Aaron Schmidt wrote:

Wednesday, August 07, 2024, 15:36: Roughing. Had initially been roughed & TP started w/ Marla CS, however it timed out. Restarting. Wednesday, August 07, 2024, 15:37: TP on. Wednesday, August 07, 2024, 15:46: Tripped at 4 KRPM. Restarted. Up to 5 KRPM. Failed to start. Thursday, August 08, 2024, 10:00: TP started.  Thursday, August 08, 2024, 10:12: TP Tripped but nearly spun up. Reset & Restarted. TP Green / on.

Thursday, August 08, 2024, 10:43

A cartridge was filled with graphite foils and loaded in an uncoated tantalum tube. The tube was wrapped with four Ta-sheets. A Ta-foil was placed in the tube's right end for measuring the temperature.

Good vacuum 3e-5 Torr

Bad vacuum 5e-5 Torr

Initial IGP1 = 5.06E-7 Torr

Starting ramp at 1A/min to 200 A

Friday, August 09, 2024, 09:40 Pressure started to rise, but temperature is not within pyrometer range yet. Current 42 A, Voltage 0.5 V

Friday, August 09, 2024, 10:46 Pressure started to reduce (peak 1.4e-5 Torr). Temperature is not within pyrometer range yet Current 100 A, Voltage 1.3 V

Friday, August 09, 2024, 11:28 Temperature started to be detected, but not stable enough. Current 135 A, Voltage 1.9 V

Friday, August 09, 2024, 12:54 Temperature 1129 °C, current 196 A, voltage 3 V.

Friday, August 09, 2024, 12:56

Next ramp 0.5A/min while taking temperature readings periodically until 250A

Friday, August 09, 2024, 14:45

IGP1 = 1.0e-6 Torr

Next ramp 1A/min to 480 A aiming at 2000 °C

Friday, August 09, 2024, 17:13

IGP1 = 1.9e-6 Torr, Current 327A, Voltage 5.3V

Ramp changed to 2A/min to 480 A aiming at 2000 °C

Coolded down after 4 hours at ~2000°C

at -2A/min

Tuesday, August 13, 2024, 17:20 Pressure kept increasing when turning the turbo pump on

Tuesday, August 13, 2024, 18:00 Pressure stayed constant when turning the turbo pump on

Marla Cervantes wrote:

Tuesday, August 13, 2024, 17:20 Pressure kept increasing when turning the turbo pump on Tuesday, August 13, 2024, 18:00 Pressure stayed constant when turning the turbo pump on

Wednesday, August 14, 2024, 10:18

The turbo pump started up normally. System is purging. and tomorrow the target will be heated.

Marla Cervantes wrote:

Marla Cervantes wrote: Tuesday, August 13, 2024, 17:20 Pressure kept increasing when turning the turbo pump on Tuesday, August 13, 2024, 18:00 Pressure stayed constant when turning the turbo pump on Wednesday, August 14, 2024, 10:18 The turbo pump started up normally. System is purging. and tomorrow the target will be heated.

 Wednesday, August 14, 2024, 16:19

• Next ramping: 0.5 A/ 2min  to 250 A.

Very slow rate to allow thermal equilibrium and temperature measurements. Estimated time 3h.

Thursday, August 15, 2024, 08:21

IGP1 = 5.3e-7 Torr

Good vacuum 3e-5 Torr

Bad vacuum 5e-5 Torr

Initial ramping: 2 A/min to 200 A.

Thursday, August 15, 2024, 09:01. Pressure starting to increase at 74 A

Thursday, August 15, 2024, 09:15. Pressure stabilizing 1.8e-6 Torr. Current 103 A, voltage 1.3 V

Thursday, August 15, 2024, 09:21. Pressure increasing (116 A).

 Thursday, August 15, 2024, 09:29 Pressure dropping (Current approx. 120 A)

Thursday, August 15, 2024, 10:54

Started ramping to find a pressure peak corresponding to V vaporization.

IGP1 = 6.4e-7

TGHT = 200 A, 2.9 V, omega 1152 °C

Next ramping: 0.5 A/ 2min  to 250 A

Thursday, August 15, 2024, 11:17

Ramp seem to slow. The temperature change was too subtle (according to the omega).

IGP1 = 6.5e-7

TGHT = 205 A, 3.03 V, omega 1157 °C

Next ramping: 1 A/ 2min  to 250 A

Thursday, August 15, 2024, 11:32

Ramp changed to 0.5 A/min

Thursday, August 15, 2024, 11:54

Ramp was stopped because the pressure was increasing, suggesting the V vaporization.

IGP1 = 6.9e-7

TGHT = 222 A, 3.3 V

Omega 1210 °C, filament 1280 °C

The difference between pyrometers is negligible, suggesting that the V vaporization temperature at 6e-7 Torr of approx. 1300 °C

 Thursday, August 15, 2024, 13:15

IGP1 = 7.9e-7

TGHT = 250 A, 3.8 V

Omega 1289 °C

Thursday, August 15, 2024, 13:16

Ramp set to 0.5 A/min to 300 A

 Pressure mini-spike at 13:18

Omega reading 1291 °C

Thursday, August 15, 2024, 14:08

IGP1 = 8.5e-7

TGHT = 270 A, 4.18 V

Omega 1375 °C, filament 1400 °C

The system stayed at those conditions for 15min

Thursday, August 15, 2024, 14:11

Ramping to 0A at 2A/min

 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.

 Thursday, March 29, 2012, 19:17

Target boat contains 3 BeO pellets :

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

1    9.06,  1.9713,  1.413

2    9.11,  1.9900,  1.419

3  13.54,  1.9916,  0.956

Samples 1 and 2 are made of BeO powder with 30% PVB which was washed with excess acetone and let to dry on a greased baking sheet (with PAM Butter flavoured). The flakes were then milled for 26 minutes at 400 RPM. It resulted in a very fine grey powder, much denser than the BeO powder with 30% PVB (not washed with acetone) that was used for Sample 3.

The initial settings on Evaporator #2 were 100 A and 0.83 V until the vacuum increased.

Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 700 A, with the maximum voltage limited at 14 V, between 5.00e-05 (Good vacuum) and 6.00e-05 Torr (Bad vacuum).

Nikita Bernier wrote:

Thursday, March 29, 2012, 19:17   Target boat contains 3 BeO pellets : Sample,   Thickness (mm),   Mass (g),  Density (g/cm3) 1    9.06,  1.9713,  1.413 2    9.11,  1.9900,  1.416 3  13.54,  1.9916,  0.956   Samples 1 and 2 are made of BeO powder with 30% PVB which was washed with excess acetone and let to dry on a greased baking sheet (with PAM Butter flavoured). The flakes were then milled for 26 minutes at 400 RPM. It resulted in a very fine grey powder, much denser than the BeO powder with 30% PVB (not washed with acetone) that was used for Sample 3. The initial settings on Evaporator #2 were 100 A and 0.83 V until the vacuum increased. Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 700 A, with the maximum voltage limited at 14 V, between 5.00e-05 (Good vacuum) and 6.00e-05 Torr (Bad vacuum).

 Thursday, March 29, 2012, 22:31:

TGHT tripped off a few times over the past hours.  After changing the Good Vac to 2.00e-5 torr and Bad Vac to 3.00e-5 Torr, the target heater are regulating properly and the max pressure is well maintained below 6.5e-5 Torr [Trip point @ 8.0e-5 Torr].  (see attachment#1: parameter.jpg)

John Wong wrote:

Nikita Bernier wrote:  Thursday, March 29, 2012, 19:17   Target boat contains 3 BeO pellets : Sample,   Thickness (mm),   Mass (g),  Density (g/cm3) 1    9.06,  1.9713,  1.413 2    9.11,  1.9900,  1.416 3  13.54,  1.9916,  0.956   Samples 1 and 2 are made of BeO powder with 30% PVB which was washed with excess acetone and let to dry on a greased baking sheet (with PAM Butter flavoured). The flakes were then milled for 26 minutes at 400 RPM. It resulted in a very fine grey powder, much denser than the BeO powder with 30% PVB (not washed with acetone) that was used for Sample 3. The initial settings on Evaporator #2 were 100 A and 0.83 V until the vacuum increased. Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 700 A, with the maximum voltage limited at 14 V, between 5.00e-05 (Good vacuum) and 6.00e-05 Torr (Bad vacuum).        Thursday, March 29, 2012, 22:31: TGHT tripped off a few times over the past hours.  After changing the Good Vac to 2.00e-5 torr and Bad Vac to 3.00e-5 Torr, the target heater are regulating properly and the max pressure is well maintained below 6.5e-5 Torr [Trip point @ 8.0e-5 Torr].  (see attachment#1: parameter.jpg)

Friday, March 30, 2012, 23:19  

Archive of the target current and vacuum over the past 24 hours.  (see attachment #1: archive_24hr)

Saturday, March 31, 2012, 12:12

The organic materials have been burnt off.  The target heater ramping up is no longer restricted by the vacuum limit. 

Archive of the target current and vacuum over the past 10 hours. (see attachment #2: TGHT@240A). 

 Saturday, March 31, 2012, 22:52

TGHT has stayed at 700A/12.37V, local @ 693A/12.43 = Temp @ 1780C.  

The striptool shows some out-gassing when TGHT reached to 700A. (see attachment #3 marked with black circle: TGHT@700A.jpg)

Increasing TGHT to 750A to see if there is any further reaction...  

Sunday, April 01, 2012, 10:24  

TGHT was ramped up to 750A, local 730A/13.90V.  The pressure has come down to low 10e-6 but not stable;  Some reaction may be ongoing therefore it's causing the vacuum excursion.  (See attachment #4: TGHT @ 750A).  Notice the current readback is not constant and it's slowly decreasing as the voltage readback is increasing.  There might be some resistant building up.

--> Initiating the cool-down process at 2A/min. 

Sunday, April 01, 2012, 19:30  

TGHT has ramped down to 0A, and the pressure is going down (currently at 7.e-8 Torr) with no excursion.  (see attachment #5: TGHT@0A). 

The chamber will be vented tomorrow, and the target materials will be inspected. 

John Wong wrote:

John Wong wrote: Nikita Bernier wrote:  Thursday, March 29, 2012, 19:17   Target boat contains 3 BeO pellets : Sample,   Thickness (mm),   Mass (g),  Density (g/cm3) 1    9.06,  1.9713,  1.413 2    9.11,  1.9900,  1.416 3  13.54,  1.9916,  0.956   Samples 1 and 2 are made of BeO powder with 30% PVB which was washed with excess acetone and let to dry on a greased baking sheet (with PAM Butter flavoured). The flakes were then milled for 26 minutes at 400 RPM. It resulted in a very fine grey powder, much denser than the BeO powder with 30% PVB (not washed with acetone) that was used for Sample 3. The initial settings on Evaporator #2 were 100 A and 0.83 V until the vacuum increased. Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 700 A, with the maximum voltage limited at 14 V, between 5.00e-05 (Good vacuum) and 6.00e-05 Torr (Bad vacuum).        Thursday, March 29, 2012, 22:31: TGHT tripped off a few times over the past hours.  After changing the Good Vac to 2.00e-5 torr and Bad Vac to 3.00e-5 Torr, the target heater are regulating properly and the max pressure is well maintained below 6.5e-5 Torr [Trip point @ 8.0e-5 Torr].  (see attachment#1: parameter.jpg) Friday, March 30, 2012, 23:19   Archive of the target current and vacuum over the past 24 hours.  (see attachment #1: archive_24hr) Saturday, March 31, 2012, 12:12 The organic materials have been burnt off.  The target heater ramping up is no longer restricted by the vacuum limit.  Archive of the target current and vacuum over the past 10 hours. (see attachment #2: TGHT@240A).   Saturday, March 31, 2012, 22:52 TGHT has stayed at 700A/12.37V, local @ 693A/12.43 = Temp @ 1780C.   The striptool shows some out-gassing when TGHT reached to 700A. (see attachment #3 marked with black circle: TGHT@700A.jpg) Increasing TGHT to 750A to see if there is any further reaction...   Sunday, April 01, 2012, 10:24   TGHT was ramped up to 750A, local 730A/13.90V.  The pressure has come down to low 10e-6 but not stable;  Some reaction may be ongoing therefore it's causing the vacuum excursion.  (See attachment #4: TGHT @ 750A).  Notice the current readback is not constant and it's slowly decreasing as the voltage readback is increasing.  There might be some resistant building up. --> Initiating the cool-down process at 2A/min.  Sunday, April 01, 2012, 19:30   TGHT has ramped down to 0A, and the pressure is going down (currently at 7.e-8 Torr) with no excursion.  (see attachment #5: TGHT@0A).  The chamber will be vented tomorrow, and the target materials will be inspected.

 Monday, April 02, 2012, 16:11

After sintering , the 3 BeO pellets have shrunk and feel robust.

The first sample ate through the Ta target boat, shrank a lot and has white and black marks. We suspect the PAM (mostly made of canola oil) to be responsible for the boat damage and the weird sintering process (see John's posts).

Sample 2 is holding well.

Sample 3, which was not washed with acetone, shows some cracks.

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

1    -----,  0.6254,  -----

2   5.81,  0.9229,  1.032

3   8.89,  1.1073,  0.809

The average mass before sintering was 1.9843 g. After sintering, 0.8852 g. Thus the average mass loss is 0.9757  (49.0%).

We are starting a new batch of treated powder washed with acetone without PAM.

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.

 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.

 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 Pictures)

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).

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.