• M. Nakao, T. Hiromasa, A. Noda, H. Souda, H. Tongu
  Kyoto ICR, Uji, Kyoto
• M. Grieser
  MPI-K, Heidelberg
• K. Jimbo
  Kyoto IAE, Kyoto
• H. Okamoto
  HU/AdSM, Higashi-Hiroshima
• T. Shirai
  NIRS, Chiba-shi
• A.V. Smirnov
  JINR, Dubna, Moscow Region

Experiments of transverse laser cooling for 24Mg+ beam have been performed at the small ion storage and cooler ring, S-LSR. It is predicted that the longitudinal cooling force is transmitted to the horizontal direction with synchro-betatron coupling at the resonant condition*. The laser system consists of a 532nm pumping laser, a ring dye laser with variable wavelength around 560nm, and a frequency doubler. The horizontal beam size and the longitudinal momentum spread were optically measured by a CCD and a PAT (Post Acceleration Tube) respectively**, ***. The CCD measures the beam size by observing spontaneous emission from the beam and records in sequence of 100ms time windows the development of the beam profile. The time variation of the beam size after beam injection indicates the transverse cooling time. The initial horizontal beam size, which was about 1mm, was decreased by 0.13mm in 1.5s. The longitudinal momentum spread measured by PAT is increased at the resonant condition. This suggests transverse temperature was transferred to longitudinal direction by synchro-betatron coupling. Both measurements denote the horizontal cooling occurred only in the resonant condition ****.

* H. Okamoto, Phys. Rev. {E50}, 4982 (1994)
** M. Tanabe et. al, Appl. Phys. Express 1 (2008) 028001
*** T. Ishikawa Master Thesis, Kyoto Univ.(2008)
**** H. Souda et. al., contribution to IPAC10.

• H. Souda, T. Hiromasa, M. Nakao, A. Noda, H. Tongu
  Kyoto ICR, Uji, Kyoto
• M. Grieser
  MPI-K, Heidelberg
• K. Jimbo
  Kyoto IAE, Kyoto
• H. Okamoto
  HU/AdSM, Higashi-Hiroshima
• T. Shirai
  NIRS, Chiba-shi
• A.V. Smirnov
  JINR, Dubna, Moscow Region

Transverse laser cooling with the use of a synchro-betatron coupling is experimentally demonstrated at the ion storage/cooler ring S-LSR. Bunched 40keV ²⁴Mg⁺ beams are cooled by a co-propagating laser with a wavelength of 280nm. Synchrotron oscillation and horizontal betatron oscillation are coupled by an RF drifttube at a finite dispersive section (D = 1.1m) in order to transmit longitudinal cooling force to the horizontal degree of freedom*. Time evolution of horizontal beam size during laser cooling was measured by a CCD camera**. Horizontal beam sizes were reduced by 0.13mm within 1.5s after injection when the tune values satisfy a difference resonance condition, ν_s - ν_h = integer, at the operating tunes of (ν_h, ν_v, ν_s)=(2.067, 1.104, 0.067) and (2.058, 1.101, 0.058). Without resonance condition, the size reduction was negligibly small. The momentum spread was 1.7x10^-4 on the resonance otherwise 1.2x10^-4. These results show that the horizontal heats are transferred to the longitudinal direction through the synchro-betatron coupling with the resonance condition and are cooled down by a usual longitudinal bunched beam laser cooling.

* H. Okamoto, Phys. Rev. E 50, 4982 (1994).
** M. Nakao et. al., contribution to this conference.

• A.O. Sidorin, N.N. Agapov, A.V. Eliseev, V. Karpinsky, H.G. Khodzhibagiyan, A.D. Kovalenko, G.L. Kuznetsov, I.N. Meshkov, V.A. Mikhaylov, V. Monchinsky, A.V. Smirnov, G.V. Trubnikov, B. Vasilishin
  JINR, Dubna, Moscow Region
• A.V. Butenko
  JINR/LHE, Moscow

The main goal of the Nuclotron booster construction are following: accumulation up to 4·10⁺⁹ Au³²⁺ ions; acceleration of the ions up to energy of 600 MeV/u that is sufficient for stripping of the ions to the bare nucleus state; simplification of the requirements to the vacuum conditions in the Nuclotron; forming of the required beam emittance at the energy of 100 MeV/u with electron cooling system. The features of this booster, the requirement to the main synchrotron systems and their parameters are presented.