NIST: X-Ray Mass Attenuation Coefficients

X-Ray Mass Attenuation Coefficients

4. Summary

Values of the mass attenuation coefficient, mu over rho

, and the mass energy-absorption coefficient, mu e n over rho

, for photon energies 1 keV to 20 MeV, including all absorption edges, are given for all elements Z = 1 to 92 in Table 3 and for 48 compounds and mixtures of radiological interest in Table 4. Graphs of mu over rho

and

are presented for all materials included in Tables 3 and 4. Table 1 lists the values of Z/A, the mean excitation energy I, and the density used in the calculations of mu e n over rho

for Table 3; Table 2 gives similar information used to obtain results for Table 4, including the fractions by weight w_i of the constituent elements assumed for each material.

A journal publication of this material is planned by the authors, adding tables also of the mass energy-transfer coefficient mu t r over rho as defined in (eq 7) to (eq 12), and with the photon energy range extended up to 100 MeV. Corrections, criticisms and suggestions on the presentation in this interim work will be welcomed by the authors.

Acknowledgments

The authors thank Prof. Hisashi Maekoshi, Nagoya University, for his suggestions on the presentation of the tables and graphs, and the authors also thank Gloria Wiersma for her editorial assistance in the preparation of this manuscript.