[Dsg-ltcc] LTCC S5 test, C4F10 usage update

[Amrit Yegneswaran]

george, 
good e-mail. 
question is even if we start procurement today will we have the gas in time, or will we have to say goodbye to the LTCC, temporarily at least! 
amrit 


From: "George Jacobs" <jacobsg at jlab.org> 
To: "Maurizio Ungaro" <ungaro at jlab.org>, "Stepan Stepanyan" <stepanya at jlab.org> 
Cc: "dsg-ltcc" <dsg-ltcc at jlab.org> 
Sent: Thursday, April 5, 2018 11:53:58 AM 
Subject: Re: [Dsg-ltcc] LTCC S5 test, C4F10 usage update 

Hi Mauri, 

If there are plans to run the LTCC this Fall using C4F10 gas, you will need to purchase an additional supply of this gas. 

I estimate that there will be <30kg of gas remaining in the supply tank at the end of this run. This amount of gas may not be sufficient to refill the S5 LTCC prior to running in the fall. 

Assuming an average leak rate of 0.5 kg/day for LTCC S5 and the 75 Kg required to fill the sector, with a 200 day run time, an additional 175 Kg of C4F10 gas should be purchased in order to operate the S5 LTCC. The start of the procurement process should not be excessively delayed due to the potentially long lead time. 

If the run plan includes a 2nd LTCC sector, additional gas will be required. Using the same assumptions as for S5, a minimum of 175kg plus a contingency of 75kg, a total of 225kg should be purchased for this 2nd sector. This would bring the total minimum amount of gas required to 400 kg, in order to operate 2 LTCC sectors for 100 days with some small contingency to account for a small increase in the detector leak rate. 

If a 2nd LTCC sector is in the run plan, the leakage rate of this sector should be minimized prior to filling with C4F10 gas. Using our S5 experience as a guide we can assume that the S6 position will fill and operate the similarly if the box is leak tight. 

There is significant additional complexity for the S2-S3 location. If we take into account that the "nose" area of the LTCC box is where the majority of the leakage is concentrated, we can assume that the S2 and S3 position may have a larger leak rate due to the increased pressure at the "nose" due to the S2-S3 orientation. 

There is also some uncertainty as to how efficiently the S2-S3 volume will fill with a shorter vent line due to the increase in height location of the S2-S3 volumes. Also, due to the orientation of the volume and location of the gas lines, there will be no direct measure of the pressure inside the detector volume or fill level associated with it as we have for S5 or S6. Pressure control may not be as straight forward as it is for S5. 

The S2-S3 bubbler will need to be relocated to the top of the fwd carriage to become the vent bubbler. The vent bubbler location for S2-S3 will require an elevated shelf to maximize the separation column height for the C4F10 gas during filling. 

Cheers, 
George 


On 3/20/2018 1:58 PM, Maurizio Ungaro wrote: 


Thanks George, these are all good news. 

Indeed we need to address your questions at the end. 

Mauri 



BQ_BEGIN

On Mar 20, 2018, at 12:56 PM, George Jacobs < jacobsg at jlab.org > wrote: 

Please find attache power point update of the C4F10 gas usage for the single sector test. 
-- 
George Jacobs
Jefferson Lab (TJNAF)
STE 12
12000 Jefferson Ave.
Newport News, VA 23606

(office) 757-269-7115

(cell)   757-876-0480

(email) jacobsg at jlab.org (website) https://userweb.jlab.org/~jacobsg 
<LTCC Single Sector Test Status-20Mar2018.pptx> _______________________________________________ 
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BQ_END

-- 
George Jacobs
Jefferson Lab (TJNAF)
STE 12
12000 Jefferson Ave.
Newport News, VA 23606

(office) 757-269-7115

(cell)   757-876-0480

(email) jacobsg at jlab.org (website) https://userweb.jlab.org/~jacobsg 

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