reactive scattering to the key resonant reaction in the muon catalyzed
fusion (MCF) cycle that leads to the formation of a dtμ muonic molecular ion, in which fusion takes place very rapidly. We
calculated reaction probabilities for tμ + D2 scattering for incident kinetic energies less than 0.6 eV in the centre of mass frame and total angular momentum J
tot=0, using the APH (adiabatically adjusting, principal axes hyperspherical) formalism of Pack and Parker [2], which had previously
been applied to simple chemical reactions. This was the first successful application of the above methods to the tμ + D2 reaction. In this paper, we examine a significant discrepancy between our values for the back decay partial width for the
resonances we consider and the results that have been obtained using previous methods.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
K. Ishida K. Nagamine T. Matsuzaki N. Kawamura S. N. Nakamura Y. Matsuda M. Kato H. Sugai M. Tanase K. Kudo N. Takeda G. H. Eaton 《Hyperfine Interactions》2001,138(1-4):225-234
Precise measurements of the absolute yields and the disappearance rates were carried out for both the X-rays from the (αμ)+ ion formed by muon to alpha sticking after the muon catalyzed fusion and for the fusion neutrons from 3He-free liquid and solid D/T mixtures. While the αμ X-ray yield does not contradict the values predicted by the atomic-process
theories, the effective sticking probability (ω
s
) obtained by neutron measurement is much smaller than that from any of the calculations published so far, suggesting, e.g.,
enhanced reactivation.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
V.I. Savichev R. Blümel 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(1):3-12
We present the first thorough theoretical discussion of non-monotonic structure in the temporal behavior of X-ray fluorescence
intensity spectra of muon charge-exchange reactions of the type pμ + Z→p + μZ. Our discussion is based on semiclassical methods; our results are almost entirely analytical. We find that the reported
experimental maxima of muon charge-exchange rates are very close to the theoretical limits. We identify a new quantum mechanism,
quantum impedance matching, which explains observed inelastic transitions close to the Unitarity Limit. We investigate the specific example of the reaction
pμO
8 + in detail using two-center Coulomb adiabatic potential terms. We find that quantum impedance matched higher-order partial-wave
resonances yielding muon-transfer rates close to the Unitarity Limit are responsible for the remarkable non-monotonic structure
in the X-ray fluorescence spectra.
Received 7 January 2002 / Received in final form 15 April 2002 Published online 24 September 2002 相似文献
7.
K. Ishida K. Nagamine T. Matsuzaki S.N. Nakamura N. Kawamura S. Sakamoto M. Iwasaki M. Tanase M. Kato K. Kurosawa H. Sugai I. Watanabe K. Kudo N. Takeda G.H. Eaton 《Hyperfine Interactions》1999,118(1-4):203-208
We measured the yields of K-series X-rays from (αμ)+ ion formed by muon to alpha sticking as well as the yields and the disappearance rates of fusion neutrons in 3He-free solid and liquid D-T mixtures. The effective sticking probability ωs obtained by neutron measurement is much smaller than any theoretical values so far published, while the discrepancy in αμ
X-ray yield seems less significant.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
N. Kawamura K. Nagamine T. Matsuzaki K. Ishida S.N. Nakamura S. Sakamoto M. Iwasaki M. Tanase M. Kato K. Kurosawa T. Hashimoto H. Sugai K. Kudo N. Takeda G.H. Eaton 《Hyperfine Interactions》1999,118(1-4):213-215
This article reports the accumulation effect of the 3He originating from tritium β decay; 3He created in solid remains in it, while one in liquid diffuses and goes out to the vapor gas. We observed this effect through
the neutron detection from muon catalyzed fusion phenomenon (μCF), and gave it qualitative understanding, by which the muon
transfer rate from (dμ) and (tμ) to helium was derived.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
10.
The Geant4 CHIPS model simulates both decay and nuclear capture of negative muons. In hadron level models the muon is captured
by a proton, p(μ,νμ)n , and the neutron transfers to the nucleus only 5MeV, which is not enough to split a nucleon from the nucleus, while the
measured spectra of emitted nucleons reach 80MeV. In CHIPS, which considers asymptotically free quark-partons, the muon can
be captured by a quark, u(μ,νμ)d , and transfers 52MeV to the nucleus. This capture mechanism fits the main part of the nucleon spectra, while the high-energy
part of the spectra is not fitted. A precise fit of the high-energy part of the nucleon spectra can be made if the muon decay
μ → dˉνμ is taken into account. 相似文献
11.
The results of an experiment on muon catalyzed dd-fussion in HD gas are presented. The experiment was performed at the muon beam of PSI using a high-pressure ionization chamber
filled with pure HD-gas of low D2 concentration on the level 1%, at temperatures 50, 150 and 300 K. The non-resonant character of ddμ-molecule formation on HD molecules was confirmed by measuring the ratio of yields of the two ddμ-fusion channels, R=Y(3He,n)/Y(3H,p), which proved to be close to unity. The ddμ formation rate was found to vary from λddμ-HD=0.05· 106 s-1 at T=50 K to λddμ-HD=0.12· 106 s-1 at T=300 K, in agreement with the theoretical prediction. A prominent peak at t<60 ns was observed in the time spectrum of fusion neutrons indicating a resonant contribution of ddμ formation from epithermal dμ atoms.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
Rabindra N. Mohapatra 《Zeitschrift fur Physik C Particles and Fields》1992,56(Z1):S117-S128
Rare muon processes such as muonium to antimuonium conversion, μ→eγ and μ→3e provide sensitive tests of new physics beyond the standard model. Specifically the left-right symmetric models of weak interaction
with a low scale for the right-handedW
R
boson (in the TeV range) provide a whole range of rare muon processes which are experimentally accessible. In this talk,
I discuss the implications of the left-right symmetric models for rare muon processes and also briefly touch on the SUSY models
with R-parity violation and their implications for these processes. 相似文献
13.
Influence of ion-molecular reactions on μ-capture in hydrogen and on fusion in 3Hedμ muonic molecule
The de-excitation processes (J=1)→ (J=0) in muonic molecular ions (ppμ)+ and (3Hedμ)+ are studied. It is shown that the rate of such transitions substantially depends on the chain of ion-molecular reactions
initiated by positively charged muonic ions.
The probabilities of ortho-para transition in the [(ppμ)+H2] and [(ppμ)+e] complexes formed as a result of chemical reactions in the pure hydrogen were estimated.
Taking into account the ion-molecular processes in D2 + He mixtures, the evaluation of the observed rate λf of nuclear fusion in the 3Hedμ muonic molecules was performed. The expected yield of fusion reactions per muon at the mixture density φ=0.1 and concentration
C
He
=0.05 was obtained to be equal to
.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
W. Bernreuther 《Zeitschrift fur Physik C Particles and Fields》1992,56(Z1):S97-S100
The forthcoming experiment [1] on the anomalous magnetic moment of the muon will be able to search also for an electric dipole
momentd
μ of the muon with increased sensitivity. A brief survey is given on what various models of CP violation predict ford
μ. 相似文献
15.
S. N. Nakamura D. Tomono Y. Matsuda G. Mason M. Iwasaki K. Ishida T. Matsuzaki I. Watanabe S. Sakamoto K. Nagamine 《Hyperfine Interactions》2001,138(1-4):445-450
The lifetime of the positive muon (τμ
+) can be directly associated with the Fermi Coupling Constant (G
F
), which is one of the most basic parameters of the Standard Model. However, the current experimental accuracy of the τμ
+ is ∼30 ppm and it has not been improved for more than 15 years. We propose a new experiment for a pulsed muon facility such
as RIKEN-RAL to measure the muon lifetime with multi-decay per one time window method. The advantage of our setup, no time
window limitation, enables us to test the exponential decay law (EDL) in the long decay time region at the same time. The
preliminary analysis set a new upperlimit for the EDL deviation in the muon decay. We accumulated ∼1010 muon decays and analysis is in progress.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
16.
Relative energies of muon probe sites in the chain region of RBa2Cu3O7 (RBCO) are investigated using a molecular quantum chemistry calculation for (Oμ)− embedded in a cluster of point charges to simulate local charge distributions in RBCO. Partial Cu−O chain covalency results
in a O-μ...O muon site between the chain and bridging oxygens. However, Cu-μ “hydride”-like sites are suggested by results
for nominally ionic clusters. 相似文献
17.
V. R. Bom J. N. Bradbury J. D. Davies A. M. Demin D. L. Demin C. W. E. van Eijk V. V. Filchenkov A. N. Golubkov N. N. Grafov V. G. Grebinnik S. K. Grishechkin K. I. Gritsaj V. G. Klevtsov A. D. Konin A. A. Kukolkin S. V. Medved' V. A. Nazarov V. V. Perevozchikov A. N. Ponomarev V. Ya. Rozhkov A. I. Rudenko S. M. Sadetsky Yu. V. Smirenin N. I. Voropaev A. A. Yukhimchuk S. A. Yukhimchuk V. G. Zinov S. V. Zlatoustovskii 《Hyperfine Interactions》2001,138(1-4):213-223
Experiments on the study of the muon catalyzed fusion (μCF) process in a double D/T mixture of hydrogen isotopes in the temperature
range 300–800 K at densities 0.3–0.5 LHD are performed at the JINR phasotron. The values of the effective μCF parameters (cycling
rate λ
c
, neutron yield Y
n
, muon losses w) are obtained. Tentative dtμ-molecule formation rates on D2 and DT molecules (λ
dtμ−d
and λ
dtμ−t
) are obtained for different mixture temperatures and densities. The results obtained show that λ
dtμ−t
increases with temperature, but its value is smaller than theoretical predictions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
18.
L. N. Bogdanova V. R. Bom A. M. Demin D. L. Demin C. W. E. van Eijk S. V. Filchagin V. V. Filchenkov N. N. Grafov S. K. Grishechkin K. I. Gritsaj A. D. Konin A. V. Kuryakin S. V. Medved’ R. K. Musyaev A. I. Rudenko D. P. Tumkin Yu. I. Vinogradov A. A. Yukhimchuk S. A. Yukhimchuk V. G. Zinov S. V. Zlatoustovskii 《Journal of Experimental and Theoretical Physics》2009,108(2):216-225
The muon-catalyzed fusion (μCF) process in tritium was studied by the μCF collaboration on the muon beam of the JINR Phasotron.
The measurements were carried out with a liquid tritium target at the temperature 22 K and density approximately 1.25 of the
liquid hydrogen density (LHD). Parameters of the μCF cycle were determined: the ttμ muonic molecule formation rate λ
ttμ = 2.84(0.32) μs−1, the ttμ fusion reaction rate λ
f
= 15.6(2.0) μs−1, and the probability of muon sticking to helium ω
tt
= 13.9(1.5)%. The results agree with those obtained earlier by other groups, but better accuracy was achieved due to our unique
experimental method.
The article is published in the original. 相似文献
19.
V. G. Grebinnik V. N. Duginov V. A. Zhukov S. Kapusta A. B. Lazarev V. G. Olshevsky V. Yu. Pomjakushin S. N. Shilov I. I. Gurevich B. F. Kirillov E. P. Krasnoperov B. A. Nikolsky A. V. Pirogov A. N. Ponomarev V. A. Suetin A. I. Morozov 《Hyperfine Interactions》1991,63(1-4):241-247
High temperature superconductors HoBa2Cu3O7−δ (T
c
≅93 K), Ho0.5Y0.5Ba2Cu3O7−δ (T
c
≅93 K) and ErBa2Cu3O7−δ (T
c
≅95 K) were investigated by the zero-field μSR-technique. The muon spin depolarisation rate connected with the fluctuation
frequency of rare-earth ion magnetic moments was measured. It was found that the samples with holmium show a fast increase
of the muon spin depolarisation rate at temperatures below 20 K, while in ErBa2Cu3O7−δ the depolarisation rate remains low in the whole temperature region studied (4.2 K-270 K). The sharp difference between the
behaviours of the muon spin depolarisation rate may be explained by the difference between the ground state of Ho3+ and Er3+ ions in the crystalline field of the lattice. 相似文献
20.
F. N. Gygax P. Birrer B. Hitti E. Lippelt A. Schenck M. Weber 《Hyperfine Interactions》1991,64(1-4):489-495
μ
+ SR measurements have been performed in a single crystal indium sample between 12 K and 300 K with a stroboscopic μSR spectrometer.
The muonic Knight shiftK
μ and the muonic depolarization rate σ were obtained for various angles θ between the tetragonal crystallinec-axis and the direction of the external field. The isotropic part ofK
μ is only weakly temperature dependent and is consistent with the estimated Pauli spin susceptibility value. At a temperature
of 12 K the angular dependence ofM
2 (the second moment of the field distribution at the muon, obtained from the measured σ(θ) values) allows a clear determination
of the muon location — the symmetric tetrahedral site. The observed anisotropicK
μ cannot be explained by the dipoles at the In atoms responsible for the bulk magnetic susceptibility but probably originates
from an anisotropic Pauli spin susceptibility. 相似文献