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

Laura Lambert wrote:

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

 Thursday, September 22, 2016, 12:07

Temperature reader on OMEGA dropped slightly to 1785C overnight.  The temperature on the leg remained at 1800C (MIKRON).  No coating on windows.  

Increased TGHT to 635A/10.12V (local 10.40V).  OMEGA reads 1800C, MIKRON ~1817C.  

Continue to monitor… (see dropbox for captured photos) 

John Wong wrote:

Laura Lambert wrote: 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    Thursday, September 22, 2016, 12:07 Temperature reader on OMEGA dropped slightly to 1785C overnight.  The temperature on the leg remained at 1800C (MIKRON).  No coating on windows.   Increased TGHT to 635A/10.12V (local 10.40V).  OMEGA reads 1800C, MIKRON ~1817C.   Continue to monitor… (see dropbox for captured photos)

 Monday, September 26, 2016, 13:24

Temperature decreased over weekend.

MIKRON dropped from ~1800C to ~1670C, OMEGA on right side remained ~1800C

Comparing screen shots of temperature readings and camera looking at target from left side, changes can be seen:

-darker area on top edge of target tube, above inside tube, grows larger when temperature drops - indicating 'cooler area' has grown

-initially darker area covers top above target materials on tube, when drops to ~1670C darker area extends down sides of target tube and reaches past target material area

See attached picture showing these details

Target has remained at this max setpoint for ~4-5 days

Windows remain un-coated.

Current and voltage readings remain un-changed.

Initiating auto-cool at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

 Wednesday, September 28, 2016, 17:05

Vented in air, target taken out today.

Target looks good!

A small amount of material was removed from the windows in evap2, very thin layer of coating.

Will update tomorrow with photos

Endcaps inserted.

 Tuesday, June 17, 2014, 13:11

Target container is coated with TaC.

Container is wrapped with 3x Ta-heat shields.

Currently being pumped down.

For sintering process:

TGHT and TBHT will be ramped up to 820A and 300A respectively at 0.1A/min

 Tuesday, June 17, 2014, 14:22

HS water cooling valves opened, no leaks detected.

IGP1 @1.8e-6 Torr

TGHT max = 820A/ 17V

TBHT max = 300A/ 5V

Stepped up manually to 40A, waited ~20min, vacuum stable.

Initiating auto-ramp @ 1.0A/min

 Wednesday, June 18, 2014, 11:24

TGHT and TBHT reached their respective 820A and 300A last night.

Internal temp measured from side of EVAP2 with mikron = 1830C

IGP1 = 7.6e-7 Torr

Initiating auto-cool down process at 2.0A/min and 1.0A/min for TGHT and TBHT respectively

vented and opened this morning.

smooth run

 Friday, June 20, 2014, 11:14

Made from batch's: oct 23/2013, oct 31/2013 and june 2012

Total number of foils: 515 discs

Total mass of materials [incl graphite foils]: 64.7224g

Total length packed: 17.8cm

Container is wrapped with 3x Ta-heat shields.

Currently being pumped down.

 Friday, June 20, 2014, 14:56

HS cooling water valves opened, no leaks detected.

IGP1 = 6.2e-6 Torr

TGHT max = 820A/ 17V

TBHT max = 300A/ 5V

Stepping up manually to 40A

 Friday, June 20, 2014, 16:04

IGP1 = 8e-6 Torr

Slowly stepped up to 35A manually.

Vacuum has stabilized.

Initiating auto-ramp at 0.1A/min

Laura Lambert wrote:

Friday, June 20, 2014, 11:14 Total number of foils: 515 discs Total mass of materials [incl graphite foils]: 64.7224g Total length packed: 17.8cm Container is wrapped with 3x Ta-heat shields. Currently being pumped down.  Friday, June 20, 2014, 14:56 HS cooling water valves opened, no leaks detected. IGP1 = 6.2e-6 Torr TGHT max = 820A/ 17V TBHT max = 300A/ 5V Stepping up manually to 40A  Friday, June 20, 2014, 16:04 IGP1 = 8e-6 Torr Slowly stepped up to 35A manually. Vacuum has stabilized. Initiating auto-ramp at 0.1A/min

 Friday, June 20, 2014, 16:16

Changing the heating current... 

From the previous SiC targets, TGHT was ramped up to 800A and yellow crystals were found; the end caps and target legs were also found broken (see my iPad).  This might be too hot for the Ta-boat to handle the sintering process. 

For this process,

TGHT will ramp up to 600A and TBHT to 230A over the weekend. 

Then, the temperature will be measured.  The sintering temperature of SiC is ~1800 - 2000C. 

John Wong wrote:

Laura Lambert wrote:  Friday, June 20, 2014, 11:14 Total number of foils: 515 discs Total mass of materials [incl graphite foils]: 64.7224g Total length packed: 17.8cm Container is wrapped with 3x Ta-heat shields. Currently being pumped down.  Friday, June 20, 2014, 14:56 HS cooling water valves opened, no leaks detected. IGP1 = 6.2e-6 Torr TGHT max = 820A/ 17V TBHT max = 300A/ 5V Stepping up manually to 40A  Friday, June 20, 2014, 16:04 IGP1 = 8e-6 Torr Slowly stepped up to 35A manually. Vacuum has stabilized. Initiating auto-ramp at 0.1A/min    Friday, June 20, 2014, 16:16 Changing the heating current...  From the previous SiC targets, TGHT was ramped up to 800A and yellow crystals were found; the end caps and target legs were also found broken (see my iPad).  This might be too hot for the Ta-boat to handle the sintering process.  For this process, TGHT will ramp up to 600A and TBHT to 230A over the weekend.  Then, the temperature will be measured.  The sintering temperature of SiC is ~1800 - 2000C.

 Monday, June 23, 2014, 09:45

IGP1 = 5e-6 Torr

TGHT and TBHT are at ~200A

Increasing ramping rate to 0.2A/min

 Monday, June 23, 2014, 11:19

IGP1 = 6.9e-6 Torr

Increasing ramping rate to 2.0A/min

Monday, June 23, 2014, 12:09

JW:  Pressure went up too fast... lower the TGHT ramping up rate to 1A/min.

 Tuesday, June 24, 2014, 16:06

Increasing current with respect to temperature: See attached table

Laura Lambert wrote:

John Wong wrote: Laura Lambert wrote:  Friday, June 20, 2014, 11:14 Total number of foils: 515 discs Total mass of materials [incl graphite foils]: 64.7224g Total length packed: 17.8cm Container is wrapped with 3x Ta-heat shields. Currently being pumped down.  Friday, June 20, 2014, 14:56 HS cooling water valves opened, no leaks detected. IGP1 = 6.2e-6 Torr TGHT max = 820A/ 17V TBHT max = 300A/ 5V Stepping up manually to 40A  Friday, June 20, 2014, 16:04 IGP1 = 8e-6 Torr Slowly stepped up to 35A manually. Vacuum has stabilized. Initiating auto-ramp at 0.1A/min    Friday, June 20, 2014, 16:16 Changing the heating current...  From the previous SiC targets, TGHT was ramped up to 800A and yellow crystals were found; the end caps and target legs were also found broken (see my iPad).  This might be too hot for the Ta-boat to handle the sintering process.  For this process, TGHT will ramp up to 600A and TBHT to 230A over the weekend.  Then, the temperature will be measured.  The sintering temperature of SiC is ~1800 - 2000C.     Monday, June 23, 2014, 09:45 IGP1 = 5e-6 Torr TGHT and TBHT are at ~200A Increasing ramping rate to 0.2A/min  Monday, June 23, 2014, 11:19 IGP1 = 6.9e-6 Torr Increasing ramping rate to 2.0A/min Monday, June 23, 2014, 12:09 JW:  Pressure went up too fast... lower the TGHT ramping up rate to 1A/min.  Tuesday, June 24, 2014, 16:06 Increasing current with respect to temperature: See attached table

 Tuesday, June 24, 2014, 23:44

Target has been heated at 600A.  Local temperature measured on the right leg = 1814C. 

RGA/ striptool/temperature data can be found on this link: 

https://www.dropbox.com/sh/69memvh6fthodoz/AABZiSKAR9njhbqO4sBATVbla

Something interesting was observed about the out gassing of this target - the right window was coated when the temperature rose above 1500C (on the right end, could be hotter inside?) - see attachment.

I suspect this is Si vapour deposited on the window when the target heater got closed to the sintering temperature for SiC (1800 - 2000C).  

Once the chamber is vented, the coated window will be inspected and analyzed.  More details later...  

Initiate auto-cooling (slow cool down)  TGHT 1A/min; TBHT 0.5/min.  Chamber should be able for venting tomorrow afternoon.  

 Thursday, October 23, 2014, 15:34

*See elog #142 for target description*

one endcap still in place, one removed for OMEGA-IR2C beam to reach material [see pic]

no heat shields

currently being pumped down

 Friday, October 24, 2014, 11:34

EVAP2 pumped down overnight.

IGP1 = 7e-7 Torr

HS water valves opened, no leaks detected.

TGHT will be ramped up to 1400C

TBHT will be ramped up to 230A

 Friday, October 24, 2014, 14:32

TBHT reached 230A, TGHT reached 1400C

Stepped TGHT up manually to 1600C; TGHT = 693A, 10.6V [see pic]

 Friday, October 24, 2014, 15:58

TGHT = 760A, 12.07V [local read back] = setpoint.

epics readback TGHT = 754.8A, 11.76V

OMEGA = 1700C

Friday, October 24, 2014, 16:26

OMEGA = 1800C

epics readback TGHT = 828.7A, 13.15V

Friday, October 24, 2014, 16:34

OMEGA = 1900C

epics readback TGHT = 899A, 14.53V

Friday, October 24, 2014, 16:46

OMEGA = 2000C

epics readback TGHT = 967A, 15.8V

MIKRON target spot on SiC = 1650C, e = 0.97

Laura Lambert wrote:

Thursday, October 23, 2014, 15:34 *See elog #142 for target description* one endcap still in place, one removed for OMEGA-IR2C beam to reach material [see pic] no heat shields currently being pumped down  Friday, October 24, 2014, 11:34 EVAP2 pumped down overnight. IGP1 = 7e-7 Torr HS water valves opened, no leaks detected. TGHT will be ramped up to 1400C TBHT will be ramped up to 230A  Friday, October 24, 2014, 14:32 TBHT reached 230A, TGHT reached 1400C Stepped TGHT up manually to 1600C; TGHT = 693A, 10.6V [see pic]  Friday, October 24, 2014, 15:58 TGHT = 760A, 12.07V [local read back] = setpoint. epics readback TGHT = 754.8A, 11.76V OMEGA = 1700C Friday, October 24, 2014, 16:26 OMEGA = 1800C epics readback TGHT = 828.7A, 13.15V Friday, October 24, 2014, 16:34 OMEGA = 1900C epics readback TGHT = 899A, 14.53V Friday, October 24, 2014, 16:46 OMEGA = 2000C epics readback TGHT = 967A, 15.8V MIKRON target spot on SiC = 1650C, e = 0.97

 Tuesday, November 04, 2014, 15:59

Target was heated up to 2000C and last for about 1.5 days before the right leg (ionizer points into the page) broke off. 

Interesting discovery...  The "yellowish" crystals are forming on the discs. 

Suspecting a phase transformation of 6H (hexagonal/- alpha SiC (hexagonal) polytype to 3C(cubic) - beta SiC

More study needs to be done... 

See elog # 168.

The leg of this target was repaired in the Machine shop. 

THIS TARGET WILL NOT BE USED ONLINE -  IT WILL BE USED FOR OFFLINE R&D PURPOSES.

Thursday, August 08, 2013, 15:19

NiO target materials loaded into the container yesterday.

Total discs = 530, (5 discs/pack)

length [after loaded] = 9.0cm

Target container is wrapped with Ta-heat shields, and will be removed after sintering process.

No end caps were inserted.

The chamber has been pumped down and currently IG1 = 3.8x10-06 Torr.

The HS cooling water was turned on and no leaks were detected.

TGHT and TBHT have been stepped up to 50A.

Auto-ramping setting:

0.2A/min for TGHT max = 250A, TBHT max = 230A.

Good vacuum = 3.00e-05 Torr

Bad vacuum = 4.00e-05 Torr

**See attachment #1 for pictures of target pre-sintering