Tuesday, April 13, 2021, 09:51

IGP1 = 2.5e-7 Torr

Tuesday, April 13, 2021, 10:17 

The wire was heated in the same manner as the last three runs

From 0A to 7A the autoramp was set to 0.5A/min

At 8A the wire started the glow dimmly 

Above 8A, the wire was heated manually at 0.5A until 15A where the step was changed to 1A, 

the temperature was measured with the filament pyrometer every 2 A starting at 10A

At 42 A the step was changed to 0.5A until 44.5A, 4.61V (2120 °C), the wire was kept at that temperature for 6 hours.

After that time, the current was ramped to 0A at 0.5A/min.

 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. 

 2021-04-04 16:07 New container is in with heatshields, vacuum 8.6E-6 torr. leak check done. ramping up current, checking both pyrometer and TC, 1A/10s.

 2021-04-04 16:49 200A TGHT 250degC on TC 1130degC on pyrometer. Too low on TC, ramping down and venting to reposition TC in the foil. 

 2021-04-04 18:00 TC was slightly broken, repaired now. Pumping chamber.

 2021-04-04 18:41 ramping up to 200A 1A/10s.

2021-04-04 18:41 200A TGHT, TC 389degC pyro 1130degC. ramping to 400A 1A/10s.

2021-04-04 18:41 300A TGHT, TC 554degC pyro 1440degC. 

2021-04-04 18:41 400A TGHT, TC 735degC pyro 1720degC. ramping to 600A 1A/10s. 

2021-04-04 20:15 500A TGHT, TC 891degC pyro 1990degC

2021-04-04 20:15 553A TGHT, TC 975degC pyro 2129degC, ramping down.

2021-04-06 13:44 Parasitic target plus thermocouples were introduced in evap2 the day before and put under vacuum. IG1 3E-7 torr, leak check done. Putting some power into HE while ramping up container to 100A 1a/10s.

2021-04-06 14:06 20W on HE 100A on target container. Everything stable. Ramping up to 200A 1A/10s 

2021-04-06 14:06 20W on HE 200A on target container. Everything stable. Ramping up to 300A 1A/10s 

2021-04-06 14:06 20W on HE 300A on target container. Everything stable 4.6E-7 torr. Ramping up HE to 40W.

2021-04-06 14:06 40W on HE 300A on target container. Everything stable 4.6E-7 torr. Ramping up container to 400A 1A/10s.

2021-04-06 14:06 40W on HE 400A on target container. Everything stable 1E-6 torr. Ramping up container to 500A 1A/10s.

2021-04-06 15:52 35W on HE 500A on target container. Everything stable 1.6E-6 torr. Ramping up He to 65W.

2021-04-06 18:40 at 50W on HE one of them broke, system ramped down, vented, HE replaced, pumping down system again.

2021-04-07 10:38 HE at 70W, ramping up container to 200A 1A/10s. Vacuum 3.3E-7 torr.

2021-04-07 10:59 HE at 70W, 200A on container, ramping up container to 300A 1A/10s. Vacuum 3.9E-7 torr.

2021-04-07 10:59 HE at 65W, 300A on container, ramping up container to 400A 1A/10s. Vacuum 4.5E-7 torr.

2021-04-07 11:50 HE at 70W, 400A on container, ramping up container to 500A 1A/10s. Vacuum 7.8E-7 torr.

2021-04-07 11:50 HE at 65W, 500A on container, ramping up container to 553A 1A/10s. Vacuum 1.4E-6 torr.

2021-04-07 11:50 HE at 65W, 553A on container. All good, ramping down. 1A,10s.

 2021-03-30 7:48 Target loaded with parasitic target only. No container. Leaving under vacuum over night.

 2021-03-31 13:43 Leak check performed. Water on. Need to vent system, electric connection disconnected.

 2021-03-31 15:02 First test successfully finished. Venting to introduce container with radiating heating gun.

 2021-04-01 14:58 Vacuum 3.5E-7 torr. Leak check done. Ramping up target heater to 100A at 1A/10s

 2021-04-01 14:58 Vacuum 5E-7, 100A all ok. Temp foil 24.3DegC. ramping to 500A at 1A/10s.

 2021-04-01 14:58 Temp of foil not increasing much. Probably issue with TC. ramping down at 1A/10s to vent and inspect.

 2021-04-02 11:03 Target reinstalled, foil TC reinstalled. Vacuum 3E-7 torr. Leak check done. Ramping up container to 500A 1A/10s. 

 2021-04-02 13:07 Still isues with TC. Container ramped down at 1A/10s. Venting, brought heat gun to check TC.

 2021-04-02 15:10 TC connection fixed, origin of issues. Vacuum down to 3E-5 torr. Ramping up container to 200A 1A/10s.

 2021-04-02 18:32 TGTH 200A Tc temp 327.5degC. ramping up to 300A. 1A/10s.

 2021-04-02 18:32 TGTH 300A Tc temp 500degC. ramping up to 400A. 1A/10s.

 2021-04-02 19:17 TGTH 400A Tc temp 618degC. ramping down.

 2021-04-03 13:37 Foil was changed, ramped up to 200A at 1A/10s, Temp TC 360degC. Ramping to 300A. Vac 8.6E-6 torr.

 2021-04-03 13:59 300A Temp TC 580degC. Ramping to 500A, 1A/10s. Vac 7.6E-6 torr.

 2021-04-03 14:36 500A Temp TC 836degC. Ramping to 600A, 1A/10s. Vac 9E-6 torr.

 2021-04-03 14:36 600A Temp TC 960degC. Vac 1.1E-5 torr. Ramping down. 

2021-04-03 19:00 After venting an opening the evap2, it was found that remaining from a past heat treatment where on the Tantalum container. The sublimation of the material coated the inner walls of the evap.2. Now cleaned.

Objective: Coating the inner surface of a tantalum tube to make a destructive test and use a reference for the tantalum boats coatings

Results: The tube was coated

Sunday, March 28, 2021, 11:23

No water leak

IGP1 = 2.3e-7 torr

Sunday, March 28, 2021, 16:10

The wire was heated in the same manner as the last three runs

From 0A to 7A the autoramp was set to 0.5A/min

At 8A the wire started the glow dimmly 

Above 8A, the wire was heated manually at 0.5A until 16A where the step was changed to 1A, 

the temperature was measured with the filament pyrometer every 2 A starting at 10A

At 42 A the step was changed to 0.6A until 42.6A, 4.38V (2020 °C), the wire was kept at that temperature for 90 min

After that time, the current was ramped down at 0.5A/min until ~20A when the current rampping was changed too 1A/min

Objective: Coating the inner surface of a tantalum tube to make a destructive test and use a reference for the tantalum boats coatings

Results: 

Sunday, March 27, 2021, 11:23

No water leak

IGP1 = 3.7e-7 torr

Sunday, March 27, 2021, 16:10

The wire was heated in the same manner as the last three runs

From 0A to 7A the autoramp was set to 0.5A/min

At 8A the wire started the glow dimmly 

Above 8A, the wire was heated manually at 0.5A until 16A where the step was changed to 1A, 

the temperature was measured with the filament pyrometer every 2 A starting at 10A

At 42 A the step was changed to 0.6A until 42.6A, 4.38V (2020 °C), the wire was kept at that temperature for 90 min

After that time, the current was ramped down at 0.5A/min until ~20A when the current rampping was changed too 1A/min

Friday, March 26, 2021, 13:55

Yesterday a heat shield was installed in the EVAP2.

A 1mm thick rhenium wire was held within two copper brackets to pass through a Cu tube with the intention of coating its inside face.

The desired temperature of the Re wire is 2500 degC

A water leak was performed and no leak was detected

Objective: Coating the inner surface of a short tantalum tube with rhenium.

Result:

• The wire snnaped around 376 W (53 A, and 7.09 V) and 2170 °C (measured with filament pyrometer)
• The tube is coated

Thursday, March 25, 2021, 11:23

Yesterday a heat shield was installed in the EVAP2.

The desired temperature of the Re wire is 2500 degC

A water leak was performed (elog 539 describes it), no leak was detected.

Tuesday, March 23, 2021, 11:01

Pressure 3.8e-7 Torr, current rate set to 6 A @ 0.5 A/min

The wire started glowing at TGHT =  4W, 7A, 0.56V

When reaching 7A the current was increased 0.5 A manually 

When reaching 16 A,  the current was increased 1 A manually until reaching 54 A when the wire snapped

Thursday, March 25, 2021, 07:55: Vacuum @ 5.12e-07T. Waterlines opened.

Thursday, March 25, 2021, 07:55: Vacuum @ 5.09e-07T. Stable.

Objective: Coating the inner surface of a short tantalum boat with rhenium.

Result:

• The wire snnaped around 376 W (53 A, and 7.09 V) and 2170 °C (measured with filament pyrometer)
• The tube does not have indications of coating

Thursday, March 25, 2021, 11:23

Yesterday a heat shield was installed in the EVAP2.

The desired temperature of the Re wire is 2500 degC

A water leak was performed (elog 539 describes it), no leak was detected.

Tuesday, March 23, 2021, 11:01

Pressure 3.8e-7 Torr, current rate set to 6 A @ 0.5 A/min

The wire started glowing at TGHT =  4W, 7A, 0.56V

When reaching 7A the current was increased 0.5 A manually 

When reaching 16 A,  the current was increased 1 A manually until reaching 54 A when the wire snapped

 Modified HS installed with new brackets as per Marla.

Tuesday, March 23, 2021, 08:02: Vacuum @ 3.64e-07T. Waterlines opened.

Tuesday, March 23, 2021, 08:06: Vacuum @ 3.60e-07T. Stable.

 Tuesday, March 16, 2021, 08:28 

Each endcap is separated with a disc of graphite foil and rolled into packs of 5 within a foil envelope in a target boat.

There are also 4 coated springs, one in between endcaps and three on the ends

The boat is wrapped with 3-layers of Ta heatshields.

Chamber pumping down

OMEGA slope = 0.99

Will ramp TGHT up to 40 A then autoramp to 400A at 1A/min.

Final desired temperature on OMEGA (tap)= 1800C

Tuesday, March 16, 2021, 11:22

 IGP1= 3.5e-06 Torr

TGHT = 40A, 0.4V

Will ramp up at 1A/min to 400 A

Wednesday, March 17, 2021, 08:06

IGP1=  2.98 e-07 Torr

TGHT = 400 A, 4.3V

OMEGA shows no temperature reading.  Will ramp up to 450A at 1A/min

Wednesday, March 17, 2021, 08:58

OMEGA still shows no reading

IGP1= 4.2e-07 Torr

ramping to 470A @ 1A/min 

Wednesday, March 17, 2021, 09:21

OMEGA no reading

IGP1 = 4.4 e-07 Torr

TGHT = 470 A, 5V

ramp up to 490 A at 1A/min

Wednesday, March 17, 2021, 11:05 

TGHT at 490 A, 5.2 V since 10 am.  Will start cooling at 2 pm.  

Wednesday, March 17, 2021, 13:47

TGHT = 493A, 5.3V

IGP1= 3.2e-07 Torr and stable

Start ramp down at -2A/min

Thursday, March 18, 2021, 11:20 

The boat was dismounted but the materials had not sintered properly.  The boat looked very twisted.  Everything was transferred to a new boat with uncoated Ta caps at either end.  

It was left overnight to establish vacuum.

Friday, March 19, 2021, 08:23

IGP1= 2.2 e-07 Torr

initiate heating at 1A/min on TGHT to 60 A

Friday, March 19, 2021, 10:04

IGP1= 3.6 e-07 Torr

TGHT = 60 A, .73 V

Ramp up to 450 A @ 2A/min

Friday, March 19, 2021, 14:26

OMEGA 1895 at 455A, 8.4 V

manually ramp down to 1800C

OMEGA 1800C at 416A, 7.6V

will leave like that for 3 hours more

Friday, March 19, 2021, 17:12

OMEGA 1795 C

 TGHT = 415A, 7.6V

IGP1= 6.8e-07 Torr

Start ramp down at -2A/min

Monday, March 22, 2021, 23:07 

Marla removed from Evap 2.  Sintering vwas very good.  The container with Ta caps is better for sintering these pieces.

Tuesday, March 09, 2021, 11:54 

 Container coated with TaC and wrapped with 3 Ta heat shields.

Desired temperature= 1900 C, Omega Slope set = 0.990, Auto TGHT at 0.2A/min to reach 400A, TGHT will be increased  accordingly to reach desired Temp.

TBHT will be set fixed at 230 A max).

Good vac at 3.00e -5 Torr

Bad vac at 5.00e-5 Torr

Chamber pump down

Wednesday, March 10, 2021, 08:32

IGP1 = 2.6 e -07 Torr

Start autoramp @ 1A/min to 40 A on both TGHT and TBHT

***Autoramp aborted due to work on EF12 affecting EVAP2***

Will have to resume Thursday or Friday

Saturday, March 13, 2021, 7:54

  IGP1= 3.8e-07 Torr

Initiate heating @ 0.5A/min TBHT and TGHT to 60 A

Saturday, March 13, 2021, 23:01

IGP1 = 2.7e-07Torr

TGHT = 60.5A, 0.7V

TBHT= 60.0A, 0.7V

Initiate ramp @ 1 a/min to 400 A on TGHT and 230A on TBHT

Sunday, March 14, 2021, 08:45

IGP1= 8.2e-07 Torr

TGHT = 400A, 5.6V

TBHT = 232.9A, 3.0V 

OMEGA = 1142 C

Continue ramping to 460 A on TGHT at 1a/min

 Sunday, March 14, 2021, 10:11

IGP1 = 1.0 e-06 Torr

TGHT= 460.4 A, 6.5 V

TBHT = 232.9 A, 3.0 V

OMEGA = 1239 C

Will ramp up to 500 A at 1a/min on TGHT

Sunday, March 14, 2021, 10:53

 IGP1 = 1.3 e-06 Torr

TGHT= 495 A, 7.2 V

TBHT = 232.9 A, 3.0 V

OMEGA = 1316 C

Will ramp up to 600 A at 1a/min on TGHT

Sunday, March 14, 2021, 12:45

IGP1 = 3.0 e-06 Torr

TGHT= 604 A, 9.1 V

TBHT = 232.9 A, 3.1 V

OMEGA = 1610 C

Will ramp up to 660 A at 1a/min on TGHT 

Sunday, March 14, 2021, 17:01

IGP1= 2.4e-06 Torr

TGHT =  664 A, 10V

TBHT = 232.9 A, 3.1V

OMEGA = 1733 C

tapping TGHT to 740 A

OMEGA = 1883 C

 Sunday, March 14, 2021, 21:45

IGP1= 3.1e-06 Torr

TGHT =  744A, 11.5V

TBHT = 232.9 A, 3.2V

OMEGA = 1875 C

Start cooling TGHT @-3A/min and TBHT @-1A/min

 Friday, March 05, 2021, 10:47

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

Initial weight including heat-shields = 431.0 g

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

Evap 2 will be pumped down over night.

Good vacuum = 3.00 e-5 Torr

Bad vacuum = 5.00 e-5 Torr

 Saturday, March 06, 2021, 10:29

IGP1= 2.7 e-07 Torr and stable

AutoRamp at 1A/min to 40 A on TGHT and TBHT

Saturday, March 06, 2021, 22:36

IGP1= 2.2e-07 Torr

TGHT = 40.3 A, .46V

TBHT = 38.48 A, .48 V  (set to 40 A)

Start Autoramp at 0.5A/min to 400 A on TGHT and 230A on TBHT

Sunday, March 07, 2021, 07:48

IGP1=8.5e-7 Torr

TGHT = 287 A, 4.6V

TBHT = 232 A, 4.0 V

OMEGA = 1493C

 Increase ramp speed on TGHT to 2A/min to 400A

Sunday, March 07, 2021, 08:36 

 IGP1=1.7 e-06 Torr

TGHT = 373.7 A, 6.3V

TBHT = 232.9 A, 4.1 V

OMEGA = 1752 C

Sunday, March 07, 2021, 08:53

 IGP1= 1.7e-06 Torr

TGHT = 400 A, 6.8 V

TBHT = 232.8 A, 4.1 V

OMEGA= 1842

Ramp TGHT @ 2A/min to 420 A as per attached current approximation

Sunday, March 07, 2021, 09:25

OMEGA=1915 C

TGHT = 420A, 7.2V

TBHT= 232.8 A, 4.1V

IGP1= 1.6 e-06 Torr

Tap down manually to approx 1900 C

TGHT = 412.9 A, 7.0 V and OMEGA=1900 C

Will leave for about 4 hours at this temperature

Sunday, March 07, 2021, 13:05

IGP1= 1.1 e-06 Torr

TGHT = 415 A, 7.2 V

TBHT = 232.8 A, 4.1 V

OMEGA = 1880C

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

Tuesday, March 02, 2021, 11:26 

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

Initial weight including heat-shields = 433.8 g

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

Evap 2 will be pumped down over night.

Good vacuum = 3.00 e-5 Torr

Bad vacuum = 5.00 e-5 Torr

Wednesday, March 03, 2021, 13:28

IGP1 = 4.0 e-7 Torr

Start ramping @ 1A/min to 20A on both TGHT and TBHT

Wednesday, March 03, 2021, 15:03

Start ramping @1/min to 60A on Both TGHT and TBHT

Wednesday, March 03, 2021, 22:42

TGHT = 60A, TBHT = 60A

IGP1= 4.2 e-7 stable

Start ramping to 400A @ .5A/min for TGHT and @0.5A/min for TBHT to 230A

Thursday, March 04, 2021, 11:56

TGHT = 400 A, TBHT =230A

IGP1= 1.9e-6 Torr

OMEGA = 1695 C

Continue ramp up @0.5A/min to 430A on TGHT

Thursday, March 04, 2021, 14:02

IGP1 = 1.87e-6 Torr

TGHT = 434 A , 7.2 V

OMEGA = 1787 C

Will tap up manually 450A @ on TGHT and leave at that current for ~4 hours

Thursday, March 04, 2021, 19:35

After ~ 5 hours at 1829 C max OMEGA reading

OMEGA = 815 C 

Start ramp down at 1A/min on TGHT and 0.8A/min for TBHT

IGP1= 1.2e-6 Torr

Flex-Line HS had been fully scrubbed out earlier. All gaskets replaced.

Empty. Quick check for leaks.

Monday, March 01, 2021, 13:57: Roughing.

Monday, March 01, 2021, 14:13: TP1 on. 

Monday, March 01, 2021, 15:18: Vacuum @ 1.01e-05T. Open HS waterline. 

Monday, March 01, 2021, 15:24: Vacuum @ 9.30e-06T & dropping. Waterline ok. 

Monday, March 01, 2021, 15:25: Turbo pump off. Vent when ready. 

 Tests were performed with external power supply. No target boat or container.

Small power on heating small heating elements on parasitic target attached on isac heatshield with water cooling on. 

 Tuesday, February 23, 2021, 08:49

Yesterday a heat shield was washed and when dry it was installed in the EVAP2,

A 1mm thick rhenium wire was held within two copper brackets to pass through a Cu tube with the intention of coating its inside face

Tuesday, February 23, 2021, 08:58  IGP1 = 7.7e-7 Torr

Pressure 5.88e-7 Torr, current rate set to 10 A @ 0.5 A/min

Pressure 6.1e-7 Torr, current rate set to 20 A @ 0.5 A/min

Pressure 8.51e-7 Torr current rate set to 30 A @ 0.5 A/min, temperature corrected 1800 degC (measured with filament pyrometer)

After 10 min the current and voltage are stable and the pressure is going down

Tuesday, February 23, 2021, 16:25

It seems like the wire is touching the tube so the system will be cool down.

Pressure 6.8e-7 Torr current rate set to 0A at -0.1 A/min

 Tuesday, February 23, 2021, 17:38

Pressure 6e-7 Torr, TGHT = 23.3 A, 4.854 V, Temp 1788 deg C Omega, 1540 degC filament

current rate set to 0A at 0.2A/min 

Wednesday, February 24, 2021, 09:37

Venting EVAP2 

Wednesday, February 24, 2021, 16:47

The wire and Cu tube were  fix such that the wire's deformation does not lead it to touch the tube, then the assembly was attached again and the EVAP2 was pumped down.

IGP1 = 9.3e-7 Torr, current rate is set to 5 A at 0.5 A/min

Wednesday, February 24, 2021, 17:04

IGP1 = 9e-7 Torr TGHT = 5.175A, 0,749 V

current rate is set to 10 A at 0.5 A/min

Wednesday, February 24, 2021, 17:23

IGP1 = 8.8e-7 Torr, TGHT = 10A, 1.78V

current rate is set to 20 A at 0.5 A/min

Since the wire seemed to be touching the tube, the system was vented.

The tube was shifted and the heat shield installed again, the system was pumped over nigth.

Thursday, February 25, 2021, 09:15

A water leak was performed and no leak was observed

IGP1= 4.95e-7 Torr

Thursday, February 25, 2021, 09:32  The current is increased at 0.5 A/min to 5 A

Thursday, February 25, 2021, 10:00

The current was tapped manually at 0.5 A to 6 A the wire is now glowing dimmly

Current rate set to 10A at .5 A/min

Current rate set to 20 A at 0.5A/min

Current rate set to 30 A at 0.5A/min

Thursday, February 25, 2021, 11:17  IGP1= 5.7e-7 Torr, TGHT=30.5A, 6.718V, filament=1740 degC

voltage and current stable, pressure going down.

Thursday, February 25, 2021, 11:21

Current rate set to 40 A at 0.4 A/min

Thursday, February 25, 2021, 11:53 IGP1 = 5.9e-7 Torr, TGHT = 9.267V, 39.15A, filament = 2060 degC

voltage and current stable, pressure going down.

Current rate set to 50 A @ 0.2A/min

During ramping the voltage reduced a bit and I decided to stop the ramp and reduce the current, the voltage stayed constant but the current started increasing slowly without me inputting it so I decided to ramp down the current at 0.2A/min.

When the current reached 0A the power supplies and the pumps were turned off, after an ~1h when the turbo pump had already stopped, the EVAP2 was vented and open.

The wire sintered to the copper tube confirming that the wire was in contact with the tube during heating.

The Cu tube present a grey metallic coloration indicating a Re coating.

The set up together with the copper heat shield were removed from the

Saturday, February 13, 2021, 08:10

Ta boat loaded with 80 discs enclosed in graphite foil in pockets of 20.  Sample A at both ends and sample B in the middle spaced out. Boat wrapped in Ta heat-shields (3 layers).

(A B B A)

Desired temperature= 1800C (expected TGHT approx 410 A).

good vacuum = 3.00 e-05 Torr

bad vacuum = 5.00 e-05 Torr

Evap2 left to pump down over previous night.

IGP1= 5.4e-7 Torr and stable

Initiating TGHT ramp up at 1 A/ min to 30 A

Saturday, February 13, 2021, 12:19

IGP1= 6.9e-06 Torr

Ramp to 50 A 1A/min

Saturday, February 13, 2021, 14:35

IGP1 = 6.4e-6 Torr

Pressure trending down. 

Saturday, February 13, 2021, 14:56

IGP1= 4.9 e-6 Torr

Initiate Ramp up @ 1 A/min to 400 A

Changed ramp up to 0.5 A/min at around 11:30 pm

Sunday, February 14, 2021, 11:43

The current will be ramped up to 420 A according to the trendline approximation (see attachement 1)

Sunday, February 14, 2021, 12:26

IGP1 = 8.9 e-06 Torr and trending down

TGHT = 420 A, 7.5 V

OMEGA = 1730 C

Will ramp up to 428 A manually 

Sunday, February 14, 2021, 12:30

Reached 428 A on TGHT.  

OMEGA = 1760 C

Will bump to 430 A and hold for 4 hours

OMEGA= 1765 C

Sunday, February 14, 2021, 18:00

OMEGA = 1789 C

IGP1= 7.5 e -7 Torr

TGHT = 430.5 A , 7.8 V

Start ramping down at -1A/min to zero A

Thursday, February 10, 2021, 12:00

Objective: Heat a Re wire to evaporate it and deposit a layer of Re on the inner surface of a Ta tube.

A Re wire of 1mm diameter was clamped with Cu brackets in EVAP2, the wire is partially enclosed in a Ta tube. EVAP2 pumping down 

The wire needs to be heated to 2500 degC since this is its sublimation temperature at 8e-7 Torr

There is not a reliable system to measure the temperature of the wire but the readings of the micron, manual, and omega pyrometers will be register.

According to COMSOL simulations a power and taking in consideration the EVAP2's power loss, a power of 520 W (5A, 10V) is required.

Thursday, February 11, 2021, 15:39

Pressure 3.78e-7 Torr, current rate set to 10 A @ 0.5 A/min

Thursday, February 11, 2021, 16:32

Pressure: 4.01e-7 Torr, TGHT = 10A, 1.719 V. The voltage has stabilized, the wire is glowing but not enough for reading with micron nor omega, manual reads 970 degC. Also, the wire formed an arc (crest).

Thursday, February 11, 2021, 16:44

 Pressure 3.8e-7 Torr, TGHT  = 10 A, 1.723 V ramp set to 20A @ 0.2 A/min

Thursday, February 11, 2021, 17:26  

Pressure increasing 4.7e-7 torr, TGHT = 20 A, 4.016 V, the wire does not seem to be changing, 

Thursday, February 11, 2021, 18:02

Ramp set to 30A @0.4A/min

Pressure  7.2e-7 Torr, TGHT = 30A, 6.561V, manual pyrometer reads 1720degC

Ramp set to 40A @0.4A/min

Thursday, February 11, 2021, 18:35

 Pressure 2.1e-6Torr and increasing, TGHT = 40A, 9.1V, manual pyrometer reads ~1880 degC

Ramp set to 50A @ 0.4 A/min