Friday, February 03, 2017, 14:17

The endcaps are stacked together with a punched out disc of graphite foil placed in between each endcap for separation so endcaps won't fuse together.

The end caps are further wrapped in a larger piece of graphite foil to hold together as a tube [same method used in elogID # 158 and 235]

There are also 4 coated springs, 2 on each side of the endcaps tube, with the endcaps tube residing in the middle of the boat.

The boat is wrapped with 3-layers of Ta heatshields.

Chamber is currently being pumped down.

Good vac at 3.0e-5, bad vac at 4.0e-5 Torr.

OMEGA slope = 0.98

 Monday, February 06, 2017, 09:29

Power outage this weekend and evap2 tripped off.

Re-pumping down now...

 Tuesday, February 07, 2017, 08:54

HS water valves opened, no leaks detected.

IGP1 = 1.9e-7 Torr

Tapped up manually to 35A

Vacuum stable.

IGP1 = 2.0e-7 Torr

Initiating auto-ramp at 0.2A/min with a final setpoint of 450A.

Final desired temperature = 1800C

 Wednesday, February 08, 2017, 09:52

IGP1 = 2.98e-7 Torr

TGHT = 325A, 3.5V

Vacuum stable.

Increasing ramping rate to 1.0A/min

 Wednesday, February 08, 2017, 11:46

IGP1 = 6.3e-7 Torr

TGHT = 433A, 4.89V

Increasing max setpoint to TGHT = 500A

OMEGA has still yet to show a temperature...should be reading points at this high in current

Will go down to the lab and follow up on OMEGA settings to confirm everything is set up ok before proceeding to a higher current...

 Wednesday, February 08, 2017, 16:03

IGP1 = 4e-7 Torr

TGHT = 500A, 5.75V

OMEGA still not reading

Initiating auto-cool at -2A/min

Will update elog with more details tomorrow

 Thursday, February 09, 2017, 10:52

Evap2 was cooled down and opened up this morning.

Turns out both legs on the target boat were touching the new heatshield and therefore had been loosing power.

Normally a boat at 500A would read ~1800C, in this scenario at 500A the boat read ~1000C.

A lot of power was being lost into the heatshield.

See photos attached of target boat sitting at 500A.

The heatshield is currently being ground down in those two spots to accommodate the target boat.