Matteo,
There is a simple tof example at:
http://community.dur.ac.uk/john.evans/topas_workshop/tutorial_zrw2o8riet.htm.
I'll paste the "answer" .inp file below. I'd suggest you make sure it runs ok then try and swap your data and instrument calibration lines into that. If you do it one step at a time you should be able to find the mistake. My guess is that it's something to do with units (e.g. msec vis microsec) in your calibration line.
John
'--------------------------------------------------------------
'Input File for simple tof Rietveld Refinement
'Use save/set current button then run with F6 in topas
'Replace $ and # symbols with text/numbers as needed
'--------------------------------------------------------------
r_wp 20.192 r_exp 18.912 r_p 16.594 r_wp_dash 37.484 r_p_dash 36.551 r_exp_dash 35.109 weighted_Durbin_Watson 1.848 gof 1.068
'--------------------------------------------------------------
'General information about refinement here
'Remove comments as required
'--------------------------------------------------------------
iters 100000
chi2_convergence_criteria 0.001
'do_errors
'--------------------------------------------------------------
'Information on datafile etc here
'--------------------------------------------------------------
TOF_XYE( ZX002.xye, 3)
x_calculation_step = Yobs_dx_at(Xo); convolution_step 4
TOF_LAM(0.001)
scale_pks = D_spacing^4;
bkg @ 5.91530497` 0.530246694` -0.564438765` -0.0911685297` -0.401631019` 0.0391190616`
start_X 34000
finish_X 120000
bkg @ -0.0774822324` 0.0434841174` -0.0480854841` 0.0668878424` -0.00781048048` -0.0386024626`
'--------------------------------------------------------------
'Change instrument/peak shape constants from a recent silicon calibration
'Only refine these parameters if you're sure what you're doing
'Peak shape macro courtesy of Bill David
'Get macros you need from
http://www.dur.ac.uk/john.evans/topas_academic/topas_macros.htm
'or use the alternate peak shape description currently commented out
'--------------------------------------------------------------
TOF_LAM(0.001)
TOF_x_axis_calibration(!t0_bs, 0.27394, !difc_bs, 48213.48769, !difa_bs, -5.50739)
wifd_pkshape(!two_theta, 168.657, !aprm, 2.50000, !tauf_2, 9.80744, !tauf_1, 0.43977, !tauf_0, 0.000, !taus_0, 25.27420, !taus_1, 2.66797, !t_eff, 144.41296, !hhh, 3.58595, !hhh_0, 11.61348)
'TOF_Exponential(!a1_bs, 230.98670,!a2_bs, 27.018, 4, difc_hrpd_bs, +)
'--------------------------------------------------------------
'Information on structure
'Type in phase/space group/cell etc
'Comment in/out sections as needed
'--------------------------------------------------------------
str
a lpa 9.18000`
b lpa 9.18000`
c lpa 9.18000`
al 90.
be 90.
ga 90.
volume 773.620133`
space_group "P213"
site Zr1 x xzr1 0.00125` y xzr1 0.00125` z xzr1 0.00125` occ Zr+4 1. ADPs { @ 0.00384` = Get(u11); = Get(u11); @ 0.00056` = Get(u12); = Get(u12); }
site W1 x xw1 0.34204` y xw1 0.34204` z xw1 0.34204` occ W+6 1. ADPs { @ 0.00454`_LIMIT_MIN_0 = Get(u11); = Get(u11); @ 0.00190` = Get(u12); = Get(u12); }
site W2 x xw2 0.59990` y xw2 0.59990` z xw2 0.59990` occ W+6 1. ADPs { @ 0.00638`_LIMIT_MIN_0 = Get(u11); = Get(u11); @ -0.00213` = Get(u12); = Get(u12); }
site O1 x xo1 0.20661` y yo1 0.43931` z zo1 0.44662` occ O-2 1. ADPs { @ 0.00177`_LIMIT_MIN_0 @ 0.01027` @ 0.00654` @ 0.00317` @ -0.00521` @ 0.00068` }
site O2 x xo2 0.78662` y yo2 0.56784` z zo2 0.55573` occ O-2 1. ADPs { @ 0.00644` @ 0.00134`_LIMIT_MIN_0 @ 0.00997` @ 0.00126` @ 0.00552` @ -0.00099` }
site O3 x xo3 0.49088` y xo3 0.49088` z xo3 0.49088` occ O-2 1. ADPs { @ 0.00779` = Get(u11); = Get(u11); @ 0.00091` = Get(u12); = Get(u12); }
site O4 x xo4 0.23212` y xo4 0.23212` z xo4 0.23212` occ O-2 1. ADPs { @ 0.00424`_LIMIT_MIN_0 = Get(u11); = Get(u11); @ -0.00076` = Get(u12); = Get(u12); }
scale @ 0.636539579`
r_bragg 3.41625525
tof_sample_peakshape(lor, 0.250876733`,dsp, 46.68249`,dspsq, 0.00000`_LIMIT_MIN_0)
Phase_Density_g_on_cm3( 5.03920`)