Thursday, October 25, 2012, 14:50

Previous sintering BeO tests, pellets 1 to 4 were done in Evaporator#2.

3 BeO pellets were made.  Each weights about 1.3g (including org mass). 

A piece of Re foil (0.002" thick) is used as the under layer to protect the reaction between Be(g) and the Ta-boat.  (see attachment#1)

Another layer of Ta-foil is used as the heat-shield to wrap around the Ta-boat.

The chamber is currently being pumped down. 

TGHT will be ramped up to 600A (~1360C) at 0.2A/min.

The pressure, voltage and current will be closely monitored. 

If the Ta-boat survives, the TGHT will continue to ramp up to max 800A (~1580C).

 Friday, October 26, 2012, 11:15

Chamber has been pumped down over night. 

IG1 @ 8.93e-6 Torr. 

Auto-ramping parameter:

Good Vac @ 2.0e-5 Torr, Bad Vac @ 3.0e-5 Torr.

rate @ 0.2A/min. 

 Tuesday, October 30, 2012, 10:57

TGHT has reached to 370A. The organic binder has burnt off. 

The pressure came down to  6.6e-6 Torr, but it is slowly going up to 8.6e-6 Torr (something is outgassing... Dissociation of BeO --> Be(g) + O(g) ?).  BP @ 39mTorr.  (see attachment#2).

 Wednesday, October 31, 2012, 12:07

TGHT has reached to 600A/6.338V for just over 6 hours.  IG is slowly coming down fro 1.2e-5 Torr.  BP @ 38mTorr. (see attachment #3)

 Wednesday, October 31, 2012, 16:49

Vacuum is coming down to 8.49e-6Torr.  TGHT has stayed at 600A/6.24V for over 11hrs.  (see attachment #4)

Auto-cooling initiated at 1A/min. 

The chamber will be vented tomorrow and the material will be inspected.

 Thursday, November 01, 2012, 10:57

TGHT has reached to 0A.  Vacuum holding at 1.9e-6Torr.

Turning off P/S and pumps prior to venting chamber.