The refractive index for x-rays and gamma rays depends essentially only on the electron density. As BECs are just very cold gasses with a not so high density, the refractive index will be very close to 1, just as for any other gas.
I am new to XPS Data analysis, and I have a .sle file that I got out of XPS Machine Software, and I am using CasaXPS to analyse the data. This software takes only .vms files. I want to convert the .sle to a .vms file for analysis. How or where can I do this? Any help on this will be deeply appreciated.