[Eg6_analysis] meeting tomorrow

[Hovane Egiyan]

Nathan,

That plot shows the absolute pressure, most of the variations probably 
follow the
atmospheric pressure,  unless something changed in the gas enclosure. 
What may affect
the shape of the cathode is the differential pressure between the 
chamber and inner volume with He.
We did not archive gauge pressure since it was fixed by the depth of the 
bubbler stick (and also
we did not have a digital readout of that quantity). We had to
lower the depth of the stick so that we restore bubbles to visually 
verify the gas flow, otherwise the
gas was leaking through some new hole and we did not know where the gas 
was going.
But most of the gauge pressure drop could have occurred before that when 
a new hole in the chamber
appeared.

Reducing the depth of the bubbler and the gauge pressure might also 
allowed more air or He into
the chamber through diffusion.

Hovanes.


On 11/7/2013 1:33 PM, Nathan Baltzell wrote:
> Following up on today's RTPC discussion, here's a plot of drift gas
> pressure over time.  The available data starts on Nov 3, 2009, which
> is after the early 1 GeV runs.  I also checked any other epics variables
> that seemed possibly relevant (Ne/DME gas flows and valve amps, cat/gem
> voltages), but they are all stable.
>
> http://www.jlab.org/~baltzell/EG6/RTPC/driftpressure.png
>
> -Nathan
>
>
> On Wed, 06 Nov 2013 10:10:52 -0600, Stepan Stepanyan <stepanya at jlab.org>
> wrote:
>
>> Dear all,
>>
>> We will have eg6 meeting tomorrow, Thursday, November 7, at 10am in F226.
>>
>> Please add items to the agenda at -
>> https://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Meeting_on_November_7_at_10:00am
>>
>> Calling instructions can be found at -
>> http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Agendas_and_Minutes_of_the_meetings#Agendas
>>
>> Regards, Stepan
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