RF shield thinning 17/05/2013 CERN Massimiliano Ferro-Luzzi 1

LHCb upgrade: thin VELO RF shieldLHCb upgrade: thin VELO RF shield

Thinning by chemical etching– an investigation on a backup solution, in case fabrication of 0.2mm

RF boxes is not possible in the given time scale. New solutions ?

– 3D printing

– electromagnetic forming

RF shield thinning 17/05/2013 CERN Massimiliano Ferro-Luzzi 2

Thinning by chemical etchingThinning by chemical etching

The idea is to «post-process» the RF box a box is produced in Amsterdamsuppose the achievable thickness is larger than 0.2mm: can we thin down the most relevant area of the RF box ? CERN (TE-VSC) has the infrastructure/labs to make chemical etching of large objects such as our RF box

– Start investigations with NaOH

– How well can the thickness be locally controlled on complex ciorrugated shapes ?

– Microleaks ?After etching, the box must be coated with Torlon and NEG (heat treaments!)

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what needs to be thinned ?what needs to be thinned ?

Most particles do not at all go through the side corrugations!

Only this region needs to be thinned down

~20cm~20cm

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R&D programme at CERNR&D programme at CERN

Design a small sample RF foil with chuck/support Produce it by precision machining

– aim for 0.2 or 0.3mm Metrologize, vacuum-test Etch Metrologize, vacuum-test

we are about to startwe are about to start

about 20cm

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The sample foilThe sample foil

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Chuck/supportChuck/support

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Chuck/supportChuck/support

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3D printing3D printing

Contacted belgian company Layerwise They specialize in high-tech 3D metallic

printinting (medical, aerospace, ...)

They normally use Ti, but can do other metals (incl. Al) They visited us at CERN, saw the prototype Amsterdam RF box, and... winced.

– They need a good/solid starting surface, then print up vertically (this could be the back side of the box)

– The inclinations should not be more than about 30 deg from the vertical

– They never made such a large thin piece, though they are developing machinery for that (would be on time scale of 1-2 years)

– They have much experience with Ti, less with Al... (they were proposing, if we go on, to make a small prototype of Ti)

Will send us the design rules, but I have little hope for this route– Could be more realistic if we would split the box in 2 or 3 elements

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Electromagnetic pulse forming/weldingElectromagnetic pulse forming/welding

We had a visit from specialized company An interesting method, similar to explosive forming, but without

springback One could perhaps start from a simple flat-walled box and obtain

corrugated shape by this electrohydraulic forming (immersion and «instantaneous» electromagnetic pulse)

CERN TE is interested. Will have more technical discussion in June