Wednesday, August 28, 2019, 06:00

A graphite insert (with conical caps) was loaded in tantalum tube 

the Ta tube was wrapped with 3 tantalum foils,

a tantalum cap was inserted in one side of the Ta tube and sealed.

The tube was set in the EVAP2 and the furnace was pumped down.

IGP1 = 1.23e-6 Torr.

The current was tapped to 50 A

Autoramp was set to 1 A/min to 400 A.

 Wednesday, August 28, 2019, 12:02

Autoramp reached 400 A

TGHT = 6.57 V, 404.4 A, IGP1=4.7e-6 Torr

Autoramp was set to 450 A at 1A/min

 Wednesday, August 28, 2019, 12:48

Autoramp reached 450 A

TGHT =7.526 V, 450.188 A, IGP1=5.88e-6 Torr

Autoramp was set to 500 A at 1A/min

Wednesday, August 28, 2019, 13:40

Autoramp reached 500 A, temperature 1880 C

TGHT =8.79 V, 501.094A, IGP1=7.48-6 Torr

Autoramp was set to 540 A at 1A/min 

Wednesday, August 28, 2019, 14:03

The autoramp was stopped at 520 A, because according to previous tests that current is enough to have 2000 C,

the temperature read was 1930 C

TGHT =9.23 V, 520.7 A, IGP1=7.8-6 Torr

Wednesday, August 28, 2019, 15:20

The autoramp was set to 540 A at 1A/min

When the ramp stopped the conditions were:

TGHT=9.59 V, 539.5 A, IGP1= 6.08e-6 Torr

Temperature= 1988 C

Manually tapped to 545 A the temperature reached 2000 C

Wednesday, August 28, 2019, 17:08 

To keep the temperature at 2000 or less the current was decreased,

TGHT= 8.91 V, 445.125 A, IGP1=9.93e-7 Torr

Max temperature read: 2001 C

Min temperature read: 1996 C

Tuesday, September 03, 2019, 11:15

The tube was stable at 1950-1960 C during the weekend but today at around 6 am it had a drop in the current indicating mechanical failure 

The autoramp was set to -2A/min to 0 A. 

The tube will be examined and in case that it is not broken it will be set in the EVAP1 to continue heating it.

Monday, September 09, 2019, 16:35  

The tube became brittle and broke.