Tables of X-Ray Mass Attenuation Coefficients and Mass Energy-Absorption Coefficients
ABSTRACT This page provided by the National Institute of Standards and Technology (NIST) presents tables and graphs of the photon mass attenuation coefficient and the mass energy-absorption coefficient for all of the elements Z = 1 to 92, and for 48 compounds and mixtures of radiological interest. The tables cover energies of the photon (x-ray, gamma ray, bremsstrahlung) from 1 keV to 20 MeV. The compilation is intended to be used as reference data in radiation shielding and dosimetry computations.
- SourceAvailable from: Friedrich -K. Thielemann[Show abstract] [Hide abstract]
ABSTRACT: We have investigated the (n,γ) cross sections of p-process isotopes with the activation technique. The measurements were carried out at the Karlsruhe Van de Graaff accelerator using the 7Li(p,n)7Be source for simulating a Maxwellian neutron distribution of kT=25 keV. Stellar cross section measurements are reported for the light p-process isotopes 102Pd, 120Te, 130,132Ba, and 156Dy. In a following paper the cross sections of 168Yb, 180W, 184Os, 190Pt, and 196Hg will be discussed. The data are extrapolated to p-process energies by including information from evaluated nuclear data libraries. The results are compared to standard Hauser-Feshbach models frequently used in astrophysics.Physical Review C 01/2010; 81(1). · 3.88 Impact Factor
Conference Paper: Multiple-hit parameter estimation in monolithic detectors[Show abstract] [Hide abstract]
ABSTRACT: We examine a maximum-a-priori (MAP) method for estimating the primary interaction position of gamma rays with multiple-interaction sites (hits) in a monolithic detector. In assessing the performance of a multiple-hit estimator over that of a conventional one-hit estimator, we consider a few different detector and readout configurations of a 50-mm-wide square LSO block. For this study, we use simulated data from SCOUT, a Monte-Carlo tool for photon tracking and modeling scintillation-camera output. With this tool, we determine estimate bias and variance for a multiple-hit estimator and compare these with similar metrics for a conventional ML estimator, which assumes full energy deposition in one hit. We also examine the effect of event filtering on these metrics; for this purpose, we use a likelihood threshold to reject signals that are not likely to have been produced under the assumed likelihood model. Depending on detector design, we observe a 1-12% improvement of intrinsic resolution for a 1-or-2-hit estimator as compared with a 1-hit estimator. We also observe improved differentiation of photopeak events using a 1-or-2-hit estimator as compared with the 1-hit estimator; more than 6% of photopeak events that were rejected by likelihood filtering for the 1-hit estimator were accurately identified as photopeak events and positioned without loss of resolution by a 1-or-2-hit estimator.Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2011 IEEE; 01/2011
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ABSTRACT: In the enclosure of synchrotron radiation experiments using a monochromatic beam, secondary radiation arises from two effects, namely fluorescence and scattering. While fluorescence can be regarded as isotropic, the angular dependence of Compton scattering has to be taken into account if the shielding shall not become unreasonably thick. The scope of this paper is to clarify how the different factors starting from the spectral properties of the source and the attenuation coefficient of the shielding, over the spectral and angular distribution of the scattered radiation and the geometry of the experiment influence the thickness of lead required to keep the dose rate outside the enclosure below the desired threshold.Radiation Physics and Chemistry 02/2015; 108. · 1.19 Impact Factor