A NEW BEAM EXTRACTION SCHEME FROM A SYNCHROTRON USING A MAGNETIC SHIELD AS A SEPTUM

A.V. Bondarenkoª, S.V. Miginsky, N.A. Vinokurov

Budker Institute of Nuclear Physics Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia

Abstract

A new scheme of beam extraction from a synchrotron is put forward. The main difference from other schemes of extraction is the use of magnetic shields instead of a septum. The magnetic shields are located in the central dipole magnets of a pulsed chicane. A magnetic shield is a multi-layer copper-iron tube. The presented numerical simulations and experimental results for the magnetic shields are in good agreement. The advantages and the area of application of the new extraction scheme are discussed. The proposed scheme will be used for extraction from the booster synchrotron to the storage ring of the new synchrotron radiation source in Novosibirsk.

ª – corresponding author

Paper 

1

NOVOSIBIRSK FREE ELECTRON LASER: OPERATION AND SECOND STAGE COMMISSIONING

N.A. Vinokurovª, E.N. Dementyev, B.A. Dovzhenko, N.G. Gavrilov, 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, Yu.F. Tokarev, P.D. Vobly

Budker Institute of Nuclear Physics Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia

Abstract

The first stage of Novosibirsk high power free electron laser (FEL) is in operation since 2003. It is based on the normal conducting CW energy recovery linac (ERL). Now the FEL provides electromagnetic radiation in the wavelength range 120÷230 micron. The maximum average power is 400 W. The minimum measured linewidth is 0.3%, which is close to the Fourier-transform limit. Four user stations are in operation now. Two other are in progress. Novosibirsk ERL has rather complicated magnetic system. 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. First multi-orbit ERL operation was demonstrated successfully.

ª – corresponding author

Paper Slides

181