[Dsg-rich] RICH cooling system instability

[Marc McMullen]

We have looked at the signals and are seeing a correlation between the signal dips and activity in the hall. The low point of the dip in signal is right around mid-day, but it starts between 7 and 8 am.The signal is back to the previous level between 3 and 5 pm. This essentially looks like the bulk of the Hall B Mechanical/Engineering staff work day, primarily when the roll-up door is used/open. This does not happen on the weekend . We looked into other flow signals (LTCC) on the forward carriage and the same thing happens. The dominant culprits look like hall temperature and pressure. This looks like it may be related to the roll-up door, which is generally open during work days. 




This is a long plot (7/15 to 8/6). Here you can see the some of the RICH temperatures reacting to daily temperature spikes (bright green). On the 25th the compressors are switch on (dk green) and (teal), during the dips in airflow1 and 2 hall pressure (red) has a sharp drop. 




Here i have zoomed in (7/31 to 8/3), and the dip spike correlation is more evident. 

Here is a finer X scale view. 




Marc McMullen 
Physics Division 
Detector Support Group 
7738 


From: "Valery Kubarovsky" <vpk at jlab.org> 
To: "Peter Bonneau" <bonneau at jlab.org> 
Cc: "dsg-rich" <dsg-rich at jlab.org>, "Marco Mirazita" <marco.mirazita at lnf.infn.it> 
Sent: Monday, August 6, 2018 3:18:04 PM 
Subject: Re: [Dsg-rich] RICH cooling system instability 

Thank you Peter! 

I switched the detector ON to monitor the RICH parameters. 

Regards, 
Valery 




From: "Peter Bonneau" <bonneau at jlab.org> 
To: "Valery Kubarovsky" <vpk at jlab.org>, "Tyler Lemon" <tlemon at jlab.org> 
Cc: "dsg-rich" <dsg-rich at jlab.org>, "Marco Mirazita" <marco.mirazita at lnf.infn.it> 
Sent: Monday, August 6, 2018 3:00:42 PM 
Subject: Re: [Dsg-rich] RICH cooling system instability 



BQ_BEGIN


Hi Valery, 

DSG is looking into this issue. 

I've checked the Hardware Interlock system and it's running normally. 

Mark and George are investigating the compressor for the drop in flow and pressure that occurs around 12:00. 

Peter 



On 8/6/2018 10:32 AM, Valery Kubarovsky wrote: 

BQ_BEGIN

Hi Tylor, 
I observe some instability in the RICH cooling system. Please take a look to the log entry 

https://logbooks.jlab.org/entry/3584390 

It is happening around 12:00. The temperature increase is obviously connected with the change in the 
airflow1 and airflow2, as well as with the change in the airpr1. As a result we got interlock signal from sensor temp4 and temp11. 

Could you please take a more careful look. 
Thank you, 
Valery 


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BQ_END



BQ_END


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