[BTeam] large radiation readings during 980 setup

[Brian Freeman]

However, it does show that the NDX detectors will be very useful in determining beam loss when we are doing Physics.

-B
________________________________
From: BTeam <bteam-bounces at jlab.org> on behalf of Brian Freeman <bfreeman at jlab.org>
Sent: Tuesday, August 24, 2021 8:50 AM
To: Jay Benesch <benesch at jlab.org>; BTeam <bteam at jlab.org>
Subject: Re: [BTeam] large radiation readings during 980 setup

If you look in the logbooks from last night, the beam got stuck in 1L after changing the energy. Much steering was required to get the beam into 1R

https://logbooks.jlab.org/entry/3896169

The message is that we do produce significant radiation in Tune mode when steering the machine. Is anyone surprised by this?

-Brian


________________________________
From: BTeam <bteam-bounces at jlab.org> on behalf of Jay Benesch <benesch at jlab.org>
Sent: Tuesday, August 24, 2021 6:41 AM
To: BTeam <bteam at jlab.org>
Subject: [BTeam] large radiation readings during 980 setup

In the few minutes since I first read this I haven't come up with
anything actionable, which is why I didn't send it to mcc_ops.

https://logbooks.jlab.org/entry/3896176  by Pavel Degtiarenko

The 7A15 detector is operational, further troubleshooting is not needed.
All NDX detectors are live and produce signals now. Few photon channels
are noisier than others, not critical for the neutron measurements in
normal conditions.
Illustrations to the beam losses during beam recovery are shown in the
attachments. Observed signals at 1L08, 1S01, and 7A15.
The beam first produced spiked dose rates at 1L08, at the levels ~550
R/h photons, ~90 rem/h neutrons.
Then for about 10 min intermittent dose rates at 1S01 at levels ~30 R/h
photons, ~20 rem/h neutrons.
Then a single spike at 1S01 at the level of ~230 R/h photons, ~70 rem/h
neutrons.
Then there was a photon flash at 7A15 at 20:49:05, very short, even not
registered in the beam current PV, at the level of about 1 kR/h photons,
and no neutrons. The currents in the photon and neutron ICs were about
the same, and their weighted difference was corresponding to -1 rem/h
neutrons, meaning that there was no neutrons during that flash. The
illustration to the limitations of the method: can't measure neutrons if
their dose rate level is about or below ~1/1000 of that of photons'.
Then at 21:04:45 there was a "normal" beam loss around the Arc 7A15,
with the dose rates about 16 R/h photons, and 11 rem/h neutrons, for a
couple minutes.

http://devweb.acc.jlab.org/CSUEApps/atlis/view_attachment.php?attachment_id=14980

http://devweb.acc.jlab.org/CSUEApps/atlis/view_attachment.php?attachment_id=14981
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