Laura Lambert wrote:

Thursday, October 02, 2014, 11:51 Target container sprayed with TaC, currently drying in fume hood  Monday, October 06, 2014, 12:11 Target container & back block is wrapped with 3 layers of Ta-heat shield.  The chamber has been pumped down over the weekend.  Pressure currently at 2.23e-7 Torr.  HS water valves open; no leaks detected. TGHT will be ramped up to 580A at 0.2A/min TBHT will be ramped up to 230A at 0.2A/min.

 Monday, October 06, 2014, 12:16

Stepped up both TGHT/TBHT to 35A. 

Tuesday, October 07, 2014, 12:54

TBHT reached to 230A/3.7V and TGHT is still ramping up, currently at 303A/4.5V. Temp measured with Omega-IR2 = 1165C with e'=0.85

Pressure @ 5.2e-7 Torr. 

Increase ramping rate to 2A/min.

 Tuesday, October 07, 2014, 16:21

TGHT is now at 580A and TGHT at 230A.

Temperature is measured with OMEGA-IR2, MIKRON, and analog pyrometer - All the measurements are agreed at 1700C (without the tantalum emissivity correction of 250C)

The OMEGA-IR2 slope has changed to 0.97 for the correction - The real temperature reading from the display is showing 1935C.

Now... attempting to low TBHT to see any temperature change.

 Tuesday, October 07, 2014, 17:01

TGHT @ 580A.

TBHT = 180C, Temp = 1925C

TBHT = 130C, Temp = 1920C

Not much of change in the temperature on the target tube...

Tuesday, October 07, 2014, 17:07

Attempting to increase the temperature to 2000C

TGHT = 600A, Temp = 1955C

TGHT = 620A, Temp = 2000C

Target will continue heating at this temperature overnight... Will continue to monitor.

 Tuesday, October 07, 2014, 20:59

After almost 4 hours of heating at 620A on TGHT, the temperature has dropped to 1980C.  

Pressure is coming down to 1.17e-6 Torr.  

Increased TGHT to 630A to maintain temp @ 2000C