• H. Delsim-Hashemi, O. Grimm, J. Rossbach, H. Schlarb, B. Schmidt, P. Schmuser
  DESY, Hamburg
• A.F.G. van der Meer
  FOM Rijnhuizen, Nieuwegein

Funding: DESY

FEL facilities are pushing to achieve higher peak currents mainly by means of compressing bunches longitudinally. This process defines a machine parameter that has to be fine-tuned empirically. Among the operational types of diagnostic tools for longitudinal phase-space are those based on IR spectroscopy. The most commonly used IR spectrometers at the FEL facilities are operating in the scanning mode and are not fast enough to be applicable for monitoring bunch compression. On the other hand, any non-scanning spectrometer may suffer from the low intensity that is available from coherent IR radiation in short time intervals in different wavelengths. The proposed "Single Shot Spectrometer" is based on using gratings as dispersive elements. Pioneering tests with a transmission grating have shown the feasibility of the concept. In a second step, a version with "Reflective Blazed Grating" will be tested and should allow getting the maximum available signal for the whole spectrum and improved resolution. Parallel to the study of optical parts, an array of pyroelectric detectors with integrated multi-channel readout is under development.