15.08.2012 Simulators meeting Lund 1

VITESS Team 2012

We thank the BMBF for their support through the contribution to the ESS update phase.

Klaus Lieutenant Carolin Zendler

Daniil Nekrassov Leo Cussen

Advanced Conic Section Guide design for ESSEXLieutenant Group HZB

(presented by Leo D. Cussen)AbstractDescription of a novel 150 m long “guide“ design

which delivers these required design features

• A kink which avoids line o f sight very comfortably; • Eye-of-the-needle at guide start, midpoint and end;• Excellent transmission especially at short wavelengths• There is a a variant which gives better at large • Smooth spatial and divergence distributions

Performance is only slightly affected by gravity and by the new HZB bispectral feeder design

Elliptic “guides“ *• Many parameters - the effects of only a few are well understood• Multiple reflections normal – Not single bounce• Rays undergo an angle inversion in a single ellipse• Extended sources produce a coma aberration.• Guide shape must be a very precise approximation to an ellipse.• Extreme ESS radiation levels =>

avoidance of line-of-sight likely to be essential and not simply an option – difficult

• Most ESS guides will require many chopper positions – difficult

Sample beam need not be an exact image of the source but must have smooth distributions

My view Simulations cannot solve problems

but once you start it is very hard to stop simulating and start thinking

* Focussing Optic

Short and Sweet

– this is the short variant - a long one too

Brilliance Transfer - from guide feeder entry - NOT FROM SOURCE!

Parameter choice is critical. This is some local minimum. Not optimised (obviously! No Q) It took 6 months of hard work to tame this and be sure.

Is there another solution? At first I expected many - now I think this may be unique.

That’s all, Folks.