Wed May 18 13:12:24 2011: Target is wrapped with 3 Ta-heat shields and is installed in the evaporator which is being pumped down.
Wed May 18 23:11:42 2011: TGHT was raised to 40A and held for about 6 hours; Vac gradually came down to 2.1e-6 Torr. TGHT increased to 90A and pressure is going up, currently vac @ 2.9 e-5 Torr. Auto heating will begin soon at 0.5A/min --> 820A.
Thu May 19 10:23:34 2011: TGHT at 92A/0.32V, vac @ 4.47 e-5 torr. (See Attachment#1: heating_past_12hrs)
Tue May 24 10:22:59 2011: TGHT reached to max currrent 820A and held for over the long weekend. The cooling process began at 15:00 yesterday. Evaporator is vented. P/S off.
Mon May 30 17:03:01 2011
The end caps of the target after the sintering process were found damage; the caps were vaporized just like the previous SiC target w.o#38481-8. (See attachments#2: SiC000-003). After some investigation, it looks like some reaction had occurred when the target heater was ramped up beyond 550A. (See Attachment#3: SiC_striptool).
The yellow solid will be analyzed using EDX/SEM. More details will be posted later....
Wednesday, September 14, 2011, 10:16
SEM/EDX were done. See attachment #9 for the EDX results.
The formation of the yellow solid is the condensation of silicon. As seen on the EDX results, the solid is mainly Si, C and some trace of Al (could be from the loading rod).
The new D-end cap has be used to allow a better out-gassing.
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