From: Frank Geurts (geurts_at_rice.edu)
Date: Wed Mar 19 2003 - 09:22:57 EST
i copy&pasted the relevant log file entries below. As you can see the
freon flow dropped very suddenly. The isobutane flow follwed but not
fast enough causing the ratio to jump up (to 2.58 for isob/freon) and
only stabilize after 4min. We'll have to check whether or not this slow
response time of the slaved mode is a feature of this system.
After Leonid "unstuck" the freon valve everything came back to normal.
Considering the time of this interruption (<6min) and the low flow rate,
I don't think the gas mixture ever got critically altered. A good test
for our SC system, though!
I am not sure about the sf6/isob ratio: this one jumps up to 1. but is
physically disconnected which puzzles me somewhat. Might be calibration
non-linearity near 0 of the freon channel ... not sure.
-frank
2003-03-19 08:30:01 #-- GasFlow: 61.9ccm 3.44ccm 0.15ccm #-- Ratios:
1.00 0.04
2003-03-19 08:31:01 #-- GasFlow: 61.9ccm 3.44ccm 0.15ccm #-- Ratios:
1.00 0.04
2003-03-19 08:32:00 #-- GasFlow: 61.9ccm 3.44ccm 0.15ccm #-- Ratios:
1.00 0.04
2003-03-19 08:33:00 #-- GasFlow: 7.1ccm 0.64ccm 0.15ccm #-- Ratios:
1.61 0.39
2003-03-19 08:34:01 #-- GasFlow: 2.7ccm 0.39ccm 0.15ccm #-- Ratios:
2.58 1.01
2003-03-19 08:35:01 #-- GasFlow: 2.7ccm 0.27ccm 0.15ccm #-- Ratios:
1.78 1.01
2003-03-19 08:36:00 #-- GasFlow: 2.7ccm 0.15ccm 0.15ccm #-- Ratios:
0.98 1.01
2003-03-19 08:37:01 #-- GasFlow: 2.7ccm 0.15ccm 0.15ccm #-- Ratios:
0.98 1.01
2003-03-19 08:38:01 #-- GasFlow: 61.9ccm 3.19ccm 0.15ccm #-- Ratios:
0.93 0.04
2003-03-19 08:39:00 #-- GasFlow: 61.9ccm 3.44ccm 0.15ccm #-- Ratios:
1.00 0.04
Frank Geurts wrote:
>
> Just talked to Jamie: we decided to keep the HV off for now. Apparently
> the ratio isob/freon went up and triggered the SC red alarm. Will look
> into history shortly.
>
> more later
>
> -frank
>
>
>
>
>
> James Dunlop wrote:
>
>> Followup:
>> Leonid went out there and adjusted the Freon regulator.
>> It had gotten stuck and the flow was dropping to zero.
>> It is now at 1.5 atm, checking for stabilization with time.
>> Turned off the TOFr HV as indicated on the procedure sheet.
>> Please call the control room.
>>
>> --Jamie
>>
>>
>>> Guys,
>>> Red alarm on tof gas.
>>> --Jamie
>>>
>>>
>>> --
>>> James C Dunlop jcdunlop_at_star.physics.yale.edu
>>> Room 11, Bldg. 902B Ph: (631)344-7781
>>> Brookhaven National Laboratory Fax: (631)344-7566
>>> Upton, NY 11973 Mobile: (631)834-7782
>
>
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