time_of_flight_tof_peak_fitting
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time_of_flight_tof_peak_fitting [2011/08/26 14:08] – alancoelho | time_of_flight_tof_peak_fitting [2022/11/03 15:08] – external edit 127.0.0.1 | ||
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+ | ====== Time of Flight Peak Shape Fitting ====== | ||
+ | ====== Using a hkl_Is phase ====== | ||
+ | |||
+ | A Pawley hkl_Is phase with a single peak can be inserted. The two numbers in the macro are the d-spacing of the peak and its intensity. | ||
+ | |||
+ | <code topas> | ||
+ | prm dsp 51.70683` | ||
+ | prm !dspsq 0 | ||
+ | tof_peak_fit( @, 2.92093`, @, 2.64961`) | ||
+ | |||
+ | macro tof_peak_fit(p1, | ||
+ | #m_argu p1 | ||
+ | #m_argu p2 | ||
+ | If_Prm_Eqn_Rpt(p1, | ||
+ | If_Prm_Eqn_Rpt(p2, | ||
+ | hkl_Is phase_name CeV(p1,v1) a =10*CeV(p1, | ||
+ | peak_type pv pv_lor =lor; pv_fwhm = dsp*CeV(p1, | ||
+ | } | ||
+ | </ | ||
+ | |||
+ | [Note changed =CeV(p1, | ||
+ | |||
+ | You can add a line like the one below to the macro to report tof: | ||
+ | |||
+ | <code topas> | ||
+ | |||
+ | |||
+ | ====== TOF Peak fitting using d_Is or xo_Is phases ====== | ||
+ | |||
+ | --- // | ||
+ | |||
+ | d_Is phases can be used in TOF data as follows: | ||
+ | |||
+ | <code topas> | ||
+ | | ||
+ | | ||
+ | | ||
+ | d 2 I 10000</ | ||
+ | |||
+ | If the peak is simply to describe a background anomaly then the TOF peak shape convolutions may not be wanted. In this case it’s possible to put the tof convolutions at the str level. In TEST_EXAMPLES\TOF_BANK2_1.INP this would look like: | ||
+ | |||
+ | <code topas> | ||
+ | | ||
+ | | ||
+ | bkg @ 0 0 0 0 0 0 0 0 0 0 0 | ||
+ | | ||
+ | | ||
+ | Cubic(5.402187) | ||
+ | site Ce1 x 0.00 y 0.00 z 0.00 occ Ce 1 beq @ 0.5 | ||
+ | site O1 x 0.25 y 0.25 z 0.25 occ O 1 beq @ 0.5 | ||
+ | scale @ 1 | ||
+ | TOF_PV(@, 100, @, .5, t1) | ||
+ | | ||
+ | TOF_Exponential(a0, | ||
+ | TOF_Exponential(b0, | ||
+ | scale_pks = D_spacing^4; | ||
+ | d_Is | ||
+ | peak_type pv | ||
+ | | ||
+ | | ||
+ | d 2 I 10000</ | ||
+ | |||
+ | |||
+ | The text marked " | ||
+ | |||
+ | xo_Is phases can also be used in TOF data but the pk_xo (inside the TOF_x_axis_calibration macro) needs to be moved to the str level. Additionally the No_Th_Dependence is necessary; ie. | ||
+ | |||
+ | <code topas> | ||
+ | | ||
+ | | ||
+ | TOF_PV(@, 100, @, .5, t1) | ||
+ | TOF_x_axis_calibration(t0, | ||
+ | TOF_Exponential(a0, | ||
+ | TOF_Exponential(b0, | ||
+ | xo_Is | ||
+ | No_Th_Dependence | ||
+ | peak_type pv | ||
+ | | ||
+ | | ||
+ | xo 12000 I 10000</ | ||
+ | |||
+ | In this way the xo value is not transformed according to pk_xo. | ||