progress on coatings and grooves m.taborelli progress on c based coatings
DESCRIPTION
Progress on coatings and grooves M.Taborelli Progress on C based coatings Progress on rough coatings Progress on SEY instrument Grooves calculation (Pivi, Wang). Progress on coatings. Carbon deposited with Ne: low yield is reproducible…at least in the same geometry. Thickness problem. - PowerPoint PPT PresentationTRANSCRIPT
SPSU 13.5.2008
Progress on coatings and grooves
M.Taborelli
-Progress on C based coatings-Progress on rough coatings-Progress on SEY instrument-Grooves calculation (Pivi, Wang)
SPSU 13.5.2008
Carbon deposited with Ne: low yield is reproducible…at least in the same geometry
Progress on coatings
0
0.2
0.4
0.6
0.8
1
1.2
C-Kr run 3 ,2hair
C-Kr run 4,(SPS) 2h air
C-Ne, 3h air C-Ne run3,2hair
C Ne run4, 2hair
SE
Y (
in A
ES
)500eV Kr deposited Ne deposited
old new
last,
tube geometry
The reason of the low yield might be the higher deposition p with Ne
Thickness problem
SPSU 13.5.2008
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;
Progress on coatings
SPSU 13.5.2008
Progress on coatings
Powder, particles and dust
Results:
Progress on coatings
0.0E+00
2.0E+04
4.0E+04
6.0E+04
8.0E+04
1.0E+05
1.2E+05
1.4E+05
1 3 5 7 9 11 13 15 17 19
0.3um before coating
0.3um after coating
Particles between 0.3m and 0.5m: Particles larger than 0.5m:
0.0E+00
1.0E+03
2.0E+03
3.0E+03
4.0E+03
5.0E+03
6.0E+03
1 3 5 7 9 11 13 15 17 19
0.5um before coating
0.5um after coating
After coating about 10x more particles. (7.3x for 0.3m, 13x for 0.5m)
After gentle hammering no further particles produced.
Coated chamber stored under vacuum to check particle evolution after 1 week.
run# (min) run# (min)
SPSU 13.5.2008
0
0.5
1
1.5
2
2.5
3
Zr smooth Zr rough
SE
Y(A
ES
)
500eV
SEY or smooth and rough Zr coating:
The relative improvement is some 15%.....which means that coating witha layer having delta=1.2 would result in a delta of 1 ( ….. a little more complex due to the energy dependence of the effect)
Progress on coatings
SPSU 13.5.2008
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
Progress on coatings and instrumentation
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Energy [eV]
SE
Y
bias -18V
bias -45V
bias 0V
AES
Zr rough
SPSU 13.5.2008
0
0.5
1
1.5
2
2.5
smooth Au black Au
SE
Y(A
ES
)
500eV
Black Au: SEY at 500eV on smooth and black gold
Progress on coatings
SPSU 13.5.2008
0.50
0.60
0.70
0.80
0.90
1.00
1.10
1.20
0 0.5 1 1.5 2
energy [KeV]
SE
Y (
AE
S)
Black Au, energy dependence: maximum is at very high energy
Progress on coatings
SPSU 13.5.2008
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
Progress on coatings
SPSU 13.5.2008
Plans for SEY instrument
Still to be done on new instrument:
- Control of focussing (at present some 2 mm spot, but notwell 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
SPSU 13.5.2008
Grooves, calculation of L.Wang at SLAC on the geometryobtained on copper
Progress on grooves
2mm
100 200 300 400 500 600 7000.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Energy (eV)
SE
Y
0=1.50,Height=1.0mm, =150, B=0
CERN workshop onCopper (S.Atieh, J.M.Geisser)
0 100 200 300 400 500 600 7000.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Energy (eV)
SE
Y
0=1.50,Height=1.0mm, =15o
B=0.2TeslaB=2 Tesla
B=0
Assuming delta-max=1.51mm
15º
Reduction also for B=0so that we can measure in the lab
B=0.2TB=2T