Nikita Bernier wrote:

Tuesday, May 07, 2013, 16:48   5 BeO pellets were made.  Each weights about 1.3 g (including org mass).  A piece of Re foil (0.002" thick) is used as the under layer to protect the reaction between Be(g) and the Ta-boat.  (see Attachments) Another layer of Ta-foil is used as the heat-shield to wrap around the Ta-boat. The chamber was pumped down.  TGHT will be ramped up to 600 A (~1360°C) at 0.2 A/min. The vacuum limit parameter was set for good vacuum at < 3.0e-5 Torr and bad vacuum at > 4.0e0-5 Torr. The pressure, voltage and current will be closely monitored.  If the Ta-boat survives, the TGHT will continue to ramp up to max 800 A (~1580°C).

 Monday, May 13, 2013, 12:48

TGHT has been at 600 A for about 13 hours with stable very low vacuum (10^-7). See Attachment #1.

Temperature measurement has been lost on Saturday. Last measurement was was above 1350°C, at around 480 A.

TGHT was ramped down at 1 A/min.

The chamber will be vented later today. The pellets and the thermocouples will be inspected.

Nikita Bernier wrote:

Nikita Bernier wrote:  Tuesday, May 07, 2013, 16:48   5 BeO pellets were made.  Each weights about 1.3 g (including org mass).  A piece of Re foil (0.002" thick) is used as the under layer to protect the reaction between Be(g) and the Ta-boat.  (see Attachments) Another layer of Ta-foil is used as the heat-shield to wrap around the Ta-boat. The chamber was pumped down.  TGHT will be ramped up to 600 A (~1360°C) at 0.2 A/min. The vacuum limit parameter was set for good vacuum at < 3.0e-5 Torr and bad vacuum at > 4.0e0-5 Torr. The pressure, voltage and current will be closely monitored.  If the Ta-boat survives, the TGHT will continue to ramp up to max 800 A (~1580°C).    Monday, May 13, 2013, 12:48   TGHT has been at 600 A for about 13 hours with stable very low vacuum (10^-7). See Attachment #1. Temperature measurement has been lost on Saturday. Last measurement was was above 1350°C, at around 480 A. TGHT was ramped down at 1 A/min. The chamber will be vented later today. The pellets and the thermocouples will be inspected.

 Monday, May 13, 2013, 17:21

The following table shows the characteristics of the pellets after sintering at 600 A for 13 hours.

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

1    0.8904 4.875 1.364 13.058

2    0.8991 4.744 1.396 13.148

3    0.8846 4.579 1.482 12.884

4    0.9142 4.981 1.254 13.650

5    0.9022 4.978 1.250 13.586

Avg 0.8981 4.831 1.345 13.265

Thursday, April 05, 2012, 16:31

Target boat contains 6 BeO pellets :

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

1   1.2842,    5.406,        1.4647
2   1.2619,    5.150,        1.5108
3   1.2886,    5.316,        1.4946
4   1.2858,    5.310,        1.4931

5   1.3382,    5.520,        1.4948
6   1.3916,    5.650,        1.5187

Samples are made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 1:0.1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets.

Pellets are loaded on a target boat coated/sintered with TaC. The target boat is wrapped with a Ta foil that is 0.002 inches thick.

**** Sintering is postponed until the situation with the ventilation in the lab06 is cleared. ****

Nikita Bernier wrote:

Thursday, April 05, 2012, 16:31 Target boat contains 6 BeO pellets : Sample,   Mass (g),   Thickness (mm),   Density (g/cm3) 1   1.2842,    5.406,        1.4647 2   1.2619,    5.150,        1.5108 3   1.2886,    5.316,        1.4946 4   1.2858,    5.310,        1.4931 5   1.3382,    5.520,        1.4948 6   1.3916,    5.650,        1.5187   Samples are made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 1:0.1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets. Pellets are loaded on a target boat coated/sintered with TaC. The target boat is wrapped with a Ta foil that is 0.002 inches thick. **** Sintering is postponed until the situation with the ventilation in the lab06 is cleared. ****

 Tuesday, May 22, 2012, 16:44

Target chamber is currently being pumped down. Leak check will be done tomorrow by turning on the cooling water for the heat shield.

Nikita Bernier wrote:

Nikita Bernier wrote: Thursday, April 05, 2012, 16:31 Target boat contains 6 BeO pellets : Sample,   Mass (g),   Thickness (mm),   Density (g/cm3) 1   1.2842,    5.406,        1.4647 2   1.2619,    5.150,        1.5108 3   1.2886,    5.316,        1.4946 4   1.2858,    5.310,        1.4931 5   1.3382,    5.520,        1.4948 6   1.3916,    5.650,        1.5187   Samples are made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 1:0.1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets. Pellets are loaded on a target boat coated/sintered with TaC. The target boat is wrapped with a Ta foil that is 0.002 inches thick. **** Sintering is postponed until the situation with the ventilation in the lab06 is cleared. ****    Tuesday, May 22, 2012, 16:44 Target chamber is currently being pumped down. Leak check will be done tomorrow by turning on the cooling water for the heat shield.

 Wednesday, May 23, 2012, 17:38

TGHT was stepped up to about 55A before the auto ramping was initiated.  The vacuum limit parameter was set for good vac at <4.0 e-5 Torr and bad vac at >5.0 e0-5 Torr. 

The pressure is coming close to the trip limit (8.5 e-5 Torr) (see attachment 1: strip tool over the past 5 hours).  Changed the vacuum limit parameter:  good vac =3.0e-5 Torr, bad vac= 4.0e-5 Torr. 

 Saturday, May 26, 2012, 10:44

TGHT is auto ramping up smoothly as the pressure is regulating between 1e-5 to 4 e-5 torr.  (See attachment 2, past 21 hr)

Sunday, May 27, 2012, 12:25  

There could be a power bump  early this morning at 06:30hr, and tripped off the TGHT power supply (see attachment #3).  The computer in the cold lab was found to be off expectedly, so the alarm handler running on that computer was also shut off (*Need a UPS on this computer!)  

Called the ISAC Ops, and  nothing about any power bump around that time was noticed.  

Turned on TGHT p/s and set TGHT at 318A, local at 315A/4.58V.  TGHT has been running for about 10 mins.  Currently vac at 4.2e-7 Torr.  

Sunday, May 27, 2012, 12:35

Initiating TGHT auto ramping... 

 Monday, May 28, 2012, 00:20

TGHT has reached to 600A and will remain at that current for the rest of the night.  The target oven temperature will be measured tomorrow.

See attachment#4 for the striptool over the past 10hr.

 Monday, May 28, 2012, 10:56

TGHT stayed at 600A for about 12 hours.  Pressure gradually came down to 7.6e-7 Torr. (See attachment #5). 

At TGHT=600A, The target boat temperature was measured at 1400C (with the pyrometer), and the Ta-heat shield (1-layer) was at 1050C. [Note: These temperature measurements are very closed to the measurements with an empty LP target (with not heat shield), TGHT @ 600A = 1360C].

Monday, May 28, 2012, 11:04

Due to the water leak from the Evap2 chiller, the system has to be shut off for inspection. 

TGHT was tapped down to 0A.  The target was cooled down for about 20min before the chiller was turned off.

Will continue with the process after the problem is solved...

John Wong wrote:

Nikita Bernier wrote: Nikita Bernier wrote: Thursday, April 05, 2012, 16:31 Target boat contains 6 BeO pellets : Sample,   Mass (g),   Thickness (mm),   Density (g/cm3) 1   1.2842,    5.406,        1.4647 2   1.2619,    5.150,        1.5108 3   1.2886,    5.316,        1.4946 4   1.2858,    5.310,        1.4931 5   1.3382,    5.520,        1.4948 6   1.3916,    5.650,        1.5187   Samples are made of BeO powder with 30% PVB which was treated at 400 RPM for 26 minutes. A ratio of 1:0.1 of mineral oil was added before another high speed treatment for 10 minutes. The powder was then pressed into pellets. Pellets are loaded on a target boat coated/sintered with TaC. The target boat is wrapped with a Ta foil that is 0.002 inches thick. **** Sintering is postponed until the situation with the ventilation in the lab06 is cleared. ****    Tuesday, May 22, 2012, 16:44 Target chamber is currently being pumped down. Leak check will be done tomorrow by turning on the cooling water for the heat shield.  Wednesday, May 23, 2012, 17:38 TGHT was stepped up to about 55A before the auto ramping was initiated.  The vacuum limit parameter was set for good vac at <4.0 e-5 Torr and bad vac at >5.0 e0-5 Torr.  The pressure is coming close to the trip limit (8.5 e-5 Torr) (see attachment 1: strip tool over the past 5 hours).  Changed the vacuum limit parameter:  good vac =3.0e-5 Torr, bad vac= 4.0e-5 Torr.   Saturday, May 26, 2012, 10:44 TGHT is auto ramping up smoothly as the pressure is regulating between 1e-5 to 4 e-5 torr.  (See attachment 2, past 21 hr) Sunday, May 27, 2012, 12:25   There could be a power bump  early this morning at 06:30hr, and tripped off the TGHT power supply (see attachment #3).  The computer in the cold lab was found to be off expectedly, so the alarm handler running on that computer was also shut off (*Need a UPS on this computer!)   Called the ISAC Ops, and  nothing about any power bump around that time was noticed.   Turned on TGHT p/s and set TGHT at 318A, local at 315A/4.58V.  TGHT has been running for about 10 mins.  Currently vac at 4.2e-7 Torr.   Sunday, May 27, 2012, 12:35 Initiating TGHT auto ramping...   Monday, May 28, 2012, 00:20 TGHT has reached to 600A and will remain at that current for the rest of the night.  The target oven temperature will be measured tomorrow. See attachment#4 for the striptool over the past 10hr.  Monday, May 28, 2012, 10:56 TGHT stayed at 600A for about 12 hours.  Pressure gradually came down to 7.6e-7 Torr. (See attachment #5).  At TGHT=600A, The target boat temperature was measured at 1400C (with the pyrometer), and the Ta-heat shield (1-layer) was at 1050C. [Note: These temperature measurements are very closed to the measurements with an empty LP target (with not heat shield), TGHT @ 600A = 1360C]. Monday, May 28, 2012, 11:04 Due to the water leak from the Evap2 chiller, the system has to be shut off for inspection.  TGHT was tapped down to 0A.  The target was cooled down for about 20min before the chiller was turned off. Will continue with the process after the problem is solved...

 Tuesday, May 29, 2012, 15:30

Evap2 was vented out and the pellets were taken out of the boat and examined.

The six pellets are cracked and have a greyish colour. The cracking is probably caused by the instant cooling and reheating when the system tripped on Sunday morning.

The light grey colour and white spots suggest that the sintering process was not completed and so the shrinkage cannot be determined.

A new batch of BeO pellets will have to be prepared and sintered in order to determine the dimensions of the final die.

 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.

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.

 Tuesday, March 20, 2012, 14:35

It was found out that the Evaporator #2 backing pump (IEVAP2BP1) muffler is not connected to the exhaust system.  The sintering process is on hold until the pump is properly setup (see message ID#7 for more details). 

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.   * Note: Target a boat is wrapped with a piece of Ta-foil as a heat shield - JW. 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.

 Thursday, March 22, 2012, 00:25

TGHT SETPOINT was ramped up to 266A but the actual p/s current remained at 90A; that was because the voltage was set 1.05V.  (See attachment1: voltage_limiting.jpg). 

Increased TGHT voltage to 20V, and increased the auto-ramping final value from 500A to 1000A (~1780C as previously measured by a pyrometer, see Attachment 2: Temp-Cal vs Measured.jgp)

Thursday, March 22, 2012, 10:17 

TGHT  ramped up at the rate of 1A/min to 534A/8.89V, local @ 525A/8.90V.  Pressure is coming down to low 10e-6. (See attachment 3: TGHT_525A.jpg)

Increased ramping rate to 2A/min until TGHT reaches to 1000A.

Thursday, March 22, 2012, 13:32

A decision was made to stop the TGHT autoramping program, and set the current to 700A, (local at 690A).  The temperature was measured to be around 1780C on the target boat, and

1500C on the Ta-heat shield.  The current remained at that current for about 2 hours before it's ramping down at zero at -10A/min.

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.

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).