[Dsg-ltcc] stop gas flow?

[Stepan Stepanyan]

Hi George,

OK, thank you.

Stepan

On 3/9/18 3:19 PM, George Jacobs wrote:
> Hi Stepan,
>
> The only way to keep the window inflated is to flow gas. We could 
> switch to N2 to maintain sufficient pressure to maintain window shape. 
> But, that may result in an increase is gas C4F10 loss during during N2 
> flow operation and again during the later "topping off" process. Since 
> we have not done this before, there is no reference to point to. It 
> does add an additional layer of complexity to the activity.
>
> George
>
> On 3/9/2018 2:54 PM, Stepan Stepanyan wrote:
>> George,
>>
>> Thanks for the details. Yes, it seems not much can be saved, but 
>> anything we can save is a plus.
>> Of course we cannot allow window come down on mirrors. In that 
>> respect, is there a option to reduce the loss?
>>
>> Regards, Stepan
>>
>>
>>> On Mar 9, 2018, at 2:23 PM, George Jacobs <jacobsg at jlab.org 
>>> <mailto:jacobsg at jlab.org>> wrote:
>>>
>>> Ho Mauri,
>>>
>>> An additional 2 weeks of running  will result in a decrease of ~7 kg 
>>> gas from the supply tank, assuming 0.5kg per day usage.
>>>
>>> Currently, ~56 kg C4F10 remains in the supply tank. This is a 112 
>>> day supply assuming 0.5 kg per day usage.
>>>
>>> So, if we do nothing, in 2 weeks there will be ~49 kg C4F10 
>>> remaining in the tank. No change in detector pressure. Same as now.
>>>
>>>  If we do turn it off, there will be ~56 kg remaining in the tank 
>>> when we restart flow. Detector pressure and fill will be reduced due 
>>> to gas leakage and the loss from ambient pressure changes during the 
>>> outage. The detector will need to be "topped off" once we turn the 
>>> gas back on. This will require X amount of gas. Since X is unknown, 
>>> but most likely X < 7 kg and most definitely X > 0, the amount of 
>>> gas saved will definitely be < 7kg. So, we do not know how much gas  
>>> this will actually save. Once gas flow is restarted, it may require 
>>> 1-2 days to refill. My only real concern is if the window deflates 
>>> to the point were it contacts and applies pressure to the mirrors. 
>>> That would be bad
>>>
>>> I do not see much of a savings or advantage in turning it off. But, 
>>> that's not my call, it's yours. We can turn gas flow off if you want 
>>> it off. Let me know what you decide. We will need to turn the gas 
>>> off at the supply tank.
>>>
>>> Cheers,
>>> George
>>>
>>> On 3/9/2018 11:03 AM, Maurizio Ungaro wrote:
>>>> Hi George,
>>>>
>>>> We'll have a downtime in accelerator that may run for a couple of weeks.
>>>>
>>>> In the spirit of saving as much gas as possible, what are our options?
>>>>
>>>> Thanks,
>>>> Mauri
>>>>
>>>
>>> -- 
>>> 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
>>
>
> -- 
> 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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