[dsg-hallb_rich] [EXTERNAL] report on the RICH assembly work

[Patrizia Rossi]

Thank you Marco for this very useful summary!

patrizia

On Apr 11, 2022, at 11:11 AM, Marco Mirazita <Marco.Mirazita at lnf.infn.it<mailto:Marco.Mirazita at lnf.infn.it>> wrote:

Hi all,
here is a report on the RICH assembly work performed in the last few weeks. Several things have been done, but many have not been done, because of the delay in the spherical mirror production, and therefore will be postponed to the next visit of INFN personnel in May.
Please let me know if I forgot something or if you have corrections or comments.
Marco


1) Summary of what has been done

Tedlar window
The panel was assembled by the Argonne personnel. We tested its installation on the RICH. We left it installed.

Other mechanics activities
An issue in the position of the patch panel fixing holes has been found and fixed.
The lateral cable raceways have been worked to cut the holes for the feed-throughs and then reinstalled and sealed.
The connectors for the nitrogen, the humidity and temperature sensors and for the cameras have been installed. The connectors for the fibers and for the light of the cameras are still missing.
The modifications of the system to install the electronic panel on the RICH have been verified.
The installation of the sealing foam of the frontal panels has been completed.

Planar mirrors
We tested the installation of the mirrors. No problems found

Aerogel
The thick foam to replace the missing tiles of the last row and the thin one to be put between the tiles has been prepared.
The holding system of the 3+3 cm sector has been installed on the frontal panel.
A visual inspection of few tiles has been done, nothing obviously bad to report.

Cooling
The smaller compressor with the tank has been moved in the EEL building.
The cooling system has been slightly revised to take fix an issue with the first two larger holes in the pipes. The fix has been reviewed, tested and approved by Bob Miller.
The system has been installed and a preliminary functionality test has been performed.
The connectors to join the exhaust air pipes to the electronic panel are being 3D-printed at JLab.
Note that we have now 3 compressors available: the original smaller one, and two bigger ones, both of which have sufficient power to supply the cooling air to two modules.

Nitrogen
The nitrogen system has been installed and a preliminary functionality test has been performed. Few new plastic blowers are being 3D-printed at JLab and will be replaced.
The humidity and temperature sensors have been installed. The cables connecting the sensors to the feed through panel on the RICH are very long, several meters. Each cable will be cut shorter to the minimal necessary length by DSG personnel.

Electronics
We continued to work on the tests on the readout electronics. The issue with the tiles randomly disconnecting has not been solved yet, Ben is working on it and we may have good news soon.
We found a strange pedestal shape when the MAROC gain is bigger than 1. It could be due to a saturation of the scaler readout, but a similar behavior has never been observed in RICH-1. It should be investigated more, in particular with better grounding, but it should not be a major concern for the data taking.
We tested the functionality of the HV of all the tiles every time some hardware work on the electronic panel has been done (eg after the installation of the cooling pipes).
We tested the CODA data acquisition taking few runs with random trigger in two conditions: i) PMT off and threshold set around the pedestal tail; ii) with 28 PMT on and the threshold set at pedestal+25 (CLAS12 set up). We visualized the data using richmon and compared the results with the scaler readout, the two systems looked qualitatively in agreement, besides the fact that few tiles were missing in richmon due to the different mapping between RICH-1 and RICH-2.
We started to pull all the LV, HV cables and optical fibers to be able to close the panel, but the work has not been concluded.
The installation of the PMTs has been started.

Services
The scaler and temperature maps now include 2 RICH sectors. The mapping of the tiles on the monitor has been verified.
No tiles with significantly higher heat production has been found so far.
The temperature and humidity sensors of RICH-2 are available on a separate monitor, they need to be included in the main RICH monitor.
The interlock has been tested.

Software
The software for the scaler readout is being rewritten to include the second RICH sector. It should be ready for test soon.
Other software to be extended to 2 RICH sectors: monitoring histograms in mon12, richmon, CODA with 2 sectors.


2) What has not been done

- Installation and alignment of the mirrors
- Test of the installation of the cover of the electronic panel with the boards and cables.
- Full test of the cooling system, with the electronic panel closed and the LV on, and optimization of the open hole position.
- Full test of the nitrogen system, with the RICH sealed, to reach the few % humidity required.
- A test of the electronic panel installation after the revision of the new procedure.
- Preparation of the tents for the aerogel assembly.
- Installation of the temperature sensors in the electronic panel

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