Steck, M.

Paper	Title	Page
MOM2C05	Longitudinal Accumulation of Ion Beams in the ESR Supported by Electron Cooling	21
	C. Dimopoulou, B. Franzke, T. Katayama, G. Schreiber, M. Steck GSI, Darmstadt D. Möhl CERN, Geneva
	Recently,two longitudinal beam compression schemes have been successfully tested in the Experimental Storage Ring (ESR) at GSI with a beam of bare Ar ions at 65 MeV/u injected from the synchrotron SIS18. The first employs Barrier Bucket pulses, the second makes use of multiple injections around the unstable fixed point of a sinusoidal RF bucket at h=1. In both cases continuous application of electron cooling maintains the stack and merges it with the freshly injected beam. These experiments provide the proof of principle for the planned fast stacking of Rare Isotope Beams in the New Experimental Storage Ring (NESR) of the FAIR project.
	Slides
TUA2C08	Lattice Considerations for the Collector and the Accumulator Rings of the FAIR Project	106
	A. Dolinskii, F. Nolden, M. Steck GSI, Darmstadt
	Two storage rings (Collector Ring (CR) and Recycled Experimental Storage Ring (RESR)) have been designed for efficient cooling, accumulation and deceleration of antiproton and rare isotopes beams. The large acceptance CR must provide efficient stochastic cooling of hot radioactive ions as well as antiproton beams. The RESR will be used as an accumulator of high intensity antiproton beams and a decelerator of rare isotopes. Different lattice structures have been considered in order to achieve good properties for the stochastic cooling and at the same time the maximum dynamic aperture. The structure of the ring lattices and its ion optical properties are described in this contribution. The beam dynamics stability and flexibility for operation in different modes are discussed.
	Slides
THAP20	Internal Target Effects in the ESR Storage Ring with Cooling	210
	V. Gostishchev, C. Dimopoulou, A. Dolinskii, F. Nolden, M. Steck GSI, Darmstadt
	The accurate description of the internal target effects is important for the prediction of operation conditions which are required for the performance of experiments in the storage rings of the FAIR facility at GSI. A number of codes such as PTARGET, MOCAC, PETAG01 and BETACOOL have been developed to evaluate the beam dynamics in the storage ring, where an internal target in the combination with an electron cooling is applied. The systematic benchmarking experiments were carried out at the ESR storage ring at GSI. The ‘zero’ dispersion mode (dispersion at target position is about 0 m) was applied to evaluate the influence of the dispersion function on the beam parameters when the internal target is ON. The influence of the internal target on the beam parameters is demonstrated. Comparison of the experimental results with the Bethe-Bloch formula describing the energy loss of the beam particles in the target as well as with simulations with the BETACOOL code will be given.
THAP22	Limitations of the Observation of Beam Ordering	217
	M. Steck, K. Beckert, P. Beller, C. Dimopoulou, F. Nolden GSI, Darmstadt
	One dimensional beam ordering of electron cooled low intensity heavy ion beams has been evidenced at the ESR storage ring as a discontinuous reduction of the momentum spread. Depending on the beam parameters, technical imperfections or any sources of heating can hamper or even prevent the observation of the momentum spread reduction. Limitations for the detection of the ordered beam will be described and illustrated by experimental results.
FRM2C05	Simulation Study of Beam Accumulation with Moving Barrier Buckets and Electron Cooling	238
	T. Katayama, C. Dimopoulou, B. Franzke, M. Steck GSI, Darmstadt T. Kikuchi Utsunomiya University, Utsunomiya D. Möhl CERN, Geneva
	An effective ion beam accumulation method in NESR at FAIR project, is investigated with numerical way. The princile of accumulation method is as follows: Ion beam bunch from the collector ring or synchrotron is injected in the longitudinal gap space prepared by moving barrier voltage in NESR. Injected beam becomes instantly coasting beam after switching off the barrier voltage and is migrated with the previously stacked beam. After the momentum spread is well cooled by electron cooling, the barrier voltage is switched on and moved to prepare the empty gap space for the next injection. This process is repeated say 20 times to attain the required intensity. We have investigated this stacking process numerically, including the Intra Beam Scattering effect which might limit the stacking current in the ring. Detailed simulated results will be presented for the NESR case as well as the ESR experimental parameters.
	Slides
FRM1C02	Schottky Noise Signal and Momentum Spread for Laser-Cooled Beams at Relativistic Energies	226
	M. H. Bussmann, D. Habs LMU, München K. Beckert, P. Beller, B. Franzke, C. Kozhuharov, T. Kuehl, W. Noertershaeuser, F. Nolden, M. Steck GSI, Darmstadt Ch. Geppert, S. Karpuk Johannes Gutenberg University Mainz, Mainz C. Novotny Johannes Gutenberg University Mainz, Institut für Physik, Mainz S. Reinhardt MPI-K, Heidelberg G. Saathoff MPQ, Garching, Munich U. Schramm FZD, Dresden
	We report on the first laser cooling of a bunched beam of C3+ ions at the ESR (GSI) at a beam energy of E = 1.47 GeV. Combining laser cooling of the 2S1/2-2P3/2 transition with moderate bunching of the beam lead to a reduction of the longitudinal momentum spread by one order of magnitude if compared to pure electron cooling. If additional electron cooling was applied, thus increasing the coupling between the longitudinal and transverse degree of freedom, three-dimensional cold beams with a plasma parameter of unity could be attained. In a second measurement campaign, a combination of a sweeping-frequency and a fixed-frequency laser beam was succesfully implemented to increase the momentum acceptance of the narrow band laser force. This cooling scheme improved the match of acceptance of the laser force to the momentum spread of the beam and reduced heating due to intra beam scattering. In addition to the interesting beam dynamics observed at low momentum spreads of ∆p / p < 10-6 precision spectroscopy of 2S1/2-2P1/2 and 2S1/2-2P3/2 transition was performed, both absolute and relative, at a precision challenging the best theoretical models available. The laser cooling schemes used at the ESR can be directly extended to the regime of ultra-relativistic ion energies at the new FAIR facility. There, it becomes possible to cool a large number of ion species using a single laser beam source, exploiting the relativistic Doppler shift of the laser frequency. Finally, the fluorescence photons emitted by these ultra-relativistic laser cooled ion beams can be directly used for precision X-ray spectroscopy of the cooling transitions. The resolution of such measurements would essentially be only limited by the resolution of the X-ray spectrometers available.
	Slides