Laura Lambert wrote:

Laura Lambert wrote: John Wong wrote: John Wong wrote: Laura Lambert wrote: Laura Lambert wrote: Laura Lambert wrote: Laura Lambert wrote: Laura Lambert wrote:  Monday, January 20, 2014, 16:32 A new target boat was sprayed with TaC coating and let dry this morning. The target boat is NOT wrapped with Ta-heat shield. The boat was installed in Evap#2, chamber is currently being pumped down overnight.    Tuesday, January 21, 2014, 11:10 Chamber was pumped down to ~2e-7 Torr. HS cooling water valves were opened, no leaks detected. TGHT was stepped up to 35A, voltage max set at 13V. TBHT currently @ 0A. Waited ~20min, current stabilized, vacuum started to drop, auto-ramp initiated at 2.0A/min and max setpoint to 700A. Good vacuum: 3.00e-5 Torr, Bad vacuum 4.00e-5 Torr.    Tuesday, January 21, 2014, 11:51 Vacuum was grumpy and was well on it's way to tripping off [reached 5e-5 Torr], auto ramping was stopped at ~95A and quickly stepped down to 90A to avoid tripping it off. Allowed vacuum to settle back down to 2.3e-6 Torr. Auto ramping changed to 0.2A/min and re-started.  close-call!    Wednesday, January 22, 2014, 09:46 TGHT has been slowly ramping up overnight at a rate of 0.2A/min. IGP1 = 2.9e-7 Torr, TGHT = 342A; stepping ramping rate up to 2.0A/min.    Wednesday, January 22, 2014, 13:43 TGHT is sitting at 693A, IGP1 = 1.3e-6 Torr. Stepping up TGHT voltage up to 14V from 13.05V to reach the max current of 700A.    Wednesday, January 22, 2014, 15:09 TGHT reached to 700A/12.83V.  Local temperature on the boat surface was measured at ~1500C. Target will be heated for a few hours and will be cooled down later tonight. The chamber will be vented tomorrow and the boat will be inspected.    Wednesday, January 22, 2014, 18:09 After the boat was heated for ~4hrs, TGHT tripped off on IEVAP2:TBHT2 (see attachment #1, #2).  Tried clearing the water interlock via EPICS - failed to clear.  Checked the local water valves - ALL VALVES are OPEN  Tried closing and re-opening the IEVAP2:TBHT2 valves, interlock cleared after a few minutes.  Maybe a fault in the water signal.  If it happens again, the water signal should be replaced. Turned back on the power supply - TGHT current/voltage are holding.  Target boat may be OK! Chamber is a bit warm now.  Will allow time to cool down. Will vent the chamber tomorrow and the boat will be inspected.     Thursday, January 23, 2014, 16:18 Chamber vented overnight and was opened up this morning. Target boat not fully sintered [see attached photos]. Chamber currently being pumped down again in order to continue with sintering TaC coating. HS cooling water valves were opened, no leaks detected. Will ramp up to 700A again over the weekend.  Friday, January 24, 2014, 14:21 Chamber was pumped down to 1.7e-7 Torr. TGHT was stepped up to 35A, voltage max set at 14V. TBHT currently sitting at 0A. Waited 20min, vacuum consistently stable. Auto-ramp initiated at 2.0 A/min and max setpoint to 700A.

 Monday, January 27, 2014, 10:05

TGHT reached 700A over the weekend. Measured temp @ 2000C.

TGHT auto-cool inititated at 2.0A/min.