AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40
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Message ID: 27     Entry time: Mon Oct 19 13:57:52 2020
Author: JM 
Subject: Neg Activation 

Neg and Neg-Ion pumps have been connected up to the control modules. Controller on the right is connected to the D-2000s. Middle controller is connected to the wall section negs (1x2negs in series and 1x3negs in series) and the moving detector negs (2x2 negs in series). Left controller is connected to the intermediate section negs (2x2 negs in series). Must connect IN/OUT interface on the back of the controller or the alarm for an open circuit is triggered. When no thermocouple is connected Tmax must be set to zero otherwise the thermocouple alarm is triggered.

13:00 Pressure on chamber= 6e-9mbar

13:55 I have begun ramping up the middle controller. Ramp time is 45 minutes, slightly longer than the recommended 15-30 mins in the manual to see how well vaccum reacts.  Controller will hold maximum power for one hour for activation. Controller has 4 outputs, one for each neg cable. Outputs 1-3 are the 2 negs in series, output 4 is the 3 negs in series. Parameters for outputs 1-3 are; Vmax=100V, Imax=5A, Pmax= 400W. Parameters for output 4 are; Vmax=110V, Imax=5A, Pmax=600W. 

14:05 Pressure chamber = 1.92e-6mbar. Power per output is 60, 78, 79, 87 W. 

14:15 Pressure chamber = 2.4e-6mbar. Power per output is 114, 148, 150, 168 W.

14:25 Pressure chamber = 1.44e-6mbar. Power per output is 201, 261, 264, 300W.

14:35 Pressure chamber =  1.12e-6mbar. Power per output is 305, 398, 397, 466W

14:56 Pressure chamber = 1.52e-6mbar. Negs are on max power and are holding for an hour.

15:45 Intial activation completed. Negs have been set to half power to maintain temperature at ~200-250C. Parameters set for outputs 1-3; Vmax= 50V, Imax=5A, Pmax=200W. Parameters set for output 4; Vmax=70V, Imax=5A, Pmax=300W. Pressure on the chamber is now 4.4e-8mbar. The pressure tomorrow morning should tell us if the activation has been successful, afterwhich I will activate the next lot of negs. Average vessel temperature is now 146C. I believe our 'internal thermocouple' isn't reading the internal temp after all and is just the temperature of the bottom feedthrough flange, as its temp maxed out at 175C and followed a similar gradient to the other vessel thermocouples.  See attached temperature plot.

20 October

08:30 Pressure on the vessel = 2e-8mbar. Pressure hasn't dropped significantly probably due to negs maintaining a temperature of 200-250C causing significant outgassing. Chamber temperature has maintained at 145C so outgassing from chamber will also have increased also. 

08:45 2nd set of negs activated. Intermediate chamber negs activated (2x 2 negs in series) which are connected to outputs 3+4 on the left controller. Parameters for outputs; Vmax=100V, Imax=5A, Pmax=400W, Rise time= 30mins, Hold = 60mins. 

First set of negs remains at half power. 

Pressure on the vessel =8e-8mbar

08:55 Pressure on vessel = 1e-6mbar. Outputs; V=74, 74W I=2.2, 2.2A P=79, 79W

09:05 Pressure on vessel = 2.2e-7mbar. Outputs; V=58,58V I=3,3A P=175,175W

09:10 Pressure on vessel = 3e-7mbar. Outputs are; V=79,79V I=3.7A P=300,300W.

09:20 Pressure on vessel = 1.2e-6mbar. Outputs are; V=100V, I=4A, P=400W. Negs are now on hold for the hour activation. Chamber temperatures are stable at ~145C still

10:45 Negs are being held at half power to maintain temperature. All that is left is the D2000's on Thursday. Pressure in the vessel is staying constant at ~8e-8mbar. Chamber temperatures ae stable at ~145C. 

 

 

Attachment 1: Photos.zip  5.238 MB  Uploaded Mon Oct 19 15:13:19 2020
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