[Dsg-ltcc] leak rate

[David Anderson]

No Marc I'm playing catch-up due to being out several days.
I'm extremely busy with solenoid work but send me your number and a good time to call you and I'll see what I can do.

Thanks,
David

----- Original Message -----
From: "Marc McMullen" <mcmullen at jlab.org>
To: "David Anderson" <dla at jlab.org>, "Amrit Yegneswaran" <yeg at jlab.org>
Cc: "Patrizia Rossi" <rossi at jlab.org>, "Douglas Tilles" <tilles at jlab.org>, "dsg-ltcc" <dsg-ltcc at jlab.org>
Sent: Tuesday, April 18, 2017 12:06:13 PM
Subject: Re: [Dsg-ltcc] leak rate

Hi Dave,

I need to get with you to go over the ltcc leak testing, are you 
attending the engineering meeting?

Marc


On 4/18/2017 10:24 AM, David Anderson wrote:
> I do not recall exact numbers however, any drop that couldn't be accounted for due to barometric pressure changes
> (Thanks to Steve Cristo' Math) were considered leaks and I started over sniffing/fixing leaks until I was satisfied all pressure changes could be accounted for.
> Sorry I cannot be of more help than that....
>
> David
>
> ----- Original Message -----
> From: "Amrit Yegneswaran" <yeg at jlab.org>
> To: "David Anderson" <dla at jlab.org>, "dsg-ltcc" <dsg-ltcc at jlab.org>, "Douglas Tilles" <tilles at jlab.org>, "Maurizio Ungaro" <ungaro at jlab.org>
> Cc: "Patrizia Rossi" <rossi at jlab.org>
> Sent: Tuesday, April 18, 2017 8:50:34 AM
> Subject: Re: [Dsg-ltcc] leak rate
>
> hi dave,
> thanks for the info.
> this is good news.
> do you remember what the pressure dropped to after 3 days (from 2 in H2O).
>
> hi brian, george, and marc.
> given this information by dave, and what marc showed me, i'm not convinced that the epics archiver is working properly.
> we should investigate this issue (cRIO side as well as the epics side) and come up with a leakage rate for each sector.
> amrit
>
>
> From: "David Anderson" <dla at jlab.org>
> To: "Maurizio Ungaro" <ungaro at jlab.org>
> Cc: "Amrit Yegneswaran" <yeg at jlab.org>, "dsg-ltcc" <dsg-ltcc at jlab.org>, "Patrizia Rossi" <rossi at jlab.org>, "Douglas Tilles" <tilles at jlab.org>
> Sent: Tuesday, April 18, 2017 7:07:08 AM
> Subject: Re: [Dsg-ltcc] leak rate
>
> The procedure was as Mauri stated, that was the procedure that was decided upon.
>
> However, to be thorough leak checking, each box was injected with R134a and leak checked over the course of a week.
> Once no more leaks were found the boxes was left pressurized @ 2" WC and monitored for a minimum of 3 days, barometric pressure was taken into account for pressure changes.
> This procedure was repeated in the hall before installation and if needed once again when installed.
> After isolating the chambers from the gas system (After installing) only 2 leaks were found in the boxes and repairs were made as needed.
> No more leaks were evident.....
>
> Thanks,
> David
>
> ----- Original Message -----
> 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: Friday, April 14, 2017 2:33:25 PM
> Subject: Re: [Dsg-ltcc] leak rate
>
> Hi Amrit,
>
> The boxes were leak tested in two ways:
>
> 1. sniffing freon from around the box - fixing all detectable leaks
> 2. filling the boxes with nitrogen and checking that, taking atmospheric pressure into account, the box hold the pressure
>
> We didn't quantify the leaks.
>
> David, who is cc-end and did this work, can provide further details. He did it three times:
>
> 1. as preparation, in TED.
> 2. once the boxes were in the hall
> 3. once the boxes were mounted on the forward carriage.
>
> He found considerable leaks in both 1 and 3 cases.
>
> Regarding your question on the LTCC window.
> That was 3mils or mylar = 0.0762mm, which has radiation length of 285 mm.
> So radiation length X/X0 = 0.0267%.
>
> It was sandwiched betwen 1.5 mils of tedlar, I think it has similar rad length.
>
> Regards,
> Mauri
>
>
>
>
>
>
>
>> On Apr 14, 2017, at 11:53 AM, Amrit Yegneswaran <yeg at jlab.org> wrote:
>>
>> hello,
>>
>> i see from my records that the ltcc leak test was performed jul/aug of 2015.
>> i do not have records of what the leak rate was at that time.
>> all i have e-mails saying that the leak test was successful and that the ltcc were taken to the hall before the final seal was done.
>>
>> i'm sure that someone has a record of the leaks, for each sector, that were measured at that time.
>> i would like to compare the present leak rate with that measured at that time.
>>
>> thank you for your help.
>> sincerely
>> amrit
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-- 
Marc McMullen
Detector Support Group
757-269-7738