Log entry time 11:16:05 on March 29, 2010

Entry number 314480

This entry is a followup to: 314429

Just to clarify, the purposes of running spot are

1) At 5 uA with T8 -- to look at the BPMs (T8 = unbiased sampling)
2) At 10 nA with T5 -- to look at the raster-current (T5 = biased by target)

The former gives the size of the spot (should be 4x4).
The latter gives the info on whether you are hitting a frame.

Note, the BPMs dont work below ~2 uA, so at 10 nA they should
be ignored.

The logic is that the raster needs to be on to avoid melting the 
lead target, and hitting the copper frame would cause an unacceptable
physics background.

More info:

hallaweb.jlab.org/prex/runinfo/How_to_recover_beam.html