Changeset 545

Timestamp:

Aug 7, 2009 2:00:32 PM (13 years ago)

Author:

srkline

Message:

(1) changed the "guessing" of transmission files to be tolerant (within 1%) of mismatches in the wavelength. With the VAX, I had required them to be equal. ICE reports a FP number that varies in the 3rd decimal place (from the RPM?).

(2) Changed the calculation of errors and total detector count in 1D simulation to be correct.

Location:

sans/Dev/trunk/NCNR_User_Procedures/Reduction/SANS

Files:

• SASCALC.ipf (modified) (4 diffs)
• Transmission.ipf (modified) (3 diffs)

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

@@ -908 +908 @@
                                 
                                 Wave inten=$"root:Simulation:Simulation_i"              // this will exist and send the smeared calculation to the corect DF
+                                
+                                // the resolution-smeared intensity is calculated, including the incoherent background
                                 func($coefStr,inten,qval)
 
@@ -932 +934 @@
                                 Variable sig_sas=0
                                 
+                                // remember that the random deviate is the coherent portion ONLY - the incoherent background is 
+                                // subtracted before the calculation.
                                 CalculateRandomDeviate(funcUnsmeared,$coefStr,wavelength,"root:Packages:NIST:SAS:ran_dev",sig_sas)
                                 
@@ -940 +944 @@
                                 Print "Sig_sas = ",sig_sas
                                 
-                                Duplicate/O qval prob_i,circle_fraction,rval,nCells_expected
-                                rval = sdd*tan(2*asin(qval*wavelength/4/pi))            //radial distance in cm
-                                nCells_expected = 2*pi*rval/pixSize                                     //does this need to be an integer?
-                                circle_fraction = nCells / nCells_expected
+                                Duplicate/O qval prob_i,countsInAnnulus
+                                
+                                // not needed - nCells takes care of this when the error is correctly calculated
+//                              Duplicate/O qval circle_fraction,rval,nCells_expected
+//                              rval = sdd*tan(2*asin(qval*wavelength/4/pi))            //radial distance in cm
+//                              nCells_expected = 2*pi*rval/pixSize                                     //does this need to be an integer?
+//                              circle_fraction = nCells / nCells_expected
                                 
                                                         
-                                prob_i = trans*thick*nCells*(pixSize/sdd)^2*inten                       //probability of a neutron in q-bin(i) that has nCells
+//                              prob_i = trans*thick*nCells*(pixSize/sdd)^2*inten                       //probability of a neutron in q-bin(i) that has nCells
+                                prob_i = trans*thick*(pixSize/sdd)^2*inten                      //probability of a neutron in q-bin(i) 
                                 
                                 Variable P_on = sum(prob_i,-inf,inf)
                                 Print "P_on = ",P_on
-                                fracScat = P_on
                                 
-                                aveint = (Imon*ctTime)*prob_i / circle_fraction / nCells_expected
-
-                                SimDetCts = sum(aveint,-inf,inf)
+//                              fracScat = P_on
+                                fracScat = 1-estTrans
+                                
+//                              aveint = (Imon*ctTime)*prob_i / circle_fraction / nCells_expected
+                                aveint = (Imon*ctTime)*prob_i
+
+                                countsInAnnulus = aveint*nCells
+                                SimDetCts = sum(countsInAnnulus,-inf,inf)
                                 estDetCR = SimDetCts/SimCountTime
                                 
@@ -961 +973 @@
                                 NVAR addNoise = root:Packages:NIST:SAS:g_1D_AddNoise
                                                         
-                                sigave = sqrt(aveint)           // assuming that N is large
+                                sigave = sqrt(aveint/nCells)            // corrected based on John's memo, from 8/9/99
                                 
                                 // add in random error in aveint based on the sigave

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

@@ -1615 +1615 @@
 // apply TWO criteria
 // (1) the label must match "well enough"
-// (2) the wavelength must be the same
+// (2) the wavelength must be the same "enough", given the unnecessary precision reported by ICE
+//
+// (for example, "6" can be anything from 6.0008 to 6.0020 in a recent experiment)
 //
 // passes the matching rows in the sample table back
@@ -1630 +1632 @@
         Wave tLam = root:myGlobals:TransHeaderInfo:T_Lambda             //Transmission file wavelength
         
-        Variable num,ii,found
+        Variable num,ii,found,tolerance=0.01            //0.01 = 1% tolerance
         String transStr = "",testStr=""
         
@@ -1642 +1644 @@
                 testStr=sw[ii]
                 found = stringmatch(testStr, transStr )
-                if( (found == 1) && (sLam[ii] == tLam[row]) )           // both must match
+                if( (found == 1) && (abs(sLam[ii] - tLam[row]) < tolerance) )           // both must match
                         Print "Match Found at:  ",transStr,snam[ii],sw[ii]
                         InsertPoints numpnts(matchRows), 1, matchRows