MPI-K, Heidelberg
Several experiments at the heavy ion storage ring TSR have shown the feasibility of wide range, efficient acceleration and deceleration. The newly developed method of mass selective acceleration enables an effective separation of ion species with relative mass differences of ∆m/m = 3.7 · 10-4. Parabola shaped short bunch lengths were measured for an electron cooled 50 MeV 12C6+ ion beam in the space charge limit. To overcome the space charge limit the TSR was operated at a momentum compaction of α = 1.57.
MPI-K, Heidelberg
Weizmann Institute of Science, Rehovot
TU Dresden, Dresden
UCL, Louvain-la-Neuve
A novel next generation electrostatic Cryogenic Storage Ring (CSR) for heavy ions, molecules and clusters up to bio-molecules in the energy range of 20-300 keV is under construction at MPI Heidelberg. A unique feature of this ring is the possibility to operate it at all temperatures between room temperature down to 2 K. Operation at cryogenic temperatures is inevitably necessary to investigate the properties and reaction modes of molecular ions in their ground state as ,e.g., in interstellar environment. Therefore only cold wall surfaces have to be used to eliminate black body radiation exciting molecular quantum states. In addition, surfaces of 2-10 K will act as a large cryo-pump, expected to achieve a vacuum of better than 10-15 mbar (corresponding to 10-13 mbar at room temperature), which is mandatory for sufficiently large storage times for slow heavy ions. Considerable progress towards realization of this technologically ambitious project can be reported. The detailed layout of the storage ring CSR has been defined. A 2 K-21 W helium refrigerator system was designed, ordered and successfully commissioned at MPI, where it is now in operation to cool the prototype cryostat with its cryogenic ion trap CTF to 2 K temperature.
Kyoto University/ICR, Kyoto
JINR, Dubna
NIRS, Chiba-shi
Kyoto University/IAE, Kyoto
MPI-K, Heidelberg
Funding: The present work was supported by Advanced Compact Accelerator Development program by MEXT of Japanese Government. Support from Global COE, The Next Generation of Physics, is also greatly appreciated.
Laser cooling for bunched Mg ion beam with the kinetic energy of 40 keV has been applied with S-LSR at ICR, Kyoto University. Up to now, clear peaking of equilibrium momentum spread after laser cooling has been observed at such a synchrotron tune as resonates with the horizontal betatron tune, which is considered to be due to heat transfer from the horizontal degree of freedom to the longitudinal one. In order to demonstrate transverse cooling by observation of reduction of the horizontal beam size, spontaneous emission from laser induced excited state of the Mg ion, has been observed with the use of CCD camera. Some reduction of horizontal beam size has been observed with a certain synchrotron tune, a little bit smaller compared with the fractional part of the horizontal tune.