[Halld-cpp] CPP Meeting Minutes, March 23, 2022

[Mark Ito]

Folks,

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/%CE%A0_polarizability_Meeting_Mar_23,_2022#Minutes> 
and below.

   -- Mark

      _____________________________________


    Minutes, Π polarizability Meeting Mar 23, 2022

Present: Alex Austregesilo, Albert Fabrizi, Sergey Furletov, David 
Hornidge, Mark Ito (chair), Igal Jaegle, Nikhil Kalra, Ilya Larin, Rory 
Miskimen, Simon Taylor, Beni Zihlmann

There is a recording of this meeting 
<https://jlab-org.zoomgov.com/rec/share/Wm2xjPp033bWQXRTmj3OaICnctXANcD-f_KLfl_7ycZidpu2CzwK8SFr_N_Kg_yM.wp1IrII1OPQXB4sq> 
(Passcode: n.1a#yZ9) on the ZoomGov website.


      Cables

Beni reported that the LV and HV cables for the chambers were being 
installed yesterday. The signal cables are still in productions. He 
reminded us that we have 6 signal cables in hand that can be used to 
test one chamber at a time.

[Added in press, from Beni: the crimp tool loan mentioned at the last 
meeting was approved yesterday and has been shipped to the company. Also 
Chris Stanislav is connecting the LV boxes to the wire chambers as of 
this afternoon.]


      Run Start Date

Beni reminded us that the run is scheduled to start June 8. We should 
not now that a budget has passed, we should not assume that there will 
be a CR-related delay in the start of the run.


      TAC Status

Beni had a look at the lead glass TAC in the Hall. He led us through his 
logbook entry <https://logbooks.jlab.org/entry/3989007>. All indications 
are that the device looks good. He mentioned that that TAC was last used 
with GlueX in November/December 2019.

Beni also mentioned Sascha Somov's plan to use a new, 3×3 lead tungstate 
array as a TAC for CPP and PrimEx. We had some discussion of the 
relative merits of lead glass TAC vs. lead tungstate TAC.

  * possible leakage of showers from the sides of PbWO_4 vs. large size
    of Pb-glass
  * better intrinsic energy resolution of PbWO_4
  * possible need for calibration, block-to-block of a PbWO_4 array
      o TAC stage only has horizontal motion. Snake scan requires
        two-dimensional motion
  * PbWO_4 is a new detector

Rory suggested that Mark ask Sascha to come to tomorrow's CPP Design 
meeting to present his plan.


      Amount of Empty Target Data to Take

TBD


      Diamond Simulations

No news.


      Software/Calibration

  * Simon has moved the kinematic fit of pairs from a plugin to a
    factory in the FMWPC library. It has not been tested on
    electron-positron pairs yet. Rory remarked that its location in this
    library is motivated by having results of the fits available for
    online e/π separation monitoring. Without the kinematic fit, this
    would be difficult due to the relatively poor momentum resolution
    for forward-going tracks.
  * Simon is working on putting the survey numbers in. He has a version
    in a private HDDS directory.


      Scintillators

The CTOF paddles are being installed in the Hall this week. Bobby Bunton 
3D-printed mounting brackets, at Beni's request, so that mechanical 
support attachments are only made on the light guides and not to the 
scintillators or the phototube/base.


      Translation Tables for Scalers

Beni has a meeting with Justin scheduled for Friday to discuss how this 
is to be done.


      Low Voltage Feedback for the Chambers

Beni confirmed with Chris that the feedback system for regulating low 
voltage at the distribution box is hooked up.


      Lead Shielding Alignment

The lead shielding in front of the first MWPC will be positioned, at the 
1 mm level, from a study using rates, with beam on, of the MWPCs at 
several positions of the shield. Position adjustment is done by hand in 
the Hall, so Rapid Access will be necessary to carry out the program. 
Ilya will draft a run plan for this activity.


      CPP Trigger Tests

Sergey reported that the CDC AI tests are done. Sascha is aware of this 
and he will start back on trigger tests. Ben Raydo may have to be pulled 
in at some point. Rory emphasized that this is on the critical path.


      DAQ and Electronic Setup

Sergey reported that the CDC crate with the FADC-125s is mounted in its 
new location for use with the MWPCs. A new VME computer has been put in 
the crate. The crate has no power and it needs a optical fiber for 
read-out still.

[Added in press, from Beni: the VXS crate has now power. There is also 
AC 120V regular power available in the rack.]


      Tagger Hodoscope Location 7

Mark mentioned that at yesterday's Hall D Staff meeting Tim Whitlatch 
mentioned that he was waiting on a decision from the CPP group on 
installing a plate, at location 7, for mounting tagger hodoscope 
counters. We think we need this. We will try to clarify the issue at 
tomorrow's Design Meeting.

[Added in press: Mark asked and Sascha agreed to attend the meeting.]


      CTOF Trigger

Rory asked about readiness of the various components needed to form a 
trigger from the downstream scintillators. Beni reported that all the 
components were in-hand or easily acquired.

  * The PMTs have two outputs, one will to the FADCs, the other to a
    discriminator
  * The discriminator has two outputs. One will go to a CAEN TDC, the
    other to the trigger logic.
  * Trigger logic is housed in a NIM crate.
  * The output of the trigger logic modules is sent over fiber to the GTP.


      Schedule for Chamber Data

Alex asked about the schedule for reading out the chambers so that 
monitoring and reconstruction can start to be tested. Beni thought that 
it would be at least couple of weeks. Not only does the chamber read-out 
chain need to be established, but the CTOF trigger has to be working.

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  * This page was last modified on 23 March 2022, at 21:41.
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