Antiproton Lens Replacement (Unfortunately Part 2)

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Antiproton Lens Replacement (Unfortunately Part 2)

• Keith Gollwitzer
• Antiproton Source Department
• for the Experts and Mechanical Support Department
  Target Station Group
• Thanks also to the Radiation Technicians of AD
  ESH

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Disconnected from power supply HiPot of module
lens/transformer find 1.7µA _at_ 3000V!! Vault
stripline HiPot is also fine Connect power
supply to pulse ground fault Problem getting
power supply to turn on with dummy load Movement
of control cards about get supply to pulse with
Back to original configurationable to pulse
dummy load Another HiPot of module
lens/transformer shows good Power supply
re-connected to lens/transformer
Pulsing!!! Will gradually bring up to operation
gradient and then put rest of shielding blocks
back. Should be stacking within a few hours
Last Slide From Last Week
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Mon after AEM meeting Started at 1715 with low
intensity beam Did nominal orbit position scans
and started increasing beam intensity
1808 water conductivity interlock trip Looks
like Lithium leak into cooling water
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Tue 0700 to Wed 0130 Replacement of 10mm-2 with
lens 32 went well Lower gradient lens Ran 20
minutes of beam and then conductivity interlock
trip Looks like Lithium leak into cooling
water Two for two!?!?!?! Investigate further
with beam Noted that conductivity also increases
with lens off and beam pulse but not when pulsing
lens with no beam Not look like Lithium lens
leak?
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Wed 0700 to Wed 2200 Checked conductivity probes
with calibrated solution Replaced one of two
probemeter (twice) Changed DI cartridge of
water system Further beam studies Concluded
either Lithium leak or other contamination Set
conservative lens gradient and beam intensity for
stacking and watched for conductivity to be
cleaned-up
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Thu and Fri Continue to stack with conservative
running conditions while contamination
clean-up Could still be Lithium leak Held a
small debriefing of lens change-outs Realization
of possible ethanol alcohol introduced during
Saturdays separation of the stuck module water
tube from the 10mm-2 lens/transformer brass block
water connection. Estimated quantity of possible
contaminate Performed test of intentionally
adding ethanol alcohol to system and saw response
as seen earlier Returning slowly to normal
operating conditions
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Other Lenses 10mm-2 is believed to be good due
to Lens 32 running 10mm-1 and 10mm-3 may be
recoverable (two weeks for the latter to be
recovered?) Lens 23 already has 9.5M pulses Lens
30 has sputtered material on it Lens 4 has to run
at even lower gradient New lenses Estimated
for complete lens/transformer assembly (taking
into account furloughs, vacation, material,
additional manpower) Late April Mid-June,
Late summer/Fall (2)
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Last Weeks Slides
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Initial Failure at 1840 Friday Determined
problem in vault and not the power
supply Appeared as open circuit
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Lens change-out crew arrive, open vault, remove
module with lens/transformer assembly and
discover problem
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• Strip-line failure (1st time seen)
• Moved on to installing previously used 10mm-2
  lens (high gradient)
• 10mm-2 history
• Used 1 week in May07 before water leak caused
  transformer to fail
• Lens installed in a new transformer during
  shutdown07
• Used Oct-Dec07
• During Target change-out photograph showed
  tie-rod working its way out
• Tie-rod repaired early Jan08

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10mm-2 lens put upon module and connections
made Failed water circuit test (pressurized
gas) 2 pairs of 8ft tubes run though module
(provide water cooling for lens and transformer)
connect to brass block (patch panel) of
lens/transformer assembly. Depending upon brass
block, order of connection can make difference of
leak Could not disconnect one water tube
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Meeting to discuss options Repair 10mm-2 brass
block water tube connection vs installing low
gradient lens 32 Low gradient means a 12-15
loss of yield 8days low gradient 7days high
gradient Repair plan was chosen
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Water tube was forcibly removed from brass
block 10mm-2 lens/transformer assembly
un-installed from module New water tube
installed on module New brass block was taken
from another low gradient lens Brass block
swap-out performed on 10mm-2 Re-install 10mm-2
lens/transformer assembly to module Pressurize
gas test - still leak 10mm-2 lens/transformer
assembly un-installed from module Determine leak
on connection of line into lens -- tightened
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Upon moving lens/transformer assembly to prepare
for re-connection to module, hit a water
line Replaced water line Reconnect
lens/transformer assembly to module Passed water
circuit test!! HiPot of module
lens/transformer find 1mA _at_ 1500V New lens are
lt1µA _at_ 3000V Earlier HiPot of 10mm-2 was
reasonable Experts decided to install into vault
and pulse at low setting to see if can change
HiPot Power supply trip on load overcurrent
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Disconnected from power supply HiPot of module
lens/transformer find 1.7µA _at_ 3000V!! Vault
stripline HiPot is also fine Connect power
supply to pulse ground fault Problem getting
power supply to turn on with dummy load Movement
of control cards about get supply to pulse with
Back to original configurationable to pulse
dummy load Another HiPot of module
lens/transformer shows good Power supply
re-connected to lens/transformer
Pulsing!!! Will gradually bring up to operation
gradient and then put rest of shielding blocks
back. Should be stacking within a few hours