Thursday, March 01, 2012, 14:35

Both the IEVAP2:TBHT and IEVAP2:TGHT maximum current setpoints on the vacuum page (see page: /edl/ievap2_vacuum1.edl) are wrong. 

For IEVAP2:TGHT, the maximum current setpoint should be 1500A (see page: /edl/ievap2tghtcp.edl), not 1000A. 

For IEVAP2:TBHT, the maximum current setpoint should be 500A (see page: /edl/ievap2tbhtcp.edl), not 300A. 

See attachement#1 for grabscreen. 

Fault: 5853

 Tuesday, March 20, 2012, 14:22

The Evaporator #2 backing pump (IEVAP2:BP1) muffler has not connected to the exhaust duct.

 See attachment#1 as to where the muffler should be connected to the exhaust ducting system.  

The Evaporator chamber is currently under vacuum; the BeO sintering process will be pending for now until the backing pump is properly installed. 

(ISAC E-fault 5880) 

 Wednesday, March 21, 2012, 13:55

Edi Dalla Valle is connecting the evaporator backing scroll pump exhaust to the existing nuclear exhaust. (See attachment#2: scroll_pump_exhause.jpg).  A filter is also added between the exhaust line 

to prevent any back flow of oil from the Evaporator #1 backing pump (An oil pump). 

Work is covered under ISAC WP# 2012-03-21-3.

The evaporator is now operational. 

 Tuesday, May 15, 2012, 13:45

It was discovered that one of the insulators that supported the target module broke apart (see Attachment#1).  This might be caused by the heat from the target legs that reflected back from the base to the insulators.  The burnt marks are the evidence.  

A stainless metal sheet is used as the heat shield  (see Attachment #2). 

 Tuesday, May 15, 2012, 17:00

It was found that there were water droplets from the TBHT cooling line.  The joint is leaky.  (see attachment 1) 

A message has sent to Rick M. 

 Tuesday, May 15, 2012, 17:03

The tube heater power supply current readback and setpoint are not matching.  Ray Dube checked the power supply and confirmed that it is faulty.  He will replace a functional p/s tomorrow. 

 Friday, May 18, 2012, 13:24

The original p/s was replaced with a new one and there was still a discrepancy between the readback and the setpoint.  After checking with the drawings for the ITE/ITW tube heaters, it was confirmed that the connections for the Evap#2 tube heater control were wrong.  (see attachment 1).  The connections were corrected and the power supply is now operational. 

John Wong wrote:

Tuesday, May 15, 2012, 17:00 It was found that there were water droplets from the TBHT cooling line.  The joint is leaky.  (see attachment 1)  A message has sent to Rick M.

 Wednesday, May 16, 2012, 14:01

The connector was re-tighten.  The water valve was opened, and no water leaks were found.

Monday, May 28, 2012, 11:08

It was discovered this morning that the Evaporator #2 chiller was leaking water from the bottom (see attachment 1).  A puddle of water was formed and eventually found its way down to the Hotcell. 

The evaporator was running over the weekend for the BeO pellets process.  The TGHT is now off and the chiller will be inspected... 

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. 

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".