Neutron TOF profile problem

dboldrin

Dear topas users,

I am trying to refine some data measured at WISH, ISIS, but having problems modelling the profile. As I understand, the neutron pulse shape at WISH is dealt with using an Ikeda-Carpenter type function convoluted with a pseudo-Voigt, which has previously been written into Fullprof. Can this be found in topas or has anyone written a macro to deal with this?

Many thanks,
David

johnsoevans

Try: http://www.dur.ac.uk/john.evans/topas_workshop/tutorial_zrw2o8riet.htm

dboldrin

Thanks for your reply.

I have tried the macros described in your tutorials, but none are doing a satisfactory job at fitting the profile. What are the physical meanings of the constants in the wifd_pkshape macro, such as tauf_0/1/2 and taus_0/1? They don't change between the twotheta banks, so I assume they are suitable for HRPD in general. Should they also be suitable for WISH?