Tuesday, November 24, 2020, 09:23

A batch of 60 discs of 18 mm diameter were loaded in a tantalum tube. The tantalum tube was wrapped with 3 layers of Ta foil for heat shielding and mounted in the EVAP2. EVAP2 pumped down overnight and Aaron made a leak test this morning (elog 524). 

The target material will be heated to 1990 degC. To measure the temperature, the tube has a Ta foil close to the graphite foils and it is held in place with a tantalum spring. Another Ta spring holds the graphite foils in the opposite side of the tube. The temperature will be measured with the Omega pyrometer (slope 0.99)

IGP1 = 6e-7 Torr. Note: The pressure has an usual behavior (see 2020-11-24-IGP1  and 2020-11-24IGP1-zoom out). After ~9 hrs, the pressure became stable (see 2020-11-24IGP1 -stable)

Tuesday, November 24, 2020, 13:00

IGP1 = 6.7e-7 Torr

Good vacuum of 3e-2 Torr and Bad vacuum 5e-2 Torr

The autoramp is set to 80 A at 1 A each 10 s 

 Tuesday, November 24, 2020, 13:43

IGP1 = 2.7e-5 Torr

TGHT = 1.13 V 80.5 A

Autoramp is set to to 100 A at 1 A each 20 s

Tuesday, November 24, 2020, 13:57 

IGP1 = 2.5e-5 Torr and going down

TGHT = 100.2 A, 1.47 V

Autoramp is set to to 120 A at 1 A each 20 s

Tuesday, November 24, 2020, 14:06 

IGP1 = 2.09e-5 Torr

TGHT = 1.6 v, 122 A

Autoramp is set to 200 A at 2 A each 10 s

Tuesday, November 24, 2020, 14:18 IGP1 = 5.4e-5 Torr

IGP1 = 1.5e-5 Torr

TGHT = 2.9 V, 200.5 A

Omega = 1123 °C

Autoramp is set to 450 A, conditions:

2 A each 10 s with a good vacuum of 3e-2 Torr and a bad vacuum 5e-2 Torr 

Tuesday, November 24, 2020, 14:45

The autoramp was stopped at 424 A 

TGHT = 421.65 A, 8.353 V

IGP1= 2.5e-5 Torr and going down

Omega 2020 degC

The TGHT current was reduced to 420 A (8.27 V) and the temperature reduced to 2007 degC

Tuesday, November 24, 2020, 21:03

IGP1 = 2.09e-6 Torr

TGHT = 7.899 V, 421.312 A

Temperature = 1870 degC

Autoramp is set to 0 A at 1 A/min