title: Helios: a new type of linear/helical undulator.
abstract: A new class of undulator capable of producing linear and/or helical polarization is described. The magnetic field, power, spectral flux, brilliance and interactions with the electron beam of such undulators are discussed. The case of Helios, an undulator presently installed on the ESRF, is discussed in detail.
authors.forename: P
authors.initials: P
authors.lastname: Elleaume