Letter of Intent for Laser Cooling of Beams of Highly Charged Ions at SIS 100 / 300 1

We propose the laser cooling of bunched relativistic beams of Alkaline-like and especially all Lithium-like ions in SIS 100/300, where due to the huge Doppler-shifts (γmax=35; Bρ=300Tm) optical ground state transitions can be excited employing existing laser technology. To avoid optical pumping between hyperfine levels e-e nuclei are preferred. The principle aim is the strong improvement of the beam quality in an energy range where electron cooling is not applicable. Depending on the strength of the competing heating mechanisms a relative momentum spread between 10 and some 10 seems attainable. Laser cooling is applicable for intense beams, still, for beams with less than 10 ions even crystalline strings with dramatically reduced heating rates might be in reach due to the high symmetry of the large machines. Furthermore, the high resolution spectroscopy of the cooling transitions is of interest in atomic physics. More complex scenarios might open further applications. Stripping heavy Alkaline-like ion beams after laser cooling in SIS 100/300 cold beams could be transferred to NESR (Bρ=13Tm), where the charge states required for laser cooling cannot be stored. A transfer of stochastically pre-cooled radioactive beams from CR to the large synchrotrons could enable laser cooling of a series of radioactive isotopes which, again after stripping, could be used in the NESR for further experiments like the e-A collider. Following detailed studies of laser cooling Be ions in the TSR Heidelberg (β = 0.04) and low energy Mg beams in PALLAS Munich, we currently prepare the demonstration of combined laser and electron cooling of Li-like C beams at ESR at the comparatively high energy of 122 MeV/u (β = 0.47). The outcome of this experiment scheduled for May 2004 will strongly influence the preparation of the proposed experiments at highly relativistic beam energies and will lead to an addendum of this letter of intent. The experiments require the use of a straight section with 35m length in SIS 300 (SIS 100). For this, bumper magnets have to be installed to tilt the beam, in combination with the action of the installed dipole and quadrupole magnets, by 3mrad to provide free access for the laser beam(s). Obviously, also space for windows, remote controlled optical beamlines, and diagnostics, as well as a dedicated small laser building has to be foreseen.