Monday, November 19, 2018, 08:57

Tantalum tube was coated with TaC and wrapped with Ta heat-shield (3 layers)

Desired temp = 1900 C (expected TGHT ~445A/7.5V), TBHT will be set fixed at 230A (max).

Pressure at IGP1 2.61-7 Torr. 

Tapped up TGHT and TBHT manually to 40 A

Waited ~1 hr for vacuum to stabilize.

IGP1 = 4.27e-7 Torr

Good vac at 3.00e-5 Torr

Bad vac at 5.00e-5 Torr.

Initiating auto ramp for TGHT @ 1 A/min to a max setpoint of 350 A

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

Monday, November 19, 2018, 18:14

Temperature was 1755 C at 350 A

IGP1 = 9.28e-7 Torr

Tapped manually to 393 A (6.83 V)

IGP1 = 1.4e-6 Torr

Temperature 1904 C

The tube will stay at max current point overnight.

Tuesday, November 20, 2018, 08:17

 IGP1 = 9.28e-7 Torr

TGHT = 395 A, 6.98 V

Temperature 1903 C

Auto-ramp set to TGHT 0 A @ -2 A/min.