XMM-Newton Users Handbook RGS flux to count rate conversion

For the conversion of flux to RGS count rates or of count rates from other X-ray satellites to count rates expected for the RGS instruments, we recommend the use of the SAS task 'rgsrmfgen' to generate a response matrix to be used for simulations, and/or the use of the PIMMS software at NASA's HEASARC 5.

European Space Agency - XMM-Newton Science Operations Centre