Angelina Chen wrote:

Thursday, July 25, 2024, 15:18 Target container consists of two np-Ta fibres disk samples. Both disks are made from heat stabilized np-Ta fibres (150 C for 17 hours) and were pressed at 8 tons / 300 MPa. Sample 1 was made from np-Ta fibres spun using Dope solution #1. The sample 1 disk has an average thickness of 0.727 mm and a diameter of 17.113 mm. The mass of the green sample 1 disk is 0.1957 g.  Sample 2 was made from np-Ta fibres spun using Dope solution #6. The sample 2 disk has an average thickness of 0.688 mm and a diameter of 17.123 mm. The mass of the heat stabilized fibres used to make the green sample 2 disk is 0.1860 g. The mass loss from pressing the heat stabilized fibres was virtually zero. Therefore, while the mass of the green sample 2 disk was not measured, it can be extrapolated to be 0.1860 g.  The target container was wrapped with Ta foil. Each sample disk was wrapped in graphite foil and placed inside the target container horizontally near the center.  The Omega slope was initially set to 0.980. After reviewing previous logbook on np-Ti The chamber is currently being pumped down. The current reading (as of 15:40) is 4.70e-05 Torr.  Two heating schedules will be tested. Heating schedule 1 entails heating both sample disks at ~1000 C until the pressure reaches below 1.00e-06 Torr. Once heating schedule 1 is completed, sample 1 will be removed. Heating schedule 2 entails heating sample 2 to ~1800 C until the pressure reaches below 1.00e-06 Torr. TGHT is estimated to be approximately 440A/7.6V to reach 1875 C (348A/5.8V to hold temperature at 1600 C). Refer to e-log ID#605.

 Friday, July 26, 2024, 09:52

Chamber has been pumped down overnight, pressure currently at 1e-6 Torr.

Initiate auto ramping 1A/min to reach 200 A. 

Good vac = 3 e-5 Torr

Bad vac = 5 e-5 Torr. 

Continue to monitor.

 Friday, July 26, 2024, 17:06

Gas evolution has seen observed to be completed as TGHT slowly ramping up.  Temp is currently reading at 1015 C, TGHT 164A/2.43V.  Pressure holding at 2.4e-6 Torr but slowly coming down, see attachment 1.  Will keep this setting and cool it down on Sunday.

 Sunday, July 28, 2024, 11:27

Temperature has been holding sturdy at ~1000C for over 36 hours, TGHT at 164A/2.59V (a slight increase in the voltage).  Pressure is currentlyat 4.5e-7 Torr (see attachment #2 for the archiver).

Ramping down TGHT at 1A/min. 

Will remove both samples on Monday to measure the mass loss.  Sample 1 will be analyzed.  Sample 2 will be loaded back to the Evap 2 for further heating to reach about 1800 C.

 Monday, July 29, 2024, 14:29

Both samples were removed from the chamber and measured for weight loss, and Sample 2 was put back for further heating; Thanks Darwin for helping up with this. 

Chamber is currently pump down, pressure at 6.0e-5 Torr. Will ramp up TGHT once the pressure has come down to 10e-6 Torr. 

 Monday, July 29, 2024, 16:52

Pressure at 6.5e-6 Torr.  Ramping up TGHT at 2A/min to reach 164A (previous setting at ~1000C).

 Tuesday, July 30, 2024, 09:02

Temperature has been holding at about 1000C. THGT at 160A(readback,, 164A setpoint)/2.56V.  Pressure 7e-7 Torr.

Stepping up 1A/min in 20A increment to reach 1800C. 

Continue to monitor.

 Tuesday, July 30, 2024, 10:07

Plotting out THGT (readback) vs Temp:

181 A/2.91V, 1070C

206A/3.34V, 1153C

225A/3.7V, 1213C

245A/4.1V, 1277C

Wednesday, July 31, 2024, 11:26

TGHT tripped off due to HS water flow NOT oK,  Attempted to clear it but did not work, see attachment #3. 

Will stop the process for now and investigate the problem. 

 Wednesday, July 31, 2024, 12:10

Darwin helped to check the surrounding of the lab for water leaks; everything was good and the chamber remained under vacuum. 

All the water paddle wheels were moving.  A slight touch of the HS paddle wheel somehow cleared the interlock. Maybe the connection was loose. 

We checked all the paddle wheels by shutting and opening the water valves.  All the interlocks responded correctly. 

Continue with the heating process...

Ramping up TGHT at 2A/min to reach 300A.

 Wednesday, July 31, 2024, 15:27

TGHT vs temp:

294A/5.1V 1477C

343A/6.0A, 1633C

402A/7.2V, 1818C

Will keep TGHT at 410A (setpoint) for night.(see attachment#4)

 Tuesday, August 06, 2024, 10:00

Venting Evap 2; the process is done.

The sample will be analyzed.