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--- wifd_mic [2009/08/06 11:12] – clare
+++ wifd_mic [2025/09/19 15:18] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+====== Wifd_mic ======
+Description: Bill David peak shape for GEM diffractometer
+Contributed by: Originally by Bill David at Denver topas meeting, updated by John Evans January 2012
+Original wifd_mic macro is included at the bottom of the page for legacy reasons.  Suggest using the wifd_mic_new macro instead.  This (January 2012) corrects a scaling inconsistency between the code and the manual.  It should help convergence of tof peak shapes.  In the specific example I tested the two peak shapes give equivalent fits in minimum.
+<code topas>
+macro wifd_mic_new(two_theta,two_thetav,tspow,tspowv,tauf_0,tauf_0v,tauf_1,tauf_1v,taus_0,taus_0v,taus_1,taus_1v,t_eff,t_effv,hhh,hhhv,double_pulse,double_pulsev) {
+   local  !two_theta two_thetav
+	prm tspow   tspowv min 1.5 max 5.5
+	prm tauf_0  tauf_0v min 0.001
+	prm tauf_1  tauf_1v min 0.01
+	prm taus_0  taus_0v min 0.001
+	prm taus_1  taus_1v min 0.001
+	prm t_eff  t_effv min 90.0
+   prm hhh  hhhv min .001
+   prm double_pulse  double_pulsev min 0.001
+	local  !lam = 2 D_spacing Sin(0.00872664626 two_theta)  ;
+ 	user_defined_convolution = X^tspow Exp(-X / (tauf_0 + tauf_1 lam ));
+   min 0 max = 10 (tauf_0 + tauf_1 lam );
+	local !storage = Exp( -950 /(t_eff lam^2)) hhh;
+        push_peak
+                hat = double_pulse ;
+                scale_top_peak = (1-storage);
+        bring_2nd_peak_to_top
+                exp_conv_const = -Ln(0.001) / (taus_0 + taus_1 / lam^2);
+                scale_top_peak = storage;
+        add_pop_1st_2nd_peak
+}
+</code>
+<code topas>
+macro wifd_mic(two_theta,two_thetav,tspow,tspowv,tauf_0,tauf_0v,tauf_1,tauf_1v,taus_0,taus_0v,taus_1,taus_1v,t_eff,t_effv,hhh,hhhv,double_pulse,double_pulsev) {
+   local  !two_theta two_thetav
+	prm tspow   tspowv min 1.5 max 5.5
+	prm tauf_0  tauf_0v min 0.001
+	prm tauf_1  tauf_1v min 0.01
+	prm taus_0  taus_0v min 0.001
+	prm taus_1  taus_1v min 0.001
+	prm t_eff  t_effv min 90.0
+   prm hhh  hhhv min .001
+   prm double_pulse  double_pulsev min 0.001
+	local  !lam = 2 D_spacing Sin(0.00872664626 two_theta)  ;
+ 	user_defined_convolution = X^tspow Exp(-X / (tauf_0 + tauf_1 lam ));
+   min 0 max = 10 (tauf_0 + tauf_1 lam );
+	local !storage = Exp( -950 /(t_eff lam^2)) hhh;
+        push_peak
+                hat = double_pulse ;
+                scale_top_peak = (1-storage)/double_pulse;
+        bring_2nd_peak_to_top
+                exp_conv_const = -Ln(0.001) / (taus_0 + taus_1 / lam^2);
+                scale_top_peak = storage/double_pulse;
+        add_pop_1st_2nd_peak
+}
+</code>
+Some untested/caveat emptor parameters to get you going for the 6 banks on gem are:
+<code topas>
+local !bank_two_theta 91.3
+wifd_mic_new(two_theta, =bank_two_theta;, !tspow, 3.34670, !tauf_0, 1.13998, !tauf_1, 1.07527, !taus_0, 0.02876, !taus_1, 0.01314, !t_eff, 234.52357, !hhh, 0.02063, !double_pulse, 0.07775)
+</code>