March 28, 2011

12:28:  Target oven is wrapped with 3 Ta-heat shields.  Pumping down evaporator

March 29,

12:14  Evaporator has been pumped down over night.  Vac @ 1.74e-6 Torr. 

12:24  TGHT @ 20A, Vac @ 1.66e-6 Torr.

12:29  TGHT @ 40A, Vac @ 1.56e-6 Torr.

12:30  Auto heating begins,  Paramenter Setup:  TGHT: 2A/min -->  max 820A.  Incrementing if Vac < 4.5e-5 Torr; backing off if vac > 6.5e-5 Torr.

18:37  TGHT @ 772A/7.395V  (see attachment#1 for the striptool).  Auto heating will stop when the TGHT gets to 820A, and the current will stay there over night. 

March 30

11:31 TGHT has been at 820A/7.8V for the past 17 hours.  (See attachment#2 for the striptool details.)

11:34 Auto-cooling beings

19:40 Auto-cooling has finished. TGHT is at zero and p/s has turned off.  Cooling water has stopped running.  Evaporator will be vented tomorrow.

March 31, 2011

11:13:  Venting evaporator.  All pumps are off and TGHT p/s has turned off. 

Thu Mar 31 11:57:20 2011 After removing the target from the evaporator,  some white coating (could be Tantalum oxide?) was found on the copper plate of the evaporator.  The white coating was found to have more on the left end side of the target and some just below the transfer tube.  The white coating was wiped off but it showed black residual on the wipers.  The target over looks fine.  Marik was informed, and we think this white coating could be  the organic substance burnt off from the target or the Tantalum oxide from the re-used Ta heat shields.