Tuesday, December 02, 2024, 15:35    - Target loaded into the test stand

Thursday, December 03, 2024, 14:33 - as per elog entry 1033, test stand has been changed to CATHODE mode, and wiring within the Faraday cage has been altered appropriately. Additionally, a GeMov resistor has been added to potentially reduce the sparking problems that have previously tripped the TGHT power supply

Thursday, December 04, 2024, 10:00    - Roughing pump having trouble reaching suitable vacuum - possible replacement required.

Thursday, December 05, 2024, 13:37  - Turbo pumps on

Wednesday, December 11, 2024, 15:02   dropped bias/ee/ezl to 0

Wednesday, December 11, 2024, 15:02    Must cool target to investigate Cathode short. Prior to installation, target isolation was confirmed. If the cathode dropped to contact the copper plate shielding the coil, this would be evidence to support keeping the retainer.

Thursday, December 12, 2024, 09:24   after cooling, cathode power supply was checked to see if shorted and it is indeed still shorted out.

 Thursday, December 12, 2024, 09:25   turning off turbo pumps to spin down 

Thursday, December 12, 2024, 11:30:     venting chamber  

 Friday December 13:   after venting the chamber and removing the target. The target appears to be unshorted and intact. However, upon inspection of the test stand, there appears to be a ~100Ω load between the cathode and ground. This load is able to sustain voltage from the cathode power supply, but draws a significant amount of current. It is too much for operation, and might be further aggravated by the presence of the target. Further, when the TGHT and TBHT terminals are shorted together, the resistance from cathode to ground drops to ~1Ω. Perhaps this could be associated with the installation of the TGHT power supply, as FEBIAD has not been run on this machine since it was installed.   Wiring at the feedthroughs as been quadruple checked, I don't believe that the problem lies there.

With no target in place, the cathode was able to hold a voltage, despite drawing 100+mA current. However, I was unable to repeat further tests, as the power supply stopped responding. Despite ramping up to ~10V in epics, the readback is 0V/0A, unlike before.

  Friday, December 06, 2024, 16:03 Heated and cooled a sample in the ATTS 3x

  Tuesday, December 10, 2024, 14:38 Depressurized ATTS using argon, switched out samples, and repressurized ATTS. Heated new sample to 1000 degrees Celsius.

Friday, December 20, 2024, 09:37    turned off all 4 turbopumps. winding down prior to evacuating.

Friday, December 20, 2024, 11:43 Purged and closed all water cooling lines.

Friday, December 20, 2024, 15:54   removed target and installed Uline.

 roughing down test stand 

Friday, December 20, 2024, 16:17    valves closed and roughing pump off. 

Friday, December 20, 2024, 16:17   shut down test stand computer for holiday break 

Recent tests have shown that CATHODE voltage breaks down at ~130V, continually leaking current and progressively dropping voltage, making febiad CATHODE testing impossible.

Thursday, January 23, 2025, 15:18    disconnected cathode wire from TBHT feed through, simply suspended in cage.

voltages are held for ~1min prior to increase. current will be reported after 1min and stable.

100V - 0.000mA

120V - 0.000mA

130V - 0.000mA

140V - 0.000mA

150V - 0.000mA

170V - 0.000mA

200V - 0.000mA

- the Cathode wire and power supply have no leak problem

Thursday, January 23, 2025, 15:42

Reattached the CATHODE line to TBHT feedthrough. Removed the 100||100kΩ resistor pair that connects TBHT to HVC.

Same process as before:

100V - 0.000mA

120V - 0.000mA

125V - 0.000mA

130V - 0.000mA

135V - 0.000mA

140V - current limit ---> dropped to 52V

-- The TBHT resistor pair is not the problem

venting chamber to investigate lines.

Thursday, January 23, 2025, 17:05

removed piece of broken ceramic that held the coil terminal

still current leaking, but it's not as immediate or as shorted. more resistive.

__V__mA__

30    0

35    2.4

40    6.1 

45   12.2

50   19.5

55   32

60   gradually ramped up to limited

Thursday, January 23, 2025, 17:10

Disconnected COIL terminal.  Behaviour still similarly bad. Doesn't seem to have improved.

Disconnected all TBHT and TGHT feedthroughs. ALL are now isolated from ground (AS BEFORE). TBHT + and - are isolated from all others, TGHT + and - are isolated from all others but 100R apart due to resistor at feedthroughs (as expected).

Increasing CATHODE voltage on TBHT+ feedthrough to test isolation.

V ____ mA

120  ___ 0

135 ____ 0

150 ____ 0

200 ____ 0

- The TBHT+ terminal does not leak directly to ground

Connecting CATHODE cable to TBHT(-) feedthrough to test

V___mA

130 __ 0

150 __ 0

200 __ 0

- the TBHT- terminal does not leak directly to ground.

Connecting CATHODE to TGHT+ feedthrough , and disconnected the 100R between - and +

V ___ mA

100 __ 0

150 __ 0

200 __ 0

- the TGHT + terminal does not leak directly to ground

Connecting CATHODE to TGHT-  feedthrough:

V __ mA

125 __ 0

150 __ 0

200 __ 0

- the TGHT- terminal does not leak directly to ground.

connected cathode cable to TBHT+ cable.

V __ mA

30 __ 0

40 __ 0

50 __ 12

60 __ 35

70  -> 60__ 80 current limited

Disconnected 100R path between TBHT and TGHT power supply

CATHODE cable still on TBHT+ cable

V __ mA

150 __ 0

200 __ 0

TBHT is not the problem

reconnected 100 path from TBHT to TGHT.  REMOVED varistors that connect TGHT to ground

V __ mA

100 __ 0

200 __ 0

These are likely the issue.

Reconnected varistors to confirm

SHORTED at 50 V -- 10mA, 65V gives 80mA, current limited.

Removed varistors.  WIll have to acquire appropriately specced ones

Thursday, April 17, 2025, 15:46  target installed. now roughing

Thursday, April 17, 2025, 17:12 Turbo pumps on.