Friday, July 15, 2016, 11:49

Container previously coated with TaC using 'flushing technique', cleaned ionizer tube with acetone, so no coating inside ionizer tube

Wrapped with 3 x Ta heat shields, incl center block - new method of each layer being one long single Ta foil covering entire container incl center block

Currently pumping down in evap2

 Friday, July 15, 2016, 14:35

Turbo pump broken 

Currently being replaced...

 Friday, July 15, 2016, 17:04

Turns out its not the turbo pump...TP controls and pump replaced, problem still happening.

Took out heat shield and used a closed loop to rule out leak in chamber, emptied all water lines - turbo pump now on.

Took v.long time to pump down. TP will remain on over wknd.

BP turns on, PV1 turns on, RV turns on - then takes very long time for vacuum to drop ~45min? before BV and TP can be turned on.

Possibly problem with threads on heat shield and not creating proper seal?

Will continue monday with evap2 mystery problem solving...

Monday, July 18, 2016, 16:14

Replaced heat shield and copper seals.

Container re-loaded.

Turbo pump on and good vacuum achieved! YAY!

Finished pumping down, opened HS water valves - no leaks detected.

Tapped up manually to 35A

Vacuum stable, IGP1 = 3e-6 Torr

Initiating auto ramp for TGHT @ 0.2A/min to a max setpoint of 400A

Initiating auto ramp for TBHT @ 0.1A/min to a max setpoint of 230A

Once max setpoints achieved, will tap up manually to final desired temperature of 1900C

 Tuesday, July 19, 2016, 09:21

TGHT = 242A, 2.76V

TBHT = 162A

IGP1 = 5.05e-6 Torr

Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.

 Tuesday, July 19, 2016, 13:04

TGHT = 400A, 4.4V

TBHT = 230A, 2.6V

OMEGA = 1120C

Reached max setpoints ~1hr ago.

Tapping up manually to 1900C...

Tuesday, July 19, 2016, 16:32

MORE problems with evap2 

TGHT reads 460A, 5.1V, 1170C - a lot of power is being lost somewhere...

Comparison from elog i.d. 291 [the last IGLIS container sintering of TaC coating] the TGHT read 460A, 7.5V, 1900C

Another problem: the read out on the power supply and read out on epics of the TBHT reads 215A; however, the 'current set' says 177A - two very different numbers?!

Ramping down evap2 at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively to further inspect chamber and hopefully solve this...

 Wednesday, July 20, 2016, 13:34

Chamber was vented in air and opened up for inspecting.

Fixed!

One of the steel plates used to stop reflection onto the door of the chamber was inserted improperly, resting on top of the 2 negative copper lines to the target leg, this was causing a short.

There was also a short from the right target leg touching the copper heat shield, the heat shield has been shaved down and corrected. It is no longer touching.

There were also 2 brackets that had fallen behind evap2 inside the cage, one was touching the positive lines - it wasn't quite touching the ground, but may have grounded it, causing another possible short.

The chamber was pumped back down and the HS water valves re-opened. No leaks detected.

Evap2 was tapped up manually to 35A.

Vacuum stable = 1.0e-6 Torr.

Initiating auto-ramp at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Final setpoints are TGHT = 400A and TBHT = 230A

 Wednesday, July 20, 2016, 16:25

TGHT = 315A, 4.5V

TBHT = 174A, 2.1V

IGP1 = 2e-6 Torr

OMEGA = 1518C

Lowering auto-ramp to 0.2A/min and 0.1A/min for the TGHT and TBHT overnight while unable to keep watch on the vacuum.

 Thursday, July 21, 2016, 09:09

Evap 2 reached max setpoints ~7.5hrs ago.

TGHT = 400A, 6.3V

TBHT = 230A, 2.9V

IGP1 = 5.1e-7 Torr.

OMEGA = 1882C

Tapping up manually to 1900C...

 Friday, July 22, 2016, 16:18

Container has remained at ~1900C for ~31hrs

TGHT reached 405A/1900C - then after ~23hrs dropped in temperature down to 1895C so was tapped up further to 410A/1910C for another ~8hrs.

TGHT = 410A, 6.57V

IGP1 = 3.1e-7 Torr

TBHT = 230A, 2.9V

Initiating auto-cool at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Will remove from evap2 after the weekend.

 Tuesday, July 26, 2016, 16:49

vented in air.

container looks good, fully sintered.

will update with photos tomorrow...