共查询到20条相似文献,搜索用时 109 毫秒
1.
B. A. Kalin N. V. Volkov S. E. Sabo S. V. Zaitsev 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(5):845-851
The results of studying the redistribution of Be, Al, Ti, Fe, Cu, Zr, Mo, and W atoms incorporated in polycrystalline metal
samples under irradiation with He+, (He+ + Ar+), and Ar+ ion beams with a broad energy spectrum and an average energy of 10 keV at irradiation doses of 1 × 1021 ion/cm2 are studied. It is discovered that irradiation at doses exceeding 1 × 1019 ion/cm2 results in local small-crystal formations being produced in a near-surface substrate layer. Their typical dimensions are
less than 1–5 μm, and their the density is up to 1–100. They contain incorporated atoms and impurity atoms with a concentration
of 0.1–10 at %. Subsequent irradiation at a dose of 1 × 1020 ions/cm2 or more leads to disappearance of these formations, mainly because of sputtering processes. 相似文献
2.
通过X射线光电子能谱和低能电子衍射实验研究了10~180 eV的Ar+、 He+、S+离子轰击n-InP(100)表面, 发现S+离子轰击可以产生In-S组分,减轻离子轰击对表面的物理损伤.对于Ar+离子轰击后的表面,经过S+离子处理和加热过程以后,表面损伤得到了修复,最终得到了2×2的InP表面,进一步验证了S+离子对InP表面的修复作用. 相似文献
3.
The surface composition of PbO has been studied with X-ray photoelectron spectroscopy after bombardment with several inert gas ions of 400 eV. The results show reduction of PbO to metallic Pb with the degree of damage following the order He+ > Ne+ >Ar+. Both Kr+ and Xe+ did not reduce the oxide. The depth of damage varied from ≈9 Å for He+ to ≈1 Å for Ar+ bombardment. The results were compared to a collisional and a thermal model of the sputtering process. 相似文献
4.
Using the technique of helicity amplitudes, the electromagnetic process e
+
e
− → μ+μ− is theoretically investigated in the one-photon approximation. The structure of the triplet states of the final (μ+μ−) system is analyzed. It is shown that in the case of unpolarized electron and positron the final muons are also unpolarized,
but their spins are strongly correlated. Explicit expressions for the components of the correlation tensor of the final (μ+μ−) system are derived. The formula for the angular correlation at the decays of final muons μ+ and μ−, produced in the process e
+
e
− → μ+μ−, is obtained. It is demonstrated that spin correlations of muons in the process of electron-positron pair annihilation have
the purely quantum character, since one of the incoherence inequalities for the correlation tensor components is always violated.
The additional contribution of the weak interaction of lepton neutral currents through the virtual Z
0 boson is considered; it is established that, taking into account the weak interaction, the qualitative character of the muon
spin correlations does not change. 相似文献
5.
ALEPH Collaboration D. Buskulic I. De Bonis D. Decamp P. Ghez C. Goy J. P. Lees A. Lucotte M. N. Minard P. Odier et al. 《Zeitschrift fur Physik C Particles and Fields》1996,71(1):31-44
The lifetimes of theB
0 andB
+ mesons have been measured with theAleph detector at LEP, using approximately 3 million hadronic Z decays collected in the period 1991–1994. In the first of three
methods, semileptonic decays ofB
0 andB
+ mesons were partially reconstructed by identifying events containing a lepton with an associatedD*− or meson. The second method used fully reconstructedB
0 andB
+ mesons. The third method, used to measure theB
0 lifetime, employed a partial reconstruction technique to identifyB
0→D*−
π
+
X decays. 相似文献
6.
ARGUS Collaboration H. Albrecht T. Hamacher R. P. Hofmann T. Kirchhoff R. Mankel A. Nau S. Nowak D. Re?ing H. Schr?der et al. 《Zeitschrift fur Physik C Particles and Fields》1995,69(1):405-408
Using the ARGUS detector at the e+e− storage ring DORIS II at DESY we have measured the parameters of a charmed strange meson D*
s2
+
(2573) decaying into D0K+. The mass of this state was found to be (2574.5±3.3±1.6) MeV/c
2. The measured value of its width is (10.4±8.3±3.0) MeV and the product of the production cross section and branching ratio
for this channel was determined to be (10.6±4.2
−1.2
+2.3
) pb.
Supported by the German Bundesministerium für Forschung und Technologie, under contract number 054DO51P. 相似文献
7.
Irina Kudryavtseva Aleksandr Lushchik Aarne Maaroos Zhannur Azmaganbetova Turlybek Nurakhmetov Zhussupbek Salikhoja 《Central European Journal of Physics》2012,10(4):995-1001
A comparative study of the excitation of luminescence by VUV radiation as well as of thermally and photostimulated luminescence
has been carried out for CaSO4:Tb3+ and CaSO4:Gd3+ phosphors, where Na+ or F− ions are used for charge compensation. The distinction in hole processes for the phosphors with Na+ or F− compensators is determined by the differing thermal stability of the holes localized at/near Tb3+Na+ and Gd3+Na+ (up to 100–160 K) or at/near Tb3+F−
V
Ca and Gd3+F−
V
Ca centers involving also a cation vacancy (up to 400–550 K). Tunnel luminescence in the pairs of localized electrons and holes
nearby Tb3+ or Gd3+ has been detected. The mechanisms of electron-hole, hole-electron and tunnel recombination luminescence as well as a subsequent
released energy transfer to RE3+ ions are considered. 相似文献
8.
N. M. Agababyan V. V. Ammosov M. Atayan N. Grigoryan H. Gulkanyan A. A. Ivanilov Zh. Karamyan V. A. Korotkov 《Physics of Atomic Nuclei》2007,70(10):1739-1742
Using the data obtained with the SKAT bubble chamber, the total yields of K*(892)+, Σ+(1385), and Σ0 are estimated for the first time in neutrino-induced reactions at moderate energy 〈E
v〉 = 10.4 GeV. It is shown that the recently observed enhancement of the K
0 and Λ yields in vA interactions as compared to vN interactions is contributed only slightly by the K*(892)+ and Σ+(1385) production. The contribution of resonances to the K
0 and Λ yields is found to be in qualitative agreement with higher energy (〈E
v〉 ≳ 40 GeV) data. It is shown that the energy dependence of the K*(892)+ mean multiplicity in vN interactions is approximately linear in the range of 〈E
v〉 ≈ 10−60 GeV, while that for Σ0 in vA interactions (A = 20−21) is approximately logarithmic in the range of 〈E
v〉 ≈ = 10−150 GeV.
The text was submitted by the authors in English. 相似文献
9.
Zhang Xiaoan Xiao Guoqing Yang Zhihu Chen Ximeng Zhao Yongtao Li Fuli Zhang Yinping Cui Ying Zhang Hongqiang Xu Xu Shao Jianxiong Zhan Wenlong 《中国科学G辑(英文版)》2006,49(2):203-212
By use of optical spectrum technology, the spectra of X-ray induced by highly charged 40Ar
q+ ions interacting with Au surface have been studied. The results show that the argon Kα X-ray were emitted from the hollow
atoms formed below the surface. There is a process of multi-electron exciting in neutralization of the Ar16+ion, with electronic configuration 1s2 in its ground state below the solid surface. The yield of the projectile Kα X-ray is related to its initial electronic configuration,
and the yield of the target X-ray is related to the projectile kinetic energy. 相似文献
10.
E. P. Shabalin 《Physics of Atomic Nuclei》2005,68(1):88-93
The amplitudes of the K
± → 3π and K→ 2π decays are expressed in terms of different combinations of one and the same set of CP-conserving and CP-odd parameters. Extracting the magnitudes of these parameters from the data on K → 2π decays, we estimate an expected CP-odd difference between the values of the slope parameters g
+ and g
− of the energy distributions of “odd” pions in K
+ → π+π+π− and K
− → π−π−π+ decays.
From Yadernaya Fizika, Vol. 68, No. 1, 2005, pp. 89–94.
Original English Text Copyright ? 2005 by Shabalin.
This article was submitted by the author in English. 相似文献
11.
《The European Physical Journal C - Particles and Fields》2007,52(4):875-891
A measurement of the direct CP violating charge asymmetries of the Dalitz plot linear slopes Ag=(g+-g-)/(g++g-) in K±→π±π+π- and K±→π±π0π0 decays by the NA48/2 experiment at CERN SPS is presented. A new technique of asymmetry measurement involving simultaneous
K+ and K- beams and a large data sample collected allowed a result of an unprecedented precision. The charge asymmetries were measured
to be Ac
g=(-1.5±2.2)×10-4 with 3.11×109K±→π±π+π- decays, and An
g=(1.8±1.8)×10-4 with 9.13×107K±→π±π0π0 decays. The precision of the results is limited mainly by the size of the data sample. 相似文献
12.
M. A. Khodorkovskii T. O. Artamonova S. V. Murashov D. Michael L. P. Rakcheeva A. A. Belyaeva N. A. Timofeev A. S. Mel’nikov A. L. Shakhmin I. A. Dement’ev 《Technical Physics》2009,54(1):1-6
Signals from ions forming in a supersonic molecular beam consisting of an argon-water vapor mixture are measured as functions
of the exciting electron energy in the range to 120 eV. The thresholds of electron impact excitation of (H2O)
n − 1H+ and Ar
n
(H2O
m
+ clusters are determined for the first time. It is found that the proton-hydroxyl group binding energy decreases considerably
both in the case of water molecule clustering and when mixed Ar
n
(H2O)
m
clusters arise. 相似文献
13.
《The European Physical Journal C - Particles and Fields》2006,48(2):343-352
The effect of the final state Coulomb interaction on particles produced in Pb+Pb collisions at 158 AGeV/c has been investigated in the WA98 experiment through the study of the π-/π+ and K-/K+ ratios measured as a function of mT-m0. While the ratio for kaons shows no significant mT dependence, the π-/π+ ratio is enhanced at small mT-m0 values with an enhancement that increases with centrality. A silicon pad detector located near the target is used to estimate the contribution of hyperon decays to the π-/π+ ratio. The comparison of results with predictions of the RQMD model in which the Coulomb interaction has been incorporated allows to place constraints on the time of the pion freeze-out. 相似文献
14.
Yields, Y, of H+ and He+ emerging specularly with the energy for single binary elastic collisions have been measured from polycrystalline Ag and Pd surfaces bombarded with mixed monoenergetic (300 < E0 < 2600 eV) beams of H2+3He+ impinging at an angle of 45° from the surface normal. The surfaces were exposed to H2+ at a dynamic pressure of 8 × 10?3 Pa (6 × 10?5 Torr) during the measurements. The He+ yields from Pd are slightly larger than from Ag, and the H+ yields from Pd are 10 to 40 times as large as those from Ag. These results suggest that differences between Pd and Ag in the amount of hydrogen adsorbed and in the character of the hydrogen-metal bond may be responsible for the yield differences through shadowing by, and possibly the sputtering of, adsorbed hydrogen. The Y versus E0 curves for all four systems have qualitatively the same singly peaked shape which implies that reactive and noble gas ions undergo similar neutralization processes during elastic surface collisions. The ratios of the yields from Ag and Pd do not exhibit the theoretically expected exponential dependence on collision time over the entire range studied, but at the lowest energies the ratios lead to estimates of the difference of neutralization constants which do agree with theory. The potential utility of the large difference in proton yields from Ag and Pd for studying the Ag-Pd alloy system is noted. 相似文献
15.
I. P. Chernov S. V. Ivanova M. Kh. Krening N. Koval’ V. V. Larionov A. M. Lider N. S. Pushilina E. N. Stepanova O. M. Stepanova Yu. P. Cherdantsev 《Technical Physics》2012,57(3):392-398
A pulsed action of an electron beam on a Zr-1% Nb zirconium alloy is studied. Alloy samples are irradiated by three 50-μs
pulses at an energy density of 15–25 J/cm2, a power of (3–6) × 104 W/cm2, a current density of 10–50 A/cm2, and an electron energy of 18 keV. This method of processing is found to modify the surface layer of the alloy without changing
the structure-phase state of its volume. This surface modification increases the hydrogen saturation resistance of the alloy. 相似文献
16.
U. O. Yilmaz 《The European Physical Journal C - Particles and Fields》2008,58(4):555-568
The rare B
s
→φ
ℓ
+
ℓ
−decay is investigated by using the most general model-independent effective Hamiltonian for ℓ=μ,τ. The calculated value of Br(B
s
→φ
μ
+
μ
−)=1.92×10−6 is consistent with the experimental upper bound. The dependencies of the branching ratios and polarization asymmetries of
leptons and combined lepton–antilepton asymmetries on the new Wilson coefficients are presented. The analysis shows that the
branching ratios and the lepton-polarization asymmetries are very sensitive to scalar- and tensor-type interactions. The results
obtained in this work will be very useful in searching new physics beyond the standard model. 相似文献
17.
《The European Physical Journal A - Hadrons and Nuclei》2008,35(3):333-342
The exclusive reactions γp → K
*0Σ+(1189) and γp → K
0π0Σ+(1189) , leading to the p 4π0 final state, have been measured with a tagged photon beam for incident energies from threshold up to 2.5GeV. The experiment
has been performed at the tagged photon facility of the ELSA accelerator (Bonn). The Crystal Barrel and TAPS detectors were
combined to a photon detector system of almost 4π geometrical acceptance. Differential and total cross-sections are reported.
At energies close to the threshold, a flat angular distribution has been observed for the reaction γp → K
0π0Σ+ suggesting dominant s -channel production. Σ*(1385) and higher-lying hyperon states have been observed. An enhancement in the forward direction in the angular distributions
of the reaction γp → K
*0Σ+ indicates a t -channel exchange contribution to the reaction mechanism. The experimental data are in reasonable agreement with recent theoretical
predictions. 相似文献
18.
19.
S. S. Bulanov 《Physics of Atomic Nuclei》2004,67(2):314-327
The dependence of K
S, L
→ π
+
π
−
γ decay probabilities on photon polarization is calculated. The phases of the terms of the amplitude that arise from the pion-pion
interaction are obtained by using a simple realistic model of pion-pion interaction via virtual ρ meson, instead of chiral perturbation theory (ChPT). The results are compared with those of other authors and the origin
of the discrepancies is explained. It is shown that the standard ChPT approach for K
S, L
→ π
+
π
−
γ decays cannot reproduce the contribution of the ρ meson to the P-wave ππ interaction. The departure of the photon spectrum from pure bremsstrahlung due to the pion-loop contribution to the electric
direct emission amplitude is calculated. It is shown that the interference between the terms of amplitude with different CP parity appears only when the photon is polarized (linearly or circularly). Instead of measuring the linear polarization,
the angular correlation between the π
+
π
− and e
+
e
− planes in K
S, L
→ π
+
π
−
e
+
e
− decay can be studied.
From Yadernaya Fizika, Vol. 67, No. 2, 2004, pp. 332–345.
Original English Text Copyright ? 2004 by Bulanov.
This article was submitted by the author in English. 相似文献
20.
ZhiHu Yang Ying Cui XiMeng Chen ZhangYong Song JianXiong Shao FangFang Ruan HongQiang Zhang Juan Du YuWen Liu ZhiMing Gao XiaoAn Zhang KeXin Zhu DeYang Yu XiaoHong Cai 《中国科学G辑(英文版)》2008,51(10):1463-1469
The X-ray spectra of Nb surface induced by Ar
q+ (q = 16,17) ions with the energy range from 10 to 20 keV/q were studied by the optical spectrum technology. The experimental
results indicate that the multi-electron excitation occurred as a highly charged Ar16+ ion was neutralized below the metal surface. The K shell electron of Ar16+ was excited and then de-excited cascadly to emit K X-ray. The intensity of the X-ray emitted from K shell of the hollow Ar
atom decreased with the increase of projectile kinetic energy. The intensity of the X-ray emitted from L shell of the target
atom Nb increased with the increase of projectile kinetic energy. The X-ray yield of Ar17+ is three magnitude orders larger than that of Ar16+.
Supported by the National Natural Science Foundation of China (Grant Nos.10774149 and 10405025) 相似文献