Changeset 465

Timestamp:

Dec 12, 2008 3:14:07 PM (14 years ago)

Author:

srkline

Message:

Tiny fixes and comments. nothing major.

Location:

sans/Dev/trunk/NCNR_User_Procedures

Files:

• Analysis/Models/NewModels_2008/Two_Power_Law_v40.ipf (modified) (2 diffs)
• Reduction/SANS/MultScatter_MonteCarlo_2D.ipf (modified) (2 diffs)
• Reduction/SANS/SASCALC.ipf (modified) (2 diffs)

sans/Dev/trunk/NCNR_User_Procedures/Analysis/Models/NewModels_2008/Two_Power_Law_v40.ipf

@@ -18 +18 @@
         Make/O/D/n=(num) xwave_TwoPowerLaw, ywave_TwoPowerLaw
         xwave_TwoPowerLaw =  alog(log(qmin) + x*((log(qmax)-log(qmin))/num))
-        Make/O/D coef_TwoPowerLaw = {1e-6, 4, 1, 0.01, 0}
+        Make/O/D coef_TwoPowerLaw = {1, 1, 4, 0.04, 0}
         make/o/t parameters_TwoPowerLaw = {"Coefficient, A ", "(-)Low Q Power","(-) high Q Power","Crossover Qc (A-1)","Incoherent Bgd (cm-1)"}
         Edit parameters_TwoPowerLaw, coef_TwoPowerLaw
@@ -50 +50 @@
         
         // Setup parameter table for model function
-        Make/O/D smear_coef_TwoPowerLaw = {1e-6, 4, 1, 0.01, 0}
+        Make/O/D smear_coef_TwoPowerLaw = {1, 1, 4, 0.04, 0}
         make/o/t smear_parameters_TwoPowerLaw = {"Coefficient, A ", "(-)Low Q Power","(-) high Q Power","Crossover Qc (A-1)","Incoherent Bgd (cm-1)"}
         Edit smear_parameters_TwoPowerLaw,smear_coef_TwoPowerLaw                                        //display parameters in a table

sans/Dev/trunk/NCNR_User_Procedures/Reduction/SANS/MultScatter_MonteCarlo_2D.ipf

@@ -11 +11 @@
 //
 // - Why am I off by a factor of 2.7 - 3.7 (MC too high) relative to real data?
-//   I need to include efficiency (70%?) - do I knock these off be fore the simulation or do I 
+//   I need to include efficiency (70%?) - do I knock these off before the simulation or do I 
 //    really simulate that some fraction of neutrons on the detector don't actually get counted?
-//   Is the flux estimate up-to-date?
+//   Is the flux estimate up-to-date? !! Flux estimates at NG3 are out-of-date....
+// - my simulated transmission is larger than what is measured, even after correcting for the quartz cell.
+//   Why? Do I need to include absorption? Just inherent problems with incoherent cross sections?
+
 // - Most importantly, this needs to be checked for correctness of the MC simulation
 // X how can I get the "data" on absolute scale? This would be a great comparison vs. the ideal model calculation
 // X why does my integrated tau not match up with John's analytical calculations? where are the assumptions?
 // - get rid of all small angle assumptions - to make sure that the calculation is correct at all angles
-// - my simulated transmission is larger than what is measured, even after correcting for the quartz cell.
-//   Why? Do I need to include absorption? Just inherent problems with incoherent cross sections?
+
 //
 // X at the larger angles, is the "flat" detector being properly accounted for - in terms of
@@ -50 +52 @@
 //
 // X why is "pure" incoherent scattering giving me a q^-1 slope, even with the detector all the way back?
-// - can I speed up by assuming everything interacts? This would compromise the ability to calculate multiple scattering
+// -NO- can I speed up by assuming everything interacts? This would compromise the ability to calculate multiple scattering
 // X ask John how to verify what is going on
 // - a number of models are now found to be ill-behaved when q=1e-10. Then the random deviate calculation blows up.
 //   a warning has been added - but some models need a proper limiting value, and some (power-law) are simply unuseable
 //   unless something else can be done.
+// - if the MC gags on a simulation, it often gets "stuck" and can't do the normal calculation from the model, which it
+//   should always default to...
 //
 //

sans/Dev/trunk/NCNR_User_Procedures/Reduction/SANS/SASCALC.ipf

@@ -799 +799 @@
                 Variable rad=beamstopDiam()/2           //beamstop radius in cm
                 rad /= 0.5                              //convert cm to pixels
-                rad += 1                                        // add an extra pixel to each side to account for edge
+                rad += 0.                                       // (no - it cuts off the low Q artificially) add an extra pixel to each side to account for edge
                 Duplicate/O linear_data,root:Packages:NIST:SAS:tmp_mask
                 WAVE tmp_mask = root:Packages:NIST:SAS:tmp_mask
@@ -1640 +1640 @@
 End
 
+
+// not part of SASCALC, but can be used to convert the SSD to number of guides
+//
+// SSD in meters
+Function numGuides(SSD)
+        variable SSD
+        
+        Variable Ng
+        Ng = SSD*100 + 5 - 1632
+        Ng /= -155
+        
+        Ng = round(Ng)
+        return(Ng)
+End
+
+
 //returns the offset value
 // slider and setVar are linked to the same global