| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1824181 | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | 2011 | 8 Pages |
The required high peak current in free-electron lasers (FELs) is realized by longitudinal compression of the electron bunches to sub-picosecond length. In this paper, a frequency-domain diagnostic method is described that is capable of resolving structures in the femtosecond regime. A novel in-vacuum spectrometer has been developed for spectroscopy of coherent radiation in the THz and infrared range. The spectrometer is equipped with five consecutive dispersion gratings and 120 parallel readout channels; it can be operated either in short (5–44μm) or in long wavelength mode (45–430μm). Fast parallel readout permits the spectroscopy of coherent radiation from single electron bunches. Test measurements at the soft X-ray free-electron laser FLASH, using coherent transition radiation, demonstrate excellent performance of the spectrometer. The device is planned for use as an online bunch profile monitor during regular FEL operation.
