John Wong wrote:

Nikita Bernier wrote: Wednesday, June 20, 2012, 17:23 New Target boat, with no coating, wrapped with a 0.002 inches thick Ta foil, contains NiO D-shape discs : Sample,   # Disks,    Mass (g),    Thickness (mm) 1    12,  1.9396,  1.938 2    13,  0.9592,  0.847 3    25,  2.6675,  3.06 See John's Ipad for their recipes. Evaporator #2 is now auto-ramping overnight at 0.5 A/min, up to 580 A, with the maximum voltage limited at 14 V, between 3.00e-05 (Good vacuum) and 4.00e-05 Torr (Bad vacuum).   Wednesday, June 20, 2012, 22:28 TGHT tripped off at 78A due to high out-gassing pressure.  The current was tapped down to 75A before it was turned back on.  Changed ramping rate from 0.5A/min to 0.2A/min.   Initiate auto-ramping...   Thursday, June 21, 2012, 08:35 Vacuum has come down to 7e-7 as TGHT is being ramped up at 0.2A/min. (see attachment#1). Increase TGHT rate to 2A/min. The temperature should be measured when the heater gets up to around 500A.

 Thursday, June 21, 2012, 17:37

The NiO discs were heated up to 1500C at 560A.  The target heater was lowered in steps and the temperature was measured.  At 320A, the target container was ~1110C.  (see attachment #1) 

There was a sign of resistant on the target container as the p/s voltage started to go up at a higher rate.  (see attachment#2, 3, 4 for the archived striptool).

Unfortunately, the target container was broken; it was most likely reacted with the Ni.  (see attachment#5)

So.... the possible solution?!  TRY coating the container with Ta2O5.  Will discuss more in the Friday Jun 22 meeting. 

Thursday, July 12, 2012, 17:29

NiO was sprayed on Ni foil.

Average/discs: mass= 0.075g, thickness=0.076mm, density = 7.023g/cm3.

4 set of samples were loaded onto the targetboat (coated/sintered with TaC).  A piece of Ta foil was used as the under layer (see attachment #1).

A 0.002" thick Ta foil was wrapped around the container as the heat-shield.

The chamber was pumped down to 5.0e-6 Torr before the cooling water valve was opened; no leaks was detected.

For this process, the target heater will only go up to 250A (~1100C), with auto-ramping rate at 0.5A/min.

The heater has been stepped up to 50A, local 32A/ 0.23V.  The vacuum reached to max 1.6e-5 Torr, and it's coming down.

Thursday, July 12, 2012, 17:51

Auto-ramping initiated...

 Friday, July 13, 2012, 09:42

TGHT reached to 250A and stayed for 6 hrs (see attachment #2).  At that current, the target wasn't glowing so the temperature could not be measured. 

Initiated auto-cooling at 2A/min. 

Friday, July 13, 2012, 11:00  

TGHT reached to 65A.  Stopped the auto-cooling process and manually tapped down the p/s to 0A.  

Vacuum is stable at 5.7e-7 Torr.  

In the next 30 min or so, the chamber will be vented and the NiO target material will be taken out for inspection. 

Tuesday, July 17, 2012, 15:45

Target boat is filled with TaC coated regular- and D-endcaps. 

The boat is wrapped with a Ta heat-shield. 

Chamber is being pumped down, currently at 5e-6 Torr.

Tuesday, July 17, 2012, 15:58

Heat-shield cooling water valve opened; no leaks detected.

Initiated TGHT auto-ramping at 0.5A/min, set TGHT max at 580A.

 Wednesday, July 18, 2012, 10:44

Yesterday evening, the target heater tripped off a few times due to high vacuum excursion.  The TGHT ramping rate was low to 0.2A/min.  The current was ramped up sturdily to 500A this morning.  

Wednesday, July 18, 2012, 10:46

Increased ramping rate to 2A/min.  Vacuum currently at 2.2e-6 Torr.

 Wednesday, July 18, 2012, 16:18

TGHt has reached to 580A and stayed for about 5 hrs. 

Cooling down in process...  2A/min for TGHT --> 0A.

 Thursday, July 19, 2012, 10:31

TGHT reached to 0A. 

Evaporator is off. 

Venting chamber... 

Monday, July 30, 2012, 15:38

The evaporator was used for the processing the NiO target for 8 days and it was discovered today that there was a puddle of water underneath the chiller. 

The cover of the chiller was removed and some water around the plumbing was found (see attachment #1). 

Will continue to keep running the chiller to see if there is more water leaking out...

 Friday, August 10, 2012, 19:54

Target boat with TaC coating, inside covered with a 0.002 inches thick Ta foil, wrapped with a 0.002 inches thick Ta foil, contains a Ta foil with TaO coating.

See John's Ipad for their recipes.

Evaporator #2 is now auto-ramping overnight at 0.2 A/min, up to 830 A, with the maximum voltage limited at 14 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum).

Nikita Bernier wrote:

Friday, August 10, 2012, 19:54   Target boat with TaC coating, inside covered with a 0.002 inches thick Ta foil, wrapped with a 0.002 inches thick Ta foil, contains a Ta foil with TaO coating. See John's Ipad for their recipes. Evaporator #2 is now auto-ramping overnight at 0.2 A/min, up to 830 A, with the maximum voltage limited at 14 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum).

 Saturday, August 11, 2012, 19:15

Heating process was going smoothly up to 400 A. See Attachment 1.

Around 420 A, vacuum went up again and the voltage increased more quickly. It seems like resistance is building up. After reaching 530 A, the current was tapped down to 420 A in an effort to save the Ta boat. See Attachment 2.

The current will stay at 420 A for the weekend until John takes a look at this.

Nikita Bernier wrote:

Nikita Bernier wrote:  Friday, August 10, 2012, 19:54   Target boat with TaC coating, inside covered with a 0.002 inches thick Ta foil, wrapped with a 0.002 inches thick Ta foil, contains a Ta foil with TaO coating. See John's Ipad for their recipes. Evaporator #2 is now auto-ramping overnight at 0.2 A/min, up to 830 A, with the maximum voltage limited at 14 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum).    Saturday, August 11, 2012, 19:15 Heating process was going smoothly up to 400 A. See Attachment 1. Around 420 A, vacuum went up again and the voltage increased more quickly. It seems like resistance is building up. After reaching 530 A, the current was tapped down to 420 A in an effort to save the Ta boat. See Attachment 2. The current will stay at 420 A for the weekend until John takes a look at this.

 Monday, August 13, 2012, 13:46

 TGHT was ramped down at 2 A/min and then tapped down to 0A. See Attachment 1.  The target boat will be cooled down for about an hour before turning off the chiller.

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).

Nikita Bernier wrote:

Nikita Bernier wrote: Nikita Bernier wrote:  Friday, August 10, 2012, 19:54   Target boat with TaC coating, inside covered with a 0.002 inches thick Ta foil, wrapped with a 0.002 inches thick Ta foil, contains a Ta foil with TaO coating. See John's Ipad for their recipes. Evaporator #2 is now auto-ramping overnight at 0.2 A/min, up to 830 A, with the maximum voltage limited at 14 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum).    Saturday, August 11, 2012, 19:15 Heating process was going smoothly up to 400 A. See Attachment 1. Around 420 A, vacuum went up again and the voltage increased more quickly. It seems like resistance is building up. After reaching 530 A, the current was tapped down to 420 A in an effort to save the Ta boat. See Attachment 2. The current will stay at 420 A for the weekend until John takes a look at this.    Monday, August 13, 2012, 13:46  TGHT was ramped down at 2 A/min and then tapped down to 0A. See Attachment 1.  The target boat will be cooled down for about an hour before turning off the chiller.

 Tuesday, August 14, 2012, 16:56

Summary:

The purpose of this experiment is to test the chemical and high temperature (1600C) resistance of a Ta foil (0.001" thick) coated with Ta2O5, so it can be used as the under-layer for the BeO sintering process.

The Ta2O5 (white powder, -325 mesh) was prepared in a non-aqueous solution and was sprayed on a piece of Ta foil. 

The coated foil was rolled up and inserted in a Ta-coated (previously sintered) target boat for heating.

The foil was heated up to 520A (~1200C) and evidently,Ta2O5 started to react with Ta foil, and the foil became brittle and cracked (see attachment#1).

In conclusion, Ta2O5 is not a good protection layer for Ta material - at least for our applications.

 Monday, September 24, 2012, 15:01

The target boat with TaC coating is being used again. The inside of the boat is covered with a 0.002 inches thick Ta foil with TaC coating, wrapped with a 0.002 inches thick Ta foil.

Chamber was pumped down to 6e-6 Torr before the Heat Shield cooling water valve was opened. A small vacuum bump was detected (See attachment #1). It is not clear if it was caused by a water leak or not.

After consulting with Peter, I will wait for the vacuum to be below e-07 Torr before turning the target heater on.

Nikita Bernier wrote:

Monday, September 24, 2012, 15:01 The target boat with TaC coating is being used again. The inside of the boat is covered with a 0.002 inches thick Ta foil with TaC coating, wrapped with a 0.002 inches thick Ta foil. Chamber was pumped down to 6e-6 Torr before the Heat Shield cooling water valve was opened. A small vacuum bump was detected (See attachment #1). It is not clear if it was caused by a water leak or not. After consulting with Peter, I will wait for the vacuum to be below e-07 Torr before turning the target heater on.

 Monday, September 24, 2012, 18:02

The vacuum was stable until 1e-06 Torr. The target heater was turned on and tapped up to 60 A (0.8 V). 

Evaporator #2 is now auto-ramping overnight at 0.2 A/min, up to 800-850 A, with the maximum voltage limited at 14 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum). 

 Tuesday, September 25, 2012, 15:11

Sintering process is going smoothly. See Attachment 1. The auto-ramping was increased to 1 A/min up to 800-850 A.

Tuesday, September 25, 2012, 16:11 

And the voltage limit was increased to 18 V ! See Attachment 2.

 Tuesday, September 25, 2012, 19:13

Around 806 A (readback), voltage increased more quickly than the current. It seems like resistance is building up. After reaching 836 A (readback), the current was tapped down to 800 A (readback)/ 816 A (setting) in an effort to save the Ta boat. See Attachment 3. The current will stay at 800 A for ~4 hours before ramping down.

Nikita Bernier wrote:

Nikita Bernier wrote:  Monday, September 24, 2012, 15:01 The target boat with TaC coating is being used again. The inside of the boat is covered with a 0.002 inches thick Ta foil with TaC coating, wrapped with a 0.002 inches thick Ta foil. Chamber was pumped down to 6e-6 Torr before the Heat Shield cooling water valve was opened. A small vacuum bump was detected (See attachment #1). It is not clear if it was caused by a water leak or not. After consulting with Peter, I will wait for the vacuum to be below e-07 Torr before turning the target heater on.        Monday, September 24, 2012, 18:02 The vacuum was stable until 1e-06 Torr. The target heater was turned on and tapped up to 60 A (0.8 V).  Evaporator #2 is now auto-ramping overnight at 0.2 A/min, up to 800-850 A, with the maximum voltage limited at 14 V, between 2.00e-05 (Good vacuum) and 3.00e-05 Torr (Bad vacuum).     Tuesday, September 25, 2012, 15:11 Sintering process is going smoothly. See Attachment 1. The auto-ramping was increased to 1 A/min up to 800-850 A.     Tuesday, September 25, 2012, 16:11  And the voltage limit was increased to 18 V ! See Attachment 2.    Tuesday, September 25, 2012, 19:13 Around 806 A (readback), voltage increased more quickly than the current. It seems like resistance is building up. After reaching 836 A (readback), the current was tapped down to 800 A (readback)/ 816 A (setting) in an effort to save the Ta boat. See Attachment 3. The current will stay at 800 A for ~4 hours before ramping down.

 Wednesday, September 26, 2012, 14:31

The current was tapped down twice as resistance was building up. After 4 hours at ~800 A, the TGHT was ramped down at 2 A/min. See Attachment 1. The target boat was cooled down for 4 hours before the chiller was turned off.

Also I had trouble measuring the temperature. I was unable to get a clear picture with the pyrometer. Therefore the exact temperature remains unknown, but from previous experiments, 800 A was about 1400°C.

The TaC coated Ta foil is very brittle. There is a lot of crystallisation on the Ta boat. See attachment 2. It is unlikely that the boat would survive many more sintering. Therefore it will be used for BeO pellets tests. 

When John gets back, I suggest we use a new boat coated with TaC, without additional layers. (See message #15 when this target boat was sintered up to 900A (local 893A/16.88V), Measured temp @ 1500°C)

 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, 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. 

 Friday, January 11, 2013, 13:52

TEST#1

A new target boat is coated with TaC and will go through the sintering process at 580A (max).  Ramping rate 5A/20min.

For this test, two thermocouples are installed to measure the temperature of the container.  The QMS is also operating to analyze the gases. 

See attachment#1 for the thermocouple setup.  Note:  No Ta heat shield is used to wrap around the target container.  

See attachment#2 for an example of the QMS and temperature measurements.  

More details about the results later...  

Tuesday, January 22, 2013, 12:19  

The test was successfully complete. 

Short summary of the results: 

1.  A significant difference in the temperature dependence on the heater current could be found when ramping up/down (see attachment #3). 

2.  A difference of 200 C at the highest temperature was between the two thermocouples were measured. 

3.  The measured temperatures are lower than previous measurements with a pyrometer on an empty LP target container (see attachment#3).

4.  RGA spectra show most of the higher mass organic molecules are gone after initial heating at low temperature.  

5.  Above 560A, CO2 shows up again and decreases up to about 680A heating current. (see attachment #4).

6.  After running at high temperature for some time, only H2O & CO and their constituents are left.  (see attachment #5).

Data can be found on my dropbox, folder "RFQ-test\Test#1-ver1.0"

Next:  Re-heating the target

Tuesday, February 12, 2013, 17:10 

TEST#2: Re-heating the target again.  See if it fit the curves. Measuring concentrations of 14N, 16O, 18H2O, 28CO, 32 CH3OH, 40Ar, 44C02. 

Ramping rate 1A/min

Wednesday, March 06, 2013, 18:14 

Test#2 complete.  Data can be found on my dropbox, folder "RFQ-test\Test#2-ver1.0"

Wednesday, March 06, 2013, 18:14 

Test#3:  RFQ target container_version 2.0, thermal test.

Measuring back block temperature & analyze gases.  

Data can be found on my dropbox, folder "RFQ-test\Test#3-ver2.0"

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".

 Monday, March 04, 2013, 17:39

This is the 2nd modified target container for RFQ LPSIS.  The container will be heated up to 650A TGHT and 150A on TBHT.  No Ta-heat shield is being used.  

Heating rate at 1A/min for both TGHT & TBHT.  Once the target is at the currents, TBHT will be further ramped up to 300A.  

Temperatures are being measured by two thermocouples (one on RFQ component and the other on the Cu heat-shield).  

Gases are being analyzed using the RGA. 

 A thermocouple feedthru was installed via 9 pin sub-D connector. It runs from the the conflat cross on the top of the evaporator to the upper 9 pin connector of the target mounting plate.

 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).