[Dsg-ltcc] ltcc leakage rates.

[Amrit Yegneswaran]

hi maurizio, 
these leakage rates are the measured rates while we are flowing N2. 
assuming low leakage rates initially, we are driven to believe that in the process of installing, something happened. 
also, since the leakage rate wasn't quantified, i don't see how you can say that these rates are an order of magnitude higher. 
amrit 


From: "Maurizio Ungaro" <ungaro at jlab.org> 
To: "Amrit Yegneswaran" <yeg at jlab.org> 
Cc: "dsg-ltcc" <dsg-ltcc at jlab.org>, "Patrizia Rossi" <rossi at jlab.org>, "David Anderson" <dla at jlab.org> 
Sent: Wednesday, April 26, 2017 2:57:41 PM 
Subject: Re: [Dsg-ltcc] ltcc leakage rates. 

Hi Amrit, 

These rates are rather big. Where do they come from? 
David took many precautions to ensure the box was tight. We didn't quantify it but I would gess the remaining leaks we had were order of magnitudes below these. 


Thanks, 

Mauri 




On Apr 26, 2017, at 2:52 PM, Amrit Yegneswaran < yeg at jlab.org > wrote: 

brian, marc, and george measured the leakage rates of the ltcc sectors over an extended period of time. 
based on these measurements the results are 
sector 
	
C4F10 
L/day 
	C4F10 kg/day 

1 
	95 
	1.06 

2 
	32 
	0.36 

3 
	118 
	1.32 

4 
	38 
	0.43 

5 
	27 
	
0.30 

6 
	101 
	
1.13 

sectors 2, 4 and 5 are best. 
sectors 1, 3, and 6 are worst. 

as we have 155 kg of C4F10, and it takes 73 kg to fill a sector we could in principle use any of the sectors for a 30 day run period, e.g. engineering run. 
of-course best would be to select a sector from 2,4,and 5. 

we advise against the removal of the good sectors (2,4, and 5), as it appears the leaks are caused during the process of installation and/or removal. 

for physics runs, if the RICH could be installed in sector 1 we could run run with sectors 2, 4, an 5 at a cost of: 
filling: 3*73kg =219kg -> cost = 219kg*170 $/kg = $37230. 
leakage(ops) : (0.36+0.43+0.30) 1.1kg/day -> cost 1.1kg/day*170 $/kg= 187$/day 




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