[BTeam] Hall A data from FFB and FF test

Fri Aug 21 13:05:28 EDT 2020

FYI!
Crew chief said the maintenance is done and beam will come soon.

________________________________
From: Sanghwa Park <sanghwa at jlab.org>
Sent: Friday, August 21, 2020 12:59 PM
To: HyeKyoung Park <hkpark at jlab.org>
Cc: Mike Spata <spata at jlab.org>; Paschke, Kent Dieter (kdp2c) <paschke at virginia.edu>; Ciprian Gal <ciprian at jlab.org>
Subject: Re: Hall A data from FFB and FF test

Again, I won't be able to post this to bteam at jlab mailing list. Please forward it to the list.

Here are the data for 1C12 BPM. We don't have anything before the arc in our data stream. We have 1C11, 1C12, 1C16, 1H01, 1H04A, 1H04E.
There is a halog with more plots (https://logbooks.jlab.org/entry/3831916) but somehow the ordering is mixed up. I put some summary here.

rms:
FF on FFB on:    90.14 (um)
FF, FFB paused: 19.18 (um)

FF off, FFB on: 13.57
FF off, FFB paused: 11.9

Note:
When FFB is paused, FF is also paused as far as I understand. During our data taking, the FFB paused period is when the beam modulation was running.
We don't see this additional noise with FF on in the X position.
Just for the complete information, we cannot run with FF off but FFB on, the beam energy modulation (dithering) doesn't work in this setting.

[image.png]
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[image.png]

On Fri, Aug 21, 2020 at 10:59 AM HyeKyoung Park <hkpark at jlab.org<mailto:hkpark at jlab.org>> wrote:
Replying to include people copied in the original message.

________________________________
From: Mike Spata <spata at jlab.org<mailto:spata at jlab.org>>
Sent: Friday, August 21, 2020 10:02 AM
To: HyeKyoung Park <hkpark at jlab.org<mailto:hkpark at jlab.org>>; bteam at jlab.org<mailto:bteam at jlab.org> <bteam at jlab.org<mailto:bteam at jlab.org>>
Subject: Re: Hall A data from FFB and FF test

It would be very helpful to have this data for 1C12 BPM and 2 vertical and 2 horizontal BPMs before the Arc. Can we see that?

Mike

--
Michael Spata
Deputy Associate Director
Accelerator Ops and R&D
Jefferson Lab
12000 Jefferson Avenue
Newport News, VA 23606
Cell: (757) 876-0528<callto:(757)%20876-0528>

________________________________
From: BTeam <bteam-bounces at jlab.org<mailto:bteam-bounces at jlab.org>> on behalf of HyeKyoung Park <hkpark at jlab.org<mailto:hkpark at jlab.org>>
Sent: Friday, August 21, 2020 9:42 AM
To: bteam at jlab.org<mailto:bteam at jlab.org> <bteam at jlab.org<mailto:bteam at jlab.org>>
Subject: [BTeam] Fw: Hall A data from FFB and FF test

________________________________
From: Sanghwa Park <sanghwa at jlab.org<mailto:sanghwa at jlab.org>>
Sent: Friday, August 21, 2020 9:32 AM
To: bteam at jlab.org<mailto:bteam at jlab.org> <bteam at jlab.org<mailto:bteam at jlab.org>>
Cc: HyeKyoung Park <hkpark at jlab.org<mailto:hkpark at jlab.org>>; Paschke, Kent Dieter (kdp2c) <paschke at virginia.edu<mailto:paschke at virginia.edu>>; Ciprian Gal <ciprian at jlab.org<mailto:ciprian at jlab.org>>
Subject: Hall A data from FFB and FF test

Hello all,

Thank you for the discussion this morning. Here is some information when we did the test with FFB system.
Please let me know if you need anything from us. We are happy to provide any information that would help.

I put the timestamps of our runs which would be useful for you to look at the archive.

We took two runs,
---------------------------------------------------------------------------------------------------------
run 7699:
Run start time: 2020-08-13 17:00:06
Run end time:  2020-08-13 17:44:58

"During" the run, we test (1) FF ON, FFB ON (2) FF ON, FFB pause. The plots below show the comparisons of BPM1Y. Note the vertical scale on the right plot.
On the right plot, x-axis is the entry number of our data, so it's time proxy. Each entry is for one helicity window at 120Hz.

Observation: With FF on, we see vertical jitter in our BPMs. The plots only show BPM1Y here but other BPMs saw it too.

[image.png]

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run 7700:
Run start time: 2020-08-13 17:46:26
Run end time:  2020-08-13 18:02:36

During this run, we test (1) FF OFF, FFB ON (2) FF OFF, FFB pause. BPM1Y comparisons plots are attached below.
Observation: whether we have FFB on or not, if FF is off we didn't see the large jitter anymore.

[image.png]
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Also, we observed that Hall A Compton central rate (backscattered photon, not background rate) behaves better with FFB and FF OFF. See https://logbooks.jlab.org/entry/3826851
The strip chat shows the compton central rate and FFB status.
Top graph is the Compton central rate. The bottom one is FFB status, =FFB ON, 0=FFB off.

Sanghwa (Hall A RC)

--
Sanghwa Park
Stony Brook University

--
Sanghwa Park
Stony Brook University
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