Laura Lambert wrote:

John Wong wrote: John Wong wrote: Laura Lambert wrote: John Wong wrote: Tuesday, September 01, 2015, 17:16 Target container contains 533 discs of SiC with packed length of 17cm.  Mass of 533 discs SiC(green)  = 57.8979g Total mass SiC(green) + target container = 1455g Container is wrapped with 3 heatshields; no end caps are inserted yet. Sintering temp at 1800C - TGHT will be set accordingly.  TBHT max at 230A.  Chamber is currently being pumped down.     Wednesday, September 02, 2015, 09:11 HS water valves opened, no leaks detected. IGP1 = 1.15e-6 Torr Tapped up manually to 40A. Waited ~1hr40 for vacuum to stabilize. IGP1 = 3.6e-6 Torr. Max setpoints set to TGHT = 630A and TBHT = 230A, ~1400C Initiating auto ramp at a rate of 0.2A/min and 0.1A/min for the TGHT and TBHT respectively. Once max setpoints achieved, will tap up manually until window port becomes coated [as previously observed] Once window port becomes coated will leave at set temp for ~4hrs to continue with outgassing, then cool down, clean window and ramp back up. If LS port still clean, will continue to ramp up to final desired temperature of 1800C.  Wednesday, September 02, 2015, 14:23 IGP1 = 4.0e-5 Torr. Vacuum too high, stopped auto-ramp and tapped down manually. Dropped TGHT down from 80A to 50A Dropped TBHT down from 55A to 50A Wednesday, September 02, 2015, 15:29 Vacuum down to IGP1 = 1.2e-5 Torr. Re-initiating auto-ramp...  Tuesday, September 08, 2015, 10:04 IGP1 = 4.5e-7 Torr. TGHT = 630A, 9.6V TBHT = 230A, 3.2V DV = 0.22V OMEGA RS = 1476C OMEGA LS = 1450C see attached photo for screenshot. will tap up manually with a visual on both window ports...    Tuesday, September 08, 2015, 15:44 TGHT has stepped up to 820A.  Coating on both windows is becoming obvious and it's interfering the temp readers; however, the left window (see attachment, which is further away from the target) is lightly coated than the right.  See attachment for The Temp (and Power) vs current plots. Target will remained heated at the current and will be cooled down later today.    The target will be re-conditioned up to 820A and temp and mass will be re-measured. Plans: The chamber will be vented tomorrow and the target will be taken out to weigh for mass change.  The chamber windows will need to be clean. A piece of Ta foil will be cover in front of the ionizer to trap any loss material (if any).  Tuesday, September 08, 2015, 17:37 TGHT was at 800A for 2 hours before ramping up 820A for another 2 hours heating.  More coating on the right window is observed and temp reading came down to 1340C.  The left window remains the same and temp reads at 1646C.   Ramping TGHT/TBHT to 0A at 2A/min and 1A/min, respectively.    Wednesday, September 09, 2015, 12:27 Result after the sintering process: No yellow crystal formed (compared to previously observed SiC targets that heated up above 1900C).  Total green mass = 57.90g  mass of graphite foil = 0.035g x 533 discs = 18.7g  mass of green SiC = 39.30g  Target container with SiC before sintered = 1455g  Target container after sintered = 1450g  mass loss ~ 5.0g ~ 13% organic mass, as expected!   The target will undergo the re-condition stage, and the temperature will be measured from 600A to 820A.     Wednesday, September 09, 2015, 17:39 Both end-caps are inserted onto the targets.  The total mass (Target, Sintered SiC, end caps, 4x 19"round graphite foils) = 1453g. Target is wrapped with 3 layers of heat shields.   The extraction electrode is wrapped with Ta-foil (see attachment).  This is to trap any lose particle, if any.   Chamber is currently being pumped down, currently at 1.2e-5 Torr.      Thursday, September 10, 2015, 09:55 HS water valves opened this morning, no leaks detected. TGHT and TBHT tapped up manually to 35A. IGP1 = 4.4e-7 Torr, vacuum stable. Initiating auto-ramp at 1.0A/min and 0.5A/min for the TGHT and TBHT respectively with final setpoints of 600A and 230A.

Thursday, September 10, 2015, 12:05  

Changed TGHT to 2A/min and TGHT remains at 1A/min.  Vacuum is table at 1.0e-6 Torr. 

Friday, September 11, 2015, 11:34  

TGHT was at 600A for almost 20 hours.  Vac at 5.2 e-7 Torr.   L-temp at 1490C, R-temp at 1685 (odd?).   Using pyrometer to measure - Right end does seem brighter than the L end.  

Continue to ramp up TGHT.  Date is collected, will be posted later.  

 Friday, September 11, 2015, 11:53

L/R-temp measurements just don't seem normal.  

Ramped up to 220A- temp reads L = 1522C, R = 1722C.  

Ramping down TBHT doesn't change the temp.  

Will cool TGHT/TBHT to 0A at 2A/min & 1A/min, respectively.  

Will vent the chamber on Monday and inspect for any wrong.

 Monday, September 14, 2015, 12:13

The target has taken out for inspection.  No visible damage/problem was observed.  The Ta-foil for loss particle capture only showed some heat marking but no material was trapped. 

Target was weighted, no mass loss was observed.

Try expending the end caps to get a good thermal conductivity and will re-conditiong again.  

 Tuesday, September 15, 2015, 12:31

The end caps have been expended. 

New Ta foils are used for the heat shields.  The foils are cut in 3 1/4" x 12" and wrapped around the target.  (see attachment).  This is to see if the heat is evenly distributed.  

Both omega optical lens are aligned properly.  

Target is installed but the chamber is NOT yet being pumped down.  Awaiting for the fume hood work in B2 level to be complete before the evaporator can be started. 

 Wednesday, September 16, 2015, 17:57

The work in the B2 level is done; the nuclear ventilation for the evaporators is now operational. 

Chamber is currently being pumped down.

 Thursday, September 17, 2015, 12:19

Chamber has been pump down overnight and pressure is currently at 5.8e-7 Torr.

HS valves are opened and no leaks are detected.

Ramping up TGHT/TBHT to 600A at 2A/min and 230A at 1A/min, respectively.

 Thursday, September 17, 2015, 17:58

TGHT has reached to 600A/9.14V.  Both the L and R temperatures are measured at 1710C and 1760C, respectively.  At 600A, the temperature now is about 300C higher compared to that during the sintering process. 

The difference in the temperature could be from Ta surface vs SiC surface.  (But the 2-color IR temp reader shouldn't matter what color it's measuring?!! I don't know!)

Note: 

Both temperature readings are fairly close.  Could this be improved from the new Ta-foils?  Possible!

It is still unclear what is the absolute temperature.  A more systematic student needs to be done. 

Using a thermocouple couple to measurement the endcaps at 600A and compared with the Omage reader may help to understand more. 

After discussing with Friedhelm, it is decided to stay the target at 600A for the conditioning process. 

 Friday, September 18, 2015, 09:10

Target has been heated at 600A at stable temperature at 1716C (LS) and 1769C (RS), see attachment. 

 Friday, September 18, 2015, 11:45

Initiated cooling down at 2A/min for TGHT, and 1A/min TBHT. 

Currently vac at 5.48e-7 Torr.

 Thursday, September 24, 2015, 11:31

Target was inspected after the 2nd conditioning, up to 1700C at 600A for overnight. 

No solid particle was observed that might have extracted from the ionizer tube.  

The heat shields have been removed and the target is ready for assembly. 

Nikita Bernier wrote:

John Wong wrote: Nikita Bernier wrote: John Wong wrote: Tuesday, May 15, 2012, 12:24 The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1.  This target is going into Evap#2 for re-conditioning.  It is currently being pumped down.    Friday, May 18, 2012, 12:19  The target is wrapped with only one heat shield. Evaporator #2 Target Heater is now auto-ramping at 0.5 A/min, up to 820 A, with the maximum voltage limited at 2 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). Tube Heater is auto-ramping at 0.5 A/min, up to 230 A, with the maximum voltage limited at 1 V. See attachments.  Friday, May 18, 2012, 13:15 Increased TBHT voltage to 5V, and TGHT to 15V.  Currently, TBHT =83A, 0.986V, TGHT= 144A, 1.65V, IGP1 = 5.2e-7 Torr, IGP2 = 4.3e-7 Torr.  Continue ramping up...   Tuesday, May 22, 2012, 12:02 TGHT and TBHT were ramped up to 830A/13.65V (local), and 235A/3.85V, respectively.  The target was conditioned over the long weekend.      Tuesday, May 22, 2012, 12:13 Initiating the cool-down process at 5 A/min. See archive plots of the Target Heater (Attachment 1) and the Tube Heater (Attachment 2).

 Tuesday, May 22, 2012, 15:24

TGHT/TBHT were ramped down to 0A.  The target has cooled for about 45 min.  All pumps and chillers are off.  The chamber has been vented.

Tuesday, May 15, 2012, 12:24

The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1. 

This target is going into Evap#2 for re-conditioning.  It is currently being pumped down. 

John Wong wrote:

Tuesday, May 15, 2012, 12:24 The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1.  This target is going into Evap#2 for re-conditioning.  It is currently being pumped down.

Friday, May 18, 2012, 12:19 

The target is wrapped with only one heat shield.

Evaporator #2 Target Heater is now auto-ramping at 0.5 A/min, up to 820 A, with the maximum voltage limited at 2 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). Tube Heater is auto-ramping at 0.5 A/min, up to 230 A, with the maximum voltage limited at 1 V. See attachments.

Nikita Bernier wrote:

John Wong wrote: Tuesday, May 15, 2012, 12:24 The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1.  This target is going into Evap#2 for re-conditioning.  It is currently being pumped down.    Friday, May 18, 2012, 12:19  The target is wrapped with only one heat shield. Evaporator #2 Target Heater is now auto-ramping at 0.5 A/min, up to 820 A, with the maximum voltage limited at 2 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). Tube Heater is auto-ramping at 0.5 A/min, up to 230 A, with the maximum voltage limited at 1 V. See attachments.

 Friday, May 18, 2012, 13:15

Increased TBHT voltage to 5V, and TGHT to 15V.  Currently, TBHT =83A, 0.986V, TGHT= 144A, 1.65V, IGP1 = 5.2e-7 Torr, IGP2 = 4.3e-7 Torr. 

Continue ramping up... 

 Tuesday, May 22, 2012, 12:02

TGHT and TBHT were ramped up to 830A/13.65V (local), and 235A/3.85V, respectively.  The target was conditioned over the long weekend.  

John Wong wrote:

Nikita Bernier wrote: John Wong wrote: Tuesday, May 15, 2012, 12:24 The HP-SIS SiC target was made on Nov 03, 2010.  The target consists of 405 discs, 18.5cm in length.  It was sintered in the Evaporator#1.  This target is going into Evap#2 for re-conditioning.  It is currently being pumped down.    Friday, May 18, 2012, 12:19  The target is wrapped with only one heat shield. Evaporator #2 Target Heater is now auto-ramping at 0.5 A/min, up to 820 A, with the maximum voltage limited at 2 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). Tube Heater is auto-ramping at 0.5 A/min, up to 230 A, with the maximum voltage limited at 1 V. See attachments.  Friday, May 18, 2012, 13:15 Increased TBHT voltage to 5V, and TGHT to 15V.  Currently, TBHT =83A, 0.986V, TGHT= 144A, 1.65V, IGP1 = 5.2e-7 Torr, IGP2 = 4.3e-7 Torr.  Continue ramping up...   Tuesday, May 22, 2012, 12:02 TGHT and TBHT were ramped up to 830A/13.65V (local), and 235A/3.85V, respectively.  The target was conditioned over the long weekend.

 Tuesday, May 22, 2012, 12:13

Initiating the cool-down process at 5 A/min.

See archive plots of the Target Heater (Attachment 1) and the Tube Heater (Attachment 2).

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

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

 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.

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

Laura Lambert wrote:

John Wong wrote: Laura Lambert wrote:  Tuesday, June 09, 2015, 9:16 Target container is coated with TaC. No Ta-heat shields are used. TGHT will be ramped up to 580A at 0.2A/min. TBHT will be ramped up to 230A at 01A/min. Chamber is currently being pumped down.  Tuesday, June 09, 2015, 15:37 HS water valves were opened. no leaks detected. Tapped up manually to 35A. Once vacuum stabilized after ~45min, initiated auto-ramp.  Wednesday, June 10, 2015, 08:02 IGP1 = 5.3e-7 Torr. TGHT = 250A and TBHT = 140A. Increasing auto ramp to 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.    Wednesday, June 10, 2015, 16:32 TGHT/TBHT are at 580A/230A for almost 6 hours, temp at 1728C. Vac at 8.5e-7 Torr.  Cooling down initiated at 1A/min. Target container should be inspected once the chamber is vented.    Thursday, June 11, 2015, 10:55 Vented in air and opened up this morning. Same as last container sintered in evap2 [IG-LIS for UCx#13] - ends not quite fully sintered and coating not very good. most likely due to old TaC spray. See link for photos. https://www.dropbox.com/sh/75o43x8y2z16e7j/AABc8Z1fTTaTRtJ5_Jr1eacWa?dl=0

 Monday, June 15, 2015, 15:24

Same problem also found for the LP-IG-LIS container, WO#40860-1, see elog id#215.  After re-coating and sintering, it seems better. 

For this container, it is re-coated and will undergo the sintering process one more time. 

Will try to go up to 1900C for the sintering process.

Target container is temporarily wrapped with 6.2cm of Ta foil as a layer for heat shield on each side of the tube, excluding the centre block.  The shield will be removed once the process is done.  

Target current will be controlled accordingly. 

Chamber is being pumped down. 

 Monday, June 15, 2015, 16:17

HS water valves open; no leaks detected. 

IGP1 at 6.8e-6 Torr and coming down.

 Monday, June 15, 2015, 17:21

Stepping up TGHT/TBHT to 60A, pressure seems pretty stable at 7.2e-6 Torr and coming down. 

Setting TGHT to 400A and TBHT to 230A, auto-ramping initiated.   Will setup up current to reach 1900C, if necessary. 

 Monday, June 15, 2015, 20:28

TGHT and TBHT reached 400A/230A, Temp at 1552C.  Vac at 2.7e-6 Torr.

Stepping TGHT

Monday, June 15, 2015, 21:16  

TGHT at 520A/9.06 V to achieve 1900C.  DV at 5.09V.  

Vac at 4.2e-6 Torr.  

Will continue the sintering process at this temperature for another 3-4 hours. 

 Tuesday, June 16, 2015, 00:15

Target container has been heated at 1900C for over 3 hours.  

Vacuum is coming down to 1.4e-6 Torr.  

Initiated cooling process at 2A/min

Chamber can be vented tomorrow and container should be inspected

 Friday, June 26, 2015, 16:04

Container looks good!

Laura Lambert wrote:

John Wong wrote: Laura Lambert wrote: John Wong wrote: Laura Lambert wrote:  Thursday, June 04, 2015, 9:07 Container was sprayed with TaC and let dry. Container has 3x Ta heat shields including center block. Container was loaded into EVAP2 yesterday and pumped down overnight. HS water valves were opened up this morning, no leaks detected. IGP1 = 4.6e-7 Torr. Tapped up manually to 40A. Waited ~25min, Vacuum stable. IGP1 = 5.0e-7 Torr. Initiating auto-ramp. TGHT will be ramped to reach 2000C  Friday, June 05, 2015, 10:01 IGP1 = 4.5e-7 Torr. TGHT = 313A, 4.47V OMEGA = 1444C Increasing ramping rate to 1.0A/min  Friday, June 05, 2015, 11:31 IGP1 = 1.2e-6 Torr. Increasing ramping rate to 2.0A/min    Friday, June 05, 2015, 12:01 TGHT reached to 465A/7.56V, temp is stable at 2000C. Current vac at 1.2e-6 Torr and coming down Cooling down process can be initiated after 4 hours.     Friday, June 05, 2015, 13:21 OMEGA = 1995C Increasing TGHT to 470A to achieve desired max temperature of 2000C Friday, June 05, 2015, 15:59 TGHT sat at max desired temperature of 2000C for ~4hrs. TGHT = 470A, 7.7V Initiating auto-cool at 1.0A/min.  Monday, June 08, 2015, 11:31 Vented in air and opened up this morning. Target container mostly sintered, two tiny patches near both ends not fully sintered. Will re-install and re-sinter next week as another container with priority needs to be sintered first.  Tuesday, June 09, 2015, 10:45 See attachements for 'not-fully-sintered' photos    Wednesday, June 10, 2015, 12:06 After inspecting the target container,  the inner tube surface has "dark" patches, which may not be evenly coated or the coating layer was too think.   See link for photos:  https://www.dropbox.com/sh/m94mjuuodwhz5jb/AADEBv_Kha_p_1An40eftWNHa?dl=0  Attempt to re-spray the container and re-sinter.        Friday, June 12, 2015, 14:58 re-sprayed with second layer of TaC spray this morning. re-loaded into evap2. HS water valves opened, no leaks detected. will ramp-up over weekend.

 Friday, June 12, 2015, 16:07

Vacuum comes down to 6.1e-6 Torr.

Initiated auto-ramping at 0.2A/min for 300A first. 

John Wong wrote:

Laura Lambert wrote: John Wong wrote: Laura Lambert wrote: John Wong wrote: Laura Lambert wrote:  Thursday, June 04, 2015, 9:07 Container was sprayed with TaC and let dry. Container has 3x Ta heat shields including center block. Container was loaded into EVAP2 yesterday and pumped down overnight. HS water valves were opened up this morning, no leaks detected. IGP1 = 4.6e-7 Torr. Tapped up manually to 40A. Waited ~25min, Vacuum stable. IGP1 = 5.0e-7 Torr. Initiating auto-ramp. TGHT will be ramped to reach 2000C  Friday, June 05, 2015, 10:01 IGP1 = 4.5e-7 Torr. TGHT = 313A, 4.47V OMEGA = 1444C Increasing ramping rate to 1.0A/min  Friday, June 05, 2015, 11:31 IGP1 = 1.2e-6 Torr. Increasing ramping rate to 2.0A/min    Friday, June 05, 2015, 12:01 TGHT reached to 465A/7.56V, temp is stable at 2000C. Current vac at 1.2e-6 Torr and coming down Cooling down process can be initiated after 4 hours.     Friday, June 05, 2015, 13:21 OMEGA = 1995C Increasing TGHT to 470A to achieve desired max temperature of 2000C Friday, June 05, 2015, 15:59 TGHT sat at max desired temperature of 2000C for ~4hrs. TGHT = 470A, 7.7V Initiating auto-cool at 1.0A/min.  Monday, June 08, 2015, 11:31 Vented in air and opened up this morning. Target container mostly sintered, two tiny patches near both ends not fully sintered. Will re-install and re-sinter next week as another container with priority needs to be sintered first.  Tuesday, June 09, 2015, 10:45 See attachements for 'not-fully-sintered' photos    Wednesday, June 10, 2015, 12:06 After inspecting the target container,  the inner tube surface has "dark" patches, which may not be evenly coated or the coating layer was too think.   See link for photos:  https://www.dropbox.com/sh/m94mjuuodwhz5jb/AADEBv_Kha_p_1An40eftWNHa?dl=0  Attempt to re-spray the container and re-sinter.        Friday, June 12, 2015, 14:58 re-sprayed with second layer of TaC spray this morning. re-loaded into evap2. HS water valves opened, no leaks detected. will ramp-up over weekend.  Friday, June 12, 2015, 16:07 Vacuum comes down to 6.1e-6 Torr. Initiated auto-ramping at 0.2A/min for 300A first.

Sunday, June 14, 2015, 09:37  

TGHT at 254.2A/3.5V3, DV = 1.614V Temp at 1177C. 

Vacuum is stable at 3.2e-7 Torr.  

Increase ramping rate at 2A/min until TGHT reached 300A. 

Sunday, June 14, 2015, 10:04  

TGHT reached 300A, temp 1368C.

Tapping up to ~1800C

Sunday, June 14, 2015, 11:26 

TGHT at 425A/6.84V, DV 3.59V, temp at 1814C, 

Vacuum coming down, currently at 7.5e-7 Torr. 

Will remain at that current for at least 4 hours before cooling down

Sunday, June 14, 2015, 17:15  

Target container has been sintered with TiC for over 6 hours at 1823C, with TGHT at 425A/6.84V, DV at 3.584V. 

Vac at 4.9e-7 Torr.  

Cooling initiated.  

Chamber can be vented tomorrow and target container can be taken out for inspection. 

 Monday, June 15, 2015, 11:38

Target container was taken out for inspection.  

It's observed that the coated/sintered TaC surface is improved.  The sintered temperature was only gone up just above 1800C, so there still some area near the ends that is still somewhat "brownish", fully sintered shows a

smooth .  (see attachment) 

Spraying into a cylinder tube can be challenging.  It was observed that the coating was dispersed out from the end cap to the centre tube.  For that reason, the container isn't has much protective layer;vthe Ta surface can

react with carbides and the container eventually breaks.  Take the endcap process for example,  the caps are evenly coated with TaC and can be sintered up to 2000C (see e-log Evap ID 202).

Suggestions:  

Using a spray ball nozzle or some sort so that the inner tube can be evenly coated. 

Under investigating...

 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

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

 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.

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

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

John Wong wrote:

John Wong wrote:  Wednesday, September 07, 2016, 14:45 Container was previously coated with TaC solution and wrapped with 1-full length layer of Ta- heat shield around the fins.   Chamber is being pumped down.  Vac at 5.6e-7 Torr before HS water valves were open; no leaks were detected.  Sintering Temperature 1900C (Omega slope @ 0.98); expected TGHT ~765A/11.90V, TGHT max at 230A.  Thursday, September 08, 2016, 18:14 At about 1600C, it was observed that the coating inside the tube seems to chip off (see attachment 1). TGHT was ramped up to 745A/11.85V and TBHT to 230A/3.25V.  Temperature measured on OMEGA/Mikron = 1914C/1881C; both instruments slopes set at 0.98. Will remain at this TGHT current over night Vac at 3.0e-6 Torr and coming down. Friday, September 09, 2016, 11:01  Target has been heated at the stable temperature at 1914C (for OMEGA) and 1881C (for Mikron) with current at 745A/11.94V (see attachment 2) for almost 19 hours.  No fluctuation in p/s current or temperature was observed.  The ramping up process is captured and can be view from the link below: https://www.dropbox.com/sh/9lgtin54o17ds6j/AABn1-XjvK44mm74TjqTAmvta?dl=0 Pressure at 1.07e-6 Torr.  Cooling down TGHT at 2A/min and TBHT at 1A/min.  Continue to capture the cooling down process.   Friday, September 09, 2016, 15:17  While the target container was cooling down, the chip-like particle began obvious (see attachment 3).   Will inspect the container.. TGHT currently at 260A.    Monday, September 12, 2016, 16:54 The TaC coating chipped off from the surface and didn't get sintered with the container.  (See attachment1).  There are a few possible reasons why this happened: 1.  The coating was too think.  This may cause the TaC  layer to curl up while the heater was ramped up.  2.  The coated material got brittle.  The container was flushed with TaC (probably a few weeks ago?) before it went through the sintering process.  Prolong exposure to air/light usually degrade the polymers viscoelasticity. 3.  TaC solution has got bad.  The particles can agglomerate over time and this can cause uneven surface. 4.  Combination of all... ??? Anyway, the chipped off TaC layer was gently scraped off with a stainless steel rod.  Then using kimwipes, i was able to remove most of the chipped off coating; it was not easy - especially trying to remove it from the inner tube. Instead of "flushing" the tube with TaC, I decided to spray it with thin layer.  And using the air supply, I could quickly dry the coating and installed it back to the evaporator for 2nd Round sintering as we are approaching the deadline! .

 Monday, September 12, 2016, 17:24

Chamber was pumped down to low 10e-6 Torr before HS water valves were open - no leaks detected.

TGHT/TBHT auto ramped at 2A/min to 600A/230A.

Will continue to monitor..

 Wednesday, September 14, 2016, 17:04

TGHT was stepped up to 700A and temp 1851C (OMEGA), 1930C(Mikron).  (see attachment 1).  The container was heated over night before it was cool down at 2A/min. 

Target container seems to properly sintered with TaC (see attachment 2); it will be used for SiC#35.