Tables of X-Ray Mass Attenuation Coefficients and Mass Energy-Absorption Coefficients 01/1995;
Source: OAI

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.

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    • "where here we have used K f = Q β β = 2.447 MeV and tabulated dE/dx from NIST [10] in xenon. "
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    ABSTRACT: We demonstrate that the application of an external magnetic field could lead to an improved background rejection in neutrinoless double-beta (0nbb) decay experiments using a high pressure xenon (HPXe) TPC. HPXe chambers are capable of imaging electron tracks, a feature that enhances the separation between signal events (the two electrons emitted in the 0nbb decay of 136Xe) and background events, arising chiefly from single electrons of kinetic energy compatible with the end-point of the 0nbb decay (Qbb ). Applying an external magnetic field of sufficiently high intensity (in the range of 0.5-1 Tesla for operating pressures in the range of 5-15 atmospheres) causes the electrons to produce helical tracks. Assuming the tracks can be properly reconstructed, the sign (direction) of curvature can be determined at several points along these tracks, and such information can be used to separate signal (0nbb) events containing two electrons producing a track with two different directions of curvature from background (single-electron) events producing a track that should spiral in a single direction. Due to electron multiple scattering, this strategy is not perfectly efficient on an event-by-event basis, but a statistical estimator can be constructed which can be used to reject background events by one order of magnitude at a moderate cost (approx. 30%) in signal efficiency. Combining this estimator with the excellent energy resolution and topological signature identification characteristic of the HPXe TPC, it is possible to reach a background rate of less than one count per ton-year of exposure. Such a low background rate is an essential feature of the next generation of 0nbb experiments, aiming to fully explore the inverse hierarchy of neutrino masses.
    • "Using Eq. 6, theoretical relations between k value and moisture content were drawn to check the possibility of the DXA method for measuring moisture content in wood. There were two references to calculate the theoretical relation: One was the gravimetric proportion of wood substance and water (Lindgren 1991), and the other was the mass attenuation coefficient of component elements including carbon (C), hydrogen (H) and oxygen (O) according to X-ray energies (45 and 60 kV) (Hubbell and Seltzer 2004). From the two references, the mass attenuation coefficients of wood substance and moisture content according to X-ray energy (45 and 60 kV) were calculated in order to find theoretical relations. "
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    ABSTRACT: To evaluate moisture content in wood, the dual-energy X-ray absorptiometry (DXA) method is presented in this paper. A digital detector was used to improve the accuracy of evaluation of moisture content, which reduced the error from the process of developing X-ray films and directly measured the quantity of transmitted X-ray energies. The theoretical equation of DXA method was developed using a relationship between the ratio of two reference X-ray energies (45 and 60 kV), which are referred to as k value, and the moisture content. From the theoretical result, a regression equation was derived to estimate moisture content of wood. The moisture contents were successfully estimated by the equation when the results were compared to experimentally measured moisture contents with root-mean-square error of prediction of 3.15 % in the 28.68-172.81 % moisture content range.
    Wood Science and Technology 07/2015; 49(4). DOI:10.1007/s00226-015-0726-8 · 1.92 Impact Factor
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    • "The photon energy cutoff was 1 keV. The tally output was modified by the corresponding water mass energy absorption coefficients, taken from the XCOM compilation [11] to convert photon energy fluence to water kerma values. The number of initial photons simulated was 3 x 109 to comply with good MC practice recommendations [3] regarding statistical uncertainty (the mean relative error was 0.2% at distances under 5 cm, the maximum standard errors of the mean were < 2% at distances under 5 cm and < 10% in the entire cylindrical mesh). "
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    ABSTRACT: To determine the relative dose rate distribution around the new (125)I brachytherapy source IsoSeed I25.S17plus and report results in a form suitable for clinical use. Results for the new source are also compared to corresponding results for other commercially available (125)I sources of similar design. Monte Carlo simulations were performed using the MCNP5 v.1.6 general purpose code. The model of the new source was prepared from information provided by the manufacturer and verified by imaging a sample of ten non-radioactive sources. Corresponding simulations were also performed for the 6711 (125)I brachytherapy source, using updated geometric information presented recently in the literature. The uncertainty of the dose distribution around the new source, as well as the dosimetric quantities derived from it according to the Task Group 43 formalism, were determined from the standard error of the mean of simulations for a sample of fifty source models. These source models were prepared by randomly selecting values of geometric parameters from uniform distributions defined by manufacturer stated tolerances. Results are presented in the form of the quantities defined in the update of the Task Group 43 report, as well as a relative dose rate table in Cartesian coordinates. The dose rate distribution of the new source is comparable to that of sources of similar design (IsoSeed I25.S17, Oncoseed 6711, SelectSeed 130.002, Advantage IAI-125A, I-Seed AgX100, Thinseed 9011). Noticeable differences were observed only for the IsoSeed I25.S06 and Best 2301 sources.
    Journal of Contemporary Brachytherapy 12/2013; 5(4):240-9. DOI:10.5114/jcb.2013.39631 · 1.28 Impact Factor
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