[Clas12_rgb] [EXTERNAL] Re: RC meeting: today @ 2pm!

[Daria Sokhan]

Dear all,

Update, as usual!

During hall access today:
* Krister traced the problem on the tripping Moller magnet to a potentially
faulty temperature sensor which causes the magnet to ramp down when it
reaches a much lower temperature than is of concern. He has replaced it
with a new one and it will need to cure for about 24h before he can bolt
things up again, for which he'll need a ~30min access at the next
opportunity from tomorrow onwards. Moller is unusable until then. He would
also like to test it by switching it on and taking regular measurements
with a heat camera for a while (~3h, whenever there's a long opportunistic
access), but says that this is not crucial -- another way to test it is to
do a Moller run when we finally need one.
https://logbooks.jlab.org/entry/3750731
* Cole debugged noisy ECAL channel: https://logbooks.jlab.org/entry/3750593
* Bob removed the two neutron counters closest to BAND on Florian's request
and installed a gamma monitor close to SVT (between target and solenoid) to
monitor radiation levels in SVT vicinity.
* Loss of communication with the BAND laser -- Florian tried to debug it
but needs more time (at the next opportunistic access: we're expecting beam
imminently).

* Nick M has updated gain calibration for sector 4 in HTCC, which looked
slightly skewed yesterday. This will apply to run 11134 onwards.

* Run 11123 with the test of trigger v13 (PCAL+ECAL E-sum > 300 MeV) had
been analysed by Rafo and Valery, they find that there's a reduction in
electron trigger rate of 10% and a reduction of 4% in the "muon" trigger
efficiency. The decision is to stick with our current production trigger,
so this special run needs no further analysis.

* Cole is producing timelines for the calorimeter to check sampling
fraction, which appears to decrease at the start of operations with beam.
This was observed before in the Spring run and last year.

* There was a discussion about which runs to cook now that the first ten
runs have been cooked for all (or almost all) good runs. We decided to put
off cooking the whole of 11102 for calibrations until a discussion with
Silvia and instead to cook the low luminosity runs 11117 and 11120 for
comparison between low and high luminosity data, in particular of the
timing.

* There was a long discussion on whether to keep a separate Google
spreadsheet of the data-runs or rely on RCDB -- this has been deferred
until RG-B meeting on Friday. The only consensus was that we need
instructions on how to extract data from the database and that shift
leaders need to enter accurate and informative information in the comment
field when starting / ending runs. I have put a loud and visible note about
this on the Short Term Schedule wiki:
https://wiki.jlab.org/clas12-run/index.php/Run_Group_B#Short_Term_Schedule

* Spin dance is likely to happen on Thursday or Friday now -- only halls
A + C will participate. It's expected to take ~8 hours and we need a clear
run plan for measurements which do not require polarisation information. We
plan to do zero field, empty target and luminosity measurements and will
define tomorrow the length of each. Please let us know of any requests /
suggestions.

And hot off the press: MCC have fixed the leak and are getting ready for
beam! We've finished up in the hall, energised solenoid and torus and are
getting ready to tune the beam!

Here's hoping for clean beam,
Daria


On Tue, 10 Dec 2019 at 11:52, Daria Sokhan <daria at jlab.org> wrote:

> Dear all,
>
> Let's have an RC meeting @ 2pm again today, upstairs in the counting
> house.
>
> Bluejeans:  https://urldefense.proofpoint.com/v2/url?u=https-3A__bluejeans.com_230805731&d=DwIBaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=p0fOsYOqPes7kSrF0-ldLy8UQdwZWwpYV125WHZsrFE&m=ht3_UVMd6GPD6IsY07jG7trMFu5AOnPku-bc3CC6cTM&s=_d6Ra0QZtqzXI4ESkrr3pKXt1jccszY_Z9T26Y3v4EA&e= 
>
> The accelerator is still down, there are some adjustments and checks
> ongoing in the hall. This is a good time to discuss any more issues that
> have been observed in the data. If experts could take a look at monitoring
> histograms which Yordanka has produced for the recent runs and report on
> anything "interesting", that would be great:
> https://clasweb.jlab.org/clas12mon/rg-b/pass0/v17_fall2019/offline/
>
> Speak to you soon,
> Daria
>
> PS: I'll make everyone speaking sit around the table so people on the
> phone can hear them!
>
>
>
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