<html><body><div style="font-family: tahoma,new york,times,serif; font-size: 14pt; color: #009900"><div>hi dave,<br></div><div>thanks for the info.<br data-mce-bogus="1"></div><div>this is good news.<br data-mce-bogus="1"></div><div>do you remember what the pressure dropped to after 3 days (from 2 in H2O).<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>hi brian, george, and marc.<br data-mce-bogus="1"></div><div>given this information by dave, and what marc showed me, i'm not convinced that the epics archiver is working properly.<br data-mce-bogus="1"></div><div>we should investigate this issue (cRIO side as well as the epics side) and come up with a leakage rate for each sector.<br data-mce-bogus="1"></div><div>amrit<br data-mce-bogus="1"></div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>From: </b>"David Anderson" <dla@jlab.org><br><b>To: </b>"Maurizio Ungaro" <ungaro@jlab.org><br><b>Cc: </b>"Amrit Yegneswaran" <yeg@jlab.org>, "dsg-ltcc" <dsg-ltcc@jlab.org>, "Patrizia Rossi" <rossi@jlab.org>, "Douglas Tilles" <tilles@jlab.org><br><b>Sent: </b>Tuesday, April 18, 2017 7:07:08 AM<br><b>Subject: </b>Re: [Dsg-ltcc] leak rate<br></div><div><br></div><div data-marker="__QUOTED_TEXT__">The procedure was as Mauri stated, that was the procedure that was decided upon.<br><br>However, to be thorough leak checking, each box was injected with R134a and leak checked over the course of a week.<br>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.<br>This procedure was repeated in the hall before installation and if needed once again when installed.<br>After isolating the chambers from the gas system (After installing) only 2 leaks were found in the boxes and repairs were made as needed.<br>No more leaks were evident.....<br><br>Thanks,<br>David <br><br>----- Original Message -----<br>From: "Maurizio Ungaro" <ungaro@jlab.org><br>To: "Amrit Yegneswaran" <yeg@jlab.org><br>Cc: "dsg-ltcc" <dsg-ltcc@jlab.org>, "Patrizia Rossi" <rossi@jlab.org>, "David Anderson" <dla@jlab.org><br>Sent: Friday, April 14, 2017 2:33:25 PM<br>Subject: Re: [Dsg-ltcc] leak rate<br><br>Hi Amrit,<br><br>The boxes were leak tested in two ways:<br><br>1. sniffing freon from around the box - fixing all detectable leaks<br>2. filling the boxes with nitrogen and checking that, taking atmospheric pressure into account, the box hold the pressure<br><br>We didn't quantify the leaks.<br><br>David, who is cc-end and did this work, can provide further details. He did it three times:<br><br>1. as preparation, in TED.<br>2. once the boxes were in the hall<br>3. once the boxes were mounted on the forward carriage.<br><br>He found considerable leaks in both 1 and 3 cases.<br><br>Regarding your question on the LTCC window. <br>That was 3mils or mylar = 0.0762mm, which has radiation length of 285 mm.<br>So radiation length X/X0 = 0.0267%.<br><br>It was sandwiched betwen 1.5 mils of tedlar, I think it has similar rad length.<br><br>Regards,<br>Mauri<br><br><br><br><br><br><br><br>> On Apr 14, 2017, at 11:53 AM, Amrit Yegneswaran <yeg@jlab.org> wrote:<br>> <br>> hello,<br>> <br>> i see from my records that the ltcc leak test was performed jul/aug of 2015.<br>> i do not have records of what the leak rate was at that time.<br>> 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.<br>> <br>> i'm sure that someone has a record of the leaks, for each sector, that were measured at that time.<br>> i would like to compare the present leak rate with that measured at that time.<br>> <br>> thank you for your help.<br>> sincerely<br>> amrit<br>> _______________________________________________<br>> Dsg-ltcc mailing list<br>> Dsg-ltcc@jlab.org<br>> https://mailman.jlab.org/mailman/listinfo/dsg-ltcc<br></div></div></body></html>