Ignore:
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/Reduction/SANS
Files:
2 edited

Legend:

Unmodified
Added
Removed
  • sans/Dev/trunk/NCNR_User_Procedures/Reduction/SANS/MultScatter_MonteCarlo_2D.ipf

    r459 r465  
    1111// 
    1212// - Why am I off by a factor of 2.7 - 3.7 (MC too high) relative to real data? 
    13 //   I need to include efficiency (70%?) - do I knock these off be fore the simulation or do I  
     13//   I need to include efficiency (70%?) - do I knock these off before the simulation or do I  
    1414//    really simulate that some fraction of neutrons on the detector don't actually get counted? 
    15 //   Is the flux estimate up-to-date? 
     15//   Is the flux estimate up-to-date? !! Flux estimates at NG3 are out-of-date.... 
     16// - my simulated transmission is larger than what is measured, even after correcting for the quartz cell. 
     17//   Why? Do I need to include absorption? Just inherent problems with incoherent cross sections? 
     18 
    1619// - Most importantly, this needs to be checked for correctness of the MC simulation 
    1720// X how can I get the "data" on absolute scale? This would be a great comparison vs. the ideal model calculation 
    1821// X why does my integrated tau not match up with John's analytical calculations? where are the assumptions? 
    1922// - get rid of all small angle assumptions - to make sure that the calculation is correct at all angles 
    20 // - my simulated transmission is larger than what is measured, even after correcting for the quartz cell. 
    21 //   Why? Do I need to include absorption? Just inherent problems with incoherent cross sections? 
     23 
    2224// 
    2325// X at the larger angles, is the "flat" detector being properly accounted for - in terms of 
     
    5052// 
    5153// X why is "pure" incoherent scattering giving me a q^-1 slope, even with the detector all the way back? 
    52 // - can I speed up by assuming everything interacts? This would compromise the ability to calculate multiple scattering 
     54// -NO- can I speed up by assuming everything interacts? This would compromise the ability to calculate multiple scattering 
    5355// X ask John how to verify what is going on 
    5456// - a number of models are now found to be ill-behaved when q=1e-10. Then the random deviate calculation blows up. 
    5557//   a warning has been added - but some models need a proper limiting value, and some (power-law) are simply unuseable 
    5658//   unless something else can be done. 
     59// - if the MC gags on a simulation, it often gets "stuck" and can't do the normal calculation from the model, which it 
     60//   should always default to... 
    5761// 
    5862// 
  • sans/Dev/trunk/NCNR_User_Procedures/Reduction/SANS/SASCALC.ipf

    r457 r465  
    799799                Variable rad=beamstopDiam()/2           //beamstop radius in cm 
    800800                rad /= 0.5                              //convert cm to pixels 
    801                 rad += 1                                        // add an extra pixel to each side to account for edge 
     801                rad += 0.                                       // (no - it cuts off the low Q artificially) add an extra pixel to each side to account for edge 
    802802                Duplicate/O linear_data,root:Packages:NIST:SAS:tmp_mask 
    803803                WAVE tmp_mask = root:Packages:NIST:SAS:tmp_mask 
     
    16401640End 
    16411641 
     1642 
     1643// not part of SASCALC, but can be used to convert the SSD to number of guides 
     1644// 
     1645// SSD in meters 
     1646Function numGuides(SSD) 
     1647        variable SSD 
     1648         
     1649        Variable Ng 
     1650        Ng = SSD*100 + 5 - 1632 
     1651        Ng /= -155 
     1652         
     1653        Ng = round(Ng) 
     1654        return(Ng) 
     1655End 
     1656 
     1657 
    16421658//returns the offset value 
    16431659// slider and setVar are linked to the same global 
Note: See TracChangeset for help on using the changeset viewer.