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GWU Status Report: 7-6-06

GWU Status Report: 7-6-06




Last time I reported on my progress reproducing Yongguang's results. Remember that "case 1" I was able to reproduce, however using a geometry file that did not match the description he gave. Unfortunately, Yongguang noticed something else that was incorrect in the case 1 geometry file that I used to reproduce his results. The "case 1" geometry file that worked to yield his results has a theta_max = 10.25 instead of 10.53. This means we now have for Case 1:

What Yongguang Claimed: What Produced the Reported Results:
  • VT Collimator
    		•
  • VT Collimator
    		•
  • 50 cm lead shield wall
    		•
  • 50 cm lead shield wall
    		•
  • Window with 2 cm clearance
    		•
  • Window with 2 cm clearance + 4 cm tungsten
    		•
  • theta_max = 10.53
    		•
  • theta_max = 10.25
    		•

    In his report, these are the values that Yongguang reported for his comparison of case's 1-3:

    Reminder: Case 1 is described above. Case 2 moves the primary collimator upstream 25 cm, reduces its thickness to 5.25 cm, makes it tungsten, adds 11.2 cm of lead behind the collimator, and reduces theta_max to 10.25. Case 3 then adds the lintel.

    Table 1: Yongguang's reported results for Case's 1-3
    Elastic Photons Elastic Photons from coll. region Inelastic Photons Inelastic Electrons Moller Photons Moller Electrons
    Case 1 0.21% 0.038% 0.014% 0.12% 0.44% 0.183%
    Case 2 0.2% 0.032% 0.015% 0.037% 0.38% 0.18%
    Case 3 0.16% 0.004% 0.013% 0.041% 0.11% 0.125%

    Since we have confirmed that one geometry file he used was incorrect and we are not sure what geometries were used for case's 2 and 3 we are hesitant to draw conclusions from this data.

    Using the claimed geometries described in his report, what I find (remember that last time I said we think the errors are being underestimated, we haven't looked into this further yet so just keep that in mind):

    Table 2: Katherine's values for Case's 1-3
    Elastic Photons Elastic Photons from coll. region Inelastic Photons Inelastic Electrons Moller Photons Moller Electrons
    Case 1 0.1954% +/- 0.0050% 0.0394% +/- 0.0019% 0.0146% +/- 0.0003% 0.0623% +/- 0.0015% 0.5134% +/- 0.0236% 0.1492% +/- 0.0190%
    Case 2 0.1970% +/- 0.0051% 0.0283% +/- 0.0016% 0.0182% +/- 0.0004% 0.0714% +/- 0.0019% 0.3133% +/- 0.0178% 0.1301% +/- 0.0250%
    Case 3 0.1709% +/- 0.0050% 0.0018% +/- 0.0003% 0.0175% +/- 0.0004% 0.0689% +/- 0.0018% 0.1117% +/- 0.0118% 0.1184% +/- 0.0265%


    Two other geometries to consider are

    The results for these geometries are

    Table 3: Case 0 and Case 1'
    Elastic Photons Elastic Photons from coll. region Inelastic Photons Inelastic Electrons Moller Photons Moller Electrons
    Case 0 0.1812% +/- 0.0051% 0.0029% +/- 0.0004% 0.0308% +/- 0.0005% 0.2057% +/- 0.0030% 0.1333% +/- 0.0116% 0.2631% +/- 0.0365%
    Case 1' 0.1858% +/- 0.0053% 0.0141% +/- 0.0011% 0.0136% +/- 0.0003% 0.0601% +/- 0.0015% 0.1608% +/- 0.0120% 0.1301% +/- 0.0230%

    From this, it seems that putting the lintel in and doing nothing to the primary collimator is a good option.

    For comparison, here are side views of the global volume for case 1' and case 3:
    Case 1' Case 3