Study of Compton scattering of gamma rays from atomic electrons

In the present work, measurements are made on the intensity and angular distribution of Compton scattered gamma rays of energy 279 keV from K-shell electrons of tin at scattering angles ranging from 30° to 150° and also determined the K-shell to free electron differential collision, absorption and scattering cross section ratio. For this purpose, two NaI(Tl) scintillation detectors working in coincidence with 30 nsec resolving time are used to record the events. The experimental results are compared with the available experimental and theoretical data.     

激光-电子康普顿散射物理特性研究

对激光-电子康普顿散射物理特性即能量特性和微分截面角分布进行了仔细的研究.计算结果显示出光子能量和微分截面角分布的简单结构.康普顿散射X射线光源具有散射光子的能量易调节、方向性好等特点.在入射电子束能量很高时,X射线近乎单向出射.光源色散度较大,但实验上可以获得色散（带宽）小的X射线.对于各种波长的激光,在很宽的电子束能量范围（1 MeV—10 GeV）内,散射X射线光子的总截面和前向发射圆锥内（半圆锥角1/γ,其中γ=E/m₀ 关键词： 康普顿散射 能量特性 微分截面 角分布     

Thick target technique for proton induced ionisation cross-section measurements—a re-evaluation

The potential of the thick target technique for the measurement of proton induced ionisation cross-section is re-examined. The usefulness of this technique is compared with that of the thin target technique. For medium Z elements and proton energies of above 1 MeV the thick target approach is found to produceK-shell ionisation cross-sections which are comparable in accuracy with those obtained from thin target measurements.     

Calculation of triple differential cross-sections ofK-shell ionization of medium-heavy atoms by electrons for symmetric geometry

Triple differential cross-section forK-shell ionization of medium-heavy atoms by relativistic electrons has been calculated for coplanar symmetric geometry. In this calculation the final state is described by a non-relativistic wave function of Das and Seal [Phys. Rev. A47 (1993) 2978] multiplied with suitable spinors. Results of the present calculation are compared with the available experimental data and with other theoretical calculations.     

双层喷气Z箍缩氖等离子体K层辐射研究

报道了"强光一号"(1.6 MA,70 ns)加速器驱动双层喷Ne气Z箍缩负载产生K层辐射(光子能量约1 keV)的实验研究.喷气负载出口半径为1.5—1.4 cm和0.75—0.6 cm(半径比2 ∶1).充气压力相同情况下外层和内层质量比约2.8 ∶1.在内爆时间约120 ns、负载线质量估计值60—70 μg/cm时,获得K层辐射产额约7 kJ、峰值功率0.28 TW,脉冲宽度20 ns.X射线分幅图像表明内爆阶段的不稳定性影响较小,最终内爆速度超过25 cm/μs,等离 关键词： 双层喷气 Z箍缩等离子体 K层辐射')" href="#">K层辐射 雪耙内爆     

TheK-shell ionization induced by protons: Projectile scattering angle and electronic relativistic effects in the SCA calculations

The behaviour ofK-shell ionization probabilities for heavy charged projectiles scattered at large angles is investigated in the SCA with hyperbolic trajectories and both relativistic and nonrelativistic functions. It is found that the increase of ionization probabilities with increasing projectile scattering angle will be less pronounced for the heavy targets.     

Low energyK + scattering onN =Z nuclei

The data for the total cross-section ofK ⁺ scattering on various nuclei have been analysed in the Glauber multiple scattering theory. Energy-dependentK ⁺ -nucleus optical potential is generated using the forwardK ⁺ -nucleon scattering amplitude and the nuclear density distribution. Along with this, the calculated totalK ⁺ -nucleus cross-sections using the effectiveK ⁺ -nucleon crosssection inside the nucleus are also presented.     

Inner shell excitation of CH 3F,CH 3Cl,CH 3Br and CH 3I by 2.5 keV electron impact

Small angle inelastic scattering of 2.5 keV electrons was used to study inner shell excitation in the methyl halides at energy transfers between 50 and 700 eV. Discrete peaks due to the excitation of carbon K, fluorine K, chlorine L, bromine M_{4, 5} and iodine N _{4, 5} electrons were observed. Correlations through the methyl halide series were used to aid in the assignment of features in the carbon K-shell spectra. A comparison of halogen inner-shell excitation structures with the carbon K-shell excitation structure in the same molecule allowed a complete assignment of all spectral features. The assignments proposed involve promotions of inner shell electrons to unoccupied valence and Rydberg orbitals. On the basis of our assignments of the chlorine L- and carbon K-shell electron energy loss spectra of CH ₃Cl we propose an alternate assignment of the previously reported CH ₃Cl chlorine K-shell photoabsorption spectrum.     

K-shell ionisation cross-sections of Cu,Ge, Mo,Ag and Sn by protons of energy 0.3 to 1.8 MeV

K-shell ionisation cross secions of Cu, Ge, Mo, Ag and Sn in proton impact have been measured systematically in the energy range 0.3 to 1.8 MeV. Thin targets have been used in transmission geometry. Data are compared with the predictions of the PWBA and the PWBA modified to include corrections due to Coulomb retardation of the projectile, increased binding of the target electron during collision and the relativistic nature of theK-shell electrons. The intensity ratiosK _α /K _β have also been obtained as a function of proton energy for all the five elements.     

Dirac-Hartree-Fock studies of X-ray transitions in meitnerium

The K -shell and L -shell ionizations potentials for ²⁶⁸ ₁₀₉Mt were calculated at the Dirac-Hartree-Fock level taking into account quantum electrodynamic and finite nuclear-size effects. The K _α1 transition energies for different ionization states are accurately predicted and compared with recent experiments in the α -decay of ²⁷² ₁₁₁Rg .     

High intensity Rayleigh scattering by atoms

We investigate the elastic scattering of coherent high intensity radiation of X-ray frequency by aK-shell electron.     

Sum peak method applied to the study of decay of Ir-192

The electron capture probabilities to 690.70 and 580.37 keV levels and theK-conversion coefficients of 205.9 and 316.5 keV transitions in the decay of Ir-192 have been determined from the measurement of gamma-ray intensities in conjunction with an analysis of theKX-ray-γ-ray sum peaks observed with a co-axial HPGe detector. TheK-capture probability to 690.70 keV level was determined by an approach which is independent ofK-shell fluorescence yield and absolute detection efficiency forKX-rays. TheK-shell fluorescence yields of the daughter products, namely, Os and Pt of Ir-192 have also been determined by the same technique and were found to be 0.964±0.077 and 0.969±0.068 respectively.     

An experimental study on cross-section ratio of coherent to incoherent scattering for 145 keV incident gamma photons

The coherent (Rayleigh) to incoherent (Compton) scattering cross-section ratio of elements, in the range 6 ≤ Z ≤ 82, are determined experimentally for 145 keV incident gamma photons. An HPGe (High purity germanium) semiconductor detector is employed, at scattering angle of 50°, 70° and 90°, to record the spectra originating from interactions of incident gamma photons with the target under investigation. The intensity ratio of Rayleigh to Compton scattered peaks observed in the recorded spectra, and corrected for photo-peak efficiency of gamma detector and absorption of photons in the target and air, along with the other required parameters provides the differential cross-section ratio. The measured values of cross-section ratio are found to agree with theoretical predictions (corresponding to 4.939, 6.704 and 8.264 Å⁻¹ photon momentum transfer) based upon non-relativistic form factor, relativistic form factor, modified form factor and S-matrix theory.     

“碰撞-辐射”模型在Z箍缩等离子体K壳层线辐射谱分析中的应用

介绍了由K壳层谱线强度比估算等离子体状态参数的"碰撞-辐射"模型的基本原理.详细描述了自行研制的基于该模型的Z箍缩等离子体K壳层线辐射谱分析程序——ZSPEC的基本情况.给出了氖等离子体的计算结果,包括不同电离态离子的相对含量随电子温度的变化曲线和K壳层谱线强度比在"电子密度-电子温度"平面内的等高线分布图.该程序已在"阳"加速器Z箍缩实验结果分析中得到应用,将椭圆晶体谱仪测得的氖等离子体K壳层谱线强度比与ZSPEC程序计算结果相比较,得出在该发实验 关键词： 碰撞-辐射模型 K壳层线辐射谱')" href="#">K壳层线辐射谱 氖气喷气Z箍缩 阳加速器     

An investigation into allegations of double scattering in the carbon K-shell electron energy loss spectrum of acetylene

In several recent publications (R. G. Cavell and D. A. Allison, J. Chem. Phys., 69 (1978) 159; A. Barth et al., Chem. Phys., 46 (1980) 149) it has been suggested that the feature at 295.6 eV energy loss in the carbon K-shell spectrum of C₂H₂ may arise from double scattering (i.e., collisions of one electron with two acetylene molecules). The pressure-dependence of the carbon K-shell excitation spectrum of C₂H₂ has been examined by inelastic scattering of 2.5-keV electrons to investigate this possibility. The intensity of all features, including that at 295.6 eV, was observed to vary linearly with pressure, indicating that the spectral features arise only from single collisions.     

Nonresonance Compton scattering of an X-ray photon by a Ni-like atomic ion

The absolute values and the shape of the double differential cross section for nonresonance Compton scattering of an X-ray photon by an atomic ion with d symmetry in the core are studied theoretically beyond the impulse approximation for the example of the Ni-like atomic ions Zn²⁺, Kr⁸⁺, and Mo¹⁴⁺. It is established that, as the nuclear charge of an ion increases, (a) in all the scattering channels, the leading harmonics of transition to states of the continuous spectrum are concentrated and (b) the integral intensities of nonresonance Compton scattering are increasingly redistributed to the energy region of resonance Lands-berg-Mandelstam-Raman scattering between the threshold of termination of the Compton profile and the line of elastic (Thomson and Rayleigh) scattering. The calculated results are predictive in character.     

Perturbative role in the inelastic electron scattering from <Superscript>29</Superscript>Si

Inelastic electron scattering form factors away from the closed sd -shell are investigated. This investigation covers the low-lying states in ²⁹Si , which is considered according to the many-particle configuration mixing shell model as the ¹⁶O core, plus thirteen nucleons distributed over the entire sd -shell orbits. The investigation concentrates on the perturbative role of the core, which is called core polarization effects, on the inelastic electron scattering form factors. Core polarization effects are taken into consideration through the excitation of nucleons from 1s and 1p core orbits, and also from the 2s -1d valence orbits into higher shells, with 2ℏω excitations. Core polarization matrix elements are calculated with the M3Y effective interaction. For the sd -shell model space, a new Hamiltonian, based on a renormalized G -matrix, USDB, is used. All calculations are performed without adjusting any parameters.     

Measurement of the generalized polarizabilities of the proton in virtual Compton scattering at MAMI

Virtual Compton scattering off the proton has been studied at Q ² = 0.33 (GeV/c)² at the MAMI accelerator in Mainz (Germany). The goal of the experiment is to measure the generalized polarizabilities (GPs) of the proton using the double polarized e p→e' p'γ reaction. This paper reports the measurement of the unpolarized photon electroproduction cross-section for the new data and the extraction of two linear combinations of GPs, which are essential for the analysis of the double spin asymmetry.     

Measurement of soil water using Compton scattering

Compton scattering method has been used as a possible tool in the study of the properties of soil for agricultural purposes. In this study, the soil water is determined by using Compton scattering method. The soil sample was collected from Erzurum and a 2 × 2 in. NaI (Tl) scintillation detector measured Compton scattered radiation from the soil sample. The radioactive source used in the experiment was a ¹³³Ba. The soil samples were irrigated by adding known quantities of water and a standard curve was constructed with the amount of water added versus Compton scattering intensity. It was observed that Compton scattering method in measurement of the soil water has advantages such as practical, inexpensive, non‐destructive and fast analysis. Copyright © 2011 John Wiley & Sons, Ltd.     

The Compton profile of Bismuth excited below the K absorption edge

A cylindrically symmetric Compton profile spectrometer stimulates resonant Raman scattering at the L₂, L₃, M and N edges in a Bi target when using a ¹⁰⁹Cd γ-ray source with energy 2.50 keV below the K-shell binding energy of Bi. Similarly, an ²⁴¹Am source (E_γ = 59.536 keV) excites a resonance response at the L₃ and M edges of Yb (B.E. = 61.332 keV) but not in Lu (B.E. = 63.314 keV).