Changeset 838 for sans/Dev/trunk/NCNR_User_Procedures/Reduction/SANS/WriteQIS.ipf

Timestamp:

Feb 28, 2012 4:51:26 PM (10 years ago)

Author:

srkline

Message:

adding two new help files for real space modeling and description of the 2D resolution function

cleaning up the FFT routines for addition as a beta operation

File:

• sans/Dev/trunk/NCNR_User_Procedures/Reduction/SANS/WriteQIS.ipf (modified) (3 diffs)

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

@@ -777 +777 @@
         Redimension/N=(pixelsX*pixelsY) qx_val,qy_val,z_val
 
-///************
-// do everything to write out the resolution too
-        // un-comment these if you want to write out qz_val and qval too, then use the proper save command
-        qval = CalcQval(p+1,q+1,rw[16],rw[17],rw[18],rw[26],rw[13]/10)
-        qz_val = CalcQz(p+1,q+1,rw[16],rw[17],rw[18],rw[26],rw[13]/10)
-        phi = FindPhi( pixSize*((p+1)-xctr) , pixSize*((q+1)-yctr))             //(dx,dy)
-        r_dist = sqrt(  (pixSize*((p+1)-xctr))^2 +  (pixSize*((q+1)-yctr))^2 )          //radial distance from ctr to pt
-        Redimension/N=(pixelsX*pixelsY) qz_val,qval,phi,r_dist
-        //everything in 1D now
-        Duplicate/O qval SigmaQX,SigmaQY,fsubS
+
 
         Variable L2 = rw[18]
@@ -796 +787 @@
         Variable usingLenses = rw[28]           //new 2007
 
+        Variable vz_1 = 3.956e5         //velocity [cm/s] of 1 A neutron
+        Variable g = 981.0                              //gravity acceleration [cm/s^2]
+        Variable m_h    = 252.8                 // m/h [=] s/cm^2
+
+        Variable acc,ssd,lambda0,yg_d,qstar
+                
+        G = 981.  //!   ACCELERATION OF GRAVITY, CM/SEC^2
+        acc = vz_1              //      3.956E5 //!     CONVERT WAVELENGTH TO VELOCITY CM/SEC
+        SDD = L2        *100    //1317
+        SSD = L1        *100    //1627          //cm
+        lambda0 = lambda                //              15
+        YG_d = -0.5*G*SDD*(SSD+SDD)*(LAMBDA0/acc)^2
+        Print "DISTANCE BEAM FALLS DUE TO GRAVITY (CM) = ",YG_d
+//              Print "Gravity q* = ",-2*pi/lambda0*2*yg_d/sdd
+        qstar = -2*pi/lambda0*2*yg_d/sdd
+        
+
+// the gravity center is not the resolution center
+// gravity center = beam center
+// resolution center = offset y = dy + (2)*yg_d
+///************
+// do everything to write out the resolution too
+        // un-comment these if you want to write out qz_val and qval too, then use the proper save command
+        qval = CalcQval(p+1,q+1,rw[16],rw[17],rw[18],rw[26],rw[13]/10)
+        qz_val = CalcQz(p+1,q+1,rw[16],rw[17],rw[18],rw[26],rw[13]/10)
+//      phi = FindPhi( pixSize*((p+1)-xctr) , pixSize*((q+1)-yctr))             //(dx,dy)
+//      r_dist = sqrt(  (pixSize*((p+1)-xctr))^2 +  (pixSize*((q+1)-yctr))^2 )          //radial distance from ctr to pt
+        phi = FindPhi( pixSize*((p+1)-xctr) , pixSize*((q+1)-yctr)+(2)*yg_d)            //(dx,dy+yg_d)
+        r_dist = sqrt(  (pixSize*((p+1)-xctr))^2 +  (pixSize*((q+1)-yctr)+(2)*yg_d)^2 )         //radial distance from ctr to pt
+        Redimension/N=(pixelsX*pixelsY) qz_val,qval,phi,r_dist
+        //everything in 1D now
+        Duplicate/O qval SigmaQX,SigmaQY,fsubS
+        
+
+
         //Two parameters DDET and APOFF are instrument dependent.  Determine
         //these from the instrument name in the header.
@@ -819 +845 @@
         // generate my own error wave for I(qx,qy)
         //      //      sw = 0.05*sw            // uniform 5% error? tends to favor the low intensity too strongly
-        // after teh SQRT(),  get rid of the "bad" errors by replacing the NaN, Inf, and zero with V_avg
+        // after the SQRT(),  get rid of the "bad" errors by replacing the NaN, Inf, and zero with V_avg
         // THIS IS EXTREMEMLY IMPORTANT - if this is not done, there are some "bad" values in the 
         // error wave (things that are not numbers) - and this wrecks the smeared model fitting.