• S. Krinsky
  BNL, Upton, Long Island, New York

Funding: Work supported by DOE contract number DE-AC02-98CH10886.

We consider three definitions of the number of temporal modes in SASE output. These are defined in terms of: (1) the number of minimum area phase space cells occupied by the radiation; (2) the pulse energy fluctuation; and (3) the Wigner function. The conditions under which these definitions are equivalent is discussed.

• T.V. Shaftan, S. Krinsky, D.F.L. Liu, J.B. Murphy, J. Rose, X.J. Wang, T. Watanabe, L.-H. Yu
  BNL, Upton, Long Island, New York
• H. Loos
  SLAC, Menlo Park, California

Funding: The manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH1-886 with the U.S. Department of Energy.

We discuss analysis of an experiment with High-Gain Harmonic Generation Free Electron Laser at BNL (DUV FEL). The tunability concept [1] of a seeded FEL with a fixed seed wavelength has been verified experimentally. During the experiment we recorded about 200 radiation spectra corresponding to different energy chirps in the electron beam. We have analyzed this set of spectral data to obtain properties of HGHG radiation. Correlations and trends in the radiation spectrum at 266 nm have been observed and studied.

[1] T. Shaftan and L.H. Yu, Phys. Rev. E 71, 046501 (2005)