Friday, June 13, 2014, 14:53

Container is filled with 400 discs of Ta foils; target length = 5.2cm;

Total mass ( Ta foils + wire) = 45.92g

No Ta foil heat shield.

No caps inserted.

Chamber pumped down this morning.

HS cooling water valves opened, no leaks detected.

IG @ 5.8e-6 Torr.

TGHT max = 580A

TBHT max = 230A

Ramping rate 0.2A/min.

 Monday, June 16, 2014, 11:46

TGHT and TBHT reached their respective 580A and 230A over the weekend.

IGP1 currently at 3.2e-7 Torr.

Internal temp [measured using mikron, right side of EVAP2, pointed at discs inside] = 1375C

Laura Lambert wrote:

Friday, June 13, 2014, 14:53 Container is filled with 400 discs of Ta foils. No Ta foil heat shield. No caps inserted. Chamber pumped down this morning. HS cooling water valves opened, no leaks detected. IG @ 5.8e-6 Torr. TGHT max = 580A TBHT max = 230A Ramping rate 0.2A/min.  Monday, June 16, 2014, 11:46 TGHT and TBHT reached their respective 580A and 230A over the weekend. IGP1 currently at 3.2e-7 Torr. Internal temp [measured using mikron, right side of EVAP2, pointed at discs inside] = 1375C

 Monday, June 16, 2014, 17:21

Further stepping up TGHT to 650A.

Temperature measured on target discs = 1542C. Vac @ 3.28e-7 Torr.

Initiate cooling down process; 2A/min for TGHT; 1A/min for TBHT

John Wong wrote:

Laura Lambert wrote:  Friday, June 13, 2014, 14:53 Container is filled with 400 discs of Ta foils. No Ta foil heat shield. No caps inserted. Chamber pumped down this morning. HS cooling water valves opened, no leaks detected. IG @ 5.8e-6 Torr. TGHT max = 580A TBHT max = 230A Ramping rate 0.2A/min.  Monday, June 16, 2014, 11:46 TGHT and TBHT reached their respective 580A and 230A over the weekend. IGP1 currently at 3.2e-7 Torr. Internal temp [measured using mikron, right side of EVAP2, pointed at discs inside] = 1375C    Monday, June 16, 2014, 17:21 Further stepping up TGHT to 650A. Temperature measured on target discs = 1542C. Vac @ 3.28e-7 Torr. Initiate cooling down process; 2A/min for TGHT; 1A/min for TBHT

 Tuesday, June 17, 2014, 10:08

TGHT and TBHT reached 0A last night.

Turned off EVAP2

Venting chamber

Process Complete

Laura Lambert wrote:

Laura Lambert wrote: Laura Lambert wrote:  Wednesday, April 05, 2017, 15:36 Coated container with TaC coating using spray technique this morning and let dry. Wrapped with one long layer of Ta heat shield, wrapped around boat 3x No ends to target boat Installed in evap2 and pumping down now...    Thursday, April 06, 2017, 08:56 Problems with IGP2 Won't turn on, has low voltage output. See screenshot attached.    Thursday, April 06, 2017, 11:12 Turns out it was just a bad connection. See attached photos.

Thursday, April 06, 2017, 13:16

HS water valves opened, no leaks detected.

Tapped up manually to 35A

Waited almost 2hrs

IGP1 = 9.9e-7 Torr

Initiating auto-ramp at 0.2A/min to 400A

Final desired temperature = 1900C

OMEGA slope = 0.98

Good vac at 3.0e-5, bad vac at 4.0e-5 Torr.

 Monday, April 10, 2017, 09:26

IGP1 = 1.79e-7 Torr

TGHT = 400A, 6.47V

OMEGA = 1505C

Tapping up manually to 1900C...

 Monday, April 10, 2017, 11:46

TGHT tripped off at 410A, ~1530C

Water is still on and good flow.

Vacuum was stable ~1.8e-7 Torr.

No power trips according to controls.

Not sure of reasoning behind trip.

Initially tried tapping back-up, no current was being applied.

Turned off and back on TGHT power supply - this restarted things and now works again.

Have tapped back up to 35A, vacuum still good.

Restarting auto-ramp to 400A at 1.0A/min

 Monday, April 10, 2017, 13:13

Vacuum looks good.

IGP1 = 1.1e-7 Torr

TGHT = 127A, 1.30V

Increasing ramping rate to 2.0A/min

 Monday, April 10, 2017, 16:08

IGP1 = 1.5e-7 Torr

TGHT = 400A, 6.24V

OMEGA = 1510V

Increasing auto ramp setpoint to 450A at a rate of 0.2A/min

 Wednesday, April 12, 2017, 11:06

IGP1 = 2.96e-7 Torr

TGHT = 555A, 9.74V

OMEGA = 1935C

Has remained at max setpoints overnight.

Initiating auto-cool at 2.0A/min

 Thursday, April 13, 2017, 11:59

vented in air and opened up this morning.

container looks good.

see photo attached.

 Tuesday, February 16, 2016, 14:19

coated with TaC yesterday and let dry overnight.

wrapped with one long Ta heat shield - wrapped around tube 3x, with Ta wire to offset Ta foil away from container

loaded into evap2 and currently pumping down.

 Wednesday, February 17, 2016, 10:51

HS water valves opened, no leaks detected.

Tapped up manually to 35A.

Waited ~20min, vacuum stable.

IGP1 = 5.9e-7 Torr.

Initiating auto-ramp at 0.2A/min to a final setpoint of 400A.

Final desired temperature = 1900C

 Thursday, February 18, 2016, 09:16

IGP1 = 6.6e-7 Torr.

TGHT = 303A, 4.3V

OMEGA = 1311C

Increasing ramping rate to 1.0A/min.

Laura Lambert wrote:

Tuesday, February 16, 2016, 14:19 coated with TaC yesterday and let dry overnight. wrapped with one long Ta heat shield - wrapped around tube 3x, with Ta wire to offset Ta foil away from container loaded into evap2 and currently pumping down.  Wednesday, February 17, 2016, 10:51 HS water valves opened, no leaks detected. Tapped up manually to 35A. Waited ~20min, vacuum stable. IGP1 = 5.9e-7 Torr. Initiating auto-ramp at 0.2A/min to a final setpoint of 400A. Final desired temperature = 1900C  Thursday, February 18, 2016, 09:16 IGP1 = 6.6e-7 Torr. TGHT = 303A, 4.3V OMEGA = 1311C Increasing ramping rate to 1.0A/min.

 Thursday, February 18, 2016, 13:10

TGHT reached to 450A, temp at 1800C.  Stepped up TGHT 490A, temp measured at ~1900C. 

John Wong wrote:

Laura Lambert wrote:  Tuesday, February 16, 2016, 14:19 coated with TaC yesterday and let dry overnight. wrapped with one long Ta heat shield - wrapped around tube 3x, with Ta wire to offset Ta foil away from container loaded into evap2 and currently pumping down.  Wednesday, February 17, 2016, 10:51 HS water valves opened, no leaks detected. Tapped up manually to 35A. Waited ~20min, vacuum stable. IGP1 = 5.9e-7 Torr. Initiating auto-ramp at 0.2A/min to a final setpoint of 400A. Final desired temperature = 1900C  Thursday, February 18, 2016, 09:16 IGP1 = 6.6e-7 Torr. TGHT = 303A, 4.3V OMEGA = 1311C Increasing ramping rate to 1.0A/min.    Thursday, February 18, 2016, 13:10 TGHT reached to 450A, temp at 1800C.  Stepped up TGHT 490A, temp measured at ~1900C.

Thursday, February 18, 2016, 17:21

TGHT remained at max setpoint for 4hrs.

IGP1 = 6.6e-7 Torr.

OMEGA = 1913C

Initiating auto-cool for TGHT at 2.0A/min.

 Friday, February 19, 2016, 14:17

evap2 vented and opened up this morning.

container looks good.

Thursday, September 26, 2013, 13:04

The LP-IG-LIS target container is coated with TaC. 

Container is wrapped with 3 layers of Ta heat shield and about to go through the sintering process.

A thermocouple is inserted to measure the temperature inside the tube (1st attempt ever). 

Click on the link for detailed pictures:

https://www.dropbox.com/sh/6dc5arajg87mws9/6cU5OxjkZg

TGHT will be ramped up to 580A at 0.2A/min

TBHT will be ramped up to 230A at 0.2A/min.

Chamber has been pumped down.  HS cooling H2O valves are opened, and no leaks are detected. 

Currently IGP1 @ 5.9e-6 Torr.

 Thursday, September 26, 2013, 15:44

TGHT stepped up to 30A.  TBHT currently @ 0A. 

Temp @ 35C, Vac @ 1.4e-5 Torr.

 Monday, September 30, 2013, 14:54

The container was heated up to 580A TGHT/ 230A TBHT for a day (see attachment #1 for vac vs cur plot).

The temperature was measure at ~1780C. (see link for details: https://www.dropbox.com/sh/d8d9j2t60qlm3jk/nkMh7dx_R8 )

The target was cooled down and vented. 

Proceed complete.

 Wednesday, August 17, 2016, 17:30

Container coated with TaC using 'flushing technique', cleaned ionizer tube with acetone, so no coating inside ionizer tube

Wrapped with 3 x Ta heat shields, incl center block

Currently pumping down in evap2

Thursday, August 18, 2016, 10:14 

HS water valves opened...leak detected  see attachment for photo from archives

Vented and opened up.

Anders performed leak check, nothing found.

Replaced all seals with blue seals.

Pumping down now

 Thursday, August 18, 2016, 16:12

HS water valves opened...leak detected again  see attachment for photo of striptool

Vented and opened up.

working with Anders on finding leak...

 Monday, August 22, 2016, 10:38

leaks FIXED!

HS water valves opened, NO leaks detected!

Tapped up manually to 70A

Vacuum stable, IGP1 = 2.5e-6 Torr

Initiating auto ramp for TGHT @ 0.2A/min to a max setpoint of 350A

Initiating auto ramp for TBHT @ 0.1A/min to a max setpoint of 230A

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

 Monday, August 22, 2016, 14:58

TGHT = 115A, 1.3V

TBHT = 89A, 0.97V

IGP1 = 4.1e-7 Torr.

Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.

 Monday, August 22, 2016, 16:01

IGP1 = 1.25e-6 torr

TGHT = 174A, 2.2V

TBHT = 118A, 1.4V

Lowering ramping rate to 0.2A/min and 0.1A/min for the TGHT and TBHT respectively for overnight ramping.

Laura Lambert wrote:

Wednesday, August 17, 2016, 17:30 Container coated with TaC using 'flushing technique', cleaned ionizer tube with acetone, so no coating inside ionizer tube Wrapped with 3 x Ta heat shields, incl center block Currently pumping down in evap2 Thursday, August 18, 2016, 10:14  HS water valves opened...leak detected  see attachment for photo from archives Vented and opened up. Anders performed leak check, nothing found. Replaced all seals with blue seals. Pumping down now  Thursday, August 18, 2016, 16:12 HS water valves opened...leak detected again  see attachment for photo of striptool Vented and opened up. working with Anders on finding leak...  Monday, August 22, 2016, 10:38 leaks FIXED! HS water valves opened, NO leaks detected! Tapped up manually to 70A Vacuum stable, IGP1 = 2.5e-6 Torr Initiating auto ramp for TGHT @ 0.2A/min to a max setpoint of 350A Initiating auto ramp for TBHT @ 0.1A/min to a max setpoint of 230A Once max setpoints achieved, will tap up manually to final desired temperature of 1900C  Monday, August 22, 2016, 14:58 TGHT = 115A, 1.3V TBHT = 89A, 0.97V IGP1 = 4.1e-7 Torr. Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.  Monday, August 22, 2016, 16:01 IGP1 = 1.25e-6 torr TGHT = 174A, 2.2V TBHT = 118A, 1.4V Lowering ramping rate to 0.2A/min and 0.1A/min for the TGHT and TBHT respectively for overnight ramping.

 Tuesday, August 23, 2016, 12:14

Initiate TGHT autoramping to 400A at 2A/min.  Vac 3.5e-7 Torr. 

 Tuesday, August 23, 2016, 14:48

TGHt tapped up to 420A/7.01V.  Local temp read at ~1900C.  Will sinter at this temp for a few hours before cooling down.

 Tuesday, August 23, 2016, 17:20

TGHT at been at 420A/7.01V for over 4 hours.  Vac at 4.8e-7 Torr.

Cooling TGHT and TBHT at 1A/min.

 Wednesday, August 24, 2016, 10:35

TGHT/TBHT at 0A.

Venting chamber.

Container looks good.

Wednesday, August 24, 2016, 17:05

Target container was previously coated with TaC and sintered up to 1900C at 420A/7.01V

Container is loaded with beta-SiC 432 discs at 16cm in length. 

Container is wrapped with Ta-heat shield; no end-caps are used at this time.

Chamber is being pumped down.

 Thursday, August 25, 2016, 12:04

Chamber has been pumped down overnight.  Pressure at 5.9e-7 Torr.

HS water valve opened; no leaks were detected.

Sintering temperature 1800C. TGHT will be set accordingly to get the desired temperature.  TBHT max at 230A.

Thursday, August 25, 2016, 12:12

Tapped up TGHT/TBHT to 40A.  Vac at 7e-6 and slowly going up  but still below limit.

 Monday, August 29, 2016, 11:04

TGHT and TBHT reached to 250A (3.65V)//230A(3.02V), respectively, and kept stable over the weekend. 

Temp measured at 1372C with slope set at 1.04 (1230C at slope 0.98). 

No visible coating on windows. 

Setting up TGHT to reach 1800C; monitoring locally

 Monday, August 29, 2016, 14:35

Stepped up TGHT to 390A/6.54V; light coating was observed on the windows.  The temperature should be around 1800C which should be in line with the power (current) deposited in the container during the TaC coat sintering process (1900A at 420A); however, with the light coating the reading may be off.  

Mikron was used to measured inside of the tube (away from the discs); temperature was measured at ~1800C, (see attachment)  [adjusted slope at 1.00 to compensate the SiC disc and Ta]  

Omega was used to measured the temperature of the discs.  It is difficult to know what's the temperature inside the tube, so this measurement  is only taken as a guideline.  Slope changed from 1.04 to 1.15 to match Mikron's reading.  

After heated at  390A for 30 mins, the windows are now coated.  Temp reading is no longer reliable.  The temperature could be above 1800C.  Keeping a close monitor!!!

No blockage inside the tube was observed.  

Will remain heating at 390A/6.44V for overnight before proceeding with the re-conditioning. 

 Tuesday, August 30, 2016, 10:41

Target was heated at 390A  for over 10 hours and then cool down at 1A/min (see attachment#2).  Windows were fully coated and Omega couldn't register any reading. 

Chamber will be vented and target will be inspected before proceeding with the re-conditioning step.

Tuesday, August 30, 2016, 12:13  

Target was inspected; no visible damage was observed (see attachment)

Material coated on the windows and the cu heat shields;  all parts were wiped off with acetone. 

No visible material build up inside the container. 

Chamber is now being pumped down for re-conditiing.  

 Tuesday, August 30, 2016, 13:05

HS water valves open; no leaks detected.  

Vac at 3.6 e-6 Torr.  

Ready to set up TGHT/TBHT

 Tuesday, August 30, 2016, 16:41

TGHT/TBHT stepped up to 340A (5.40V) /230A (3.1V), respectively. 

Temperature was measured at 1835C at TGHT of 340A.  Omega, Mikron and analogue pyrometer were all reading ~1800C inside the tube (not on the SiC surface).  For that reason, I decided to stop the current at 340A, instead of 390A.  

TGHT voltage is running stable.  

No visible coating or blockage inside the tube was observed.  

Wednesday, August 31, 2016, 11:53

A thin layer of coating is observed on both the side windows (see attachment 5).  The temp reading is no longer reliable.

TGHT remains at 340A/5.45V.  P/S voltage is performing steadily.  

No clogging inside the tube is observed. 

Setting up another Omega reader to measure temperature from the front window since this window is clear and won't get coated (see attachment #6).

Temperature measurement from the front window is ~1140C; this corresponds to the measurement from the analogue pyrometer with the correction of e=~0.2 for tantalum at 1100C.

Note:  The temperature measurements should be taken as relative.  Since the reading from the side windows isn't reliable any longer, the centre window will give some information how stable the temperature is holding during the reconditioning process.  Continue to monitor.

 Wednesday, August 31, 2016, 16:24

About two hours ago, I increased TGHT to 350A and stayed there for a few mins (see attachment 7).  No change in temp was observed - that's mainly due to the coating on the windows.  As for the temp measurement from the center window, a more power current input would require to see the change as heat is slowly propagating through the layers of Ta heatshields.

Local inspection on the target: no clogging inside the tube. Voltage/Current is stable at 340A/5.45V.  Vac at 1.43e-7 Torr.

 Wednesday, August 31, 2016, 23:00

Strange observation:  Temperature readers on both omega have gone up. (see attachment 8).

I'm not sure if the temperature is reiiable.  I actually saw the increase in temperature ~1850C  last night around the same time; no change in TGHT current/voltage.  By the next morning, it went back down to 1400C with significant coating on the windows.

 Wednesday, August 31, 2016, 23:28

I had ISAC Op (Justin) to help me go into the Hotlab and take a look at the reading on Mikron.  Indeed, it is reading about 2000C which is close to the Omega reading.  He also looked into the tube through Mikron scope and found no clogging inside the tube.

To be safe, I am going to lower the TGHT heater down to reach ~1800C.

Wednesday, August 31, 2016, 23:41

Lower TGHT to 305A/4.81V; OMEGA reading at 1830C.  Vac at 1.27e-7 Torr.  Will remain at this current over night. 

 Thursday, September 01, 2016, 12:16

Checked on the target.  

Temperature readings, right windows (omega)= 1726C, centre = 1100C (omega), left (Mikron) = 1720C.  

No blockage inside the tube.  

TGHT stabilizes at 305A/4.79V.  Vac at 1.09e-7 Torr.  

 Thursday, September 01, 2016, 16:32

 About an hour ago, the temp dropped to 1660C with no change in TGHT current/voltage (see attachment 9).

Vac is a 1.06e-7 Torr. 

After consulting with Friedhelm, we decided to cool the target down and inspect it tomorrow.

Ramping TGHT/TBHT at 2A/min.

 Wednesday, September 07, 2016, 15:13

The target was removed from the Evap and inspected. 

Some spots on both ends and ionizer tube were crystalized.  (see attachment 10). 

No blockage inside the tube was observed. 

End caps were inserted.

The target was assembled and tested - All seems fine. 

Monday, November 23, 2015, 14:29

No heat shields.

Container empty.

Loaded into evap2 and currently pumping down.

 Tuesday, November 24, 2015, 09:36

HS water valves opened this morning, no leaks detected.

IGP1 = 4.5e-7 Torr.

Changed slope of OMEGA IR to 0.98 for empty container.

Tapped up manually to 35A.

IGP1 = 4.7e-7 Torr.

Vacuum stable, initiating auto-ramp at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Final setpoints: TBHT = 230A, TGHT = 300A

Will tap up manually to 2000C

 Tuesday, November 24, 2015, 14:00

TGHT = 300A, 3.75V

TBHT = 230A, 3.08V

IGP1 = 4.7e-7 Torr

No reading yet on the OMEGA.

Re-initiating auto-ramp to final setpoint TGHT = 450A

 Wednesday, November 25, 2015, 09:11

IGP1 = 3.0e-7Torr.

TGHT = 450A, 6.37V

Tapping up manually to 2000C

 Wednesday, November 25, 2015, 15:31

container was tapped up manually to 650A, slope/emissivity settings were checked.

ramped back down to 450A and tapped up manually while recording data up to 1800C [legs = 2000C]

once reached 1800C, tapped TBHT down manually to see relation of TBHT to temperature/ TGHT

remained at 1800C for ~1hr [while tapping down TBHT] before initiating auto-cool at 2.0A/min for the TGHT

see attachment for raw data.

 Thursday, November 26, 2015, 10:08

Vented in air and took out this morning.

 Monday, November 30, 2015, 15:37

No heat shields.

Container empty.

Loaded into evap2 and currently pumping down.

Tuesday, December 01, 2015, 10:07 

HS water valves opened this morning, no leaks detected.

IGP1 = 4.3e-7 Torr.

Slope of OMEGA = 0.98

Tapped up manually to 35A.

Vacuum stable, initiating auto-ramp at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Final setpoints: TBHT = 90A, TGHT = 360A

Once final setpoints reached, will tap up manually to max 1800C [legs = 2000C]

 Monday, December 07, 2015, 09:06

Container was tapped up manually with emissivity measurements taken every 50A starting at 360A.

The final measurement was taken at 640A.

Container was ramped down for the weekend.

See attachment for raw data.

 Monday, December 07, 2015, 09:04

No heat shields.

Container empty.

IGP1 = 1.1e-7 Torr.

Slope of OMEGA = 0.98

Tapped up manually to 35A.

Vacuum stable, initiating auto-ramp at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

Final setpoints: TBHT = 90A, TGHT = 360A

Will tap up with the same parameters as last round to confirm results.

 Friday, December 11, 2015, 11:44

Took out of evap2 yesterday.

Aurelia took many emissivity measurements to compare with previous data - which matched up.

The dip in emissivity before going up again around ~560A could be due to oxidation of the materials.

 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.

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!

.                         

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. 

 Thursday, September 15, 2016, 16:23

Target container contains 487 discs of SiC 

Target packed length = 16cm. 

Mass of SiC(green)  = 58.8795g

Container is wrapped with 1x heatshield around each side of cooling fins; no end caps are inserted yet - coated spring inserted both sides to hold discs in place.

Sintering temp = 1800C

Chamber is currently being pumped down. 

 Friday, September 16, 2016, 10:50

Tapped up manually to 50A

Waited ~1hr , vacuum stable.

IGP1 = 1.24e-5 Torr

Initiating auto-ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively.

TGHT max = 500A.  TBHT max at 230A. 

Slope on OMEGA = 1.15

 Monday, September 19, 2016, 10:53

OMEGA = 1230C

TGHT = 360A, 4.75V

TBHT = 204A, 2.68V

IGP1 = 5.3e-6 Torr

Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.

 Monday, September 19, 2016, 11:57

OMEGA = ~1300C

TBHT = 230A, 3.16V

TGHT = 409A, 5.55V

Lowering ramping rate to 0.2A/min while vaccum high

IGP1 = 3.05e-5 Torr

 Monday, September 19, 2016, 13:22

OMEGA = 1350C

TGHT = 425A, 5.82V

IGP1 = 1.97e-5 Torr

Stepping ramping rate back up to 1.0A/min

Laura Lambert wrote:

Thursday, September 15, 2016, 16:23 Target container contains 487 discs of SiC  Target packed length = 16cm.  Mass of SiC(green)  = 58.8795g Container is wrapped with 1x heatshield around each side of cooling fins; no end caps are inserted yet - coated spring inserted both sides to hold discs in place. Sintering temp = 1800C Chamber is currently being pumped down.   Friday, September 16, 2016, 10:50 Tapped up manually to 50A Waited ~1hr , vacuum stable. IGP1 = 1.24e-5 Torr Initiating auto-ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively. TGHT max = 500A.  TBHT max at 230A.  Slope on OMEGA = 1.15  Monday, September 19, 2016, 10:53 OMEGA = 1230C TGHT = 360A, 4.75V TBHT = 204A, 2.68V IGP1 = 5.3e-6 Torr Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.  Monday, September 19, 2016, 11:57 OMEGA = ~1300C TBHT = 230A, 3.16V TGHT = 409A, 5.55V Lowering ramping rate to 0.2A/min while vaccum high IGP1 = 3.05e-5 Torr  Monday, September 19, 2016, 13:22 OMEGA = 1350C TGHT = 425A, 5.82V IGP1 = 1.97e-5 Torr Stepping ramping rate back up to 1.0A/min

 Monday, September 19, 2016, 18:24

Measuring the temperature on the SiC is difficult due to the changing in emissivity as the temperature goes up.  So, I will use the MIKRON to measure the temperature on the Ta surface near the end of the tube and OMEGA for measuring the inside.  

Using the analogue pyrometer, the temperature on the Ta surface at the end of the tube was measured at around ~1450C; this temperature match the temperature on the Mikron at slope 0.98 (as usual).  To match it with OMEGA, I changed the slope to 1.04 since this measurement is taking readings on the  inside of the tube and on the SiC material.   

Note:  The measurements are NOT the absolute temperature.  These are relative temperature measurements  which give some guideline where the target current should be at for the sintering process.  Please plot the temp vs current as the TGHT is being ramped up.  At some point, the windows will get coated and the measurement is no longer reliable.   The plot will be used to give an estimation of the current for 1800C.  

John Wong wrote:

Laura Lambert wrote:  Thursday, September 15, 2016, 16:23 Target container contains 487 discs of SiC  Target packed length = 16cm.  Mass of SiC(green)  = 58.8795g Container is wrapped with 1x heatshield around each side of cooling fins; no end caps are inserted yet - coated spring inserted both sides to hold discs in place. Sintering temp = 1800C Chamber is currently being pumped down.   Friday, September 16, 2016, 10:50 Tapped up manually to 50A Waited ~1hr , vacuum stable. IGP1 = 1.24e-5 Torr Initiating auto-ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively. TGHT max = 500A.  TBHT max at 230A.  Slope on OMEGA = 1.15  Monday, September 19, 2016, 10:53 OMEGA = 1230C TGHT = 360A, 4.75V TBHT = 204A, 2.68V IGP1 = 5.3e-6 Torr Increasing ramping rate to 1.0A/min and 0.5A/min for the TGHT and TBHT respectively.  Monday, September 19, 2016, 11:57 OMEGA = ~1300C TBHT = 230A, 3.16V TGHT = 409A, 5.55V Lowering ramping rate to 0.2A/min while vaccum high IGP1 = 3.05e-5 Torr  Monday, September 19, 2016, 13:22 OMEGA = 1350C TGHT = 425A, 5.82V IGP1 = 1.97e-5 Torr Stepping ramping rate back up to 1.0A/min    Monday, September 19, 2016, 18:24 Measuring the temperature on the SiC is difficult due to the changing in emissivity as the temperature goes up.  So, I will use the MIKRON to measure the temperature on the Ta surface near the end of the tube and OMEGA for measuring the inside.   Using the analogue pyrometer, the temperature on the Ta surface at the end of the tube was measured at around ~1450C; this temperature match the temperature on the Mikron at slope 0.98 (as usual).  To match it with OMEGA, I changed the slope to 1.04 since this measurement is taking readings on the  inside of the tube and on the SiC material.    Note:  The measurements are NOT the absolute temperature.  These are relative temperature measurements  which give some guideline where the target current should be at for the sintering process.  Please plot the temp vs current as the TGHT is being ramped up.  At some point, the windows will get coated and the measurement is no longer reliable.   The plot will be used to give an estimation of the current for 1800C.

 Tuesday, September 20, 2016, 15:18

there was a temperature fluctuation resulting in the MIKRON no longer matching the readout on the OMEGA

this prompted another change in the slope on the OMEGA to 1.08

TGHT was then tapped up manually to 600A/ 1800C

will remain at this max setpoint for a few days before ramping down

see attachment for raw data

 Wednesday, September 21, 2016, 11:34

temperatures dropped a small amount overnight.

tapped up manually to 625A/ 1810C

still no coating on window.

see attachment for updated raw data