• N. Vinokurov, E.N. Dementyev, B.A. Dovzhenko, N. Gavrilov, Ya.V. Getmanov, B.A. Knyazev, E.I. Kolobanov, V.V. Kubarev, G.N. Kulipanov, A.N. Matveenko, L.E. Medvedev, S.V. Miginsky, L.A. Mironenko, V.K. Ovchar, V.M. Popik, T.V. Salikova, M.A. Scheglov, S.S. Serednyakov, O.A. Shevchenko, A.N. Skrinsky, V.G. Tcheskidov, Y.F. Tokarev, P. Vobly, N.S. Zaigraeva
  BINP SB RAS, Novosibirsk

The first stage of Novosibirsk high power free electron laser (FEL) is in operation since 2003. Now the FEL provides average power up to 500 W in the wavelength range 120 - 240 micron. One orbit for 11-MeV energy with terahertz FEL lies in vertical plane. Other four orbits lie in the horizontal plane. The beam is directed to these orbits by switching on of two round magnets. In this case electrons pass four times through accelerating RF cavities, obtaining 40-MeV energy. Then, (at fourth orbit) the beam is used in FEL, and then is decelerated four times. At the second orbit (20 MeV) we have bypass with third FEL. When magnets of bypass are switched on, the beam passes through this FEL. The length of bypass is chosen to provide the delay, which necessary to have deceleration instead of acceleration at the third passage through accelerating cavities. Now two of four horizontal orbits are assembled and commissioned. The electron beam was accelerated twice and then decelerated down to low injection energy. Project average current 9 mA was achieved. First multi-orbit ERL operation was demonstrated successfully.

Slides

• G.M. Kazakevich, M.A. Davidsaver, H.T. Edwards, R.P. Fliller, T.W. Koeth, A.H. Lumpkin, S. Nagaitsev, J. Ruan, R. Thurman-Keup
  Fermilab, Batavia
• Y.U. Jeong
  KAERI, Daejon
• V.V. Kubarev
  BINP SB RAS, Novosibirsk

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359.

Noninvasive bunch duration monitoring has a crucial importance for modern accelerators intended for short wavelength FEL’s, colliders and in some beam dynamics experiments. Monitoring of the bunch compression in the Emittance Exchange Experiment at the A0 Photoinjector was done using a parametric presentation of the bunch duration via Coherent Synchrotron Radiation (CSR) emitted in a dipole magnet and measured with a wide-band quasi-optical Schottky Barrier Detector (SBD). The monitoring resulted in a mapping of the quadrupole parameters allowing a determination of the region of highest compression of the bunch in the sub-picosecond range. The obtained data were compared with those measured using the streak camera. A description of the technique and the results of simulations and measurements are presented and discussed in this report.