Wednesday, September 14, 2022, 9:30
A Ta container tube was wrapped with 3 Ta heatshields.
322 graphite discs were loaded.
one Tantalum cup (modified to fit losely) was inserted on the front end along with a Ta spring.
A Ta spring was also installed on the back end to maintain the discs inside the tube.
The system was left to establish vacuum over night.
Good vacuum set to5e-03Torr
Bad vacuum was set to 5e-2 Torr
Total weight of system including springs = 249.63 g
Two Ta foils were installed on the copper heatshield facing the ends of the container.
The initial weight of the front Ta foil = 22.5 g
The initial weight of the back Ta foil will be determined by difference after cleaning =
OMEGA slope = 0.99
The target will be heated to 2100 C, held there for 10 hours. The target will be removed, the end Ta foils will be removed to analyses, new Ta end foils will be installed and the Target will be heated to 2100 plus 10 A higher than previous and left at that temperature for 2 hours.
Wednesday, September 14, 2022, 9:47
IGP1= 4.57e--7 Torr
initial Utoramp at 1A/10s to 80A and held at 80 amps until pressure good.
Wednesday, September 14, 2022, 11:54
Start autoramp at 1A/20s to 120A
Wednesday, September 14, 2022, 12:22
Autoramp at 1A/20s to 200A
Wednesday, September 14, 2022, 12:34
Autoramp increased to 2A/20s when TGHT = 154A
Wednesday, September 14, 2022, 13:46
Autoramping to 512A as projected current for 2100 C
Wednesday, September 14, 2022, 14:24
OMEGA = 1945 C @ 512A
Tapped to 540A, 10.5V and OMEGA = 2075. Will leave at this current and see Temperature behaeviour.
After 10 min OMEGA reads 2080C. Will start cooling at 12:20 am
Wednesday, September 14, 2022, 14:29
OMEGA = 2104C will ramp down slightly to keep 2100C
Wednesday, September 14, 2022, 14:31
OMEGA = 2098 @ 530A, 10.4V
Wednesday, September 14, 2022, 14:33
OMEGA = 2100 @ 410A,9.8V
Wednesday, September 14, 2022, 14:45
OMEGA = 2093 at 500A, 9.75V
Wednesday, September 14, 2022, 15:07
497A, 9.6V, OMEGA 2100
Wednesday, September 14, 2022, 22:09
@ approximately 515 pm noticed that OMEGA was reading 1600 C while TGHT was at 497A and 10.0V
Suspect damage to the container and possible damage
Left at the same current.
Just now the OMEGA is reading 2200C at 497A and 9.7V. Out of precaution, lowered the current to 475A and the volatage is 9.2V
OMEGA now reads 2152 C. Will leave at this current until 12:30 am when the 10 hour heating will end and will start rampdown at -2A/min
Thursday, September 15, 2022, 00:05
TGHT= 475A, 9.2V
OMEGA= 2126 C
IGP1= 1.33e-6 Torr
lowered current to 470A, 9.1 V, IGP1= 1.3e-6 Torr, OMEGA stabilized at 2120C
Thursday, September 15, 2022, 00:09
IGP1= 1.3e-6 Torr
will increase 10A to see pressure response. OMEGA= 2130C
Increase in IGP1 to 1.4e-6 Torr observed but immediately started to trend down
Thursday, September 15, 2022, 00:16
IGP1= 1.36e-6 Torr
OMEGA = 2131A
TGHT = 480 A
Thursday, September 15, 2022, 00:18
Start ramp down at -2A/min
Thursday, September 15, 2022, 09:45
IGP1=4.35e-07 Torr
TGHT turned off
Starting dismounting of target tube
Thursday, September 22, 2022, 07:04
Container tube was crystalized and was easily cut with a small pair of nail scissors. All but 18 discs were transferred to a new container. WO# 44691-3 |