Here is a Plot of a pi->e nu peak from the 1997 data.

The gaussian fit has a sigma of 65.6 +/- 3.8 and a mean of 2097 +/- 5.5 which would indicate a FWHM/peak pos of about 7.4% (+/- 0.4%). An ascii file containing the data shown is this plot can be found here. The file was generated bt PAW using the hist/get/contents command and then the vect/write command. The histogram has 50 bins with limits of 1730 and 2730. You can also get the zebra file here: temp.rz.gz (~5.7MB). One should note that this file also contains Michel events cut on a high discriminator threshold and prescaled by a factor of 30 for sum_all less than 1700.

Here are the cut definitions for the cuts used to get the above peak:

- = sum_all.GT.1730
- = decay.LT.400.and.sumpvgm.LT.300
- = td0.GT.50.and.td0.LT.80
- = (c36+c37+c39+c40).LT.20
- = (maxc=14.or.maxc=16.or.maxc=22.or.maxc=26)
- = percent.LT.4
- = $1.and.$2.and.$3.and.$4.and.$5.and.$6 $7 depends on $1, $2, $3, $4, $5, $6

Cut #7 was what was actually used

- "sum_all" is the CsI sum plus the target correction.
- "decay" is the energy lost by the decay positron leaving the target. (Note: the calibration factor used to add "decay" to the CsI was 0.65).
- "sumpvgm" is the sum of plastic veto geometric means.
- "td0" is the TDC value for the first leading ege in the degrader.
- "C36,C37,C39,C40" are the half-D crystals
- "maxc=" is the index (starting from 1) of the crystal with the highest ADC value. (see note above)
- "percent" is the percentage of the shower contained in the outsie ring of CsI crystals

D. Lawrence, 6 August 1997