Velocity map imaging is used to map the 3D momentum distribution of charged particles such as ions and electrons into 2D image. This equipment relies on its ability to map particles having the same initial momentum vectors but emitted at different locations to arrive in (approximately) the same point at the detector. There have been a couple of methods to recover the 3D distribution from the measured 2D image, this includes Abel inversion, onion peeling, basis set expansion (BASEX), and many others. May be the second chapter in this pdf will help.
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.