RECENT RESULTS FROM GRAAL

2005 ◽  
Vol 20 (02n03) ◽  
pp. 503-513 ◽  
Author(s):  
◽  
D. MORICCIANI ◽  
O. BARTALINI ◽  
V. BELLINI ◽  
J. P. BOCQUET ◽  
...  
Keyword(s):  
Compton Scattering ◽  
Cross Sections ◽  
Energy Region ◽  
Laser Light ◽  
Theoretical Models ◽  
High Energy ◽  
Angular Range ◽  
High Energy Electron ◽  
Deuterium Target ◽  
Beam Polarisation

A polarised and tagged [Formula: see text] ray beam is produced at GRAAL by the Compton scattering of laser light on the high energy electron of the ESRF storage ring. We present results on the beam polarisation asymmetries and cross sections in the photoproduction of mesons on hydrogen and deuterium target in the energy region 500-1500 MeV. These very precise results cover the angular range 30°-150°, providing stringent constraints to theoretical models.

Theoretical analysis of reflection high-energy electron diffraction (RHEED) and reflection high-energy positron diffraction (RHEPD) intensity oscillations expected for the perfect layer-by-layer growth

2015 ◽  
Vol 71 (5) ◽  
pp. 513-518 ◽  
Author(s):  
Zbigniew Mitura
Keyword(s):  
Theoretical Models ◽  
High Energy ◽  
Layer Growth ◽  
Simplified Model ◽  
Layer By Layer ◽  
High Energy Electron ◽  
Realistic Potential ◽  
Simplified Approach ◽  
Electrons And Positrons ◽  
Analytical Formulas

Predictions from two theoretical models, allowing one to determine the phase of intensity oscillations, are compared for reflected beams of electrons and positrons. Namely, results of the precise dynamical calculations are compared with results obtained using a simplified approach. Within the simplified model, changes in the specularly reflected beam intensity, expected to occur during the deposition of new atoms, are described with the help of interfering waves and the effect of refraction, and respective approximate analytical formulas are employed to determine the phase of the oscillations. It is found that the simplified model is very useful for understanding the physics ruling the appearance of intensity oscillations. However, it seems that the model with the realistic potential is more suitable for carrying out interpretations of experimental data.

Dipole oscillator strength distributions, sums, and some related properties for Li, N, O, H2, N2, O2, NH3, H2O, NO, and N2O

1977 ◽  
Vol 55 (23) ◽  
pp. 2080-2100 ◽  
Author(s):  
G. D. Zeiss ◽  
William J. Meath ◽  
J. C. F. MacDonald ◽  
D. J. Dawson
Keyword(s):  
Oscillator Strength ◽  
Cross Sections ◽  
High Energy ◽  
High Energy Electron ◽  
Sum Rule ◽  
Dipole Oscillator ◽  
Scattering Cross Sections ◽  
Additional Constraints ◽  
Dipole Sums ◽  
Strength Distributions

Dipole oscillator strength distributions (DOSDs) have been constructed for ground state Li, N, O, H2, N2, O2, NH3, H2O, NO, and N2O by using experimental and theoretical photoabsoiption and high energy electron inelastic scattering cross sections. Each DOSD is required to satisfy the Thomas–Reiche–Kuhn sum rule and additional constraints derived from available accurate experimental refractivity and dispersion measurements. The DOSDs, the data and procedure used to construct the DOSDs, and the values of the dipole oscillator strength sums Sk and Lk (for a variety of k values) and related atomic and molecular properties obtained from the DOSDs are reported. The discussion includes comments regarding the importance of the constraints imposed on the DOSD with respect to the evaluation of various dipole sums and properties and the accuracy of the results.

THE SCATTERING OF PROTONS ON 7Li, 9Be, AND 12C AT 100 MEV

1966 ◽  
Vol 44 (12) ◽  
pp. 2961-2971 ◽  
Author(s):  
S. K. Mark ◽  
P. M. Portner ◽  
R. B. Moore
Keyword(s):  
Angular Distribution ◽  
Inelastic Scattering ◽  
Cross Sections ◽  
Differential Cross ◽  
Target Nucleus ◽  
Energy Region ◽  
Angular Distributions ◽  
Angular Range ◽  
Existing Data ◽  
Octupole Excitation

Elastic and inelastic scattering of protons on 7Li, 9Be, and 12C have been studied, using the 100-MeV proton beam from the McGill synchrocyclotron. Differential cross sections for the various groups of scattered protons were measured over an angular range of 5° to 90° (lab). For proton groups resulting from a quadrupole excitation in the target nucleus, the angular distribution was found to increase at scattering angles less than 10°. Angular distributions corresponding to an octupole excitation were observed to decrease at small angles. The results have been compared with existing data in this energy region.

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