Coulomb correction effect in Delbrück scattering and atomic Rayleigh scattering of<i>1–4</i>MeV photons

Kasten, B.; Schaupp, D.; Rullhusen, P.; Smend, F.; Schumacher, M.; Kissel, Lynn

doi:10.1103/physrevc.33.1606

Cited by 20 publications

(9 citation statements)

References 12 publications

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“…These figures contain data and predictions from reference [53] and the experiments performed are described both there and in references [63], [65], and [66]. The difference between the data point and the dotted lines has been attributed to the Coulomb correction.…”

Section: Scattering Amplitudes and Cross Sectionsmentioning

confidence: 99%

“…At higher Z, stronger fields make the lowest-order Born approximation inaccurate. Numerical calculations of higher-order terms in the Born series have only partially been accomplished for very few angles and energies [51], [52], but semi-empirical Coulomb correction factors have been published [49], [53], [54]. For uranium, these corrections can be a large fraction of the Delbrück differential scattering cross section, which, in turn can result in significant changes to the total theoretical elastic scattering cross section.…”

Section: Delbrück Scatteringmentioning

confidence: 99%

“…The Rayleigh scattering calculations are thought to be very accurate, but were only performed for K-shell electrons. Corrections due to L-shell electrons have indicated that the errors are less than 5% [53], however the errors were initially estimated for high-Z atoms to be up to 20% [63]. Delbrück scattering amplitudes are likewise calculated to high precision (< 3%), but only for first-order terms in the Born series.…”

Section: Scattering Amplitudes and Cross Sectionsmentioning

confidence: 99%

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Nuclear Resonance Fluorescence for Safeguards Applications

Ludewigt¹,

Quiter²,

Ambers³

2011

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Executive SummaryIn nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of gamma rays with specific energies that are characteristic of the emitting isotope. The promise of NRF as a non-destructive analysis technique (NDA) in safeguards applications lies in its potential to directly quantify a specific isotope in an assay target.This report addresses the assessment of NRF-based methods for safeguards applications in the context of related studies at LBNL, LLNL, and BNL. Our FY10 effort was comprised of three tasks: the study of the non-resonant scattering background and its simulation with MCNPX, analysis of our previously performed NRF transmission experiment, and the assessment of NRF for safeguards applications.While the recent correction of the treatment of Rayleigh scattering in MCNPX resulted in much better agreement with some experimental data, the photonuclear processes, which are important contributors to the elastic scattering background at higher energies, are still not included. Our analysis showed that calculations based on ENDF form factors as currently implemented in MCNPX could underestimate the elastic scattering cross section by as much as a factor of ten for a uranium target at photon energies above 2 MeV. Even larger discrepancies, up to several orders of magnitude, are possible for lighter elements such as zirconium. It would be desirable to at least include nuclear Thomson scattering in MCNPX simulations for NRF studies.The transmission experiment, using a bremsstrahlung beam and a target of comparable thickness to a spent nuclear fuel assembly, demonstrated sensitivity to a 238 U content of 1%. However, the precision was count rate limited. The data obtained in this experiment indicated notch refill that could change the measured NRF rates by up to 5% for the worst case. A correction based on MCNPX modeling has been implemented in the analysis.NRF-based methods were assessed for three potential safeguards applications: the isotopic assay of spent nuclear fuel (SNF), the measurement of 235 U enrichment in UF 6 cylinders, and the determination of 239 Pu in mixed oxide (MOX) fuel. Given the small integrated nuclear resonance cross sections, the main challenge in these application, albeit to a varying degree, lies in accruing of sufficient counting statistics in an acceptable measurement times for achieving the desired uncertainties.Pu isotopic masses in SNF could precisely be determined in transmission measurements using bremsstrahlung sources, but such measurements would require up to 100's of hours, a very intense bremsstrahlung source, and a very large array of fast detectors with high energy resolution. Quasimonoenergetic photon sources such as Laser Compton scattering sources could potentially enable greatly improved performance. As an example, assuming a photon source with a 1 keV energy spread, an intensity of 6x10 8 ph/eV/s, and operating continuously or at very high pulse rates, the measurement time would be on ...

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Section: Scattering Amplitudes and Cross Sectionsmentioning

confidence: 99%

Section: Delbrück Scatteringmentioning

confidence: 99%

Section: Scattering Amplitudes and Cross Sectionsmentioning

confidence: 99%

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Nuclear Resonance Fluorescence for Safeguards Applications

Ludewigt¹,

Quiter²,

Ambers³

2011

View full text Add to dashboard Cite

show abstract

“…The accuracy of photon scattering cross section measurements in the experiments [10][11][12][13] allowed one not only to observe Delbrück scattering, but to establish the importance of the Coulomb corrections to the cross section as well. Unfortunately, in this energy range (ω ∼ m) the Coulomb corrections are not calculated up to now, that does not permit to perform the detailed comparison between experiment and theory.…”

Section: Introductionmentioning

confidence: 99%

“…In the experimental investigations of Delbrück scattering carried out earlier, three different photon sources have been used : 1) Photons from radioactive sources, for instance 24 Mg (ω = 2.75 MeV) [10,11].…”

Section: Introductionmentioning

confidence: 99%