Tuesday, April 03, 2012, 08:54

Yesterday, a new target boat was sprayed with TaC coating and let dried.

The boat was then installed in the Evap#2 chamber and pumped down to 10-6 Torr before the target heater was turned on.  NOTE: Target boat is not wrapped with Ta-heat shield. 

TGHT auto ramping was initiated at 2.0A/min and max setpoint to 700A.  The voltage was set at 3V; therefore, the current only ramped up to 250A over night.

--> Increased the TGHT voltage to 15A, and continue ramping the TGHT to 700A.  Currently vac at low 2.3e-7 Torr. 

 Tuesday, April 03, 2012, 09:12

The vac is at low 10e-7 as the TGHT is ramping up.  Changing ramping rate from 2A/min to 5A/min. 

Tuesday, April 03, 2012, 12:00  

TGHT reached to 700A. Measured temp @ 1280C. 

Tapped up TGHT to:

800A.  Measured temp @ 1400C. 

850A (local 843A/15.60V). Measured temp @ 1450C.  

900A (local 893A/16.88V).  Measured temp @ 1500C

 Tuesday, April 03, 2012, 14:35:

Try autoramping TGHT to 1000A but voltage has gone up close to the max limit (20V).  TGHT could only go up to ~970A (see attachment 1: TGHT_maxcurrent.jpg).  The heater remained at that current for ~1hr but auto cooling was initiated - at 10A/min.