Operators: franklin ---- ----
First half of shift was spent leak checking target thoroughly. Details in logbook, but ultimately no leak was found, although vacuum in target region remains poor. It is possible that the problem is outgassing from an ion gauge which was added during the week.
Second half of shift was devoted to beam studies with Compton. Also
detailed in log book, but the steering problem has remained stubbornly resistant
to a solution which simultaneously produces desirable conditions for halo and
for polarimeter. It appears that we need to explore option of moving some elements of Compton backscatter line. Can try some tests tomorrow to estimate
how far detector would need to be moved and whether this would really help.
For tonight, take empty target data. This will give a worst case scenario
for the background with the 60 cm cell since the vacuum and lifetime are
presently poor.
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