multi-bank TOF refinement

samalexander

Dear all,

I have multiple banks of data from HRPD at ISIS, i am trying to load to xdds with different calibrations (i.e. t0, t1, t2) and different peak broadening. I want to refine the same phase to both datasets.

Currently I have a file like this, which I put together using a number of examples on this forum:

xdd 1

TOF_x_axis_calibration....
TOF_Exponential....
bkg .....
start_X ...
finish_X ...
local !sc_bank ...
TOF_PV 'instrumental broadening...
TOF_CS_G....
TOF_CS_L...

xdd 2

TOF_x_axis_calibration...
TOF_Exponential...
bkg ...
start_X ...
finish_X ...
local !sc_bank1 ...
TOF_PV 'instrumental broadening...
TOF_CS_G...
TOF_CS_L...

for xdds 1 to 2 {
neutron_data
x_calculation_step = Yobs_dx_at(Xo);
TOF_LAM(0.001)

str
a, b, c, etc .......
scale_pks = D_spacing^4;
scale = sc_bank;
do_errors
}

When I load this file I get a message saying "Cannot locate pk_type from exp_prm in data structures".
What have I done wrong and how do I refine 1 structure from 2 datasets?

I would appreciate any help!

Many thanks,
Sam

alancoelho

Hi Sam

Make TOF_PV str dependent; ie. place it after the str keyword
alan

johnsoevans

There are some sample input files for multibank refinements on the isis diffractometers on the wiki at:
http://topas.dur.ac.uk/topaswiki/doku.php?id=time_of_flight_tof_isis_instrument_standard_files
You should always check with the instrument scientist whether they are appropriate for your experiments.

samalexander

Thanks for the help my input file is now producing a good fit to the data. I am however not sure about some of the values in the macros used, so I am not sure if it is physically reasonable. I have started a new thread asking about these macro values.

Thanks again
Sam