Thursday, November 22, 2018, 17:25
D-shaped discs were cut from cast #26
A 13mm punch was used to punch out discs from pre-cut strips
The target consists of 236 discs of 10 cm in length - all single discs, no packs.
236 x UO2/C discs = 22.66 g
Graphite insert with caps = 11.74 g
The loaded inser is placed on target boat.
Boat previously coated with TaC and sintered.
Ta-target boat is wrapped with 3-layers (2 new one used) of heat shield and installed in evap1.
Chamber is pumping down.
Friday, November 23, 2018, 08:53
Vacuum limits:
Good vacuum 1e-1 Torr
Bad vacuum 5e-1 Torr
IGP1 = 4.12 e-6 Torr
Current tapped manually to 100 A at 1A/s in 10 A blocks with a waiting period of 20 s between each increment.
Initial IGP1 = 5.31 e-6 Torr
Max IGP1 = 0.066 Torr
Waited 20 min for pressure to rise and drop.
The current tripped off, when the 0.013 torr (Fig. Nov23-CurrentTrip1).
Increasing the current to 100 A again.
IGP1 = 7.00e-5 Torr
Rate was increased to 25 A each 20 s until 200 A
The pressure increased and IV1 opened, current was dropped to 100 A
Pressure after 5 min 4e-4 Torr
Rate was increased again to 25 A each 20 s until 200 A
The current was reduced to 110 A because the pressure was rising to fast
Rate was increased again to 25 A each 20 s until 300 A
Pressure was ok and current tripped off (Fig. Nov23-CurrentTrip2).
The automatic ramp was set to 20 A/ min from 0 to 300 A
The automatic ramp was changed to 10A/2min to 450 A
IGP1 = 2.15e-5 Torr
After 1.5 hour, the automatic ramp was set to 20 A/ min from 450 to 500 A
After 4hrs, the automatic ramp was set to -2 A/ min from 500 to 0 A |