About This Site

This website is about diffraction-limited storage rings, which are sources of intense x-rays used for research currently developed worldwide. It is meant to provide resources for researchers.

Numerical simulations

Numerical simulations are extremely important for the design of diffraction-limited storage rings, since any perturbation can compromise the performances of these facilities.

Simulation software

SPECTRA – calculate optical properties of synchrotron radiation (SR) emitted from bending magnets, wigglers and undulator

COMSYL – Coherent mode decomposition of synchrotron radiation. Reference (1, 2)

Zemax not good off axis and point sampling.

Determining tolerances

Historically, the tolerances on mirror and gratings were based on the slope error. As

Papers stemming from XFEL (Pardini, 2015) and DLSR (Shi, 2016) provide a good picture.

Slope errors and approximation
Maréchal criterion

Partial Coherence

Ray prop: only hints at aberrations
Wave is hard with off axis. Phase screens
A good discussion in (Sanchez del Rio, 2018), and an elegant way to deal with few coherent modes can be found in (Glass, 2017)
Mutual Optical Intensity propagation (Meng, 2017)
Raytracing: wavelength only matter for gratings
Wavefront propagation in principle relaxes the constraints, and should be used to validate the results from. The last step is to perform a full, partial coherence simulation using mulitple electrons.

Caustics vs Speckle (EFPL)

Design of beamlines and monochromators

A good overall reference is (Peatman, 1997), replete with equations and design insights, while some interesting thoughts on beamline layouts are available in (Shi, 2017).

Beamline layout (adapted from X Shi, 2017)

Hettrick-Underwood design (Hettrick, 1986), with a refinement (Amemiya, 1996)

VLS design (Reininger, 2005) (Reininger, 2011)

A very general review of gratings can be found here (Popov, 2012)

Atomically perfect blazed gratings at ALS (2013, adapted from youtube)

Here is a very partial list of beamline designs
(please provide additional examples!):

Influence of figure error and heatload

The heatload on mirror is important.

Effect of white beam heaload on synchrotron mirror, viewed with an IR camera (FLIR)

It can be mitigated by changing the angle of incidence on a VLS grating (Reininger, 2008), by using a bender or by resorting to adaptive optics.

Advanced Optics

Ellipsoïd are now adapted (no wide beam)
Adaptive Optics and Diaboloid (McKinney, 2009)
Wolter and Montel
Diaboloïd mirror – adapted from (McKinney, 2009)

Other topics

Liouville theorem + quantum description
How about source depth?
Premirror: reflection zp or… axo?
Air transmission
Multilayer high angle
Forgiveness factor
Aberration compensation: VLS, 1-2 toroïdal, Namioka
smaller footprint

Other resources