Measurement of the K X-ray absorption jump factors and jump ratios of Gd, Dy, Ho and Er by attenuation of a Compton peak

The X-ray absorption jump factor and jump ratio of Gd, Dy, Ho and Er were measured with a Si(Li) detector by attenuation, with Gd, Dy, Ho and Er foil, a Compton peak produced by the scattering of the Am-241 Gamma rays. Al was chosen as secondary exciter. The experimental absorption jump factors and jump ratios are compared with the theoretical estimates of WinXcom (Radiat. Phys. Chem. 60 (2001) 23), McMaster (Compilation of X-ray cross sections UCRL-50174, 1969; Sec. II. Rev. I), Broll (X-ray Spectrom 15 (1986) 271), Hubbel and Seltzer (NISTIR (1995) 5632) and Budak (Radiat. Meas. accepted for publication). The present results constitute the first measurement for this combination of energy and elements, and good agreement is obtained between experiment and theory.     

On measurement of the K X-ray absorption jump factors and jump ratios of Gd, Dy, Ho and Er by attenuation of a Compton peak

The article entitled “Measurement of the K X-ray absorption jump factors and jump ratios of Gd, Dy, Ho and Er by attenuation of a Compton peak” by Budak G, and Polat R, published in the Journal of Quantitative Spectroscopy and Radiative Transfer 2004;88:525–532, carries out an inadequate treatment of their measured data that renders their results unsuitable for practical use. The analysis and evaluation below describes precisely the mistakes that invalidate the conclusions of this article.     

Determination of probabilities of vacancy transfer from K to L shell using K X-ray intensity ratios

K to L shell vacancy transfer probabilities (η_KL) for 26 elements in the atomic region 23≤Z≤57 were determined by measuring the I_Kβ/I_Kα intensity ratios. The targets were irradiated with γ-photons at 59.543 keV from ²⁴¹Am annular source. The K X-rays from different targets were detected with a high resolution Si(Li) detector. Theoretical values were calculated using the radiative and radiationless transition rates of these elements. The measured values of η_KL are compared with the theoretical values and data of others. The measurement vacancy transfer probabilities are least-square fitted to third-order polynomials to obtain analytical relations that represent these probabilities as a function of atomic number. The measured values of η_KL for V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se and Br are being reported here for the first time.     

Determination of gold and silver in dross using EDXRF technique

Gold and silver in dross were determined by energy‐dispersive X‐ray fluorescence technique. Sample was prepared by pressed pellet method using microcrystalline cellulose powder as binder, and a method of standard additions was used for quantification. L_β X‐ray of gold (11.4 keV) and K_β X‐ray of silver (24.9 keV) were used for analysis. The measured concentrations of gold and silver were 132 ± 8 and 1181 ± 84 mg kg^?1, respectively. The results were validated by instrumental neutron activation analysis technique. The t‐test indicated that there was no significant difference between results obtained by the two techniques. Energy‐dispersive X‐ray fluorescence is a simple, precise and accurate technique for the determination of gold and silver in dross. Copyright © 2014 John Wiley & Sons, Ltd.     

Measurements of absorption spectra of thin films by the waveguide technique

The waveguide technique for measuring the absorption spectra of thin films in spectral range of their transparency is considered. The error of measuring the absorption of a ～0.1 μm thick film does not exceed 5% at an absorption coefficient of less than 50 cm^–1. Capabilities and limitations of the method are discussed.     

Measurements of the energy shifts of the K absorption edge and K X-rays of several uranium compounds

The energy shifts in the K absorption edges and the Kα₁ and Kβ_{1, 3} X rays in several uranium compounds were measured with the Caltech 2 m bent crystal spectrometer. The results are compared with free-ion relativistic self-consistent field calculations.     

Measurements of NO2 mixing ratios with topographic target light scattering-differential optical absorption spectroscopy system and comparisons to point monitoring technique

A topographic target light scattering-differential optical absorption spectroscopy(ToTaL-DOAS) system is developed for measuring average concentrations along a known optical path and studying surface-near distributions of atmospheric trace gases.The telescope of the ToTaL-DOAS system points to targets which are located at known distances from the measurement device and illuminated by sunlight.Average concentrations with high spatial resolution can be retrieved by receiving sunlight reflected from the targets.A filed measurement of NO2 concentration is performed with the ToTaL-DOAS system in Shijiazhuang in the autumn of 2011.The measurement data are compared with concentrations measured by the point monitoring technique at the same site.The results show that the ToTaL-DOAS system is sensitive to the variation of NO2 concentrations along the optical path.     

对流层低层臭氧的差分吸收激光雷达测量

利用紫外差分吸收(DIAL)激光雷达对北京南郊对流层低层臭氧垂直分布进行了测量,将探测结果与探空气球同时测量的结果进行了对比,取得了较为一致的分布趋势。选择北京南郊地区晴好天气探测的结果进行了统计分析,结果表明：近地面层内随高度增加,臭氧体积混合比逐渐减小;距地面0.5~1.5 km内平均臭氧体积混合比具有明显的日变化趋势,最大值出现在午后14点左右,相对太阳辐射最强时刻具有明显的滞后性;日平均最大体积混合比低于410-8,体积混合比起伏小于3.210-9。     

对流层低层臭氧的差分吸收激光雷达测量

利用紫外差分吸收(DIAL)激光雷达对北京南郊对流层低层臭氧垂直分布进行了测量,将探测结果与探空气球同时测量的结果进行了对比,取得了较为一致的分布趋势。选择北京南郊地区晴好天气探测的结果进行了统计分析,结果表明:近地面层内随高度增加,臭氧体积混合比逐渐减小;距地面0.5~1.5 km内平均臭氧体积混合比具有明显的日变化趋势,最大值出现在午后14点左右,相对太阳辐射最强时刻具有明显的滞后性;日平均最大体积混合比低于410-8,体积混合比起伏小于3.210-9。     

利用光热偏转技术实施光学薄膜弱吸收的多波长测量

介绍了光热表面形变光束偏转技术用于测量光学薄膜弱吸收的基本原理,简述多波长吸收测量装置的建立和测试过程,最后给出简单的测量实例.     

Measurements of exciton absorption with pico-second light pulses produced by a self-phase modulation technique

Time-resolved absorption spectra of the A exciton in CdSe are measured by using pico-second white-light pulses produced by a self-phase modulation technique. The absorption peak of the n = 1 A exciton shifts to the high-energy side due to the high-density effect. The magnitude of the shift reaches a maximum at 20 psec after the pulse excitation, which is considered to indicate that the time constant for the formation of the n = 1 excitons by band-to-band excitation is about 20 psec.     

Trace element analysis of fly ash samples by EDXRF technique

Trace element analysis of some fly ash samples and soil samples have been carried out by Energy Dispersive X-Ray Fluorescence technique. Fourteen elements namely K, Ca, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr and Pb have been quantified in the fly ash samples by this technique. It was found that there is no huge concentration difference between the fly ash and soil samples as a result of which fly ash can be used as soil manure without any adverse impact on the plants.      

Measurements of depolarization ratios and polarizability anisotropies of gaseous molecules

Values for the depolarization ratio (?^T_V) of Rayleigh scattered light are reported for a large number of gas molecules. When possible, the results are combined with refractive index data to yield the anisotropy in the optical polarizability.     

Measurement of K shell fluorescence cross-section of Ca and K compounds

The cross-section for Ca and K compounds were determined by measuring the KX-ray yields from targets excited 5.96 keV photons and using theoretical K shell photoionization cross-section. By comparing the experimental results with relativistic Hartree-Fock calculation, a good agreement has been obtained considering the experimental errors.     

Measurements of protonation reaction kinetics of histidine using a chemical relaxation technique

The rate constants for protonation reactions of histidine have been determined using a modulation chemical relaxation technique. Estimates have been made for bifunctional protonation rate constants. Activation energies have been measured.     

Measurements of carbon monoxide mixing ratios in Houston using a compact high-power CW DFB-QCL-based QEPAS sensor

Measurements of carbon monoxide (CO) mixing ratios in Houston, Texas, during the period from May 16, 2013 to May 28, 2013 were performed using a sensitive, selective, compact, and portable quartz-enhanced photoacoustic spectroscopy (QEPAS)-based CO sensor employing a high-power continuous wave (CW) distributed feedback quantum cascade laser (DFB-QCL). The minimum detectable CO concentration was 3 ppbv for the strong, interference-free R(6) absorption line at 2,169.2 cm^?1 and a 5 s data acquisition time. The average CO concentration during the measurement period was 299.1 ± 81.4 ppb with observed minimum and maximum values of 210.5 and 4,307.9 ppb, respectively. A commercially available electrochemical sensor was employed in-line for simultaneous measurements to confirm the response of the CW DFB-QCL-based QEPAS sensor to variations of the CO mixing ratios. Moderate agreement (R ² = 0.7) was found between both sets of CO measurements.     

Energy dependence of photon-inducedL shell x-ray intensity ratios in Ta and W

TheL shell x-ray intensity ratios have been measured for the elements Ta and W by photoionization ofL shell electrons in the photon energy region 14⩽E⩽44 keV. The experimental results are compared with those calculated at the photon energies used in the present measurements. The measured values show fairly good agreement with the calculated values within the experimental uncertainties.     

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.