User name R. Michaels
Log entry time 09:43:48 on June23,2004
Entry number 126669
keyword=Alum bgr. part 3
More on aluminum backgrounds.
This is a followup to
halog 126314 and
The issue here is what is the character of the aluminum background ?
Is it only the tail of the Q.E. peak, or is there also elastic and
low-lying inelastic events ? World data can answer, but also we
answered by moving the elastic peak off the HAPPEX detector and
studying it with scint. trigger data. Fig 1 shows the result
for Carbon for comparison, it is run 1117. We see the C12 elastic
and 2 well-known inelastic states (though one can quibble about the
systematics of the level spacing at the 0.3 MeV level). In contrast
for run 1144 for Aluminum dummy cell, we see no strong evidence of
the elastic nor any inelastic levels (full statistics of that run),
see bottom two panels of fig 1. Perhaps there is a nub of elastic.
This will give us an upper bound. Under normal running conditions
the region of Alum elastic is in the detector or near its edge.