Monday, December 16, 2024, 3:34 Target loaded in test stand. Confirmed correct connection to mass marker power supply through multipin. Bottom left pin (5 PS - ) connected to grounded side of the filament, top right pin (2, PS +) connected to top end of filament.
Tuesday, December 17, 2024, 09:30 Turbo pumps on
Tuesday, December 17, 2024, 16:21 water cooling on. No effect on vacuum. Vacuum stable at 1.18e-6T
Tuesday, December 17, 2024, 16:41 ramping TGHT TBHT at 1A/30s
Wednesday, December 18, 2024, 10:00 slowly increasing BIAS/EE/EZL to 30/2.5/13 kV
Wednesday, December 18, 2024, 11:40 BIAS EE EZL at 30 2.5 13 kV. 1 spark at 28kV, and there was a downward spike in the TGHT current when bias was at 28.5 kV
Wednesday, December 18, 2024, 11:41 FC0 reading 1.6E-10 A. quite low for total beam, but this is likely due to this target being hot so many times.
Wednesday, December 18, 2024, 11:51 wire scans taken (RPM0)
Wednesday, December 18, 2024, 11:54 FC) extracted for mass scan - mass scan beginning now . Background record appears to be functioning well, although it is high. comparatively to old tests. It could be that those old tests were recording irregularly low background, given the temporary solution that was implemented.
Wednesday, December 18, 2024, 12:13 it seems that a spark took down many optics elements. Going to allow conditioning at 30kV for a while before restarting . - optics elements down due to pressure sensor TMS:IG6 timing out. Vacuum group notified. Will likely bypass the interlock temporarily if it cannot be fixed fast. This should get a more permanent solution as it has failed a number of times before.
Wednesday, December 18, 2024, 13:06 sparks are occurring on average approximately once every 10 minutes. they don't seem to be tripping of any supplies or optics (after IG6). but this spark frequency is significantly higher than observed on other targets lately.
Wednesday, December 18, 2024, 13:24 restarting Mass scan with IG6 interlock forced by. scan name - 2024-12-18_13-47 SISP2N mmOFF.txt
Wednesday, December 18, 2024, 13:51 put FC0 back in, preparing to heat up mass marker. will plan to ramp to 3A to match previous MM tests. also, no sparks in the past 40 minutes, it appears they have subsided. additionally, IG6 has been fixed by vacuum group
Wednesday, December 18, 2024, 14:15 mass marker power supply is not connecting. When attempting to write to its IP address it times out. Had to drop the HV in order to investigate. Have enlisted controls group to aid as it appears to be connected and should be functional.
Wednesday, December 18, 2024, 14:30 had to reset the computer connection to the network 192.168.5. by unplugging and plugging in the usb ethernet connection at computer. situation resolved.
Wednesday, December 18, 2024, 14:40 HV back up and now increasing the mass marker current from 0A to 3A, at 0A, FC0 current is 1.4e-10, very close to previously recorded FC0 mm0A value.
Wednesday, December 18, 2024, 14:56 with mm current at 3.0A, requiring 6V, FC0 current is 2.1e-10 A.
Wednesday, December 18, 2024, 14:58 withdrawing FC0 to take mass scan
Wednesday, December 18, 2024, 15:25 mass scan complete: filename 2024-12-18 15-23 SISP2N mmON.txt
Wednesday, December 18, 2024, 15:27 further increasing mm current to 4.0A. FC0 current increasing noticeably. waiting for plateau. FC0 at 6.6e-10A. wire scans taken
Wednesday, December 18, 2024, 15:39 new mass scan: 2024-12-18 15-53 SISP2N mmON 4A.txt
Wednesday, December 18, 2024, 15:52 mm power supply turned off. 0A.
Wednesday, December 18, 2024, 15:53 rescan of high mass region. still a residual indium mass peak present. will scan again after cooling more.
Wednesday, December 18, 2024, 16:10 mass scan captured that shows the indium peak almost masked in background
Given that the indium peak for 3A was significantly lower than with a regular SIS source cup, i recommend that this target is heated up with the regular source cup again to compare.
Wednesday, December 18, 2024, 16:11 dropping HV EE EZL to 0V
Wednesday, December 18, 2024, 16:13 cooling target to 0/0A at 1A/30s
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Note, ground and HVC (high voltage common) are used interchangeably here.
Monday, December 16, 2024, in the previous test, elog 1038, it was found that the cathode was unable to hold any voltage and was shorted to HVC. The cathode was shorted directly to ground, with the cathode supply current limiting upon being powered, unable to reach even 1V.
After testing, the ANODE power supply stopped functioning and was unable to provide and voltage or current.
When the target was removed, it was found that the TBHT terminal was just ~100Ω from HVC. When I shorted the TGHT to TBHT terminal, as they are when the target is installed, the resistance from TBHT to HVC dropped to just 1Ω. Prior to the anode power supply stopping, it was found that when it was powered on with no target present, it was able to hold voltage, but still drew significant current: up to 400mA when provided less that 20V. This should be completely open, losing no current at all.
Keiko and the controls team have been looped in to address the issue with the ANODE power supply as it may be a controls issue. They believe there are a few possibilities for its error that must be investigated prior to deferring to the power supplies group. This will continue to be investigated
********** UPDATE: ISSUE RESOLVED ********* There is simply a physically triggered interlock that requires the faraday cage door to be closed to operate the ANODE power supply
When investigating the resistive short from the TBHT, I first noted the resistances between each of the channels: TGHT(-) to TGHT(+) 30↨Ω; TBHT(-) to TBHT(+) 20Ω; TBHT(-) to TGHT(-) 100Ω; TBHT(+) to TGHT(+) 140Ω. I also reconfirmed and noted relevant connections at the feedthroughs: There are NO visible shorts to HVC from the TGHT or TBHT feedthroughs. From TGHT(-), there is one 50kΩ resistor with varistor, between TGHT(-) and TGHT(+) there is a100Ω with varistor. I then removed the back of the faraday cage to investigate possible paths to ground from the TGHT and/or TBHT. This showed that TGHT- was grounded through a varistor (checked, functioning correctly, OL at low voltage), TGHT- to + has varistor||100Ω, TBHT- to + has varistor||100Ω, and TBHT- to TGHT- has varistor||100Ω. These fit in accordance with the observed resistances between the terminals.
I also disconnected the ANODE power supply from its output wire to further investigate without possible issues from the power supply. At this point, (after I had remade the varistor connections) I began to observe that the TGHT and TBHT terminals were all detached from ground by 50kΩ (expected amount, given that there is a 100k||100k resistor from TBHT- feedthrough to ground). When I reattached the anode power supply, that value dropped to 35kΩ, I assume due to internal resistance of the power supply. I placed everything back in position and (repeatedly) ensured that the 35kΩ separation persisted. It seems that this shorting issue has resolved itself. It may be that the was an accidental connection made from an unshielded wire inside the faraday cage.
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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 |