[Halld-tracking-hw] Meeting today

[Curtis A. Meyer]

Thanks Tim -

   with regard to the holes in (4), we felt that they needed to be 
fairly close to the
connector, perhaps 1mm away or so.

   curtis
On 12/21/10 11:33 AM, Tim Whitlatch wrote:
> Hi Curtis,
>
> I had discussions with Slava this morning and here are the results;
>
> 1) we are in agreement with the .05 ID conductive rubber tube and 
> shrink tube over it. This will open the hole of the swiss cheese plate 
> to .156 which we believe is ok. The existing prototype set up that 
> Slava sent should be used to open up some of the holes under the 
> aluminum fittings and retested to make sure the seal still works. We 
> believe it will.
>
> 2) The rubber orings are 75 durometer flouropolymer (Viton) with 2.6mm 
> ID and a 1.9mm cross-section (see data Slava sent with the prototype 
> set up a few weeks ago). Slava had tried several and these worked the 
> best. *The ID is snug around the wires purposely and has proved to 
> seal well*. If you wish to try other sizes, tests must be completed to 
> show they seal well
>
> 3) We will change to a hex head on the fittings if you believe this 
> will work better. I assume you would make a custom open end wrench?
>
> 4)  The holes in the solder tab is a good idea that has been kicked 
> around for a year or so. As long as Fernando has no objections, we 
> will do it. Do you want the holes as far away from the connector as 
> possible?
>
> Cheers,
>
>        Tim
>
> Curtis A. Meyer wrote:
>> On 12/20/10 2:49 PM, whitey at jlab.org wrote:
>>> Hi Curtis,
>>>
>>> Sorry about not showing for the meeting today. I did not put it on the
>>> calender and had another meeting. I forgot all about it.
>>> Why do you wish to use a bigger oring?
>>
>> The one that is there feels a little undersized in the hole. We want 
>> to investigate
>> different sizes.
>>
>>   curtis
>>> I will discuss your comments below with Beni and Slava and get back 
>>> with you.
>>>
>>> Tim
>>>
>>>> Hi Tim and Slava -
>>>>
>>>>      we connected in at 1:00pm, but when no one came on by 1:15, we
>>>> assumed that the
>>>> lab may be closed again today due to weather. We had a few small 
>>>> things
>>>> to reports that
>>>> I think I can safely summarize in an email.
>>>>
>>>> *) With regard to the wires connecting the crimp pins to to the HV
>>>> connector. The
>>>>        system that Slava built will certainly work. In fact any of the
>>>> conducting rubber
>>>>        will work, but we favored the one with the 0.05 hole and the
>>>> thicker wall.
>>>>
>>>> *)  There is a certain risk involved in not holding the conducting
>>>> rubber to the
>>>>         coax with heat shrink cable. In some cases, we have pulled the
>>>> wire out of the
>>>>         conducting rubber during installation. In the limited 
>>>> number that
>>>> we did, we were
>>>>         able to slip the wire back into the conducting rubber and
>>>> complete the connection.
>>>>         However, if we were unable to do this, we would likely be 
>>>> unable
>>>> to connect the
>>>>         straw tube. This failure scenario would not occur if the heat
>>>> shrink tube holds the
>>>>         conducting rubber to the wire. However, it requires increasing
>>>> the size of the hole
>>>>         in the Swiss-cheese plate from 0.138 to 0.156.
>>>>
>>>> *) We would like to investigate a somewhat larger o-ring for the seal,
>>>> but are having trouble
>>>>        determining the size of the one that is currently in use. 
>>>> Can some
>>>> one send us the size
>>>>        of the part?
>>>>
>>>> *)  In looking at the small aluminum screw that compresses the o-ring
>>>> and seals around the
>>>>        wire. While the slot in the top works well for initial 
>>>> tightening,
>>>> after we have soldered
>>>>        the wire to the connector to the board at the top, it is 
>>>> currently
>>>> difficult to tighten the screws
>>>>        if they need to be. This tightening is clearly the first 
>>>> step in
>>>> mitigating gas leaks.
>>>>        Our proposal is to remove the slot at the top and put a 1/4" 
>>>> hex
>>>> head on the part. This allows
>>>>        us to use standard tools to tighten it at all states of the
>>>> installation.
>>>>
>>>> *)  For soldering the wire to the connector board, we feel that a 
>>>> small
>>>> plated-through hole in
>>>>        the pcb board where the HV line solders on would be helpful. 
>>>> This
>>>> would allow us to
>>>>        form a small dog-leg at the end of the wire and use the hole to
>>>> provide some strain relief
>>>>        during soldering. This would require one hole per solder point.
>>>>
>>>> Curtis, Gary&  Naomi
>>>>
>>>> -- 
>>>> Prof. Curtis A. Meyer        Department of Physics
>>>> Phone:    (412) 268-2745        Carnegie Mellon University
>>>> Fax:    (412) 681-0648        Pittsburgh PA 15213-3890
>>>> cmeyer at ernest.phys.cmu.edu http://www.curtismeyer.com/
>>>>
>>>>
>>>> _______________________________________________
>>>> Halld-tracking-hw mailing list
>>>> Halld-tracking-hw at jlab.org
>>>> https://mailman.jlab.org/mailman/listinfo/halld-tracking-hw
>>>>
>>>
>>
>>


-- 
Prof. Curtis A. Meyer		Department of Physics
Phone:	(412) 268-2745		Carnegie Mellon University
Fax:	(412) 681-0648		Pittsburgh PA 15213-3890
cmeyer at ernest.phys.cmu.edu	http://www.curtismeyer.com/


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