Polarization of 0.411, 0.662 and 1.25 MeV γ -rays elastically scattered by lead

1958 ◽  
Vol 247 (1250) ◽  
pp. 375-380 ◽  
Keyword(s):  
Form Factor ◽  
Elastic Scattering ◽  
Compton Scattering ◽  
Rayleigh Scattering ◽  
Thomson Scattering ◽  
Experimental Results ◽  
Numerical Calculations ◽  
Γ Rays

The polarization of 0.411, 0.662 and 1.25 MeV γ -rays elastically scattered by lead at 90° has been studied with a γ -ray polarimeter using Compton scattering as the analyzing process. At these energies and this angle the only processes contributing to elastic scattering are nuclear Thomson scattering and Rayleigh scattering. Since the intensity and polarization of the Thomson component are readily calculable, the measurements provide a check of theories of Rayleigh scattering. The experimental results contradict the predictions of the form factor calculations and agree with those of the refined numerical calculations of Brown & Mayers.

THE ELASTIC SCATTERING OF Co60 γ-RAYS

1962 ◽  
Vol 40 (5) ◽  
pp. 622-653 ◽  
Author(s):  
K. G. Standing ◽  
J. V. Jovanovich
Keyword(s):  
Form Factor ◽  
Elastic Scattering ◽  
Cross Section ◽  
Cross Sections ◽  
Thomson Scattering ◽  
Special Method ◽  
Knock Out ◽  
Order Of Magnitude ◽  
Γ Rays ◽  
The Cross

Cross sections have been measured for 90° elastic scattering of Co60 γ-rays (1.33 and 1.17 Mev) from aluminum, copper, and tin. They agree with theoretical predictions for Rayleigh and nuclear Thomson scattering. A continuum between the Compton and the elastically scattered γ-rays interfered with the measurements for heavier elements, since it increased rapidly with Z.The continuum was investigated by observing the γ-rays scattered through 60° by thin gold foils. It was found to be produced directly by the γ-rays themselves, not by the electrons they knock out of the target atoms. The experimental cross section was compared with that expected for incoherent scattering from the bound atomic electrons. It agrees within a factor of 2 with the cross section given by the form factor approximation, although it is more than an order of magnitude larger than a modification of the form factor, which is based on comparison with elastic scattering calculations.The spectrum of elastically scattered γ-rays from lead was examined by a special method in order to reduce the contribution of the inelastic continuum; two photomultipliers faced a single scintillator and pulses from one photomultiplier were counted only when they corresponded to the largest pulses from the other. The cross section between 12° and 150° was found to be much lower than that of most previous measurements. It agrees with the calculated cross section for Rayleigh and nuclear Thomson scattering within the possible errors in the calculations. Therefore the measurements yield no evidence for the presence of Delbrück scattering, the upper limit on its intensity now being set primarily by the uncertainties in the theory.

Elastic Scattering of 152Eu ? Rays by Tungsten

1981 ◽  
Vol 34 (2) ◽  
pp. 125 ◽  
Author(s):  
RB Taylor ◽  
P Teansomprasong ◽  
IB Whittingham
Keyword(s):  
Form Factor ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Differential Cross ◽  
Dirac Point ◽  
Experimental Results ◽  
Large Momentum ◽  
Small Momentum ◽  
Hartree Fock ◽  
The Difference

Differential cross sections for the elastic scattering of 344, 444, 779, 964, 1086, 1112 and 1408 keY y rays by tungsten have been measured for six scattering angles ranging from 7� to 45� and are compared with theoretical cross sections for Rayleigh plus nuclear-Thomson plus, for the 1408 keY case, Delbriick scattering. For small momentum transfers the experimental results are in best agreement with cross sections computed using the Hartree-Fock form factor Rayleigh amplitudes, but at large momentum transfers the experimental results lie below these theoretical cross sections and also those computed using both the 'exact' Rayleigh amplitudes of Kissel and Pratt and the Dirac point-Coulomb form factor amplitudes. Inclusion of the Papatzacos and Mork Delbruck amplitudes at 1408 keY reduces the difference between experimental and theoretical cross sections for scattering angles less than 25�, but worsens the situation for larger angles.:

The influence of the nuclear and atomic form factors on the muon bremsstrahlung cross section

1968 ◽  
Vol 46 (10) ◽  
pp. S377-S380 ◽  
Author(s):  
A. A. Petrukhin ◽  
V. V. Shestakov
Keyword(s):  
Form Factor ◽  
Cross Section ◽  
Born Approximation ◽  
Form Factors ◽  
Experimental Results ◽  
Simple Analytical Expression ◽  
Nuclear Form Factor ◽  
The Cross ◽  
Atomic Electrons ◽  
Bremsstrahlung Process

The cross section for the muon bremsstrahlung process is calculated as a function of the nuclear form factor in the Born approximation following the Bethe and Heitler theory. The influence of the nuclear form factor is greater than that taken by Christy and Kusaka. The simple analytical expression for the effect of the screening of the atomic electrons is found. The influence of a decrease in the cross section upon the interpretation of some experimental results is estimated.

Rayleigh Scattering of 59.5 keV γ-Rays by Mo and Sn

1998 ◽  
Vol 31 (3) ◽  
pp. 595-602 ◽  
Author(s):  
Salih Erzeneoğlu ◽  
Yusuf ŞLahin
Keyword(s):  
Rayleigh Scattering ◽  
Γ Rays

scholarly journals Linearly polarized X-ray fluorescence computed tomography based on a Thomson scattering light source: a Monte Carlo study

2020 ◽  
Vol 27 (3) ◽  
pp. 737-745
Author(s):  
Zhijun Chi ◽  
Yingchao Du ◽  
Wenhui Huang ◽  
Chuanxiang Tang
Keyword(s):  
Computed Tomography ◽  
Monte Carlo ◽  
Compton Scattering ◽  
Light Source ◽  
Thomson Scattering ◽  
X Rays ◽  
X Ray ◽  
Pile Up ◽  
Linearly Polarized ◽  
Scattering Light

A Thomson scattering X-ray source can provide quasi-monochromatic, continuously energy-tunable, polarization-controllable and high-brightness X-rays, which makes it an excellent tool for X-ray fluorescence computed tomography (XFCT). In this paper, we examined the suppression of Compton scattering background in XFCT using the linearly polarized X-rays and the implementation feasibility of linearly polarized XFCT based on this type of light source, concerning the influence of phantom attenuation and the sampling strategy, its advantage over K-edge subtraction computed tomography (CT), the imaging time, and the potential pulse pile-up effect by Monte Carlo simulations. A fan beam and pinhole collimator geometry were adopted in the simulation and the phantom was a polymethyl methacrylate cylinder inside which were gadolinium (Gd)-loaded water solutions with Gd concentrations ranging from 0.2 to 4.0 wt%. Compared with the case of vertical polarization, Compton scattering was suppressed by about 1.6 times using horizontal polarization. An accurate image of the Gd-containing phantom was successfully reconstructed with both spatial and quantitative identification, and good linearity between the reconstructed value and the Gd concentration was verified. When the attenuation effect cannot be neglected, one full cycle (360°) sampling and the attenuation correction became necessary. Compared with the results of K-edge subtraction CT, the contrast-to-noise ratio values of XFCT were improved by 2.03 and 1.04 times at low Gd concentrations of 0.2 and 0.5 wt%, respectively. When the flux of a Thomson scattering light source reaches 1013 photons s−1, it is possible to finish the data acquisition of XFCT at the minute or second level without introducing pulse pile-up effects.

High-energy pion-proton elastic scattering and the pion form factor

1983 ◽  
Vol 132 (1-3) ◽  
pp. 191-194 ◽  
Author(s):  
C. Bourrely ◽  
P. Chiappetta ◽  
J. Soffer ◽  
Tai Tsun Wu
Keyword(s):  
Form Factor ◽  
Elastic Scattering ◽  
Pion Form Factor ◽  
High Energy ◽  
Proton Elastic Scattering
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