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

Rough Zr coating (fast deposition rate)

1 μm

100nm

Progress on coatings

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

Black gold: Au coating by evaporation in Kr

Progress on coatings

1 µm

200 nm

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