Low-α Operation of BESSY II and Future Plans for an Alternating Bunch Length Scheme BESSY^VSR

ISSN： 0894-0886

Source： Synchrotron Radiation News, Vol.26, Iss.3, 2013-05, pp. : 22-24

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Abstract

Significant progress has been made in the last few years in short-bunch operation of third-generation synchrotron light sources, achieved by “lowα” optics for storage rings [1–4]. The term α is a machine optics parameter describing the particle orbit length L as a function of the particle momentum p, L = L₀(1 + α(p − p₀)/p₀), with respect to the nominal values indicated by the index “₀”. The “zero current” bunch length σ is then proportional to . Included here is the rf-voltage temporal gradient, V′ = dV/dt, which additionally influences the bunch length and will be required further. Thus, lowering α leads to a reduced bunch length all around the ring and radiation of the short bunches is supplied to all beamlines. These short bunches produce short X-ray pulses of equal length suitable for time-resolved measurements. Simultaneously, the short electron pulses emit intense, coherent THz radiation.