• Ya.V. Getmanov, O.A. Shevchenko
  BINP SB RAS, Novosibirsk
• N. Vinokurov
  NSU, Novosibirsk

We con­sid­er a tech­nique for elec­tron in­jec­tion into a cyclic ac­cel­er­a­tor using the laser wake­field ac­cel­er­a­tion (LWFA) tech­nique. Ac­cel­er­a­tors with this type of in­jec­tor can be used for dif­fer­ent pur­pos­es due to lower size, cost and low ra­di­a­tion haz­ard. To use the LWFA tech­nique it is nec­es­sary to cre­ate a small gas cloud in­side the ac­cel­er­a­tor vac­u­um cham­ber. But it leads to the in­crease of par­ti­cle loss­es due to scat­ter­ing on resid­u­al gas atoms. There­fore we pro­pose to use mag­ne­sium as evap­o­rat­ed gas be­cause of its high ab­sorba­bil­i­ty ' its atoms stick to walls at the first con­tact. We pre­sent­ed es­ti­ma­tions of the LW­FA-based in­jec­tion sys­tem pa­ram­e­ters, in­clud­ing max­i­mum stored cur­rent. The pro­posed tech­nique looks very prospec­tive for com­pact ac­cel­er­a­tors and stor­age rings.

• N. Vinokurov, E.N. Dementyev, B.A. Dovzhenko, Ya.V. Getmanov, E.I. Kolobanov, V.V. Kubarev, G.N. Kulipanov, L.E. Medvedev, S.V. Miginsky, L.A. Mironenko, V. Ovchar, K.V. Palagin, B.Z. Persov, 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
• B.A. Knyazev, N. Vinokurov
  NSU, Novosibirsk

The Novosi­birsk ERL has rather com­pli­cat­ed mag­net­ic sys­tem. One orbit (11-MeV) for ter­a­hertz FEL lies in the 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 through RF cav­i­ties four times, ob­tain­ing 40-MeV. At the 4th orbit the beam is used in FEL, and then is de­cel­er­at­ed four times. At the 2nd orbit (20 MeV) we have a by­pass with an­oth­er FEL. When by­pass mag­nets are switched on, the beam pass­es through this FEL. The length of by­pass is cho­sen to pro­vide the delay nec­es­sary to re­al­ize de­cel­er­a­tion at the3rd pass through ac­cel­er­at­ing cav­i­ties. In 2008 two of four hor­i­zon­tal or­bits were 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. In 2009 the first las­ing at the sec­ond FEL, in­stalled on the by­pass of the sec­ond track, was achieved. The wave­length tun­abil­i­ty range is 40 - 80 mi­cron. En­er­gy re­cov­ery of a high en­er­gy spread used elec­tron beam was op­ti­mized. Third and fourth orbit as­sem­bly is in progress.

Slides