Re: [BLAST_SHIFTS] Shift summary 10/28/2004 A (1-9)

From: vitalik (vziskin@mit.edu)
Date: Thu Oct 28 2004 - 09:13:37 EDT


Also, I need about 40kC of hydrogen data to put missidentification of
neutrons issue to rest. It is very important for me that nothing
changes in the neutron detection from the deuterium experiment.

                                              Vitaliy

                                                

jrc@physics.unh.edu wrote:

>Regarding the neutron trigger for H running, I think the answer is "yes".
>There should be a lot of interesting events in the n + pi+ final state
>channel, with the pi+ in the left sector and the n in the right sector.
>The final electron goes down the tube.
>
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>>Operator: zwart
>>
>>Troublesome Shift.
>>
>>Running polarized H after Genya switches back from Helium test.
>>
>>Good runs 12144,12145,12146
>>
>>BLTC's stop counting. Blast_Data_Alarm reports 0 scaler events being
>>written. But HV GUI looks OK. Call TB who helps restart scaler app.
>>
>>Large asymmetry in Compton results (+90%,-50%). Larry Loncoy adjusts
>>electron beam position at Compton from ~ -10 mm to ~-6 mm. Adjust laser
>>steering to reoptimize backscatter rate (mostly M3). Laser spot moves down
>>significantly on the video monitor in the counting bay. M1 (1st remote
>>control for vertical appears not to function). The backscatter rate
>>increases to ~600 Hz/mA Las. Curiously false asymmetry is now almost
>>completely inverted to (~-90%,+50%). Larry adjusts beam position to
>>~-7.5mm, but false asymmetry is largely unchanged. This action does
>>however optimize the brem rate on the CsI. Normalized brem rate imroves
>>from ~45 --> ~75. The false asymmetry still needs attention.
>>
>>Should the Neutron trigger still be on if we are running Hydrogen?
>>
>> Then had trouble with HV IOC. The HV gui reported "restoring", but was
>>frozen. Rebooted the IOC and started running again.
>>
>>I did not have override permission set to "off" on HV GUI. Several WC
>>trips occured as the ring filled with HV on. Larry noticed and the HV was
>>appropriately reset.
>>
>>Finally things are smooth again.
>>
>>Runs 12150, 12151 are good.
>>
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