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

[Marco Mirazita]

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