Stain appeared after EP acid renewal Field emission at low gradient happened on MHI-06, MHI-07, in VT. Kyoto-camera found brown stain trace in beam pipes, irises and equators. Now we are investigating STF EP process using old MHI-#0 cavity (with simple beam pipe). They seems to be Niobium-Oxide. However, the problem is not yet solved, not yet fixed. 07.17.2009 H. Hayano, KEK ???
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Stain appeared after EP acid renewal Field emission at low gradient happened on MHI-06, MHI-07, in VT. Kyoto-camera found brown stain trace in beam pipes,
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Stain appeared after EP acid renewal
Field emission at low gradient happened on MHI-06, MHI-07, in VT.
Kyoto-camera found brown stain trace in beam pipes, irises and equators.
Now we are investigating STF EP process using old MHI-#0 cavity (with simple beam pipe).
They seems to be Niobium-Oxide.
However, the problem is not yet solved, not yet fixed.
07.17.2009
H. Hayano, KEK
???
BL#6 1-cell equator, t = 306 deg. Downstream : Outside weld area
BL#6 #9-BP, t = 241 deg. -1
BL#6 #9-BP, t = 241 deg. -2
Brown spot and traces;
MHI-06: spot or traces on BP-#1 、 #1、 #2、 #3、 #4、 #8、 #9、 #9-BP (red indicate bad)
AES001 had also similar stains, observed as received.( Jlab EP )
AES001 #2-3 iris 212°
1mm
iris
back side of EL
Other spots that have no wall gradientsOther spots that have no wall gradients
Appendixback side of EL
to Equatorof #3 cell
to Equatorof #2 cell
arc scar?The result of SI measurements shows that this spot is flat.This spots looks like a sign of Field Emission or Arcing. Many spots like this were observed.
AppendixAES001 #4-5 iris 233°
1mm
irisback side of EL back side of EL
bright belt
to Equatorof #5 cell
All the Iris regions are yellowish. This spot is locally bright. It may be caused by EP?