LESSvalues describe: LESS on Cu
Big science (accelerators, light sources, public fusion)
What it enables
Geometry instead of chemistry: laser-textured surfaces cut secondary electron yield.
Status and pusher
Beam-tested for HL-LHC; in-situ laser treatment industrialization ongoing. Pushed by CERN and STFC.
Properties
The values below are candidate: compiled from the sources named, not yet individually validated.
Provisional provenance: CERN vacuum group compilations and coating programme; CERN Accelerator School, vacuum and materials proceedings.
Wet cleaning
| Recipe | open question: the structured surface traps cleaning fluid and particles by design |
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| Forbidden | none noted |
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| Limit | the trade at the heart of the technique: the roughness that kills SEY also multiplies surface area |
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Vacuum and outgassing
| Outgassing, unbaked (10 h) | rises with area, falls after bake |
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| Vapour pressure | none |
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Temperature
| Bake, assembled | 450 °C |
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| Vacuum degas | substrate |
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| Metallurgical limit | substrate |
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Thermal
| CTE | substrate |
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| Thermal conductivity | substrate |
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| Emissivity | raised deliberately, up to 0.9 |
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Mechanical
| Strength | surface |
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| Elongation | nil |
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Electrical and magnetic
| Relative permeability | substrate |
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Engineering
| Joining | laser textured in place |
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| Process notes | SEY below 1 without any coating |
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| Availability and cost | CERN programme |
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Sources · 1
- HL-LHC project
← The Matter