Progress on coatings and grooves

1

• Progress on coatings and grooves
• M.Taborelli
• Progress on C based coatings
• Progress on rough coatings
• Progress on SEY instrument
• Grooves calculation (Pivi, Wang)

2
Progress on coatings
Carbon deposited with Ne low yield is
reproducibleat least in the same geometry
Thickness problem
The reason of the low yield might be the higher
deposition p with Ne
3
Progress on coatings
Powder, particles and dust Procedure Before
coating Chamber assembled in coating lab b.
181 Transferred to class 100 clean room in b.
101 Particles measured by pumping the chamber
with the particle counter. (1 minute
runs) Chamber back to b. 181 insert C cathode
and perform coating After coating Dismount
cathode in b. 181 Transfer to clean room in
building 101 Measure particles
4
Progress on coatings
Progress on coatings
Powder, particles and dust Results
Particles between 0.3mm and 0.5mm
Particles larger than 0.5mm
run (min)
run (min)
After coating about 10x more particles. (7.3x for
0.3mm, 13x for 0.5mm)
After gentle hammering no further particles
produced.
Coated chamber stored under vacuum to check
particle evolution after 1 week.
5
Progress on coatings
Rough Zr coating (fast deposition rate)
1 µm
100nm
6
Progress on coatings
SEY or smooth and rough Zr coating
The relative improvement is some 15.....which
means that coating with a layer having delta1.2
would result in a delta of 1 ( .. a little more
complex due to the energy dependence of the
effect)
7
Progress on coatings and instrumentation
Energy dependence of SEY (new instrument)
NB no influence of various applied potentials,
means that the system is stable and values of
potentials are not critical
8
Progress on coatings
Black Au SEY at 500eV on smooth and black gold
9
Progress on coatings
Black gold Au coating by evaporation in Kr
1 µm
200 nm
10
Progress on coatings
Black Au, energy dependence maximum is at very
high energy
11
Progress on coatings

• Plans for next coatings (.find candidate for
  next liner)
• -C(Ne) in tube geometry again still not
  sufficiently controlled and reproducible
• Particle measurement will be done again after
  some time on the same chamber to see if any
  dust is generated
• More controlled black-Au deposition (for the
  moment the layer is very inhomogenous in
  thickness) and characterization for vacuum
  properties (outgassing due to large surface)
• C coating on rough surface (Zr)
• BC with lower amount of B than B4C coating done,
  not measured yet
• SiC

12
Plans for SEY instrument

• Still to be done on new instrument
• - Control of focussing (at present some 2 mm
  spot, but not
• well controlled above 1000eV) done
• Position (distance) with respect to optics
  done
• Beam position stability at low Ep (below 50eV)
• Load lock done
• transfer to XPS will be connected when testing
  is finished
• modify software to measure with scan
• SPS transfer chamber
• Phase II
• Faster acquisition to avoid high dose...however
  it seems to be already OK
• Implement flood gun for conditioning with e-beam

13
Progress on grooves
Grooves, calculation of L.Wang at SLAC on the
geometry obtained on copper
Reduction also for B0 so that we can measure in
the lab
CERN workshop on Copper (S.Atieh, J.M.Geisser)
Assuming delta-max1.5
2mm
B0
B0.2T
B2T