X-ray spectrum determination from the angular dispersion of radiation in a diamond prism

The X-ray spectrum of hard polychromatic radiation with energies of up to 40 keV was obtained from the angular dispersion of the radiation beam in a diamond prism. In contrast to the classical optical scheme, the beam to be analyzed is passed through the entrance face of the prism without refraction and is directed onto the exit face at a glancing angle ～(2δ)^1/2, where δ is the real part of the decrement of the refractive index for the short-wavelength edge of the spectrum. The spectrum distortions caused by the intersection of the reciprocal lattice points by the Ewald sphere at a fixed number of wavelengths λ are minimized by the use of the angular divergence of the beam of ～10′ in the plane perpendicular to the refraction plane. In the energy range of 8–9 keV, an energy resolution of less than 100 eV was obtained, which exceeds the corresponding parameter for cooled semiconductor detectors. The measuring scheme suggested makes it possible to solve the problem of the analysis of spectra of directional X-ray beams when studying fast nonstationary generation processes.     

Total bremsstrahlung spectra in targets of Al,Ti, Sn and Pb produced by complete absorption of 90Sr β particles

Total bremsstrahlung (BS) spectra in thick targets of Al, Ti, Sn and Pb produced by complete absorption of ⁹⁰Sr β particles (0–546 keV) are reported in the photon energy region of 10–30 keV. The experimental BS spectral photon distributions were compared with the theoretical BS spectral photon distributions obtained from Elwert corrected (non‐relativistic) Bethe–Heitler theory, modified Elwert factor (relativistic) Bethe–Heitler theories for ordinary bremsstrahlung (OB) and the modified Elwert factor (relativistic) Bethe–Heitler theory, which include the polarization bremsstrahlung (PB) into OB in stripped atom approximation. It has been observed that the experimental results are showing better agreement with the modified Elwert factor (relativistic) Bethe–Heitler theory having the contribution of PB at photon energy from 10 to 30 keV. This indicates the importance of PB in BS spectra, while studying the spectral photon distributions produced by continuous β particles having energy range of 0–546 keV in thick metallic targets. Further, it is observed that the contribution of PB into OB increases with increase in atomic number of the target and decreases with increase in photon energy. Copyright © 2010 John Wiley & Sons, Ltd.     

Role of polarization Bremsstrahlung in the formation of thick target Bremsstrahlung spectra in the energy range of 5–10 keV

Role of polarization Bremsstrahlung in the formation of total Bremsstrahlung (BS) spectra in thick targets of Al, Ti, Sn and Pb, produced by complete absorption of ⁹⁰Sr beta particles having an energy range of 0–546 keV, are studied in the photon energy region of 5 to 10 keV. The theoretical BS spectral photon distributions, obtained from Elwert corrected (nonrelativistic) Bethe–Heitler theory, a modified Elwert factor (relativistic) Bethe–Heitler theory that describe ordinary Bremsstrahlung (OB) and a modified Elwert factor (relativistic) Bethe–Heitler theory for BS spectra that includes the polarization Bremsstrahlung (PB) into OB in stripped atom approximation, were compared with the experimentally measured BS spectral photon distributions. It has been observed that the experimental results are in agreement with the modified Elwert factor (relativistic) Bethe–Heitler theory at photon energy from 5 to 10 keV. It has been also observed that the contribution of PB into OB decreases with increase in end‐point energy of beta emitter and the energy of the emitted photon. Further, it has been found that the contribution of PB into OB increases with increase in atomic number of the target atom. This indicates the importance of PB in the formation of BS produced by continuous beta particle. Copyright © 2012 John Wiley & Sons, Ltd.     

Dispersive characteristics of diamond in the range of hard x-ray waves

Dispersive properties of natural diamonds were studied for the first time in a range of x-ray wavelengths of 0.03–0.2 nm. The dispersion element represented an analog of a rectangular prism. A collimated beam of polychromatic radiation was directed onto the refracting face from inside under a small glancing angle . The radiation was introduced into the prism through a side face oriented perpendicularly to the axis of the incident beam. In the range of energies near 8 keV, a resolution of 106 eV was achieved, which is about twice as good as the corresponding parameter for semiconductor detectors. Calculations show that under ideal conditions the limiting resolution for a diamond prism with a single refracting face can be reduced to 36–40 eV. This makes it possible to create a new type of analytical devices—dispersion x-ray spectrometers for the investigation of rapid processes involving generation and absorption of x-ray radiation.     

Measurement of the X‐ray mass attenuation coefficients of silver in the 5–20 keV range

The X‐ray mass attenuation coefficients of silver were measured in the energy range 5–20 keV with an accuracy of 0.01–0.2% on a relative scale down to 5.3 keV, and of 0.09–1.22% on an absolute scale to 5.0 keV. This analysis confirms that with careful choice of foil thickness and careful correction for systematics, especially including harmonic contents at lower energies, the X‐ray attenuation of high‐Z elements can be measured with high accuracy even at low X‐ray energies (<6 keV). This is the first high‐accuracy measurement of X‐ray mass attenuation coefficients of silver in the low energy range, indicating the possibility of obtaining high‐accuracy X‐ray absorption fine structure down to the L₁ edge (3.8 keV) of silver. Comparison of results reported here with an earlier data set optimized for higher energies confirms accuracy to within one standard error of each data set collected and analysed using the principles of the X‐ray extended‐range technique (XERT). Comparison with theory shows a slow divergence towards lower energies in this region away from absorption edges. The methodology developed can be used for the XAFS analysis of compounds and solutions to investigate structural features, bonding and coordination chemistry.     

Induced Quasi-Dynamic Disorder in a Structure of Rhenium Ion-Implanted Quartz Glass

Physics of the Solid State - The ultraviolet (UV) absorption spectra were studied in UV–Vis–IR quartz glasses exposed to the rhenium ion irradiation at the energy of 30 keV. An increase...     

Study of the104Ru(d,p)-reaction at 14 MeV

The reaction¹⁰⁴Ru(d, p) was investigated with high resolution (5 keV) at the Munich MP tandem using the Q3D spectrograph in conjunction with the precision time-of-flight system. The ground stateQ-value was determined as Q=3,684.5±1 keV. Proton spectra were measured at 7 angles in the range of 6.1°–65°. 19 levels could be identified in the excitation energy range 0–730 keV. Transferredl-values and spectroscopic factors of these levels were derived with the aid of DWBA calculations.     

Hard X-ray compton polarimetry with the PENGUIN-M instrument in the spaceborne experiment CORONAS-PHOTON

We describe the main parameters of the PENGUIN-MD detector unit of the PENGUIN-M instrument designed to measure the degree of linear polarization of X-ray radiation from solar flares in the energy range 20–150 keV and the X-ray spectra of solar flares in the energy range 2–500 keV. The method for measuring the X-ray polarization employed in the PENGUIN-MD unit is based on registration of coincidences in an active scatterer and scattered-radiation detectors. This method makes it possible to substantially reduce the background and to increase the sensitivity and reliability of the measurements.     

The properties of 116in excited states

Gamma and conversion electron spectra from the ¹¹⁵In(n, γ)¹¹⁶In reaction in the energy range 20–700 keV and 20–850 keV respectively have been measured with bent crystal and magnetic spectrometers. Gamma-gamma coincidences in the energy range 50–500 keV have been investigated with Ge(Li)-Ge(Li) arrangement. Proton spectra from the 12 MeV deuteron-induced (d, p) reaction taken at the University of Pittsburgh Tandem Van de Graaf accelerator were reanalysed. The ¹¹⁶In level scheme consisting of 56 levels in the energy range 0–1.4 MeV has been constructed. Parity is determined for all the levels introduced. Unique spin values are assigned to 37 levels. The information obtained was used to place limits to the J-values for the rest of the levels. The main components of the wave function are established for 23 levels, considered to be components of p-n multiplets in which the proton hole and odd neutron are in in one of the Z = 28 → 50 and N = 50 → 82 shell states, respectively. Energy splittings of p-n configurations by residual interactions taken as a combination of short range Wigner and singlet forces have been calculated. It is noted that many excited states cannot be described in the framework of two-quasiparticle configurations.     

Filippov type plasma focus as intense source of hard X-rays(Ex≃50 keV)

This paper evaluates the use of a plasma focus machine (Filippov type) as a pulsed intense source of hard X-rays. It is shown experimentally that discharging a capacitor bank of W=50 kJ in the new arrangement of the discharge parameters, one can deliver into the test cavity (volume of 6*10³ cm³) an average of Φ _x=8*10^-4 J/cm². The delivered energy fluence varies in the range of 2*10^-4 J/cm²⩽Φ_x⩽2.9*10^-3 J/cm², depending on the probe position. The X-ray energy spectra were established by the differential absorption method using thermo-luminescent detectors (time-integrated spectra) or plastic scintillators (time-resolved spectra). The average energy of X-ray photons is 40 keVx^av<50 keV (20 keV⩽E _x⩽170 keV) and remains quasi-constant during the main part of the pulse (~40 ns). The electron energy that can produce such bremsstrahlung radiation is in the range of 95 keV⩽E_e⩽170 keV. However, time-resolved experiments reveal that at each instant of time only one energy of electron beam occurs. The aforementioned radiation characteristics reveal new potentials for the plasma-focus machine for a variety of applications. Some insight into the physics behind production mechanism of quasi-monoenergetic relativistic-electron beams will be concurrently reviewed     

Simple parametrization of photon mass energy absorption coefficients of H-, C-, N- and O-based samples of biological interest in the energy range 200–1500 keV

In this paper, we provide polynomial coefficients and a semi-empirical relation using which one can derive photon mass energy absorption coefficient of any H-, C-, N-, O-based sample of biological interest containing any other elements in the atomic number range 2–40 and energy range 200–1500 keV. More interestingly, it has been observed in the present work that in this energy range, both the mass attenuation coefficients and the mass energy absorption coefficients for such samples vary only with respect to energy. Hence it was possible to represent the photon interaction properties of such samples by a mean value of these coefficients. By an independent study of the variation of the mean mass attenuation coefficient as well as mass energy absorption coefficient with energy, two simple semi-empirical relations for the photon mass energy absorption coefficients and one relation for the mass attenuation coefficient have been obtained in the energy range 200–1500 keV. It is felt that these semi-empirical relations can be very handy and convenient in biomedical and other applications. One possible significant conclusion based on the results of the present work is that in the energy region 200–1500 keV, the photon interaction characteristics of any H-, C-, N-, O-based sample of biological interest which may or may not contain any other elements in the atomic number range 2–40 can be represented by a sample-independent (single) but energy-dependent mass attenuation coefficient and mass energy absorption coefficient.      

A telescope for α-particle spectrometry

An alpha spectrometer based on a telescope consisting of two silicon semiconductor surface barrier detectors is described. The spectrometer has been used to study the α-particle energy spectra of an (n,α)-type reaction and ternary fission of uranium in an energy range 4–30 MeV with a resolution of 85 keV.     

Yields and energy spectra of light charged particles emitted in neutron induced fission of235U

The yields and energy spectra of light charged particles emitted in the fission of²³⁵U have been measured in the neutron energy range of 100 keV to 1 MeV. The yield of long range alpha particles is found to increase around 200 keV neutron energy compared to thermal fission. A low energy component observed in the energy spectrum was assigned to the tritons emitted in fission. The yield of this triton component is seen to have a marked increase around 500 keV. These results indicate that LCP yield is influenced by the transition state level characteristics.     

喷气式Z箍缩等离子体辐射软X射线能谱的研究

研制了一台五通道ROSS-FILTER-PIN软X射线能谱仪，能谱范围为0.28—1.56keV.它由5个连续能段组成，每个能段的起止边由罗斯滤片对(ROSS-FILTERS)的L或K吸收边确定.罗斯滤片对的厚度通过优化计算得到，为了使每个通道的灵敏区外响应(即所测能段外响应)与通道总响应之比最小，在滤片对的第二滤片上镀上了一定厚度的第一滤片材料；为了缩减滤片表面积以增强低能滤片的抗冲击能力及方便滤片加工，能谱仪采用了小探测面积的PIN探测器(1mm²).借助此能谱仪，测量得到了喷气式Z箍缩(Z-pinch)等离子体辐射软X射线能谱的分布，并研究了软X射线产额随箍缩状况的变化趋势. 关键词： Z箍缩等离子体 罗斯滤片 软X射线能谱     

气体放电中的X射线诊断

用气体放电法研究含氘金属异常现象时,发现有Ｘ射线产生．因此用吸收法、特征Ｘ射线法和ＮａＩ闪烁计数器测量了Ｘ射线能量,用７Ｌｉ热释光片估测了Ｘ射线强度．吸收法测出的Ｘ射线平均能量为（２６．９±２．２）ｋｅＶ和ＮａＩ闪烁计数器测出的（２６．０±２．４）ｋｅＶ单能Ｘ射线在测量误差内相符． X rays were observed to create when the anomalous phenomenon in the metal loaded with deuterium studied by the gas-discharge method. Therefore the X-ray energy spectra were measured by the absorption method, the specific X-ray approach and the NaI scintillation counter, while X-ray intensity was estimated by using 7Li thermoluminescent foils. The X-ray average energy measured by the absorption method is 27. 6±2. 1keV,whlch is fitted within the error extent to 26. 0±2. 4keV monoenergetic Xrays     

Studies of the gamma-strength function and low energy levels in 65Ga using the (p, γ) average resonance method

The ⁶⁴Zn(p, γ)⁶⁵Ga reaction has been studied in the proton energy ranges E_p = 2.0–2.9 and 3.3–4.3 MeV. Using a three-crystal pair spectrometer, gamma-ray spectra of primary transitions were measured throughout this proton energy interval in steps of about 20 keV. An average gamma ray spectrum for each energy region was formed by adding all the relevant individual spectra after adjustment due to the change of the proton energy. In the excitation energy range 0.0–3.7 MeV 50 levels, of which 20 are new, were observed. The gamma strength function was deduced from the average intensities of the primary gamma-rays. The absolute value of the strength function was found to be 5–10 times smaller than that expected from the extrapolation of the lorentzian shape of the El giant resonance.     

银吸收边附近X射线衰减系数测量

在北京同步辐射装置的4B7A中能X光束线上,光源能区为2.1~6.0 keV,能量分辨大于5000,高次谐波小于0.1%,光源强度大于109光子/s。通过全能区多能点的透过率精确测量Ag样品质量厚度,然后采用Ag薄膜对单能X光子的透过率进行测量,给出了Ag薄膜在吸收边（3.4~3.9 keV）的衰减系数 。建立了Ag样品吸收边附近衰减系数同步辐射测量方法。通过不确定度分析给出衰减系数测量不确定度小于1％,填补了在该区间衰减系数的空白。     

银吸收边附近X射线衰减系数测量

在北京同步辐射装置的4B7A中能X光束线上,光源能区为2.1~6.0keV,能量分辨大于5000,高次谐波小于0.1%,光源强度大于109光子/s。通过全能区多能点的透过率精确测量Ag样品质量厚度,然后采用Ag薄膜对单能X光子的透过率进行测量,给出了Ag薄膜在吸收边(3.4~3.9keV)的衰减系数。建立了Ag样品吸收边附近衰减系数同步辐射测量方法。通过不确定度分析给出衰减系数测量不确定度小于1%,填补了在该区间衰减系数的空白。     

Extended range field emission spectroscopy

We have measured the energy distribution of field emitted electrons by first accelerating them to about 20 keV and then directly energy analyzing these high energy electrons with a high-performance magnetic prism spectrometer. Our preliminary results indicate that it may be possible to extend the energy range of field emission spectroscopy to more than 5 eV below the Fermi level. This work was supported by the U.S. Energy Research and Development Administration     

The bremsstrahlung of electrons on atoms calculated in a broad range of photon energies

The total bremsstrahlung spectra for electrons colliding with atoms have been calculated for krypton atoms in a photon energy range from 10 eV to 25 keV and for lanthanum atoms in the vicinity of the 4d shell ionization energy. The generalized atomic polarizabilities were calculated using a simple semiclassical local energy density approximation and experimental data on the photon absorption. The results are compared to those obtained using the distorted partial wave approximation for Kr and to the experimental data available for La.