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code agrees with Angelika for ZDC scaler

Updated on Tue, 2009-10-13 15:48. Originally created by rcorliss on 2009-10-13 15:48.

My vernier scan analysis code is in pretty much exact agreement with Angelika's, at least for the ZDC scaler cross section:

The above plot was produced using the data given to me by Angelika.  They were already divided into bins by step, and were the average rate instead of the integrated counts.  This originally caused a factor of thirty difference, but when corrected it falls exactly in line with the value Angelika reported.

This does not vet the parts of my code that find the offset between her timestamps and the timestamps in the mudst, nor the code that divides the raw data into the vernier scan step bins, but both of these are much smaller tasks.

 

I still do not have agreement between my code's BHT3 cross section and the value Bill calculated.  For run 10097097 I have 500nb, and for 10103044 I have 466.  These numbers alter slightly when I manually remove the abort gap bunch crossings from the histogram, but they remain pretty far off of the values I get using Bill's method.

 

(Bill's method takes the ZDC scaler cross section and uses the ratio of the BHT3 rate to the ZDC scaler rate to compute the BHT3 cross section)

vernier scan values: 500nb (10097097), 466nb (10103044)

ratio values:390nb (run 10088078), 403nb (run10097087, near the first scan), 389nb (run 10103038, near the second scan)

 
Since these values can be affected by the crossing angle and the geometry of the beams, they can differ from fill to fill.  That's why I specifically chose stable runs within the same fill as the vernier scan.  Both are earlier, and hence will have higher luminosity than during the vernier scan, but I don't think this is responsible for the discrepancy.  I've sent an email to Bill and am waiting to hear back.

 

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