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Reports until 15:19, Tuesday 28 July 2015
LHO VE
kyle.ryan@LIGO.ORG - posted 15:19, Tuesday 28 July 2015 - last comment - 22:47, Thursday 30 July 2015(19998)
Y-end NEG pump regeneration (EY_NEG_REGEN1_.....) 
Kyle, Gerardo

0900 hrs. local 

Added 1.5" O-ring valve in series with existing 1.5" metal valve at Y-end RGA pump port -> Valved-in pump cart to  RGA -> Valved-in Nitrogen calibration bottle into RGA -> Energized RGA filament -> Valved-out and removed pump cart from RGA -> Valved-in RGA to Y-end 

???? hrs. local 

Began faraday analog continuous scan of Y-end 

1140 hrs. local 

Isolated NEG pump from Y-end -> Began NEG pump regeneration (30 min. ramp up to 250C, 90 min. soak, stop heat and let cool to 150C) 

1410 hrs. local 

Valved-in NEG pump to Y-end 

1430 hrs. local 

Valved-out Nitrogen cal-gas from Y-end

1440 hrs. local 

Valved-in Nitrogen to Y-end -> Stop scanning
Comments related to this report
gerardo.moreno@LIGO.ORG - 16:52, Tuesday 28 July 2015 (20004)VE
Link

Plot of pressure at Y-End station before, during and afer NEG regeneration.

Non-image files attached to this comment
gerardo.moreno@LIGO.ORG - 16:54, Tuesday 28 July 2015 (20005)
Link

Response of PTs along the Y-arm to NEG pump regeneration.

Non-image files attached to this comment
kyle.ryan@LIGO.ORG - 14:38, Thursday 30 July 2015 (20058)
Link 

RGA and pressure data files for NEG regenerations to be centralized in LIGO-T1500408
Non-image files attached to this comment
michael.zucker@LIGO.ORG - 16:35, Thursday 30 July 2015 (20074)
Link 

Interesting!  As you predicted, the RGA is not super conclusive because of the background; but there seems a clear difference when you isolate the N2 calibration source. So your water and N2 may really be comparable to the hydrogen, say several e-9 torr each (comparing sum of peaks to the ion gage).  The NEG will poop out after ingesting ~ 2 torr-liters of N2, so at 1000 l/s it will choke and need regen after a few weeks.  Which is I guess what it did. 

It would be good to clean up the RGA so we can home in on the N2 and water pressure, and especially HC's  (I expect the HC peaks in these plots are from the RGA itself). To get practical use out of the NEG we should pace how much of these non-hydrogen gases it sees. We can expect to only get about 50 regens after N2 saturation, and small amounts of HC may kill it outright. 

We should be able to estimate the net speed of the NEG before and after from the pressure rise and decay time (we can calculate the beam tube response if we presume it's all H2).
rainer.weiss@LIGO.ORG - 20:55, Thursday 30 July 2015 (20077)
Link 

I have trouble seeing even the hydrogen pumping by the NEG by looking at the different scans.
Suggest you set the RGA up to look at AMU vs time and do the leak and pump modulation again. Plot amu 2,
amu12,amu14,amu28.
john.worden@LIGO.ORG - 22:47, Thursday 30 July 2015 (20081)
Link

Rai,

That is on our list of things to do - make a table of the  relevant amus' partial pressures.

Note that all the ascii data is at:

(see LIGO-T1500408-v1 for ascii data)

caution - 15 mbytes

Kyle can probably fish out the relevant data from the RGA computer so no need to plow through the whole file.

thanks for the comments, Mike and Rai.

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