Wednesday, June 06, 2012, 16:55

The UO2/C green was prepared on June 04, 2012. 

UO2 powder used = 50.26g

C-grv used = 10.14g. 

Dry UO2/C green mass = 61.71g.

The green was rolled and wrapped in a piece of graphite sheet.

The target boat was wrapped with 3 Ta-heat shield and installed in the Evap#1. 

The chamber is currently being pumped down.

 Tuesday, June 12, 2012, 11:42

Currently, IEVAPIG1= 1.83e-6 Torr, IEVAP:CG2= 48 mTorr.

Backing line pressure is slightly high.  Will get Edi to look into this.

 Tuesday, June 12, 2012, 14:38

The backing pump oil was changed (ISAC WP#2012-06-12-1).  IEVAP:CG2 is currently reading 27mTorr and IEVAPIG1 at 1.66e-6 Torr.

 Tuesday, June 12, 2012, 16:06

TGHT was tabbed up to 50A and stayed for 1.5 hrs.  Not much change in the pressure, currently at 1.8e-6 Torr, BP @ 25mTorr.  

Keep stepping up TGHT current...

 Tuesday, June 12, 2012, 16:37

TGHT at 65A.  Pressure is starting to rise.

 Tuesday, June 12, 2012, 16:46

Pressure at  6.8e-6 Torr and going up slowly. 

Initiated TGHT auto-ramping:

Max current = 525A,  rate @ 0.1A/min (see attachment #1)

 Wednesday, June 13, 2012, 13:22

TGHT has almost reached to 80A.  Pressure is limiting at 4.5e-6 Torr. (see attachment#2)

Thursday, June 14, 2012, 17:11

TGHT has reached to 95.40A, local @ 92A & 0.48V.  Pressure is still limiting at 4e-6 Torr.  (see attachment #3)

The TGHT current can not go up above 232A because it's voltage limiting at 1.953V (see attachment#4).  The carbon thermal-reduction process stops and the vacuum is going down to low 10e-6 Torr. 

The voltage can not be increased on EPICS; it has to be adjusted locally.  

Auto-ramping aborted.  

The TGHT current setpoint was lowered down to 228A.

Sunday, June 17, 2012, 12:03  

Asked ISAC Ops (Ed Parton) to help me increase the voltage locally.  The voltage nob was turned 1/4 clockwise, and the current was tapped up from 228 to 231A, and it was responding.  The voltage nob was further turned to 3/4 clockwise. 

Initiated auto-ramping. 

Currently, TGHT setpoint at 234.90A, local 231A/1.95V.  

Vacuum is responding and it's slowly going up (currently at 2.8e-6 Torr) - The carbon thermal reduction process continues... 

Monday, June 18, 2012, 00:20  

TGHT is going up slowly, currently at  285A.  The pressure is limiting as the carbonization process is under way (see attachment 5).

 Monday, June 25, 2012, 16:00

The EPICS control was down on Sunday night. So the auto-ramping was aborted.  

Control group fixed the problem, and the network is back online.

The auto-ramping has been re-initiated. 

TGHT is currently at 314.70A, local at 311/3.04V.  IG at 4.21e-5 Torr, BP at 15mTorr.

 Saturday, June 30, 2012, 23:08

The carbonization process has finished.

TGHT has reached to 520A and maintained at that current for about 5hrs. (see attachment #6).

Initiated auto-cool down.

Tuesday, July 03, 2012, 13:05 

TGHT is now at 0A.  The carbonization process is done.  

It took over 20 days for this process (see attachment #7), due to some control issues & power supply problem. Also the vacuum limit was set to 4.0e-5 Torrr; that might increase the pumping time.  

Next time, try setting the pressure limit to 5.0e-5 Torr.  

The chamber will be vented with Ar, and the UC2 flakes will be transferred to the Ar-glove box.