Working Group III

Ring-Based Sources

• Identificaion of new research opportunities made possible by extending the performance of storage rings
• Present and ultimate performance of storage rings in comparison with alternative sources
• Storage ring longitudinal/transverse dynamics experiments versus theory

Session 1: Introduction to Coherence

Temporal coherence, spatial coherence, and their relation to brilliance

Comparison of coherence of spontaneous synchrotron radiation, storage ring FEL, and linac-driven FEL sources

Reports of operating performance from facilities worldwide

Recent results, new projects, operation with low momentum compaction

Assessment of the capability of modelling tools to predict the length and energy spread of a high-current bunch in a storage ring

Sub-picosecond experiments on rings, diffraction-limited soft x-ray sources (e.g. SOLEIL)

Comparison with alternative sources, user applications, compatibility with programs at other beamlines, dedicated versus non-dedicated operation of storage-ring FELs

Interaction of a stored electron beam with laser light

Externally applied lasers, beam cooling, energy modulation

Oscillators, harmonic generation by the FEL or by means of an externally applied laser; performance limits of optics and status of optics R&D; limits on pulse duration, brilliance and stability.

Group members making presentations are requested to bring color copies and, if possible, electronic files of their presentation material for inclusion in the workshop proceedings.

• What performance parameters of storage rings and storage ring FELs are most imporant targets for improvement?
• How can one characterize the relative importance of brilliance versus other parameters, such as flux?

From Working Group II:

• In what ways may ring-based sources complement linac-based sources and vice versa?

From Working Group IV:

• Are there any innovations in insertion device design that should be taken into account in exploring the limits of storage ring performance?

From Working Group V:

• What are the performance limits of conventional lasers that might be used in conjunction with a sycnhrotron radiation source? For example, what limits are there on repetition rates?

From Working Group VI:

• Please provide information on new detectors for understanding beam and light source dynamics.

• Tolerable trajectory wander and tolerable phase errors in long undulators.
• What is the appropriate parameterization for specifying integrated multipoles of insertion devices in storage rings:
  1. multipole expansion with respect to the ID-center
  2. a transverse distribution of integrated fields
  3. something else
• Are there important tolerances that have not yet been addressed like second field integrals for quadrupole or sextupole errors?
• Is there a chance for energy spread reduction in third-generation storage rings?
• Are the tracking tools for insertion devices sufficient and is there evidence from measurements that the codes yield correct answers?

• Input on the impact of laser beams on storage rings.