Monday, November 01, 2021, 07:37

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

Note* on the leading end of the assembly I placed tantalum foil heatshield similar to what I previously observed there.  I believe it may impact temperature at the entrance of the container tube. 

Desired temperature = 1800 C (expected TGHT ~430 A), TBHT will be set fixed at 230A (max).

Evap 2 was pumped down over the weekend

Good vacuum = 3.00 e-03Torr

Bad vacuum = 5.00 e-02 Torr

Monday, November 01, 2021, 07:39

Starting autoramp at 1 A/min to 40 A on both TGHT and TBHT 

IGP1= 3.5 e-07 Torr

Monday, November 01, 2021, 09:08

 IGP1= 1.6 e-06 Torr

TGHT = 40A, 0.99 V

TBHT = 39A, 1,2 V

Start autoramp @ 1A/min for both TGHT and TBHT to 400A and 230A respectively.

Monday, November 01, 2021, 14:33

OMEGA= 1545 C

TGHT =  354 A, 6.0 V

TBHT = 233 A, 4.8 V

IGP1= 1.7 e-05 Torr

increase ramp rate to 2A/min

Monday, November 01, 2021, 14:44 

OMEGA= 1585C

TGHT =  367A, 6.3 V

TBHT = 233 A, 4.8 V

IGP1= 1.7 e-05 Torr

Monday, November 01, 2021, 14:49

OMEGA= 1604 C

TGHT =  377A, 6.5V

TBHT = 233 A, 4.8 V

IGP1= 2.1 e-05 Torr 

Monday, November 01, 2021, 14:53 

OMEGA= 1624C

TGHT =  384 A, 6.6V

TBHT = 233 A, 4.8 V

Monday, November 01, 2021, 15:00

OMEGA= 1660C

TGHT =  400 A, 6.8V

TBHT = 233 A, 4.8 V

IGP1= 2.4 e-05 Torr 

Monday, November 01, 2021, 15:17

Initiate autoramp to 430A on TGHT @2A/min

Monday, November 01, 2021, 16:34 

 OMEGA = 1750 C

TGHT = 430 A, 7.3 V

Better heat insulation than before.  Next time need to place a Ta heatshield at the other end on the copper assembly.  Will raise T to 435 A and keep until 1930  hours.

Monday, November 01, 2021, 20:23

IGP1= 1.6 e-05 Torr

Omega = 1760 C

TGHT= 436 A, 7.4 V

TBHT = 232 A, 4.8 V

* Note: kept a approx 1 hour extra hoping that pressure would drop further

Started ramp down at -2A/min for TGHT and -1A/min for TBHT

Coating looks reasonably good.