Far Infrared Coherent Synchrotron Edge Radiation at ANKA

Abstract

A synchrotron radiation source emits coherent infrared (IR) radiation when the electron bunch length is comparable to the wavelength of the emitted radiation (see for example [1, 2]). To generate coherent radiation in the far IR (THz) region, a 'low alpha mode' has been devised at the ANKA storage ring operating at 1.3 GeV. The corresponding lattice has a significantly reduced momentum compaction factor. The spectral dependence of the emitted radiation is recorded at the ANKA-IR beam line, where the synchrotron light is produced in the fringe field of a bending magnet [3]. This edge radiation has the advantage of being more collimated than constant field radiation. This allows the observation of frequencies down to 1 cm −1 through a modest vertical aperture, which would not be possible with classical constant field emission due to the increasing beam divergence with decreasing frequency. The onset of coherent emission is found at a synchrotron frequency of about 10 kHz. At 5 kHz, an intensity enhancement of up to 5 orders of magnitude, with respect to the incoherent emission, is observed in the spectral range between 1 and 65 cm −1 .

Characterization of the THz radiation source at the Frascati linear accelerator

“…4,5 In III generation circular machines the low-momentum compaction, i.e., α-mode, has been successfully used at Bessy-II 6 and ANKA. 7 Short bunches can also be created by profiting from the bunch length energy dependence (σ z ≈ E 3/2 ), i.e., the bunch length can be reduced by lowering the machine energy. This compression scheme has been investigated, for instance, at Elettra.…”

YBa 2 Cu 3 O 7 − δ quasioptical detectors for fast time-domain analysis of terahertz synchrotron radiation

“…One is ANKA, 19 the synchrotron light source of the Karlsruhe Institute of Technology, which can accommodate up to 184 bunches. One is ANKA, 19 the synchrotron light source of the Karlsruhe Institute of Technology, which can accommodate up to 184 bunches.…”