17-Jun-2013, richard.schwartz@nasa.gov

History of coefficients used with xsec and xcross
The values in the original version of xray_coef.fits were taken from a online file obtained from Berkeley Space Sciences Laboratory in the 1980s.  Data were taken from McMaster (see below). Richard.Schwartz@nasa.gov imported these data into SSW and built the FITS file, xray_coef.fits, in the $SSW/packages/xray/dbase directory. The file is called by coefdata.pro and the data are put into common for use as needed in xsec.pro and xcross.pro

The original xray_coef.fits was found to have a flaw in the photoelectric coefficients. There is a FORTRAN program, mucal.f, in wide circulation on the internet which contains the most current version of all the coefficients.  This file was used to update the coefficients for all 87 elements covered by xsec.pro for photoelectric, Compton, and elastic scattering. That version of mucal.f is included in the $SSW/packages/xray/idl directory. The original version of xray_coef.fits is included in $SSW/packages/xray/dbase as xray_coef_old.fits  In the same directory you'll find an Excel spreadsheet, GEANT_2013_Cd_Te_all_cross_section.xls, with the cross-sections used by GEANT for Cadmium and Tellurium(de).

Richard