Saturday, February 13, 2021, 08:10

Ta boat loaded with 80 discs enclosed in graphite foil in pockets of 20.  Sample A at both ends and sample B in the middle spaced out. Boat wrapped in Ta heat-shields (3 layers).

(A B B A)

Desired temperature= 1800C (expected TGHT approx 410 A).

good vacuum = 3.00 e-05 Torr

bad vacuum = 5.00 e-05 Torr

Evap2 left to pump down over previous night.

IGP1= 5.4e-7 Torr and stable

Initiating TGHT ramp up at 1 A/ min to 30 A

Saturday, February 13, 2021, 12:19

IGP1= 6.9e-06 Torr

Ramp to 50 A 1A/min

Saturday, February 13, 2021, 14:35

IGP1 = 6.4e-6 Torr

Pressure trending down. 

Saturday, February 13, 2021, 14:56

IGP1= 4.9 e-6 Torr

Initiate Ramp up @ 1 A/min to 400 A

Changed ramp up to 0.5 A/min at around 11:30 pm

Sunday, February 14, 2021, 11:43

The current will be ramped up to 420 A according to the trendline approximation (see attachement 1)

Sunday, February 14, 2021, 12:26

IGP1 = 8.9 e-06 Torr and trending down

TGHT = 420 A, 7.5 V

OMEGA = 1730 C

Will ramp up to 428 A manually 

Sunday, February 14, 2021, 12:30

Reached 428 A on TGHT.  

OMEGA = 1760 C

Will bump to 430 A and hold for 4 hours

OMEGA= 1765 C

Sunday, February 14, 2021, 18:00

OMEGA = 1789 C

IGP1= 7.5 e -7 Torr

TGHT = 430.5 A , 7.8 V

Start ramping down at -1A/min to zero A