Tuesday, July 10, 2018, 16:40

Container was flashed with TaC solution and let dry in air. 

No Ta heat shield is used. 

Desired temperature 1900C, ramp up TGHT accordingly. (Take note at 1500 and 1600 C).  

OMEGA slope setting = 0.98

TBHT set at 250A (as usual)

Chamber is currently being pump down.

 Wednesday, July 11, 2018, 10:54

Pressure at 4.5 e-7 Torr. 

Autoramping TGHT at 0.1A/min to reach 300A and TBHT at 0.1A/min to reach 230A. 

Once TGHT setting is reached, it will be further increased according to the temp measurement. 

 Friday, July 13, 2018, 10:57

TGHT at 300A/4.02V but temp is still too low to be detected. 

Increase TGHT to 400A, ramping at 1A/min.  TBHT is already at 230A/4.0V.

Current pressure at 4.4e-7 Torr.

 Friday, July 13, 2018, 13:09

TGHT reached 400A/5.85V, temp reading 1112C.

Ramping up to 500A

 TGHT reached 500A/7.9V.  temp reading 1250 C.

Ramping up to 600A

 Friday, July 13, 2018, 17:13

TGHT reached 600A/10.74V, temp reading 1742 C.

Ramping up to 650A

 Wednesday, July 18, 2018, 11:54

TGHT has remained at 650A/12.05V since Friday July 13.

Temperature check:

pyrometer: 1650 (250 correction) = 1900 C

OMEGA:  1-color (e= 0.32 for spectral hemispherical) = 1910 C

OMEGA: 2-color (slope @ 0.99) = 1905 C

Measurements are in agreement

Cooling TGHT at 2A/min, TBHT at 1A/min. Current pressure 3.7e-7 Torr.

 Wednesday, July 18, 2018, 13:47

TGHT at 500A, 8.4V, temp at 1600 C (4.2 kW)

TGHT at 475/7.84V, temp at 1550 C (3.72 kW - Max operating target heating power)

TGHT at 450/7.31V, temp at 1500 C (3.28 kW)

With TBHT set for 230A, usual operation setting, the temperature on the transfer tube is to exceed 2000 C.  Keeping TBHT at that setting may affect the overall temperature.

Note:  To condition the nanoSiC, it is better to keep TBHT at 0A and ramp up TGHT to 475A while monitoring the vacuum.  Then step up TBHT; any increase in vacuum would indicate a local evaporation of nanoSiC close to the ionizer. 

Temp measurement is complete, cooling down TGHT/TBHT to zero.

 Thursday, July 19, 2018, 12:23

TGHT has been at 0A for over 18 hours.  Vacuum pressure at 7e-8 Torr.

Venting chamber.