K Shell Fluorescence Parameters by Impact of 5.96 keV Photons on Ti and Its Compounds

K shell fluorescence parameters of pure Ti and some of its compounds have been determined experimentally using an Ultra-LEGe detector with resolution 150 eV at 5.9 keV. The samples were excited 5.96 keV photons emitted from a 55Fe radioisotope source with 50 mCi activity. The experimental values of the K shell fluorescence parameters have been compared with the experimental and theoretical values available in the literature for pure Ti.     

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.     

Kβ/Kα x‐ray intensity ratios for bromine and iodine compounds

Kβ/Kα x‐ray intensity ratios of some Br and I compounds were studied. The samples were excited by 59.5 keV γ‐rays emitted from an Am‐241 radioisotope source and characteristic K x‐rays emitted from the samples were counted by means of an Si(Li) detector which has a resolution 155 eV at 5.9 keV. The experimental values were compared with the calculated theoretical values for elemental Br and I. Copyright © 2003 John Wiley & Sons, Ltd.     

Effect of annealing temperature on K-shell X-ray fluorescence parameters of zinc oxide thin films prepared by the sol-gel method

Zinc oxide thin films were grown on a glass substrate by a sol-gel process using a spin-coating technique. The obtained thin films were annealed between 350?°C and 550?°C in 50?°C steps and were then characterized using X-ray diffraction, scanning electron microscopy, and X-ray fluorescence techniques. The samples were stimulated by 59.5?keV gamma rays emitted from an Americium-241 annular radioisotope source. K X-rays emitted by samples were counted using an ultra-low energy germanium detector with a resolution of 150?eV at 5.96?keV. It was found that there was generally a decrease in both the Kβ/Kα X-ray intensity ratios and the K X-ray fluorescence cross sections for zinc oxide between 350?°C and 500?°C, but not at 550?°C. In addition, the X-ray diffraction patterns of the films showed that the transition phase from an amorphous to a polycrystalline hexagonal wurtzite structure was complete at an annealing temperature of 500?°C. The results show that variations in these parameters can be explained by the reorganization of atoms and the charge transfer process due to the effect of the annealing temperature on the elements forming the compounds.     

Chemical effect on the K shell fluorescence yield of Fe, Mn, Co, Cr and Cu compounds

Chemical effects on the K shell fluorescence yields of Fe, Mn, Co, Cr and Cu compounds were investigated. Samples were excited using 59.5 keV energy photons from a²⁴¹ Am radioisotope source. K X-rays emitted by samples were counted by a Si(Li) detector with a resolution 160 eV at 5.9 keV. Chemical effects on the K shell fluorescence yields (ωk) for Fe, Mn, Co, Cr and Cu compounds were observed. The values are compared with theoretical, semiempirical fit and experimental ones for the pure elements.     

Nondestructive discrimination of small glass fragments for forensic examination using high energy synchrotron radiation x‐ray fluorescence spectrometry

This paper demonstrates that high‐energy SR‐XRF (synchrotron radiation x‐ray fluorescence spectrometry) utilizing 116 keV x‐rays is a powerful technique for nondestructive discrimination of small glass fragments. An XRF spectrum of glass fragments of a standard material SRM612 gave well‐resolved K‐line peaks of 34 elements, including the rare‐earth elements. The relative standard deviations (RSD) of the ratios of the intensities of heavy elements normalized by that of Ba were less than 8.2% for the analyses of 10 fragments (<1 mg) in the energy region above 20 keV. A comparison of glass fragments (<1 mg) obtained from 26 figured glass sheet was performed using elemental intensity ratios that were defined as the intensities of detected elements divided by that of Ba. Analyses of glass fragments revealed the existence of Mo, Pd, Sb, Cs and Bi, and these trace elements could be useful as important indexes to discriminate glass samples. The Ce:Ba ratios could be measured for all the samples with precision of 1.9% and were found to be quite effective parameters for identification of glass fragments, even though these fragments would contain no other characteristic heavy elements. All glass fragments in this study that could not be distinguished on the basis of refractive index (RI) values could be discriminated by this method. Copyright © 2006 John Wiley & Sons, Ltd.     

Measurements of X-ray absorption spectra by the prism spectroscopy method

X-ray absorption spectra of a number of samples were measured in the range 5–30 keV by the prism spectrophotometry method. The spectral decomposition was performed using an optically polished diamond prism with an opening angle of 90°. The absorption spectra of liquid bromonaphthalene are presented as an example. An energy resolution of 100–130 eV was achieved in the energy range of ～10 keV, providing the unambiguous identification of elements by jumps in the K photoabsorption.     

皮秒脉冲激光产生的X射线源能谱精密诊断

针对皮秒脉冲激光产生的X射线能谱精密诊断需求,提出了一种晶体谱仪,该谱仪使用曲率为200 mm的透射式石英弯晶作为色散元件,测谱范围可覆盖8～60 keV。使用该谱仪在星光III和神光II升级装置进行了应用,成功获得了铜、钼、银等元素的特征线能谱,以及金的L壳层特征线,测量获得的能谱信噪比较高,显示了谱仪在测量皮秒激光产生的X射线能谱上的良好性能。     

Measurements of angular distributions of sputtered material as a new tool for surface-segregation studies: Segregation in CuPt alloys

The angular distribution of copper and platinum sputtered by argon ions from polycrystalline CuPt targets at 77 K has been measured by a collection technique. The argon-ion energy has been varied from 1.25 to 320 keV. For bombardment energies above 20 keV, differences in the angular distributions for the two elements indicate a strong copper segregation to the surface during bombardment.     

Investigation of multilayer X‐ray optics for the 6 keV to 20 keV energy range

The X‐ray optics group at the Swiss Light Source in co‐operation with RIT (Rigaku Innovative Technologies) have investigated seven different multilayer samples. The goal was to find an ideal multilayer structure for the energy range between 6 keV and 20 keV in terms of energy resolution and reflectivity. Such multilayer structures deposited on substrates can be used as X‐ray monochromators or reflecting synchrotron mirrors. The measured reflectivities agree with the simulated ones. They cover a reflectivity range from 45% to 80% for energies between 6 keV and 10 keV, and 80% to 90% for energies between 10 keV and 20 keV. The experimentally measured energy resolution of the samples lies between 0.3% and 3.5%.     

Effect of pressure on pressed pellets in XRS

In this study, the absorption experiments which are an application area in XRS are discussed. The effect on the absorption parameters of the pressure applied to make pellet powder samples was investigated. The mass attenuation coefficients ( μ _m ), mean free paths and half-value layers of samples prepared at different pressures were experimentally determined. C₆H₁₀O₅, VF₄, CaO and Y₂O₃ samples were pressed at 1.91, 3.82, 5.72 and 7.63 tons/cm². A variable energy x-ray source from Amersham (AMC.2084) was used in order to irradiate the samples at energies 13.39, 19.63, 24.90, 32.06, 36.39, 44.48, 51.70 and 59.54 keV. The photon intensities were measured by using an HPGe detector with a resolution of 182 eV at 5.9 keV. The theoretical radiation absorption parameters were calculated by WinXCOM program. The calculated values were compared with the experimental values. Good agreement has been observed within experimental uncertainties for low pellet pressure. The obtained results show that the radiation absorption parameters change with the amount of pressure applied to the sample.     

对40Ca9.5—10.5MeV能区内几组核能级宽度的测量

本文介绍了用γ共振吸收法测量⁴⁰Ca 9603.9keV,10321.0keV两组能级和9864.6,9868.8keV一组双重态能级的能级宽度,选用³⁹K(p,γ)反应所放出的γ射线激发相应的⁴⁰Ca吸收核能级。对于9603.9keV,10321.0keV的能级宽度,这里给出了比较精确的结果,相应的能级宽度分别为Γ=188±47eV,Γ=91±15eV。对于9864.6,9868.8keV能级,结果为Γ=100±24eV,Γ=899±214eV,由于⁴⁰Ca 9864.6,9868.8keV两能级靠得很近,因此这里用γ共振吸收法测量它们的能级宽度与以往有所不同,将同时有两组γ射线用来激发同样两个能级而发生交叉激发。我们对相应的实验处理方法作了推广。此外,用(p,γ)共振产额法测量了⁴⁰Ca 9603.9keV,10321.0keV能级宽度,得到了与γ共振吸收法一致的结果。本文还对⁴⁰Ca 9603.9keV,10321.0keV能级的(p,γ)共振强度S_pγ、同位旋T等进行了讨论。 关键词：     

Temperaturabhängigkeit der anomalen Elektronenabsorption von Wismut-Einkristallen

Polycrystalline bismuth foils could be transformed into single crystal plates by a tempering process. Using the so prepared single crystals of high atomic number and of known thickness the temperature dependence of a dynamical two-beam system for the diffraction of 80 keV electrons has been investigated between 300 K and 80 K. The measured intensities of the (¯2 20)-reflection and the primary beam were compared with the transparency of the polycrystalline foils. They increase exponentially with decreasing temperature and thickness of the crystal. This experimental behaviour can be explained by a dynamical electron-diffraction-theory.     

Magnetic moments in potassium isotopes by the time dependent recoil into gas method

Time and pressure dependent recoil into gas measurements of perturbed angular correlations have been carried out following the reactions^{24, 26}Mg+¹⁸O. The levels and |g|-values measured are:³⁹K: 2,814 keV, 1.15(12); 3,598 keV, 0.54(5);⁴⁰K: 2,543 keV, 0.63(15);⁴¹K: 2,528 keV, 0.82(19); 2,774 keV, 0.46(7); 4,983 keV, 0.74(30). Meanlives measured for the⁴¹K levels are 220(5) ps, 80(2) ps and 106(3) ps, respectively.     

Observation of nuclear excitation by electron transition in 197Au with synchrotron X rays and an avalanche photodiode

We have succeeded in observing nuclear excitation by electron transition (NEET) in 197Au by a new method. Monochromatic x-rays of synchrotron radiation were used to ionize the K shell of gold atoms in a target foil. The internal-conversion electrons emitted from excited nuclei were detected with a silicon avalanche photodiode. At a photon energy of 80.989 keV, the NEET probability in 197Au was determined to be (5.0+/-0.6)x10(-8) from a comparison of the event number per photon between NEET and the nuclear resonance at 77.351 keV.     

18～88 keV Ross滤片谱仪的设计和应用

以带通平响应为优化目标,通过残余响应、带外残余响应相对误差以及残余响应平整度3个参数来优化滤片的厚度,设计了一套共有7个能量通道、连续覆盖18~88keV能谱范围的Ross滤片谱仪。该谱仪能量通道宽度在2~20keV之间。多数能量通道的带外残余响应相对误差低于10%,残余响应平整度优于20%。将该谱仪应用于微聚焦X光机上的高Z金属球壳高能X射线背光照相实验,结果表明:在不同的实验条件下,Ross滤片谱仪测得的能谱形状与理论模型给出的结果符合较好,测得的能谱不仅能够很好地解释背光照相图像,而且可用于根据图像反推客体的面密度。     

New experimental measurement of natSe(n, γ) cross section between 1 eV to 1 keV at the CSNS Back-n facility

The ⁷⁴Se is one of 35 p-nuclei, and ⁸²Se is a r-process only nucleus, and their (n, γ) cross sections are vital input parameters for nuclear astrophysics reaction network calculations. The neutron capture cross section in the resonance range of isotopes and even natural selenium samples has not been measured. Prompt γ-rays originating from neutron-induced capture events were detected by four C₆D₆ liquid scintillator detectors at the Back-n facility of China Spallation Neutron Source (CSNS). The pulse height weighting technique (PHWT) was used to analyze the data in the 1 eV to 100 keV region. The deduced neutron capture cross section was compared with ENDF/B-VIII.0, JEFF-3.2, and JENDL-4.0, and some differences were found. Resonance parameters were extracted by the R-matrix code SAMMY in the 1 eV-1 keV region. All the cross sections of ^natSe and resonance parameters are given in the datasets. The datasets are openly available at http://www.doi.org/10.11922/sciencedb.j00113.00019.     

Radiative Auger emission in Ne K X-ray spectra

Radiative Auger emission intensity in K X-rays from neon was measured following electron bombardment by 1 to 2 keV electrons. The measured relative intensities of this process are in good agreement with calculations of Dyall using correlated final-state wavefunctions.