Thursday, July 16, 2020, 11:15

Coated Ta tube cotaining 233 SiC disks wrapped with Ta heat-shields (3 layers)

Desired temperature= 1800C (expected TGHT 410 A), TBHT will be set fixed at 230A (max).

Evap 2 was pumped down

 Friday, July 17, 2020, 08:49

 Sunday, July 19, 2020, 17:35

IGP1 = 2.6e-06 Torr

TGHT = 400 A, 7.2 V

TBHT = 233 A, 4.1 V

Tap manually  to 410 (expected 1800 C )

Note*  OMEGA reading cannot be obtained.  

Leave at 410 A on TGHT for 4 hours.

Sunday, July 19, 2020, 22:57

IGP1 = 7.0 e-07 Torr

TGHT= 410 A , 7.2 V

TBHT = 233 A, 4.2 V

Start cool down at -2A/min for TGHT and -1A/min for TBHT

 Monday, July 20, 2020, 12:20

IGP1 = 2.2e-07 Torr

Unloading target

Monday, July 20, 2020, 19:27 

Coated Ta tube cotaining 355 SiC disks wrapped with Ta heat-shields (3 layers)

Desired temperature= 1800C (expected TGHT 410 A), TBHT will be set fixed at 230A (max).

good vacuum = 3.00 e-05 Torr

bad vacuum = 5.00 e-05 Torr

Evap 2 was left to pump down over night.

 Monday, July 20, 2020, 23:06

IPG1 = 3.1e-06 Torr

Start autoramp at .25A/min to 40A for both TGHT and TBHT

Tuesday, July 21, 2020, 08:06

TGHT = 40.3 A, 0.51 V

TBHT = 39.0 A, 0.46 V

increase auto ramp limit to 50 A for both TGHT and TBHT 

IGP1=1.8e-05 Torr

Tuesday, July 21, 2020, 16:22

IGP1= 1.5 e-05 Torr 

TGHT = 50.1 A, 0.65 V

TBHT = 50.0 A, 0.60 V

 Change ramp target to 350 A for TGHT and 230A for TBHT

Wednesday, July 22, 2020, 13:24

Stopped autoramp.  Will allow pressure to drop. 

TGHT = 64.0 A, 0.86 V

TBHT = 64.5 A, 0.82 V 

Thursday, July 23, 2020, 23:55

TGHT Reached 430 A,  7.7 V

OMEGA reads 1310 C but reading is not considered accurate so will leave at this current for 4 hours.

Friday, July 24, 2020, 11:31

IGP1 = 1.98e-07 Torr

Window for pyrometer was coated with condensate.  

Dismounted target and cleaned two windows in line with the pyrometer.

 Ta#62 LP-SIS target description:

Total Ta foils = 470 [6x20 packs + 350 single discs]

Foil Thickness = 0.025mm

Target density = 13.96 g/cm3

Target length = 3.4 cm

Total Mass = 47.461 g [Incl foils + Ta wire on 6 packs]

Total mass w/ Target oven= 445 g (w/ end caps)

Discs in target are arranged as follows: 1pack / 75 singles / 1pack / 100 singles / 2packs / 100 singles / 1pack / 75 singles / 1pack

End caps installed (expanded). No Ta foil heat shield added

TBHT will be ramped up to 230A 

TGHT will be ramped up to 600A +

Final desired temperature = 1900C.

OMEGA slope = 0.98.

Thursday, April 08, 2021, 08:24: Roughing.

Thursday, April 08, 2021, 09:06: Vent & check. Roughed to only 20 T. 

Thursday, April 08, 2021, 09:18: Roughing. Loose flange found. Left side wall / upper right. 

Thursday, April 08, 2021, 09:34: TP1 on. 

Thursday, April 08, 2021, 14:41: Vacuum @ 1.65e-06T. Waterline opened.

Thursday, April 08, 2021, 14:46: Vacuum ok. Power on. TGHT / TBHT to 20 / 15 A. Ok.

Thursday, April 08, 2021, 14:50: Auto-ramping TGHT / TBHT to 300 / 100 A @ 2 A per min.

Friday, April 09, 2021, 05:08: Vacuum @ 6.23e-07T. Temp @ 1195 C. Auto-ramping TGHT / TBHT to 400 / 150 A @ 2 A per min.

Friday, April 09, 2021, 06:01: Vacuum @ 9.64e-07T. Temp @ 1447 C. Auto-ramping TGHT / TBHT to 500 / 200 A @ 2 A per min.

Friday, April 09, 2021, 07:23: Vacuum @ 1.92e-06T. Temp @ 1671 C. Auto-ramping TGHT / TBHT to 600 / 230 A @ 2 / 1 A per min.  

Friday, April 09, 2021, 08:40: Vacuum @ 3.96e-06T. Temp @ 1877 C. Auto-ramping TGHT / TBHT to 620 A @ 1 A per min.   

Friday, April 09, 2021, 09:10: Vacuum @ 3.60e-06T. Temp @ 1915 C. Drop TGHT from 620 A to 610 A manually.

TGHT to 613 A manually.

Friday, April 09, 2021, 09:15: Vacuum @ 3.60e-06T. Temp @ 1902 C. TGHT / TBHT @ 613 A / 230 A. Desired temperature reached.

Friday, April 09, 2021, 12:08: Auto-cooling @ 1 A per min initiated. 

Monday, April 12, 2021, 07:23: PS / Turbo pump / roughing pump off. 

Monday, April 12, 2021, 08:03: Vented. 

Thursday, October 03, 2019, 08:58

Ta tube was coated with TaC and wrapped with Ta heat-shields (3 layers)

Initial weight including heat-shields = 427 g

Desired temperature = 1900 C (expected TGHT ~430 A), TBHT will be set fixed at 230A (max).

Evap 2 was pumped down previous night.

IGP1= 7.81e-07 Torr

Manually tapping up to ~40A on both TGHT and TBHT at ~1A/min

Good vacuum = 3.00 e-5 Torr

Bad vacuum = 5.00 e-5 Torr

Thursday, October 03, 2019, 09:21

Manually tapped to 50A on TGHT and TBHT

Will allow pressure to stabilize and begin autoramp TGHT and TBHT at 1A/min to 400A and 230A respectively.

autoramp increments might be increased to 2A/min depending on stability of system.

Thursday, October 03, 2019, 10:00

TGHT = 51.6A, 0.36V

TBHT = 49.5A, 0.62V

IGP1=9.6e-7 Torr

Starting autoramp at 1A/min to a max of 400A for TGHT and 230A for TBHT.  Will monitor and increase ramp increments to 2A/min if stable.

Thursday, October 03, 2019, 11:09

TGHT = 103A, TBHT=97A

IGP1=9.1e-06 Torr and dropping

Will increase autoramp increments to 2A/min

Thursday, October 03, 2019, 11:41

With TGHT = 148A, 1.9V and TBHT = 141A, 2.3V

IGP1= 7.9e-6 Torr

Autoramp was increased to 3A/min

Thursday, October 03, 2019, 13:45

TGHT=401A, 6.9V

TBHT=233A, 4.2V

IGP1= 1.14e-05Torr

OMEGA = 1874

begin manual ramp to 1900C

(Temperature dropping as pressure drops)

 Thursday, October 03, 2019, 14:11

 TGHT= 416A, 7.1V

TBHT=233A, 4.2V

OMEGA = 1900 C

IGP1= 6.9e-06 Torr and trending down

Thursday, October 03, 2019, 15:24

TGHT manually bumped to 421A,  7.2 V because temperature dropped slightly.

Thursday, October 03, 2019, 19:00

TGHT manually increased to 425A, 7.3V

Thursday, October 03, 2019, 19:12

TGHT = 424.9A, 7.3V

TBHT=233.2A, 4.1V

OMEGA= 1897 C

IGPA=1.45e-06 Torr

Starting ramp-down at -1A/min on TGHT and 0.5A/min on TBHT

Friday, October 04, 2019, 11:34

Container taken out.

 Ta#59 LP-SIS target description:

Total Ta foils = 470 [6x20 packs + 350 single discs]

Foil Thickness = 0.025mm

Target density =  13.74 g/cm3

Target length = 3.4 cm

Total Mass =  46.7314 g [Incl foils + Ta wire on 6 packs]

Total mass w/ Target oven=  436 g (440 g w/ end caps)

Discs in target are arranged as follows: 1pack / 75singles / 1pack / 100singles / 2packs / 100singles / 1pack / 75singles / 1pack

End caps installed (not yet expanded). No Ta heat shield added.

Monday, September 16, 2019, 14:47: Roughing. 

Monday, September 16, 2019, 14:55: Turbo pump on. 

Monday, September 16, 2019, 15:04: Timed out. Open RV1

Monday, September 16, 2019, 15:05: Restart Turbo pump.

Monday, September 16, 2019, 15:14: Attempt stop / restart before timeout. 

Monday, September 16, 2019, 15:21: Turbo pump unable to pass 4krpm. Close for re-attempt tomorrow am.

Tuesday, September 17, 2019, 12:33: Venting. Sort out pump down issues.

TBHT will be ramped up to 230A at 1.0A/min.

TGHT will be ramped up to 650A at 2.0A/min.

Final desired temperature = 1900C.

OMEGA slope = 0.98.

Wednesday, September 18, 2019, 08:50: Omega slope set to 0.98. Power supplies / sources on. vacuum@ 3.34e-05T & dropping. 

Wednesday, September 18, 2019, 08:25: Roughing.

Wednesday, September 18, 2019, 08:34: Turbo pump on. 

Wednesday, September 18, 2019, 10:22: TGHT manually to 40A. Vacuum @ 3.18e-06T.

Wednesday, September 18, 2019, 10:25: Auto-ramping TGHT / TBHT @ 2 / 1 A per min to 350 / 180 A. 

Wednesday, September 18, 2019, 13:43: Vacuum @ 2.30e-06T. Temp @ 1120 deg C. TGHT / TBHT @ 350 / 180 A. 

Wednesday, September 18, 2019, 13:45: Auto-ramping TGHT / TBHT @ 2 / 1 A per min to 550 / 215 A.  

Thursday, September 19, 2019, 06:39: Vacuum @ 8.79e-07T. Temp @ 1722 deg C. TGHT / TBHT @ 550 / 215 A.  

Thursday, September 19, 2019, 06:42: Auto-ramping TGHT / TBHT @ 2 / 1 A per min to 600 / 230 A.   

Thursday, September 19, 2019, 08:18: Auto-ramping TGHT to 630A @ 2 A per min

Step up to desired temp

Thursday, September 19, 2019, 08:49: Vacuum @ 3.22e-06T. TGHT / TBHT 645 (642.7) / 230 (233.44) A. TGHT Voltage= 12.501V. Omega: 1902-1903 deg C. Desired temperature = 1900C reached. 

Thursday, September 19, 2019, 14:17: Vacuum @ 1.45e-06T. Begin auto-cooling TGHT / TBHT @ -1 / -1 A per min. 

Friday, September 20, 2019, 07:59: Turbo pump off. PS / Sources off. 

Friday, September 20, 2019, 08:42: Venting. 

Friday, September 06, 2019, 11:20

Container was coated with Tac and wrapped with 2 Ta heat shields.

Desired temp=1900 C, Omega slope set =0.990

Chamber pumped down over night and will be initially tapped manually to 40A for both TGHT and TBHT.

Subsequently, current will be automatically ramped up in increments of 1A/min to reach 400A for TGHT and 230A for TBHT.

Then TGHT will be manually tapped to target temperature and allow to stabilize for a minimum of 3 hours.

Good vac at 3.0e-5 Torr

Bad vac at 5.0e-5 Torr

Friday, September 06, 2019, 11:32

IEVAP2:IGP1=9.6e-7 Torr

Tapping to 40A (TGHT and TBHT).

Friday, September 06, 2019, 12:54

Start autoramp

1A/min TGHT and TBHT

IGP1=4.0e-06 Torr

Friday, September 06, 2019, 13:29

TGHT = 70A, TBHT=70A, pressure started to spike rapidly so aborted autoramp and lowered the current to 66A for both TGHT and TBHT.

pressure continued to rise so tapped current to 60A.  A drop observed.  Will allow to stabilize.

Friday, September 06, 2019, 14:06

IGP1=5.3e-06 Torr.  Restart previous ramping. 

At 66A paused ramping.  IPG1= 1.0e-5 Torr

Friday, September 06, 2019, 15:44

IGP1=6.0e-6 Torr

Start modified autoramping: 0.4A/min for TGHT and TBHT.  Will manually tap up in the morning, over ham and eggs. 

Saturday, September 07, 2019, 10:52

 Will tap up to 423 A on TGHT as per attachment #1 regression

IGP1= 1.13e-6 Torr

OMEGA = 1802 C

TGHT= 401.0 A, 6.84V

TBHT=233.6A, 4.1V

Saturday, September 07, 2019, 11:06

Tapped up TGHT to 438A

OMEGA= 1903C

Will monitor and adjust if necessary.

Saturday, September 07, 2019, 15:06

IGP1 =  1.17e-6 Torr

TGHT = 7.46 V, 439.3 A

TBHT = 4.13 V, 233.4 A

Autoramps

TGHT = -2 A/min, TBHT = -1 A/min

Monday, September 09, 2019, 16:34

The EVAP2 was vented and the target container was removed. 

 Wednesday, September 11, 2019, 15:12

A target container coated with TaC elog 455 was loaded with an empty graphite cartridge and set it in the EVAP2

The system is currently pumping down.

The target container was wrapped with 3 new Ta heat shields.

The target container will be heated to 2000 C and the temperature will be held for 4 hours.

 The autoramp was set to:

TGHT 1 A/min, 450 A

TBHT 0.5 A/min, to 230 A

At 500 A on the TGHT, 20 additional amps were programmed to increased at 1 A/min, however, the autoramp increased the current to 520 A without stepping (see figure A). 

The final conditions were:

TGHT: 9.95 V, 565.59 A

TBHT: 4.18 V, 233.43 A

IGP1: 2.2 e-6 Torr

Friday, September 13, 2019, 11:16

After 4 hours the EVAP2 was cooled down

at a rate of TGHT 1 A/min and TBHT 0.5 A/min

The EVAP2 was vented with air.

Thursday, October 17, 2019, 12:00

Ta tube was coated with TaC and wrapped with Ta heat-shields (3 layers)

Desired temperature= 1900 C (expected TGHT ~430 A), TBHT will be set fixed at 230A (max).

Evap 2 was pumped down on the previous night.

Good vacuum= 3.00 e-5 Torr

Bad vacuum = 5.00 e-5 Torr

Ramped TGHT and TBHT to 40A at 0.5A/min

Initial IGP1= 7.0 e-07 Torr

Thursday, October 17, 2019, 13:53

After pressure stabilization at 40A:

 Autoramp TGHT and TBHT at 1A/min to 400A and 230A respectively.

 Friday, October 18, 2019, 6:20

TGHT = 400A, 6.52V, TBHT= 233A, 4.1V

OMEGA = 1733C

Start autoramp to 430A on TGHT at 1A/min

Friday, October 18, 2019, 7:05

TGHT= 431A, 7.1V

TBHT= 233A, 4.1V

IGP1= 1.13e-06 Torr

OMEGA = 1828 C

Set autoramp to 465 at 1A/min

Friday, October 18, 2019, 11:13

TGHT = 465A, 7.8V, TBHT = 233A, 4.1V

OMEGA = 1865C

(Something is different with the heat dissipation on this target.  Will leave at this current and start cooling at 1200 noon to avoid container strain)

 Friday, October 18, 2019, 12:00

TGHT = 462.7A, 7.8V

TBHT= 233.4A, 4.1V

OMEGA = 1863C

IPG1= 1.02e-06 Torr

Commence cooling at -2A/min for TGHT and -1A/min for TBHT

 Monday, October 21, 2019, 09:11

Pump down and dismount.

Wednesday, August 28, 2019, 06:00

A graphite insert (with conical caps) was loaded in tantalum tube 

the Ta tube was wrapped with 3 tantalum foils,

a tantalum cap was inserted in one side of the Ta tube and sealed.

The tube was set in the EVAP2 and the furnace was pumped down.

IGP1 = 1.23e-6 Torr.

The current was tapped to 50 A

Autoramp was set to 1 A/min to 400 A.

 Wednesday, August 28, 2019, 12:02

Autoramp reached 400 A

TGHT = 6.57 V, 404.4 A, IGP1=4.7e-6 Torr

Autoramp was set to 450 A at 1A/min

 Wednesday, August 28, 2019, 12:48

Autoramp reached 450 A

TGHT =7.526 V, 450.188 A, IGP1=5.88e-6 Torr

Autoramp was set to 500 A at 1A/min

Wednesday, August 28, 2019, 13:40

Autoramp reached 500 A, temperature 1880 C

TGHT =8.79 V, 501.094A, IGP1=7.48-6 Torr

Autoramp was set to 540 A at 1A/min 

Wednesday, August 28, 2019, 14:03

The autoramp was stopped at 520 A, because according to previous tests that current is enough to have 2000 C,

the temperature read was 1930 C

TGHT =9.23 V, 520.7 A, IGP1=7.8-6 Torr

Wednesday, August 28, 2019, 15:20

The autoramp was set to 540 A at 1A/min

When the ramp stopped the conditions were:

TGHT=9.59 V, 539.5 A, IGP1= 6.08e-6 Torr

Temperature= 1988 C

Manually tapped to 545 A the temperature reached 2000 C

Wednesday, August 28, 2019, 17:08 

To keep the temperature at 2000 or less the current was decreased,

TGHT= 8.91 V, 445.125 A, IGP1=9.93e-7 Torr

Max temperature read: 2001 C

Min temperature read: 1996 C

Tuesday, September 03, 2019, 11:15

The tube was stable at 1950-1960 C during the weekend but today at around 6 am it had a drop in the current indicating mechanical failure 

The autoramp was set to -2A/min to 0 A. 

The tube will be examined and in case that it is not broken it will be set in the EVAP1 to continue heating it.

Monday, September 09, 2019, 16:35  

The tube became brittle and broke.

Friday, May 24, 2019, 15:26

 A graphite insert with tantalum wires in its caps

was loaded in a tantalum tube, the system will be heated to 2000 C

and after 6 hrs at that temperature, it will be cooled and heated to 2000 C again.

The temperature will be hold at 2000 C for a 6 days.

Currently the chamber is being evacuated.

 Saturday, May 25, 2019, 06:01

IGP1 = 2.2e-7 Torr

Manually tapping to 50 A

Autoramp set to 1 A/min to 400 A

Saturday, May 25, 2019, 13:37

The autoramp was set to 450 A

Then it was manually tappe to 475 A 

Thursday, June 6, 2019, 16:43

A graphite insert with tantalum wires in its caps was loaded in a tantalum tube.

The system will be heated to 2000 C again (see elog 446)

Currently the chamber is being evacuated.

Friday, June 7, 2019, 16:40

Autoramp was set to 450 A at 1A/min to reach 2000 C

The temperature will be hold at 2000 C for a 4 days.

Tuesday, June 11, 2019, 16:46 

Autoramp is set to -2 A/min to 0 A

Wednesday, June 12, 2019, 17:01 

The tube present sever crystallization but is not broken and has some resistance against pressure.

 Friday, May 10, 2019, 16:54

A tantalum tube was coated with TaC,and wrapped with three tantalum sheets,

the tube was set in the EVAP2 to sinter the TaC coating.

EVAP2 is currently pumping down. 

 Sunday, May 12, 2019, 18:40

IGP1 = 3.01e-7 Torr

Manually tapped current TGHT to 40 A

IGP1 = 4.89e-Torr

at the IGP1 = 1.961e-6 Torr the autoramp was set to 1 A/min to 380 A

IGP1 = 6.91e-7 Torr

TGHT = 6.133 V, 386.8 A, temperature 1682  C

IGP1 = 7.77e-7

TGHT=6.36V, 399A 1730 C

After 4 hours at 1895 C TGHT = 7.435 V and 445.781 A

TGHT was set -2 A/min to 0 A

The EVAP2 was vented with air and the tube was removed

 Tuesday, May 21, 2019, 17:57

A tantalum tube previously coated with TaC and sintered was loaded with graphite foils.

The mass of the foils was 20.04 g.

The system will be heated to 2000 C to find out the corresponding current.

After that the tantalum tube will be trasferred to the EVAP1

and it will be heated there for 5 days. 

EVAP2 currently pumping down

 Thursday, May 23, 2019, 05:48

IGP1 = 2.516e-7 Torr

Manually tap to 50 A

Autoramp set to 1 A/min to 400 A

Thursday, May 23, 2019, 13:09 

IGP1 = 3.78e-6 Torr

TGHT = 6.4 V, 401.3 A

Temperature reading = 1629

Thursday, May 23, 2019, 13:09

Autoramp was set to 550 A at 1 A/min 

Stopped at 530 A

Thursday, May 23, 2019, 21:27

IGP1 = 6.77e-7 Torr

TGHT = 9.2175 V, 507.375 A

After 6 hours at ~2000 C the autoramp was set to -2 A/min to 0 A 

Friday, May 24, 2019, 8:46

EVAP2 was vented with air and the tantalum tube was removed, examined and transferred to EVAP1

 Thursday, November 22, 2018, 10:12

A previously sintered tantalum tube with 3 layers of shielding was loaded with a graphite insert.

The tube was loaded in evaporator 2 on Wednesday 21/11/2018 and pumped down

The graphite insert will be heated to 2000 C

current pressure IGP1 =  4.2e-7 Torr

TGHT manually tapped to 40 A

Autoramp set to 2 A/min on TGHT to 400 A aiming for 1800 C

 Thursday, November 22, 2018, 17:13

TGHT 401.25 A, 6.79 V

Temperature 1780 C

IGP1 7.89e-7 Torr

Tapping manually to reach 1800 C, final current 407.2 A, 6.96 V

  Friday, November 23, 2018, 17:13

 Tuesday, December 04, 2018, 07:53

TGHT 469.1 A, 8.814 V

Temperature 1983 C

IGP1 1.52e-7 Torr

Wednesday, December 05, 2018, 21:30

 TGHT 469.1 A, 8.75 V

Temperature 1983 C

IGP1 1.22e-7 Torr

Thursday, December 06, 2018, 12:25

 TGHT 468.9 A, 8.66 V

Temperature 1977 C

IGP1 1.42e-7 Torr

Friday, December 07, 2018, 17:59

  TGHT 468.9 A, 8.80 V

Temperature 1977 C

IGP1 1.42e-7 Torr

Wednesday, December 12, 2018, 12:18 

TGHT 469.2 A, 8.7 V

Temperature 1945 C

IGP1 1.10e-7 Torr

Thursday, December 13, 2018, 10:42

TGHT 469 A, 8.7 V

Temperature 1939 C

IGP1 1.04e-7 Torr

Ramping temperature down at -2 A/min

 Friday, December 14, 2018, 10:42

TGHT 0.0 A, 0.051 V

IGP1 4.36e-8 Torr

 Monday, November 19, 2018, 08:57

Tantalum tube was coated with TaC and wrapped with Ta heat-shield (3 layers)

Desired temp = 1900 C (expected TGHT ~445A/7.5V), TBHT will be set fixed at 230A (max).

Pressure at IGP1 2.61-7 Torr. 

Tapped up TGHT and TBHT manually to 40 A

Waited ~1 hr for vacuum to stabilize.

IGP1 = 4.27e-7 Torr

Good vac at 3.00e-5 Torr

Bad vac at 5.00e-5 Torr.

Initiating auto ramp for TGHT @ 1 A/min to a max setpoint of 350 A

Once max setpoints achieved, will tap up manually to final desired temperature of 1900 C

Monday, November 19, 2018, 18:14

Temperature was 1755 C at 350 A

IGP1 = 9.28e-7 Torr

Tapped manually to 393 A (6.83 V)

IGP1 = 1.4e-6 Torr

Temperature 1904 C

The tube will stay at max current point overnight.

Tuesday, November 20, 2018, 08:17

 IGP1 = 9.28e-7 Torr

TGHT = 395 A, 6.98 V

Temperature 1903 C

Auto-ramp set to TGHT 0 A @ -2 A/min. 

Thursday, December 20, 2018, 10:24

A tantalum tube was loaded in evaporator 2 on Wednesday 19/Dec/2018.

It is going to be heated to 2000 C during 3 weeks 

Pressure IGP1 =  4.88e-7 Torr

TGHT manually tapped to 40 A

Autoramp set to 2 A/min on TGHT to 400 A aiming for 1800 C

The system tripped due to a power outage.

the current went from 57 to 0 A.

The tube did not show damage signs.

 Wednesday, March 13, 2019, 15:41

An uncoated tantalum tube was loaded with a graphite insert (with conical caps).

3 tantalum foils were wrapped around the tantalum tube and a Ta cap was added.

EVAP2 is currently pumping down

The tube will be hated for 5 days at 2000 C

Thursday, March 14, 2019, 10:07

IGP1 = 5.37e-7 Torr

The TGHT will be tapped manually to 50 A  

After aprox 1 hour IGP1 = 5.08e-7 Torr, TGHT=46.5 A, 0.224 V

Autoramp is set to 1A/min to 300 A

 Autoramp is set to 1A/min to 450 A

Autoramp was stopped at 425 A when 2000 C were achieved

 Sunday, March 17, 2019, 00:25

IGP1 = 2.03e-7 Torr

TGHT=424.2 A, 7.117 V, temp 1976 C

Sunday, March 17, 2019, 15:04 

IGP1 = 21.6e-7 Torr

TGHT=424.1 A, 7.085 V, temp 1967 C

cooling down -1 A/min

 Wednesday, April 03, 2019, 16:57

Tantalum tube was coated with TaC and wrapped with Ta heat-shield (3 layers)

Desired temp = 1900 C (expected TGHT ~445A/7.5V).

EVAP2 currently pumping down.

 Thursday, April 04, 2019, 05:12

IGP1 = 4.5e-7 Torr

The current is tapped manually to 40 A

After1 hour IGP1 = 1.18e-6 Torr, the autoramp was set to 1 A/min to 400 A

Thursday, April 04, 2019, 18:58

After 4 hours at ~1900 C:

IGP1 = 6.13e-7 Torr 

TGHT = 6.74 V, 416.06 A

 Sunday, April 07, 2019, 08:10

A graphite insert (with conical caps) was loaded in tantalum tube previously coated with TaC,

and wrapped with 3 tantalum foils,

a tanalum cap was inserted in one side of the Ta tube and sealed.

The tube was set in the EVAP2 and the furnace was pumped down.

IGP1 = 1.24e-7 Torr.

The current was tapped to 40 A

Autoramp was set to 1 A/min to 300 A.

At TGHT 335.53 S, 5.28 V the temperature was 1560

The autoramp was set to 450 A.

At TGHT 474.75 S, 7.96 V the temperature was 1560

The autoramp was set to 450 A.

To reach 2000 C, TGHT = 500.25 A, 8.45 V.

After 1hr the temperature stabilized to 1959 C

and the  current was increased to TGHT = 510.28 A, 8.64 V.

After stabilization the temperature reached 2010 C.

The current was decreased to TGHT = 503.15 A, 8.45 V

and the temperature stabilized to 2001 C.

The voltage increased  unexpectedly to 8.89 V and the temperature increased to 2055,

the current was reduced to keep the tube at 2000 C.

The voltage kept increasing and we kept decreasing the current to keep the tube at 2000

The final current before venting and getting out the container was

TGHT = 466.219 A and 8.467 V.

Test result: Broken tantalum tube.

Monday, April 01, 2019, 16:35

Container was coated with TaC and a roll of graphite inserted inside the tube.   A couple of TaC coated Ta springs inside to keep graphite pressed against walls of cylinder.

Container wrapped with 2 Ta heat shields.

Desired temp = 1900 C, Omega slope set = 0.990, Auto ramping TGHT at 1A/min to reach 400A, TGHT will be tapped up accordingly to reach desired Temp.

Good vac at 3.00-5 Torr

Bad vac at 5.0e-5 Torr.

Chamber is currently being pumped down.  Sintering will proceed tomorrow.

Tuesday, April 02, 2019, 06:27

IGP1 = 4.37e-7 Torr

Current is manually tapped to 40 A

Tuesday, April 02, 2019, 08:12 

Pressure increased to IGP1 = 1.15e-5 Torr

and it stabilized to IGP1 = 2.32e-6 Torr after ~1.5 hrs

Autoramp is set to 1 A/min to 400 A

Tuesday, April 02, 2019, 08:45

Autoramp stopped momentarily, to stop current reduction

When pressure reduced to ~4e-5Torr, current was tapped manually to 50 A

Autoramp is set again, the conditions are

IGP1 = 2.5e-5 Torr

TGHT = 58.87 A, 0.36 V

Tuesday, April 02, 2019, 09:31

Autoramp stopped momentarily, to avoid current reduction

When pressure reduced, autoramp is set again,

the conditions are:

IGP1 = 2.9e-5 Torr, TGHT = 0.52 V, 71.5 A 

 Tuesday, April 02, 2019, 15:32

 Autoramp stopped momentarily, to avoid current reduction

conditions: IGP1=4.99e-5 Torr, TGHT = 0.78 V, 85.9 A

When pressure reduced, autoramp is set again,

 Tuesday, April 02, 2019, 22:37

Camera conexion was lost

Autoramp reached 400 A

the current was manually raise to 425 A to allow the completation of the process

Wednesday, April 03, 2019, 00:27

Camera connection still off

The current was reduced to 410 A to match with the estimated temperature 

Wednesday, April 03, 2019, 06:56

Camera connection is back, temperature reading is 1786 C

IGP1  5.01e- Torr

TGHT = 6.93 V, 412.22 A

Autoramp was set to -1A/min to 0A

Wednesday, April 03, 2019, 11:01

IGP1 = 1.67e-7 Torr

TGHT = 2.25 V, 179.53 A

Autoramp changed to -2 A/min 

Wednesday, April 03, 2019, 16:54

The tube was removed from the EVAP2,

The coating has a different color than regular coatings, but it doe not seem like the graphite adhered as expected.