Log entry time 03:07:28 on May 08, 2012

Entry number 383097

Followups:

• 383219 05/08/12 14:18 pzhu BPM worse than yesterday

John and I went to the hall to check the BPM, John replaced the
cover for
the BPMB so that it can absorb the RF noise, and we moved
the BPM
receiver to the ground to avoid the potential noise.
For
the simulated signal, seems it is a little bit better ,from 0.2mm
to
0.14mm. see halog:
http://hallaweb.jlab.org/halog/log/html/1205_archive/120507215532.html
http://hallaweb.jlab.org/halog/log/html/1205_archive/120507223638.html

After
beam back, I tested the resolution with 50nA,the resolution for BPMB is
~0.2mm / 0.22mm for X/Y, 
much better than before, see halog:
http://hallaweb.jlab.org/halog/log/html/1205_archive/120508015839.html

The
gain I used for BPM B is 90, gain diff is -4/-2, div is 3.

for
noise, it is a little bit weird that sometimes it is better, it is worse.
we tested it before beam back, 
the pedestal is noisy for gain 77 and
gain 90.see halog:
http://hallaweb.jlab.org/halog/log/html/1205_archive/120507224224.html

But
after dilution, seems it is better:
http://hallaweb.jlab.org/halog/log/html/1205_archive/120508022851.html

The
noise is still in there and not stable, not sure where it is come
from.
Maybe we can look at it in Wednesday.

Also I tested the
gain linearity for BPM receiver, you can find it in halog:
http://hallaweb.jlab.org/halog/php/elog119.php