Nikita Bernier wrote:

Monday, March 19, 2012, 17:04   Target boat contains 4 BeO pellets with 30% PVB: Sample,   Thickness (mm),   Mass (g),  Density (g/cm3) 1   4.943,  0.9628,  1.265 2  4.930,  0.9685,  1.276 3  4.758,  0.9607,  1.312 4  4.979,  0.9872,  1.288   Target chamber is currently being pumped down. Leak check will be done tomorrow by turning on the cooling water for the heat shield.    Wednesday, March 21, 2012, 18:30 The Evaporator #2 backing pump (IEVAP2BP1) muffler has been connected to the exhaust system. The auto-ramp program has been tested today and works well. Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 500 A, between 5.00e-05 and 6.00e-05 Torr. ISAC ops have been informed of the process and they will include it in their walkaround.

After sintering at up to 500 A (~1000°C), the 4 BeO pellets have shrunk and feel robust. We can manipulate them with tweesers or hands. Also we can drop them from a couple of inches high and they don't break.

One of the pellets rolled to the extremity of the target boat tube and still has black traces from bad sintering on one side.

Sample,  Thickness (mm),  Mass (g),  Diameter (mm),  Density (g/cm3)

1  3.688,  0.7118,  11.231,  1.948

2  3.822,  0.7196,  11.241,  1.897

3  3.810,  0.7037,  11.188,  1.879

4  3.803,  0.7077,  11.269,  1.866

The average thickness before sintering was 4.90 mm. After sintering, 3.78 mm. Thus the average thickness loss is 1.12 mm (22.9%)

The average mass before sintering was 0.9698 g. After sintering, 0.7107 g. Thus the average mass loss is 0.2591 g (26.7%)

The average diameter before sintering was 14.35 mm. After sintering, 11.23 mm. Thus the average diameter loss is 3.12 mm (21.7%)

The average density after sintering is 1.897 g/cm3, compared to the density of BeO (3.01 g/cm3). Thus the pellets have a BeO density of 63.0%.

Evaporator #2 is now off.

 Wednesday, September 26, 2012, 15:07

The samples were made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 10:1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets.

Three pellets were loaded on the target boat coated with TaC, with an extra layer of TaC coated Ta foil. See Attachment 1. The target boat is wrapped with a Ta foil that is 0.002 inches thick.

Target chamber was pumped down. The cooling water was turned on and no leak were observed.

TGHT was stepped up to 55A before the auto ramping was initiated at 0.5 A/min.  The vacuum limit parameter was set for good vac at <3.0 e-5 Torr and bad vac at >4.0 e0-5 Torr.  

Nikita Bernier wrote:

Wednesday, September 26, 2012, 15:07   The samples were made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 10:1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets. Three pellets were loaded on the target boat coated with TaC, with an extra layer of TaC coated Ta foil. See Attachment 1. The target boat is wrapped with a Ta foil that is 0.002 inches thick. Target chamber was pumped down. The cooling water was turned on and no leak were observed. TGHT was stepped up to 55A before the auto ramping was initiated at 0.5 A/min.  The vacuum limit parameter was set for good vac at <3.0 e-5 Torr and bad vac at >4.0 e0-5 Torr.

 Friday, September 28, 2012, 12:50

Sintering was coming up smoothly. As expected, resistance started building up quickly at higher temperatures (above 600°C). See Attachment 1. The target heater tripped off twice this morning. I was able to ramp up the current after the first trip until it tripped again. After the second time, the voltage went crazy and I had to ramp down the current. Attachment 2 shows the whole process.

Evap2 will be vented out shortly and the pellets will be examined.

Friday, September 28, 2012, 15:52  

 The boat comes in two parts. One pellet is missing. The two remaining pellets are black and grey. Also they shrank a lot. See Attachment 3.

So once again, a new batch of BeO pellets will have to be prepared and sintered in order to determine the dimensions of the final die. Therefore the best approach is still loading the pellets on a target boat coated/sintered with TaC and wrapped with a Ta foil.

Friday, April 04, 2025, 06:41

Total number of foils:328

Total length packed 15.2 cm

container has 4 Ta heat shields (one inner only around fins)

No endcaps inserted to facilitate out-gassing

Ta coated spring at back, coated cap at front with perforations

ramp to 500A @ 1A/min TGHT and to 230A on TBHT

max approx 700A on TGHT and 230A on TBHT (Omega slope set = 0.990)

Then temperature = 1800C

TBHT will be set fixed at 230 A (max).  TBHT heated manually and automatically to max.

Good vac at 5.00 e -4 Torr

Bad vac at 5.00 e-2 Torr

 IGP1= 1e-06 Torr at start of initial ramp.

initiating ramp up

 Friday, April 04, 2025, 10:54

Paused ramp at 128.5A TGHT and 130.2 A TBHT.  Will hold and let pressure drop.

IGP1 = 5.43e-04 Torr currently

Friday, April 04, 2025, 14:04

restarting ramp

IGP1=2.6e-05 Torr

Friday, April 04, 2025, 16:35

increasing ramp to 3A/min

@18:15 ramp was slowed down to 2A/min and left to reach 730~A

Friday, April 04, 2025, 22:54

Current was stopped at 733A on readback and left for 3.5 hours, then manually ramped to 738A for 0.5 hours. 

This is in accordance with the initial oven (Elog 619)

Friday, April 04, 2025, 23:45

starting ramp down at -1A/min TBHT and -2A/min TGHT

Monday, March 13, 2023, 22:28

Total number of foils:380 ( including 5 analysis discs on the front side of the container)

Total length packed 17 cm (excluding 5 analysis discs that will be removed)

container has 4 Ta heat shields (one inner only around fins)

No endcaps inserted to facilitate out-gassing

Ta coated spring at  both ends

ramp to 500A @ 1A/min TGHT and to 230A on TBHT

max approx 700A on TGHT and 230A on TBHT (Omega slope set = 0.990)

Then temperature = 1800 C.  Will ramp to 1820 C

TBHT will be set fixed at 230 A (max).  TBHT heated manually and automatically to max.

Good vac at 5.00 e -4 Torr

Bad vac at 5.00 e-2 Torr

 IGP1= 2.8e-06 Torr at start of initial ramp.

Tuesday, March 14, 2023, 07:26  

Increased autoramp to 2A/min to 700 A on TGHT while keeping TBHT to 230A, 3.3V

Tuesday, March 14, 2023, 09:53

At 743A, 11.8V TGHT

OMEGA = 1780 C.  (not entirely reliable, will leave at this current for 4 hours)

Tuesday, March 14, 2023, 14:00

Starting rampdown at -2A/min on TGHT and -1A/min TBHT

Final IGP1= 5.5e-06 Torr

OMEGA= 1750C

TBHT= 230A, 3.3V

Monday, July 20, 2020, 19:27 

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

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

good vacuum = 3.00 e-05 Torr

bad vacuum = 5.00 e-05 Torr

Evap 2 was left to pump down over night.

 Monday, July 20, 2020, 23:06

IPG1 = 3.1e-06 Torr

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

Tuesday, July 21, 2020, 08:06

TGHT = 40.3 A, 0.51 V

TBHT = 39.0 A, 0.46 V

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

IGP1=1.8e-05 Torr

Tuesday, July 21, 2020, 16:22

IGP1= 1.5 e-05 Torr 

TGHT = 50.1 A, 0.65 V

TBHT = 50.0 A, 0.60 V

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

Wednesday, July 22, 2020, 13:24

Stopped autoramp.  Will allow pressure to drop. 

TGHT = 64.0 A, 0.86 V

TBHT = 64.5 A, 0.82 V 

Thursday, July 23, 2020, 23:55

TGHT Reached 430 A,  7.7 V

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

Friday, July 24, 2020, 11:31

IGP1 = 1.98e-07 Torr

Window for pyrometer was coated with condensate.  

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

 Thursday, July 16, 2020, 11:15

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

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

Evap 2 was pumped down

 Friday, July 17, 2020, 08:49

 Sunday, July 19, 2020, 17:35

IGP1 = 2.6e-06 Torr

TGHT = 400 A, 7.2 V

TBHT = 233 A, 4.1 V

Tap manually  to 410 (expected 1800 C )

Note*  OMEGA reading cannot be obtained.  

Leave at 410 A on TGHT for 4 hours.

Sunday, July 19, 2020, 22:57

IGP1 = 7.0 e-07 Torr

TGHT= 410 A , 7.2 V

TBHT = 233 A, 4.2 V

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

 Monday, July 20, 2020, 12:20

IGP1 = 2.2e-07 Torr

Unloading target

 Tuesday, January 19, 2016, 14:19

SiC nanofiber was prepared at UBC Material Engineering Sci.  

4 samples are loaded in a Ta target contained (sintered with TaC coating): 

Sample 1: 

size:  21.70 x 21.54 mm, mass: 0.0762g, thick: 0.224mm

Sample 2: 

size: 20.89mm x 23.95mm, mass: 0.0954g, thick: 0.232mm 

--> Sample 1 and 2 with graphite backing foil 

Sample 3: 

size: 22.55 x 25.56mm, mass: 0.0082g, thick: 0.110mm

Sample 4: 16.93 x 23.82mm, mass: 0.0048g, thick: 0.086mm

--> Sample 3 and 4 with no graphite backing foil. 

(see attachment) 

Test#1:  Heating temperature at 1600C for 24hrs. 

TGHT will be adjusted accordingly.  There are 2 Ta-heat shields wrapped around the container. 

Chamber is currently being pumped down.

 Tuesday, January 19, 2016, 16:19

Vacuum at 2.0e-6 Torr.

For 1600C, expected current is around 350A.

Stepping up TGHT gradually...

 Wednesday, January 20, 2016, 14:34

TGHT was ramped up to 390A/6.63V to reach 1600C.  Samples have been heated at that temp since 11pm last night.

Visual check on the fibers seem ok (see attachment).

Will continue to heat this for a total time of 24hours.

 Wednesday, January 20, 2016, 22:57

Samples have been heated at 1600C for 24hours. 

Initiated cooling at 1A/min.

 Wednesday, January 27, 2016, 12:34

First attempt - heating 1600C.  XRD result showed board "bumps" that could be SiO2? It is inconclusive. 

Second attempt - re-heating the same samples, namely

Sample 1 - only the fiber

Sample 2 - with graphite backing.  This sample is loaded with the fiber facing down to see how well it holds on the graphite foil.  (see attachment)

TGHT will be ramped up to reach 1800C

Chamber is currently being pumped down.

 Wednesday, January 27, 2016, 14:04

Water valves open; no leaks detected.

Ramping up TGHT to 400A at 2A/min

 Wednesday, January 27, 2016, 18:08

TGHT is at 481A to obtain 1800C.

Visual check on Sample 2 - fiber has fallen off graphite backing foil.

Will remain heated at this temperature for over night.

 Friday, February 12, 2016, 11:11

Heat treatment test#1 is complete.  XRD results are inconclusive.  Need to do EDX to determine Si/SiO2.  

(See my dropbox for more details)

Monday, May 27, 2024, 07:09

Small graphite cartridge was loaded with SiC discs 240523-1 and 240523-2.  Discs produced without milling using PAA as a dispersant.

The coated container tube was wrapped in four Ta foil heatshields.

two Tac Coated springs at the ends in case plugs are pushed outwards.

Target temperature on OMEGA= 1850-1900 C

OMEGA slope:= 0.990

Target time at max temperature = 4 hours

Final TGHT current= ~400A (adjustable)

Heating autoramp 2A/min to 90 A

Then at 2A/min to 120A.

Good vacuum = 5.0 e-02 Torr

Bad vacuum = 5.0E-04 Torr

 IGP1 initial 4.8e-07 Torr

Monday, May 27, 2024, 09:13

Pressure started coming down.  Heat at 2A/min to 120A.

Monday, May 27, 2024, 10:21

Started ramp 2A/30s  to 400A will monitor temperature

stopped at 490A and will hold for 4  hours. 

Monday, May 27, 2024, 12:41

temperature started creeping up past 1870C so decreased current to 461A

Current temperature is 1842 C at 461A, 7.6V

Monday, May 27, 2024, 12:55

dropped current to 441 because temperature climbed to 1899 C

Monday, May 27, 2024, 15:08

final pressure IGP1 =9.9 e-07 Torr

OMEGA= 1830 C at 410 A (reduced as needed)

Start rampdown at -2A/min

Wednesday, May 29, 2024, 10:07

Final pressure is 2.7e-7 Torr

Wednesday, May 29, 2024, 14:42

Experiment failed.  Too hot probably.  Bad temperature readings.  Will repeat after redesigning experiment.

 Thursday, April 19, 2018, 12:37

See elog i.d. 404 for target description and first round of heating.

Endcaps inserted and expanded.

No Rh foil inserted.

Loaded into evap2 and chamber currently pumping down.

Thursday, April 19, 2018, 14:00: water cooling lines opened. No response. Vacuum @ 1.8e-06T - AS

Thursday, April 19, 2018, 14:07: Power supplies swtiched on. - AS

 Monday, August 24, 2015, 12:54

The turbo pump was found to be faulty.  The pump couldn't get on full speed and eventually timed out.  Vacuum group inspected the pump and it is time for a service.  

A new pump has been installed.  Leak  check was performed and no leaks were detected.  

Pump is now fully operational. 

Back in business…. 

Tuesday, August 14, 2012, 15:01

The Cu-heatshield insulators are broken due to prolong heating time during the target processes (see attachment#1). 

The insulators are replaced with the MM800 type (see attachment #2).

Monday, March 10, 2014, 11:44

Rick replaced the backing pump hose from 1.5" to 2.0" for better flow.  And the HEPA filter was checked - it looks OK.

Friday, January 11, 2013, 10:59

The insulator that holds the terminals was broken when a target container was installed.  The insulator had seen so much heat shine from the Cu heat-shield gaps, see attachment.  Tightening the bolts on the target container might further put more force on the insulator and eventually broke it.

To prevent this to happen again.  The Cu-heat shield gaps have covered with Ta-foil to prevent any shine from the target  container onto the insulator.  Also, a torque wrench will be used to tighten the bolts on the terminals.  At this point, we don't know the max torque the insulator can tolerate.  Some measurements were done on the target resistant (ohm) as a function of torque (in pounds).  The best torque to tighten the terminal bolts is 150 lbs. 

John Wong wrote:

Friday, January 11, 2013, 10:59 The insulator that holds the terminals was broken when a target container was installed.  The insulator had seen so much heat shine from the Cu heat-shield gaps, see attachment.  Tightening the bolts on the target container might further put more force on the insulator and eventually broke it. To prevent this to happen again.  The Cu-heat shield gaps have covered with Ta-foil to prevent any shine from the target  container onto the insulator.  Also, a torque wrench will be used to tighten the bolts on the terminals.  At this point, we don't know the max torque the insulator can tolerate.  Some measurements were done on the target resistant (ohm) as a function of torque (in pounds).  The best torque to tighten the terminal bolts is 150 lbs.

The insulators were installed with torques as indicated in the attached PDF ITD0052. A torque test was performed on the broken insulator before installation. No damage was seen on torques of up to 60 in lbs for the 1/4-20 bolts, however for torques in excess of 50 in lbs the insulator material seems to "give".

 Tuesday, April 16, 2019, 13:38: Replaced the bottom insert on the heat shield. 

Used small amount of isopropyl alcohol to wipe the inside if the HS out. 

Wednesday, May 29, 2024, 22:52

Small graphite cartridge was loaded with SiC discs 240523-1 and 240523-2 and 220727-2 (baseline discs).  Test Discs produced without milling using PAA as a dispersant.

The coated container tube was wrapped in four Ta foil heatshields.

two Tac Coated springs at the ends in case plugs are pushed outwards.

Target temperature on OMEGA= 1850-1900 C

OMEGA slope:= 0.990

Target time at max temperature = 4 hours

Final TGHT current= ~400A (adjustable)

Heating autoramp 2A/min to 90 A

Then at 2A/min to 120A.

Good vacuum = 5.0 e-02 Torr

Bad vacuum = 5.0E-04 Torr

 IGP1 initial 4.8e-07 Torr

Wednesday, May 29, 2024, 22:54

Kept at 400 A for 4 hours. 

Starting autoramp down at -2A/min

Monday, March 10, 2025, 16:53

RD TGHT = 686A set to 700 A , 10.8V

TBHT = 230A, 3.2V

OMEGA reads 1700 but will keep here for 4 hours.

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.  

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.

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.