Monday, August 19, 2024, 13:06

Target container consists of 2 samples, and both samples were heat stabilized at 150 C for 24 hours then pre-oxidized at 360 C for 4 hours:

1.  PVP (7% wt/v) spun fibres 0.0569 g

2.  np-Ta (Dope 7) spun fibres: 0.1730 g

Samples are wrapped in graphite foil and loaded into a target boat which is wrapped with Ta foil.

Omega slope set at 0.99.

Similar heat treatment as the 1st attempt, see e-log #667 (1800 C = 402A/7.2V).

Good vac = 3 e-5 Torr

Bad vac = 5 e-5 Torr.

Chamber is currently pumping down.

 Monday, August 19, 2024, 16:52

Chamber pressure @ 4.6e-6 Torr.

Initiate auto-ramping at 1A/min to reach 400A.

Continue to monitor the pressure and TGHT.

Tuesday, August 20, 2024, 09:48

TGHT reached 400 A/6.87V about 10 hr ago.  But the temperature has been holding at 1665 C. 

The voltage is much lower this time compared to the previous heat treatment.  See attachment #1 for the overall process.

Ramping up to 450A.  Continue monitoring..

Tuesday, August 20, 2024, 15:43

TGHT at 450A (readback 441A)/7.892V, temperature holding at 1803C

Pressure coming down from 1.62e-6 Torr. 

Continue to hold on the temperature for a few more hours before cooling it down

 Wednesday, August 21, 2024, 09:40

Temperature was holding for about 18 hours before ramping down TGHT was initiated at 2A/min.

The samples can be taken out after 2 pm.