Tuesday, August 27, 2013, 16:48

Target boat is filled with TaC coated endcaps (brown) and some partial sinterred ones (gray) from before.  (see attachment#1).

The container is wrapped with Ta heat-shield.

Chamber has been pumped down; IG currently @ 7.3e-7 Torr. 

Heat-shield cooling water valves are open; no leaks are detected.

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

 Wednesday, August 28, 2013, 16:09

TGHT has reached to 580A and been heated for over 4 hours.

IG is coming down, currently at 1.9 e-6 Torr.

Initiated auto-cooling.  2A/min. 

John Wong wrote:

Tuesday, August 27, 2013, 16:48 Target boat is filled with TaC coated endcaps (brown) and some partial sinterred ones (gray) from before.  (see attachment#1). The container is wrapped with Ta heat-shield. Chamber has been pumped down; IG currently @ 7.3e-7 Torr.  Heat-shield cooling water valves are open; no leaks are detected. Initiated TGHT auto-ramping at 0.5A/min, set TGHT max at 580A.  Wednesday, August 28, 2013, 16:09 TGHT has reached to 580A and been heated for over 4 hours. IG is coming down, currently at 1.9 e-6 Torr. Initiated auto-cooling.  2A/min.

 Thursday, August 29, 2013, 11:50

TGHT at 0 A

IG at 3.5e-7 Torr

Turning off EVAP2 and venting chamber

Process complete

Tuesday, May 28, 2013, 17:36

The target containers endcaps were coated with TaC solution and let dry. 

Each cap is wrapped with a small piece of graphite foil and inserted in the target boat.

The chamber is currently being pumped down. 

The HS cooling water valve will be opened tomorrow; any leak will be inspected.

When the vacuum is good,  TGHT will be ramped up to 580A. 

 Wednesday, May 29, 2013, 17:06

HS water valve was opened early this morning; no leaks were detected.

TGHT has stepped up to 50A.  IG is currently at 2.0e-6Torr. 

Initiated auto-ramping at 1.0A/min.

 Thursday, May 30, 2013, 11:12

TGHT reached to 580.  The end caps have been heated at that current for more than 7 hrs.

IG is coming down, currently at 8e-7 Torr.

Auto-cooling initiated, ramping down at 2A/min .

 Tuesday, January 28, 2014, 15:43

The target containers end-caps were coated with TaC spray and let dry.

Each cap is wrapped with a small piece of graphite foil and inserted in the target boat. [see attached photo]

The chamber is currently being pumped down overnight.

 Wednesday, January 29, 2014, 11:32

Chamber was pumped down to 1.6e-7 Torr overnight.

HS cooling water valve opened; no leaks detected.

TGHT was stepped up to 35A, voltage max set at 11.05V. TBHT currently at 0A.

Waited ~20min, current stabilized, vacuum started to drop, auto-ramp initiated at 0.2A/min and max setpoint to 580A.

Good vacuum: 3.00e-5 Torr, Bad vacuum 4.00e-5 Torr.

 Thursday, January 30, 2014, 09:06

TGHT has been slowly ramping up overnight at a rate of 0.2A/min.

IGP1 = 2.4e-7 Torr, TGHT = 283A; stepping ramping rate up to 2.0A/min.

 Thursday, January 30, 2014, 15:53

TGHT reached 580A at 11:45. Measured temp @1650C.

Initiating TGHT auto-cooling now at 2.0A/min.

 Friday, January 31, 2014, 09:04

Chamber cooled down overnight, vented and opened this morning.

Smooth run!

 Friday, January 31, 2014, 11:21

Opened up the end caps, turns out it wasn't such a smooth run...they're not fully sintered 

See attached photo comparison between fully sintered end cap [silver] and end cap from this run [green].

Will re-install and re-sinter next week.

 Wednesday, February 05, 2014, 11:34

End-caps re-installed into EVAP2

Target boat is wrapped with 3 x Ta heat-shield.

Chamber is currently being pumped down.

 Wednesday, February 05, 2014, 14:31

Chamber was pumped down to 5e-7 Torr this morning.

HS cooling water valve opened, no leaks detected.

TGHT was stepped up to 35A, voltage max set at 11.05V. TBHT currently at 0A.

Waited ~20min, current stabilized, vacuum started to drop, auto-ramp initiated at 0.2A/min and max setpoint to 580A.

Good Vacuum: 3.00e-5 Torr, Bad vacuum 4.00e-5 Torr.

 Thursday, February 06, 2014, 09:06

TGHT has been slowly ramping up overnight at a rate of 0.2A/min.

IGP1 = 1.1e-7 Torr, TGHT = 259A; stepping ramping rate up to 2.0A/min.

 Friday, February 07, 2014, 10:10

TGHT reached 580A yesterday. Measured internal temp @ 1500C.

Initiated TGHT auto-cooling this morning at 2.0A/min

 Tuesday, February 11, 2014, 13:30

Vented and opened chamber this morning.

Endcaps are toast  [see pictures attached]

Some of the endcaps broke/fried, others deformed-none useable.

Possibly due to new target boat resulting in more current?

Too much heat with Ta heat shields?

Bad News Bears 

 Tuesday, February 25, 2014, 16:08

The target containers end-caps were coated with TaC spray and let dry.

The caps are inserted in the target boat vertically with no heat shield and no graphite foil. [see attached photo]

The chamber is currently being pumped down overnight.

 Wednesday, February 26, 2014, 09:54

Chamber was pumped down overnight to 4.2e-7 Torr.

HS cooling water valves opened; no leaks detected.

TGHT was stepped up to 35A, voltage max set at 14V. TBHT currently at 0A.

Waited ~20min, current stabilized, vacuum started to drop, auto-ramp initiated at 0.2A/min and max setpoint to 700A.

Will ramp up to 700A rather than the usual 580A due to last round of endcaps not fully sintering at 580A with new target boat design.

Good vacuum: 3.00e-5 Torr; Bad vacuum: 4.00e-5 Torr.

 Thursday, February 27, 2014, 09:38

TGHT has been slowly ramping up overnight at a rate of 0.2A/min.

IGP1 = 2.8e-7 Torr; TGHT = 311A, 4.3V

Stepping ramping rate up to 2.0A/min.

 Friday, February 28, 2014, 08:53

TGHT reached max setpoint of 700A yesterday evening.

Internal temp measured with Mikron = 1700C

IGP1 = 3e-7 Torr 

Power = 12.95V

Initiating auto-cooling at 2.0A/min.

 Monday, March 03, 2014, 11:46

Vented and opened chamber this morning.

End caps not fully sintered! 

See attached photo comparison of fully sintered [grey], partially sintered from this round [light green] and pre-sinter [dark green].

Will not bother re-sintering, as partial sinter is enough.

 Friday, March 07, 2014, 11:41

The target container end-caps were sintered previously, but did not fully complete the sintering process [See elog entry # 119 EVAP2]

The caps are inserted in the target boat wrapped in graphite foils with 3 x Ta-heat shields.

The chamber was pumped down overnight.

IGP1 = 2e-7 Torr

HS cooling water valves were opened; no leaks detected.

TGHT was stepped up to 35A, voltage max set at 9.05V. TBHT currently at 0A.

 Friday, March 07, 2014, 11:52

Waited ~20min, current stabilized, vacuum started to drop, auto-ramp initiated at 0.5A/min and max setpoint to 500A.

Will ramp to 500A due to last failed round of end caps breaking with 3-ta heat shields at 580A.

Good vacuum: 3.00e-5 Torr; Bad vacuum: 4.00e-5 Torr.

 Friday, March 07, 2014, 13:21

IGP1 = 8e-7 Torr.

TGHT = 72A

Vacuum stable; therefore, increasing ramping rate up to 1.0A/min

 Friday, March 07, 2014, 14:20

IGP1 = 9.8e-7 Torr

TGHT = 130A

Vacuum stable; therefore, increasing ramping rate up to 2.0A/min

Laura Lambert wrote:

Friday, March 07, 2014, 11:41 The target container end-caps were sintered previously, but did not fully complete the sintering process [See elog entry # 119 EVAP2] The caps are inserted in the target boat wrapped in graphite foils with 3 x Ta-heat shields. The chamber was pumped down overnight. IGP1 = 2e-7 Torr HS cooling water valves were opened; no leaks detected. TGHT was stepped up to 35A, voltage max set at 9.05V. TBHT currently at 0A.  Friday, March 07, 2014, 11:52 Waited ~20min, current stabilized, vacuum started to drop, auto-ramp initiated at 0.5A/min and max setpoint to 500A. Will ramp to 500A due to last failed round of end caps breaking with 3-ta heat shields at 580A. Good vacuum: 3.00e-5 Torr; Bad vacuum: 4.00e-5 Torr.  Friday, March 07, 2014, 13:21 IGP1 = 8e-7 Torr. TGHT = 72A Vacuum stable; therefore, increasing ramping rate up to 1.0A/min  Friday, March 07, 2014, 14:20 IGP1 = 9.8e-7 Torr TGHT = 130A Vacuum stable; therefore, increasing ramping rate up to 2.0A/min

Friday, March 07, 2014, 22:22  

Target current was at 500A before it tripped off on the chiller.   Tried to reset the chiller but to no avail.  Don't know what is going on yet. 

The TGHT/TBHT cooling water is still on, and this should OK while the HOT target boat is cooling down at the moment. 

Will leave it for now and further investigate on Monday

 Tuesday, August 05, 2014, 12:02

The target container end caps were coated with TaC spray and let dry.

The caps are inserted in the target boat vertically, wrapped in graphite foil with 3 x Ta-heat shield. [see attached photo]

The chamber is currently being pumped down.

Laura Lambert wrote:

Tuesday, August 05, 2014, 12:02 The target container end caps were coated with TaC spray and let dry. The caps are inserted in the target boat vertically, wrapped in graphite foil with 3 x Ta-heat shield. [see attached photo] The chamber is currently being pumped down.

 Tuesday, August 05, 2014, 17:19

HS water valve opened; no leaks detected. 

Pressure @ 2.5e-6 Torr.

Ramping up TGHT to 580A @ 1A/min.

John Wong wrote:

Laura Lambert wrote:  Tuesday, August 05, 2014, 12:02 The target container end caps were coated with TaC spray and let dry. The caps are inserted in the target boat vertically, wrapped in graphite foil with 3 x Ta-heat shield. [see attached photo] The chamber is currently being pumped down.    Tuesday, August 05, 2014, 17:19 HS water valve opened; no leaks detected.  Pressure @ 2.5e-6 Torr. Ramping up TGHT to 580A @ 1A/min.

 Thursday, August 07, 2014, 08:11

Yesterday the target boat was taken out.

The boat broke as it turns out it was used for a Niobium target and therefore wasn't coated with TaC.

The end caps were fully sintered.

 Thursday, September 11, 2014, 13:14

The target container end caps were coated with TaC spray and let dry.

The caps are inserted in the target boat wrapped in graphite foil with 3 x Ta-heat shields.

The chamber is currently pumping down.

 Friday, September 12, 2014, 14:17

Chamber was pumped down overnight.

HS cooling water valves opened, no leaks detected.

IGP1 = 7.2e-7 Torr.

TGHT stepped up to 35A, TBHT at 0A.

Waited ~30min, current stabilized, vacuum started to drop, auto-ramp initiated at 0.2A/min.

Will ramp TGHT to 580A with a max 10V.

Good vacuum: 3.00e-5 Torr; Bad vacuum: 4.00e-5 Torr.

 Monday, September 15, 2014, 11:31

TGHT stopped at 500A due to not high enough voltage max.

Increased max voltage to 12V

 Monday, September 15, 2014, 14:17

IGP1 = 6.3e-7 Torr

Increasing ramping rate to 1.0A/min

 Tuesday, September 16, 2014, 09:04

TGHT reached 577A and finished auto-ramping, then proceeded to drop down to 560A overnight.

Increased max voltage to 13.05A and TGHT to 580A.

 Tuesday, September 16, 2014, 13:52

TGHT reached 580A and sat there for ~5hrs.

IGP1 = 6.1e-7 Torr.

Initiating auto-cool at 2.0A/min.

 Wednesday, September 17, 2014, 13:03

Vented in air.

Opened up....looked 'deceivingly' ok.

then i took a layer of Ta off....grrrr  

the 1st layer of Ta was holding the boat together. as soon as that layer was taken off the target boat broke.

see attached photos.

 Tuesday, January 31, 2017, 13:43

Container coated with TaC using new method: Ends taped off,  with liquid poured in and swirled around entire container, then poured back out - 'flushing technique'

Container is wrapped with 3 x Ta heat shields, not incl center block.

Loaded into EVAP2 and currently pumping down.

Tuesday, January 31, 2017, 16:02 

IGP1 = 3.9e-6 Torr.

HS water valves opened.

No leaks detected.

Tapped up manually to 35A.

Vacuum stable.

Initiated auto ramp at 0.2A/min and 0.1A/min for the TGHT and TBHT respectively.

Final setpoints for TGHT = 450A and TBHT = 230A, with final desired temp of 1900C

OMEGA slope = 0.98

 Wednesday, February 01, 2017, 10:01

IGP1 = 5.7e-7 Torr.

TGHT = 254A, 3.0V

TBHT = 142A, 1.8V

Increasing ramping rate to 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

 Wednesday, February 01, 2017, 11:48

IGP1 = 1.7e-6 Torr.

TGHT = 450A, 6.27V

TBHT = 230A, 3.14V

OMEGA = 1176C

Increasing max setpoint of TGHT = 600A

 Wednesday, February 01, 2017, 13:09

IGP1 = 3.7e-6 Torr.

TGHT = 600A, 9.0V

TBHT = 230A, 3.18V

OMEGA = 1480C

Increasing max setpoint of TGHT = 700A

 Wednesday, February 01, 2017, 14:08

IGP1 = 3.8e-6 Torr.

TGHT = 700A, 10.96V

TBHT = 230A, 3.2V

OMEGA = 1705C

Increasing max setpoint of TGHT = 750A

 Wednesday, February 01, 2017, 15:02

IGP1 = 5.1e-6 Torr.

TGHT = 750A, 11.87V

TBHT = 230A, 3.2V

OMEGA = 1808C

Increasing max setpoint of TGHT = 800A

 Wednesday, February 01, 2017, 15:30

IGP1 = 6.6e-6 Torr.

TGHT = 800A, 12.86V

TBHT = 230A, 3.2V

OMEGA = 1903C

Will remain at max setpoints overnight.

 Thursday, February 02, 2017, 09:16

Remained at max setpoints for ~18hrs.

IGP1 = 9.5e-7 Torr.

OMEGA =1914C

TGHT = 800A, 12.83V

TBHT = 230A, 3.22V

Initiating auto-cool at 2.0A/min and 1.0A/min for the TGHT and TBHT respectively.

 Friday, February 03, 2017, 14:24

Vented in air and opened up this morning

Coating looks good.

See photos attached.

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.

Tuesday, April 03, 2012, 08:54

Yesterday, a new target boat was sprayed with TaC coating and let dried.

The boat was then installed in the Evap#2 chamber and pumped down to 10-6 Torr before the target heater was turned on.  NOTE: Target boat is not wrapped with Ta-heat shield. 

TGHT auto ramping was initiated at 2.0A/min and max setpoint to 700A.  The voltage was set at 3V; therefore, the current only ramped up to 250A over night.

--> Increased the TGHT voltage to 15A, and continue ramping the TGHT to 700A.  Currently vac at low 2.3e-7 Torr. 

 Tuesday, April 03, 2012, 09:12

The vac is at low 10e-7 as the TGHT is ramping up.  Changing ramping rate from 2A/min to 5A/min. 

Tuesday, April 03, 2012, 12:00  

TGHT reached to 700A. Measured temp @ 1280C. 

Tapped up TGHT to:

800A.  Measured temp @ 1400C. 

850A (local 843A/15.60V). Measured temp @ 1450C.  

900A (local 893A/16.88V).  Measured temp @ 1500C

 Tuesday, April 03, 2012, 14:35:

Try autoramping TGHT to 1000A but voltage has gone up close to the max limit (20V).  TGHT could only go up to ~970A (see attachment 1: TGHT_maxcurrent.jpg).  The heater remained at that current for ~1hr but auto cooling was initiated - at 10A/min.

Thursday, September 25, 2014, 17:32

Target boat is filled with Ta-coated endcaps.  The caps are stacked together.  In between each cap, a piece of graphite foil is used for separation so the Ta caps would not fused. 

See link for photos:

https://www.dropbox.com/sh/rydtdho6ggh4l3l/AAAYmvqT0mVQ_pnz4iecS4ksa?dl=0

The boat is wrapped with 3-layers of heatshields.  The chamber is currently being pumped down.

TGHT will be ramped up to 580A and the temperature will be measured.

Monday, September 29, 2014, 11:12

TGHt was stepped up to 40A on last Friday and chamber continues to pump down over the weekend.

Vac @ 2.56e-6 Torr, mp @ 19mTorr.

Ramping up TGHT 580A at 1.0A/min.

 Monday, September 29, 2014, 11:50

TGHT tripped off at 53A.  Reduce ramping rate to 0.5A/min for now.

 Monday, September 29, 2014, 16:17

Vacuum is coming down to 9.5e-7 Torr.  Increased ramping rate to 1.0A/min.

 Tuesday, September 30, 2014, 11:59

TGHT reached to 580A/10.18V.  Target has been heated at that current for almost 12 hrs. Vac @ 4.9e-7 Torr.

Local temp measured with Mikron = (1500C + 250 C correction) = 1750C

Cooling down at 2A/min.

 Thursday, October 02, 2014, 11:13

The coating is fully sintered; no sign of any damage on the endcaps.  

Process is successful.  

Laura Lambert wrote:

Tuesday, September 23, 2014, 15:00 A new target boat [new design with no end caps] was sprayed with TaC coating and let dry. The target boat is wrapped with 3-layers of Ta-heat shield. The boat was installed in EVAP2, chamber is currently being pumped down.

 Tuesday, September 23, 2014, 18:31

Chamber was pumped down to 2.5e-6 Torr. 

HS water valve open; no leaks detected.

Stepping up TGHT to 40A - pressure is increasing...

 Tuesday, September 23, 2014, 19:05

Auto-ramping TGHT to 580A at 0.5A/min.  Temperature will be measured and TGHt will be adjusted accordingly.

 Wednesday, September 24, 2014, 11:57

Pressure is stable at 2.2-6 Torr as TGHT is ramping up.  Increase ramping rate to 2.0A/min.  Currently TGHT at 540A.

 Wednesday, September 24, 2014, 15:36

TGHT at 580A for 2 hrs.  Inner tube temp (left side wall, viewing from the window port) ~1800C (measured with Mikron = 1550C +250C em. correction); Vac @ 1.67e-6 Torr.

Temperature measurement distance from the window to Mikron = 45cm.

Increase TGHT to reach 2000C (Mikron @ 1750C)

 Wednesday, September 24, 2014, 18:14

TGHT has gone up to 725A/13.2V.  Temp measured at 1740C (+250C = ~2000C).  Pressure gone up to 5.5e-6 Torr and it's coming down slowly.

Will continue heating at this temperature for a few hours; then cool down afterward.

 Wednesday, September 24, 2014, 18:56

Temperature is pretty stable at 1740C on Mikron, and pressure is still coming down, currently at 2.9e-6 Torr.

Slow ramping down TGHT at 1.0A/min.  The chamber should be ready for venting tomorrow. 

Target boat will be inspected.

 Thursday, September 25, 2014, 17:25.

The boat was inspected and it turned out great!  The coating was fully sintered and there is no sign of damage on the boat. 

See the link for photos.

https://www.dropbox.com/sh/m7ycqhkj4avfull/AABHVTweTsP4ajeWZ6uoY010a?dl=0

John Wong wrote:

Laura Lambert wrote: Laura Lambert wrote: Laura Lambert wrote: Laura Lambert wrote: Laura Lambert wrote:  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.    Tuesday, January 21, 2014, 11:10 Chamber was pumped down to ~2e-7 Torr. HS cooling water valves were opened, no leaks detected. TGHT was stepped up to 35A, voltage max set at 13V. TBHT currently @ 0A. Waited ~20min, current stabilized, vacuum started to drop, auto-ramp initiated at 2.0A/min and max setpoint to 700A. Good vacuum: 3.00e-5 Torr, Bad vacuum 4.00e-5 Torr.    Tuesday, January 21, 2014, 11:51 Vacuum was grumpy and was well on it's way to tripping off [reached 5e-5 Torr], auto ramping was stopped at ~95A and quickly stepped down to 90A to avoid tripping it off. Allowed vacuum to settle back down to 2.3e-6 Torr. Auto ramping changed to 0.2A/min and re-started.  close-call!    Wednesday, January 22, 2014, 09:46 TGHT has been slowly ramping up overnight at a rate of 0.2A/min. IGP1 = 2.9e-7 Torr, TGHT = 342A; stepping ramping rate up to 2.0A/min.    Wednesday, January 22, 2014, 13:43 TGHT is sitting at 693A, IGP1 = 1.3e-6 Torr. Stepping up TGHT voltage up to 14V from 13.05V to reach the max current of 700A.    Wednesday, January 22, 2014, 15:09 TGHT reached to 700A/12.83V.  Local temperature on the boat surface was measured at ~1500C. Target will be heated for a few hours and will be cooled down later tonight. The chamber will be vented tomorrow and the boat will be inspected.

 Wednesday, January 22, 2014, 18:09

After the boat was heated for ~4hrs, TGHT tripped off on IEVAP2:TBHT2 (see attachment #1, #2). 

Tried clearing the water interlock via EPICS - failed to clear.  Checked the local water valves - ALL VALVES are OPEN 

Tried closing and re-opening the IEVAP2:TBHT2 valves, interlock cleared after a few minutes. 

Maybe a fault in the water signal.  If it happens again, the water signal should be replaced.

Turned back on the power supply - TGHT current/voltage are holding.  Target boat may be OK!

Chamber is a bit warm now.  Will allow time to cool down.

Will vent the chamber tomorrow and the boat will be inspected. 

 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.

Laura Lambert wrote:

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.

 Tuesday, January 21, 2014, 11:10

Chamber was pumped down to ~2e-7 Torr. HS cooling water valves were opened, no leaks detected.

TGHT was stepped up to 35A, voltage max set at 13V. TBHT currently @ 0A.

Waited ~20min, current stabilized, vacuum started to drop, auto-ramp initiated at 2.0A/min and max setpoint to 700A.

Good vacuum: 3.00e-5 Torr, Bad vacuum 4.00e-5 Torr.

Laura Lambert wrote:

Laura Lambert wrote:  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.    Tuesday, January 21, 2014, 11:10 Chamber was pumped down to ~2e-7 Torr. HS cooling water valves were opened, no leaks detected. TGHT was stepped up to 35A, voltage max set at 13V. TBHT currently @ 0A. Waited ~20min, current stabilized, vacuum started to drop, auto-ramp initiated at 2.0A/min and max setpoint to 700A. Good vacuum: 3.00e-5 Torr, Bad vacuum 4.00e-5 Torr.

 Tuesday, January 21, 2014, 11:51

Vacuum was grumpy and was well on it's way to tripping off [reached 5e-5 Torr], auto ramping was stopped at ~95A and quickly stepped down to 90A to avoid tripping it off.

Allowed vacuum to settle back down to 2.3e-6 Torr. Auto ramping changed to 0.2A/min and re-started.

 close-call!