Wednesday, May 24, 2023, 15:22

A Ta container tube was wrapped with 4 Ta heatshields.  Note final container is 45220-11

219 graphite discs were loaded.

a TaC coated Ta spring at the front end.

The system was left to establish vacuum over previous night.

Good vacuum set to5e-04Torr

Bad vacuum was set to 5e-2 Torr

Total weight of system including spring= 250.1 g

OMEGA slope = 0.99

The target will be heated to 2000 C, held there for 10 hours. 

Initial ramp at 1A/min to 200A

Then ramp at 0.5A/min while taking temperature readings periodically unti l250A.

At 250 A will let pressure stabilize and then ramp at 1A/min to 2000C or 450A.  

Will hold at target Temperature or Current for 10 hours before starting ramp-down.

 Wednesday, May 24, 2023, 15:50

Currently heating at 0.5A/min to250A.  Taking temperature/current measurements

IGP1= 1.06e-06 Torr

Wednesday, May 24, 2023, 18:28

heating at 1A/min to 275A to collect more temperature data

Wednesday, May 24, 2023, 19:22

Slight offset between set and RD current observed. 

Ramping at 1A/min to 440A according to the regression below

Should be around 2000 C.

Wednesday, May 24, 2023, 20:22

Currently at 339 A, 4.8V

OMEGA = 1614 C, IGP1= 2.04e-06 Torr

Will ramp up at 2A/min to 450A as new data point suggests

Wednesday, May 24, 2023, 21:05

heating curve has new slope suggesting 500A as minimum to reach 2000 C

Increasing ramp to 1A/10s to reach 450A

Wednesday, May 24, 2023, 21:17

TGHT

IGP1= 3.9e-06 Torr

Continue ramping to 480A

Wednesday, May 24, 2023, 22:11

Offset between setpoint of current and readback.  readback 10A below. 

Will keep at this setting until 7:30 am tomorrow then start ramp down @-2A/min

Thursday, May 25, 2023, 07:25

OMEGA=1912C, IGP1 =1.29e-06 Torr, TGHT = 480A, 9.0V

begin ramp down at -2A/min

Thursday, May 25, 2023, 09:52

Some odd current readback behaeviour noticed.  Have contacted Gelo from controls.  He will look at it next week.  Discrepancy between read back and set point and drop in read back currrent. See picture