Measurement of vacancy transfer probability from K to L shell using K-shell fluorescence yields

The vacancy transfer probabilities from K to L shell through radiative decay, η _KL, have been deduced for the elements in the range 19 ≤ Z ≤ 58 using K-shell fluorescence yields. The targets were irradiated with γ photons at 59.5 keV from a 75mCi ²⁴¹Am annular source. The K X-rays from different targets were detected with a high resolution Si(Li) detector. The measurement of vacancy transfer probabilities are least-squared fitted to second-order polynomials to obtain analytical relations that represent these probabilities as a function of atomic number. The obtained results agree with theoretical and fitted values.     

Determination of K to L shell total vacancy transfer probabilities using a weak gamma source: An alternative method

The K-L total vacancy transfer probabilities (η_KL) of selected elements in the atomic range 42≤Z≤82 have been determined using a weak gamma source. The targets are excited by 123.6 keV gamma photons from a weak ⁵⁷Co source and K X-ray photons are measured by an ORTEC type GMX-10P HPGe detector coupled to 8 K multichannel analyzer. By measuring the K X-ray intensity ratio and K shell fluorescence yield, the K to L total vacancy transfer probabilities have been determined. Measured values have been compared with theoretical and other experimental values.     

Measurement of the K shell X-ray production cross-sections and fluorescence yields for Nd,Eu, Gd,Dy and Ho using radioisotope X-ray fluorescence in the external magnetic field

The effect of external magnetic field on the K_α and K_β X-ray production cross-sections and K shell fluorescence yields for ferromagnetic elements Nd, Gd and Dy and paramagnetic elements Eu and Ho have been measured at the excitation energy of 59.5 keV γ -rays from ²⁴¹Am radioactive source of strength 100 mCi in the external magnetic field of intensities ±0.75 T. Furthermore, I_Kβ /I_Kα intensity ratios for these elements have been measured in the external magnetic field. The K X-rays from different targets were detected using a high resolution Si(Li) semiconductor detector. For B = 0, the measured K X-ray production cross-sections, K shell fluorescence yields and the I_Kβ /I_Kα intensity ratios were compared with the experimental and theoretical data in literature. The results have shown that the fluorescence parameters as photoionization cross section, fluorescence yield, radiation rates and spectral linewidth can change when the irradiation is conducted in a magnetic field.     

Empirical,Semi-Empirical and Experimental Determination of K X-Ray Fluorescence Parameters of Some Elements in the Atomic Range 21 ≤ Z ≤ 30

In this study, the semi-empirical and empirical calculations of K X-ray intensity ratios, K-shell fluorescence yields, and vacancy transfer probabilities have been performed for 3d transition elements. Also, σ_Kα, σ_Kβ production cross-sections, K_β/K_α intensity ratios, ω_K fluorescence yields, and η_KL vacancy transfer probabilities of 3d transition elements have been measured. The samples were excited by 59.5 keV γ-rays from a ²⁴¹Am annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV.     

Determination of ratios of emission probabilities of Auger electrons and K-L-shell radiative vacancy transfer probabilities for 17 elements from Mn to Mo at 59.5 keV

The measurements of the K X-ray intensity ratio I(K_β)/I(K_α) for the 17 elements Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr, Nb and Mo have been done following ionization by 59.5 keV γ-rays from a ²⁴¹Am point source. Ratios of emission probabilities of Auger electrons and the vacancy transfer coefficients have been extracted in terms of the intensity ratios. It is found that the present results agree well with earlier fitted values and the semi-empirical values.     

Longitudinal field relaxation measurements in monocrystalline DyAl2

Longitudinal μSR measurements were performed on a single crystal sphere of DyAl₂ in the range 4K≤T≤300 K (i.e. both in the ferromagnetic and paramagnetic phases). Contrary to previous reports the dynamic depolarization rate does not diverge near T_C≌65 K. Rather a well defined peak in the depolariation rate is observed around 95 K with 1/T₁ (95 K)∼4 μsec⁻¹. The depolariztion rate above T_C is field independent in the range 0≤B_ext≤2.5 kG. The observed behavior may be accounted for by assuming that the effective correlation time τ is given by τ⁻=τ _4f ⁻¹ +τ _diffusion ⁻¹ . The field independence requires that τ_eff<2·10⁻¹¹. The peak in 1/T₁ could then reflect a slowing down in μ⁺.     

Measurement of angular dependence from L3-subshell to M-shell vacancy transfer probabilities for the elements in the atomic region 71?Z?78

The angular dependence of L₃-subshell to M-shell vacancy transfer probabilities for the elements Lu, Hf, Ta, W, Os and Pt have been measured at the excitation energies of and K X-rays of Zn, Ga, Ge, and As, respectively, at seven angles varying from 120° to 150°. Energies of K X-rays are above the L₃ edge but below L₂ edge energies of the respective target elements under reference; therefore, the M X-rays are produced not only due to direct interaction of incident photons with M-shell electron but also due to the decay of L₃-subshell vacancies to M-shell. Because the angular dependence from L₃-subshell to M-shell vacancy transfer probabilities is not found in the literature, to the best of our knowledge there are no experimental values for worked elements. Therefore, the results for the elements obtained in the present study constitute the first experimental measurements and no comparison was made with other experimental and theoretical results. It has been observed that angular dependence from L₃-subshell to M-shell vacancy transfer probabilities increases with increasing .     

Formation and quenching mechanisms of excited particles in an oxygen-iodine laser medium

New values of a number of kinetic constants of processes proceeding in oxygen-iodine laser media are presented. The total probabilities of formation of I₂(X, 15 ≤ v ≤ 24) and I₂(X, 25 ≤ v ≤ 47) molecules in the course of quenching of I* atoms by I₂(X) are found to be 0.9 and 0.1, respectively. The quantum yield of singlet oxygen in the reaction O(¹ D) + N₂O → N₂ + O₂(a ¹Δ) is close to 100%. The quenching rate constants of I₂(A’) by O₂, H₂O, CO₂, I₂, and Ar and of I(² P _1/2) by O(³ P), O₃, NO₂, N₂O₄, and N₂O are presented.     

57Fe Mössbauer study of ternary alloy systems Fe(Sb1−x Te x )2 for 0.5≤x≤1.0 at 4.2K

Summary We report on low-temperature (4.2 K)⁵⁷Fe M?ssbauer studies of the ternary alloy system Fe(Sb_1−x Te _x )₂ for 0.5≤x≤1.0. The M?ssbauer spectra are electric-quadrupole doublets for all the specimens, indicating a non-magnetic character. The quadrupole splitting decreases with the increase in tellurium concentration. FeTe₂ has also been studied in external magnetic fields up to 6T. These experiments show that the electric-field gradient in this alloy is negative and has an asymmetry parameter of η ≈0.7. Paper presented at the ICAME-95, Rimini, 10–16 September 1995.     

快速氩离子在固体中2s和2p空穴的产生过程

对４３—９５ＭｅＶ的氩离子在与固体靶（Ｚ_t＝６—７４）碰撞中产生的Ｋα卫星线和超级卫星线作了高精度测量，得到了氩离子２ｓ和２ｐ支壳层空穴产生的概率，并对空穴产生的过程作了解释 关键词：     

Muon diffusion in β-V2H

Hydrogen diffusion in the ordered hydride β-V₂H is mainly brought about by a minority fraction of interstitial atoms on antistructural sites. Recently, this mechanism was elucidated in a single crystal QNS study at temperatures close to the critical point (390 K≤T≤440 K) where already an appreciable amount of antistructural sites is occupied. Here we use the positive muon as a radioactive hydrogen tracer in order to show that the same diffusion mechanism is also valid at low temperatures (80 K≤T≤320 K) where the different jump processes are very slow and where the fraction of antistructural atoms is tiny but nevertheless dominates the long range diffusion.     

<Emphasis Type="Italic">K</Emphasis><Subscript>β</Subscript> to <Emphasis Type="Italic">K</Emphasis><Subscript>α</Subscript> X-ray intensity ratios and K to L shell vacancy transfer probabilities of Co,Ni, Cu,and Zn

The K to L shell total vacancy transfer probabilities of low Z elements Co, Ni, Cu, and Zn are estimated by measuring the K _β to K _α intensity ratio adopting the 2π-geometry. The target elements were excited by 32.86 keV barium K-shell X-rays from a weak ¹³⁷Cs γ-ray source. The emitted K-shell X-rays were detected using a low energy HPGe X-ray detector coupled to a 16 k MCA. The measured intensity ratios and the total vacancy transfer probabilities are compared with theoretical results and others’ work, establishing a good agreement.     

Anisotropy of the local field in anisotropic films of conjugated polymers

Using the data on dispersion of refractive indices in the visible region, the experimental values of the components L _j of the Lorentz tensor have been obtained for uniaxial (crystalline, oriented on a substrate, and stretched) films of conjugated polymers from nanometer to micrometer thicknesses. The dependence of the components L _j on the axial and planar orientations of macromolecules with respect to the optical axis of the film, technology of fabricating the films, and chemical structure of macromolecules has been elucidated. The correlation between the components L _j and the measured parameter η has been determined and the analytical dependence L _j (η) for films with both types of macromolecular orientation has been established. In the visible region (0 ≤ η ≤ 0.5), the presence of one point (η = 1/3) of isotropization of the tensor L and three points (η = 0, 1/3, and 0.5) of isotropization of the local field tensor f has been revealed. The point η = 1/3 of isotropization of the tensors L and f has been determined. A comparison has been made between the values of L _j (η) with predictions of known models of the local field for conjugated polymers.     

Influence of atomic vacancy ordering in the nonmetallic sublattice on the electronic structure of titanium hydride

We present a calculation of the electronic density of states in TiH_x alloys (x=2.0, 1.7, and 1.5) with various degrees of long-range atomic order, η, in the subsystem of hydrogen and vacancies in the nonstoichiometric hydrides. In comparing the calculated results with the features of the photoelectron spectrum of TiH_1.5 we find agreement for η=0.5. We determine the temperature range for the establishment of atomic vacancy order. Siberian V. D. Kuznetsov Physicotechnical Institute, Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 7–14, October, 1998.     

Measurements of the absolute branching fractions for D→K̄πe+νe, D→K̄*e+νe and determination of Γ(D+→K̄*0e+νe)/Γ(D+→K̄0e+νe)

Using the data of about 33 pb^-1 collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, we have studied the exclusive semileptonic decays D⁺→K^-π⁺e⁺ν_e, D⁰→K̄⁰π^-e⁺ν_e, D⁺→K̄^*0e⁺ν_e and D⁰→K^*-e⁺ν_e. The absolute branching fractions for the decays are measured to be BF(D⁺→K^-π⁺e⁺ν_e)=(3.50±0.75±0.27)%, BF(D⁰→K̄⁰π^-e⁺ν_e)=(2.61±1.04±0.28)%, BF(D⁺→K̄^*0e⁺ν_e)=(5.06±1.21±0.40)% and BF(D⁰→K^*-e⁺ν_e)=(2.87±1.48±0.39)%. The ratio of the vector to pseudoscalar semileptonic decay rates Γ(D⁺→K̄^*0e⁺ν_e)/Γ(D⁺→K̄⁰e⁺ν_e) is determined to be 0.57±0.17±0.02.     

Systematic study of photon production at forward rapidity in STAR

We present the measurement of multiplicity and pseudorapidity distributions of photons production at forward rapidity (−2.3 ≤ η ≤ −3.8) for Cu + Cu collisions at $ \sqrt {S_{NN} } $ \sqrt {S_{NN} } = 62.4 and 200 GeV. Photons are measured using the Photon Multiplicity Detector (PMD) in STAR experiment at RHIC. The distributions of (η−η _beam), where η _beam is beam rapidity is presented. Pseudorapidity distributions of photons at forward rapidities, when ob-served in the frame of one of the colliding particles show the signature of energy independent scaling at forward rapidities known as Limiting Fragmentation. Measurement of inclusive photons reflect the distribution for π ⁰ as most of the photons come from π ⁰ decay. Gluon saturation at initial conditions of the collisions is one of the possible explanations for this scaling. Study of system-size and incident energy dependence of this phenomenon help us understand the mechanisms better. The system-size and energy dependence of the widths of scaling in pseudorapidity and comparison with model predictions are presented.     

Dc and Ac conductivity of La2CuO4+δ

The complex conductivity of La₂CuO_4+δ has been investigated for frequencies 20 Hz≤ν≤4 GHz and temperatures 1.5K≤T≤450 K. Two single crystals with δ≈0 and δ≈0.02 were investigated, using dc (four-probe), reflectometric and contact-free techniques. At high temperatures the dc conductivity is thermally activated with low values of the activation energy. For low temperatures Mott's variable range hopping dominates. The real and imaginary parts of the ac conductivity follow a power-law dependence σ∼v ^s, typical for charge transport by hopping processes. A careful analysis of the temperature dependence of the ac conductivity and of the frequency exponents has been performed. It is not possible to explain all aspects of the ac conductivity in La₂CuO_4+δ by standart hopping models. However, the observed minimum in the temperature dependence of the frequency exponents strongly suggests tunneling of large polarons as dominant transport process.     

TDPAC studies of the intercalation compound Li x TiS2 in the region 0≤x≤1

The electrochemical intercalation of Li⁺ into hafnium-doped TiS₂ was studied using time-differential perturbed angular correlations (TDPAC). The¹⁸¹Ta nuclear quadrupole interaction was monitored as a function of the charge transfer,n _F. For low uptakes, 0≤n _F≤0.03, a two-phase region was found with an empty host interaction, characterized byV _q=458(4) MHz, η=0.19(3) and δ-0.083(5), and a second interaction corresponding to lithiated material withv _q=597(5) MHz, η=0.13(4) and δ=0.061(5). No evidence was found for intermediate phases.     

The model-independent analysis indications for spectroscopy of scalar mesons. Proof for the K0* (900)

In a model-independent approach the data on ππ → ππ, K $ \bar K $ \bar K , ηη, ηη′ in the I ^G J ^PC = 0⁺0⁺⁺ channel and on the Kπ scattering in the $ I\left( {J^P } \right) = \frac{1} {2}\left( {0^ + } \right) $ I\left( {J^P } \right) = \frac{1} {2}\left( {0^ + } \right) channel are analyzed jointly for studying the status and QCD nature of the f ₀- and the K*₀-mesons. It is shown that in the 1500-MeV region, there are two states, wide (interpreted as a glueball) and narrow (q $ \bar q $ \bar q ). In the Kπ-scattering data analysis, the proof for the K*₀(900) is given.     

DasKLL- Auger-Spektrum von Chlor

TheKLL Auger spectrum of chlorine in CCl₄ has been investigated with an electrostatic energy analyzer. The ionization in theK shell of chlorine was caused by electron impact. Absolute energies and relative intensities of transitionsKL ₁ L ₁(¹ S,KL ₁ L _2,3(¹ P),KL ₁ L _2,3(³ P) andKL _2,3 L _2,3(¹ D) have been determined. Via the width of theK level of chlorine also experimental values of absolute transition probabilities have been calculated. While the relative intensities deviate strongly from theoretical values, the absolute transition probabilities agree better with theoretical values, especially with those calculated byRubenstein. — In an appendix the natural line widths of theKLL components of argon have been calculated theoretically.