[Hallc_running] [New Logentry] RC Daily Update

Douglas Higinbotham doug at jlab.org
Thu Feb 23 09:12:07 EST 2023



Just to be clear, the higher current is only because Hall A is down.

The limit isn’t really current to one hall, it is the total power and that machine isn’t able to get beyond 700-800 kW.   As soon as Hall A is back then the available power will be shared.  (i.e. the 35-40 uA that you have been seeing).

NOTE:   There have also been other issues that can limit the current, but power is the one we have been fighting with the most this run period.


From: Hallc_running <hallc_running-bounces at jlab.org> on behalf of Carlos Yero via Hallc_running <hallc_running at jlab.org>
Date: Thursday, February 23, 2023 at 8:15 AM
To: Dien Nguyen <dien at jlab.org>, hallc_running at jlab.org <hallc_running at jlab.org>, weinstei at jlab.org <weinstei at jlab.org>
Subject: [Hallc_running] [New Logentry] RC Daily Update
RC Daily Update<https://logbooks.jlab.org/entry/4137303>

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Lognumber 4137303<https://logbooks.jlab.org/entry/4137303>. Submitted by cyero<https://logbooks.jlab.org/user/cyero> on Thu, 02/23/2023 - 08:11<https://logbooks.jlab.org/entries?start_date=1677154309&end_date=1677161509&book=HCLOG>.
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Changed to Au SRC kinematics yesterday ~ 9 pm, and started taking data on Au for remaining of CaFe run, (~ 8 AM Friday)

The average count rate has been 0.035 SRC counts/ sec @ ~ 30-35 uA, which gives 126 counts / hr (or 1008 counts / 8hr-shift)
We currently have a total 664 of counts as of 5 am, today. As of now, we have 3 shifts remaining ( or 1008 * 3 = 3024 counts),
which means we will end up with ~ 3700 counts assuming 100 % beam efficiency @ 35 uA, or more realistically, 1850 counts @ 50% beam efficiency.

Our MUST stats goal for this setting is 3K, ---> 1850 / 3000 = 61.4 % of stats collected

There is hope, however, . . .

During MCC meeting this morning, I asked If we could get higher current, and they agreed, and will give it a try,
since Hall A will need to make an access today. Depending on how high of a current they give, we may be able
to complete our minimum stats goal.

Also, Ops will need to make an access to North Linac (~ 1 hr) for some checks + accelerator recovery afterwards,
so they could have smooth running over weekend. The best time for this would be tomorrow at ~8:30 AM, since
at that time we will be changing kinematics from CaFe to deuteron experiment.
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