The source of the poor vacuum in the backing line seems to be related to a dirty filter. We will try to find a replacement filter next week.

The problem seem to have started September 17th, when backing preassure CG1A went from 40 mTorr to 130 mTorr. CG1B remained around 30 mTorr.

With the help of Anthony Ip from vacuum group, the problem was diagnosed to be the roughing pump itself. The pump was replaced and pumping improved. The chamber can now be evacuated and turbo ready to start in less than 10 minutes.

The filter is not stocked by vacuum group and could not be replaced.

Last week parts of the roughing line was cleaned by Rick. The PVC roughing line has been replaced with a SST bellows. The SST bellows is KF25 and should be replaced by a KF40 bellows in the long run.

The purpose of this experiment is to improve the TaC coating mixed with other metals as additives.  The coating solution will be sprayed on Ta metal (0.015" thick, same thickness as the target container).

The samples will be sintered at ~ 1800C.  Once the process is completed, a graphite tube will be inserted into the tube, and then re-heated it up to 1800C. 

This test will show how good the protective layer to prevent the graphite to react with the Ta metal.

Wednesday, November 06, 2013, 17:11

Step #1

Two samples: 

1.  A short tube (same diameter as the usual container)

2.  A cross section of the tube.

Both samples are coated with the TaC matrix spray: 

0.05 moles TaC

0.005 moles of Mo2C, VC, Cr3C2, NbC 

A Rh foil is used as a protective under layer.

see links for pictures:  https://www.dropbox.com/sh/866zsp44nnjeg2z/LqCThu-G_0

The target boat is wrapped with 3 layers of heat shields. 

Samples will be heated up to 600A ~1800C

Chamber is currently being pumped down.

 Friday, November 08, 2013, 17:13

Chamber was pumped down to ~2e-6 Torr.  HS water valve is opened and no leaks were detected. 

TGHT will be ramped up to 580A at 1A/min. 

Monday, November 11, 2013, 08:10  

TGHT has reached to 580A; samples has been heated at that current for over the weekend. 

IGP2 currently at 3.5e-7 Torr.

Auto cooling initiated, ramping rate at -2.0A/min.

 Step 2:

The coated tube is sintered with TaC-matrix.

The graphite tube is inserted in the tube and will be heated back up; see link for details:

https://www.dropbox.com/sh/ji0rhlj0v1tfj1w/cRv1I3VJXE

Chamber is currently pumped down to 1.8e-6 Torr.

TGHT will first be ramped up to 450A (1A/min) to see how the reaction behaves, then a caution ramp up to 600A will take place. 

 Friday, November 15, 2013, 11:04

TGHT reached to 450A.  Cooling down to 0A.  Chamber will be vented for inspection.

 Monday, November 18, 2013, 17:22

Continue Step#2:

The sample looks ok after heating at 450A.

Re-heating it to 500A. 

Chamber has been pumped down to 4.0e-6 Torr. 

Initiated auto-ramping...

See attached photo.

The Heat Shield has been taken to the Machine Shop for repair.

Friday, November 08, 2013

 The Heat Shield cooling line has been repaired and the lid re-installed in the evaporator. Photo attached.

Friday, November 08, 2013, 10:58 : Roughing Started

Friday, November 08, 2013, 11:05: Turbo started 

Friday, November 08, 2013, 11:15: Turbo at speed Vacuum at (IGP1) 5.7E-5 T 

 Monday, January 20, 2014, 16:32

A new target boat was sprayed with TaC coating and let dry this morning.

The target boat is NOT wrapped with Ta-heat shield.

The boat was installed in Evap#2, chamber is currently being pumped down overnight.

There was no signal going from the coils to the PLC. After manipulating the connection points on the coil a signal could again be established. Frequency is ~ 40Hz.

Monday, March 10, 2014, 11:44

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

Monday, March 10, 2014, 11:45

The chiller tripped off on March 7, 2014.

• Water is not flowing into the chiller; paddle wheel shows no signal.
• Tried turning on the chiller locally; a few seconds later, it tripped off. 
• Motor is not responding;
• EPICS is not responding;
• All other water flow signals to TGHT, TBHT, HS, are responding;

Continue investigating...

 Monday, March 10, 2014, 14:36

The water line to the chiller is disconnected, and is re-connected straight to the TGHT power supply.  The paddle wheel is responding - the cooling line in the power supply is not blocked.

It is confirmed the chiller is broken. 

Will discuss if we can use the Evaporator without a chiller but with the DI water connected directly to the TGHT power supply....

Friday, March 14, 2014, 14:50  

The chiller was replaced with a "new" one.  

Checked the chiller interlock - It's working.  

The evaporator is now operational. 

 Friday, March 21, 2014, 16:19

Note about Auto-ramping program.

Previously the auto-rampiong program takes the Chiller as part of the reference to the interlocks.  Because the New chiller is not connected to EPICS; all the references to the Chiller on the auto-ramping program has been removed in order for it to function. 

 Pressure down to 7.1e-7 Torr. Water valve to heat shield was opened; pressure remained stable. 

Current turned up to 40 A for now.  Will increase at 2 A/min up to 500 A over the weekend, then on Monday we will turn it up to 600 A and check the temperature. 

 Thursday, October 02, 2014, 11:22

It was found that after the last process, Evap#2 has broken insulators - the cylinder insulator that supports the target centre legs and the block insulator that supports the terminals.  

Informed Anders/Rick.

John Wong wrote:

Thursday, October 02, 2014, 11:22 It was found that after the last process, Evap#2 has broken insulators - the cylinder insulator that supports the target centre legs and the block insulator that supports the terminals.   Informed Anders/Rick.

 Friday, October 03, 2014

• Insulators replaced. Torque 55 in lbs on all fasteners.
• Cleaned TGHT terminals with scotch-brite and methanol.
•  New (clean) heat shield prepared WO-39230-2.
• Re-installed right side heat shield alignment pin (previously removed to allow line of sight to the target).

 Wednesday, November 26, 2014, 13:47

OMEGA-IR laser had a dark patch on it [see picture]

Cleaned window, still dark patch

When tested by itself, through air, not through window, patch still visible - cleaned lens of OMEGA-IR, still no change.

Conclusion: assuming laser used to be able to focus the OMEGA-IR to a specific area - so visual only, but the measurements itself will not be affected.

Wednesday, November 26, 2014, 13:53 

Backing pump trips off every time roughing valve turned on through epics.

Requested further investigation...

Friday, November 28, 2014, 12:09

Backing Pump has been replaced, waiting on a reply from OMEGA re: dark patch on laser

Pancake monitor was also acting funny. Background was reading 100cpm and jumping up to as high as 400cpm by simply moving the probe piece.

The wire connecting the probe to the monitor was replaced and works fine now.

 Tuesday, December 09, 2014, 15:55

Finally got a reply from the OMEGA people:

"That [ dark patch] would happen because of sharp bends in the fiber, or simply defective fiber cable.

As manufacturer we allow 2% of broken fibers, out of 870 in the bundle.

As far as measurements is concerned, if IR2 is used in dual colour mode, 

the field of view can be obstructed as much as 50%, 

without changing the readings accuracy. This laser issure should not affect readings."

-Quote from Brian Newport from OMEGA

 Thursday, December 11, 2014, 10:17

water supply and return valves closed for lab closure over the holidays.

all taps leading into evap2 have been closed.

evap2 was fully flushed leaving no water left inside the system.

 Wednesday, January 14, 2015, 13:46: Roughing

Wednesday, January 14, 2015, 14:57: Starting turbo

Monday, January 19, 2015, 13

Water opened up to one circuit at at time. No response on the vacuum could be seen.

IGP1 at 1.7E-7 T

IGP2 at 3E-8 T

Tuesday, January 20, 2015, 13:11: Stopped turbo and roughing pump.

Wednesday, January 21, 2015, 15:46: Venting

Rick and Anders found CG1A to be reading too high a value. A borrowed gauge from the vacuum group confirmed this. A new gauge will be installed

Thursday, January 22, 2015, 14:06: Roughing

Thursday, January 22, 2015, 14:18: Venting

The reading is consistent between CG1A and CG1B, which simplifies pump down.

 See previous e-log entry for details

Tuesday June 16, 2015

An Extraction Insulator ITD0381 made from a different grade of AiN was installed in Evaporator 2 for testing purposes. The sub assembly included the SIS Restraint Housing ITD0389, New Extraction Insulator ITD0381, Repeller Electrode ITD0377, Extraction Electrode ITD0374 with fingerstock mounted.

The standoff insulator ITD0400 was found to be swelled up and broken. It was replaced with and glazed alumina insulator.

The tube heater Insulator ITD0342 - central support helicoil was repaired.

 Thursday, July 30, 2015, 17:02

EVAP1 cooling system is now on the NALCW.  The city water has been removed from the system.  

Tested all the cooling system interlocks by shutting off each individual valve, and the main supply valve to the lab -  All Passed!  

Friday, July 31, 2015, 15:09

The left side port was installed on the evaporator #2.  Leak check was performed and no leak was detected. 

 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…. 

Thursday, September 24, 2015, 08:39

IGP1 = 6.5e-7Torr

HS water valves opened, no leaks detected.

Tapped up manually to 35A.

Waited ~20min.

Vacuum stable, IGP1 = 1.5e-6 Torr.

Initiated auto-ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively with final setpoints of 250A and 230A.

Final temp of 1200C on auto-ramp in order to initiate temperature measurements starting at ~1200C.

Thursday, September 24, 2015, 10:24  

IGP1 = 8.7e-7 Torr

TGHT = 44A, TBHT = 38A

Increasing auto-ramp to 0.5A/min and 0.2A/min for the TGHT and TBHT respectively.

 Thursday, September 24, 2015, 12:03

Vacuum spiking rapidly.

Stopped auto-ramp, tapped TGHT and TBHT down manually, allowing vacuum to stabilize.

IGP1 = 3.5e-6 Torr.

Re-initiating auto-ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively.