First demonstration of “white-light” laser cooling of a stored ion beam (original) (raw)
“White-light” Laser Cooling of a Fast Stored Ion Beam
Physical Review Letters, 1998
We report the experimental demonstration of "white-light" cooling of a high-velocity 7 Li 1 ion beam stored at 6.4% of the speed of light in a storage ring. In a direct comparison with single-mode laser cooling, we show that white-light cooling is much more efficient to counteract strong intrabeam heating and leads to lower longitudinal beam temperatures at higher ion densities, i.e., much higher densities in longitudinal phase space. [S0031-9007(98)05508-2] PACS numbers: 29.20.Dh, 32.80.Pj, 42.50.Vk In ion storage rings, established in the past decade as powerful instruments for precision experiments in atomic and nuclear physics [1], cooling techniques [2] play a key role in the production of beams of high brilliance and quality. In accelerator physics, very cold and highly dense ion beams are of great interest for exploring the beam dynamics at highest phase-space densities and for approaching a regime in which the beam behaves as a strongly coupled one-component plasma. Laser cooling [3-8] provides an extremely fast and efficient cooling and thus offers unique possibilities to enter this regime and to attain beams with liquidlike or solidlike Coulomb ordering .
Laser cooling of a fast ion beam
Journal of the Optical Society of America B, 1985
A theoretical analysis of light-pressure cooling of a fast ion beam is given. The light-induced velocity changes are compensated by accelerating the ions by an external electric field. By analyzing the Fokker-Planck equation, cooling times and the ultimate temperature of the ions are given. It is argued that the transverse heating and the diffusion to velocities that are not cooled should pose no serious problems in realistic experimental cases. The particular physical conditions in a heavy-ion storage ring are finally discussed.
Two-dimensional Cooling of Ion Beams in Storage Rings by Narrow Broad-Band Laser Beams
A new scheme for the two-dimensional cooling of ion beams in storage rings is suggested in which ions interact with a counterpropagating broad-band laser beam. The interaction region in the direction of the ion movement is much less then the wavelength of the ion betatron oscillations. The laser beam in the orbit plane has sharp flat edge directed to the ion beam and the width of the laser beam of the order of the ion beam width. Laser beam radial position is being displaced with some velocity at first from inside and then from outside to the ion beam and decreases both betatron and synchrotron oscillations.
From laser cooling of non-relativistic to relativistic ion beams
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2004
Laser cooling of stored 24 Mg þ ion beams recently led to the long anticipated experimental realization of Coulombordered 'crystalline' ion beams in the low-energy RF-quadrupole storage ring PAul Laser CooLing Acceleration System (Munich). Moreover, systematic studies revealed severe constraints on the cooling scheme and the storage ring lattice for the attainment and maintenance of the crystalline state of the beam, which will be summarized. With the envisaged advent of high-energy heavy ion storage rings like SIS 300 at GSI (Darmstadt), which offer favourable lattice conditions for space-charge-dominated beams, we here discuss the general scaling of laser cooling of highly relativistic beams of highly charged ions and present a novel idea for direct three-dimensional beam cooling by forcing the ions onto a helical path.
Sharp edge broad-band lasers for "white-light" cooling in storage rings
Hyperfine Interactions, 1997
We have developed broad-band laser sources which show a sharp edge in their spectra and are particularly suitable for ``white-laser'' cooling of ions in storage rings. They allow for a very large velocity capture range by maintaining the same cooling rate allowed by the single mode lasers. A large fraction of the circulating ions are expected to be cooled both in coasting and bunched beams. The device, which does not use an active medium, can easily operate at any frequency from UV to IR spectral region.
Laser cooling of stored beams in ASTRID
Conference Record of the 1991 IEEE Particle Accelerator Conference, 1991
We report the results of laser cooling experiments on 100 keV Li+ beams in the storage ring ASTRlD. The metastable fraction of the lithium beam has been laser cooled to a momentum spread dp/p-10-6, corresponding to a rest frame temperature T,, = 1 mK. Laser diagnostic methods have been employed to study the dynamics of intrabeam relaxation. A theoretical model of laser cooling has been used to interpret the experimental results. Wealso discuss Molecular Dynamics simulations of intrabeam interactions and the connection with crystalline beams.
A new concept for cooling low-energy ion beams
Journal of Physics B: Atomic, Molecular and Optical Physics, 2003
We are investigating a new concept of a buffer gas filled ion cooler built from single radio frequency (RF) ring electrodes. In such a ring electrode structure, the RF potential generates an average repelling short-range force perpendicular to the electrode surfaces. Due to the composition of single rings, the shape of the cooling channel can easily and smoothly be varied, and hence also the direction of the RF forces. As a result, the angular acceptance can be increased by a factor of two in comparison to the maximum acceptance for the present RF quadrupole coolers.
Combined Laser and Electron Cooling of Bunched C3+ Ion Beams at the Storage Ring ESR
2006
We report on first laser cooling studies of bunched beams of triply charged carbon ions stored at an energy of 1.46 GeV at the ESR (GSI). Despite for the high beam energy and charge state laser cooling provided a reduction of the momentum spread of one order of magnitude in spacecharge dominated bunches as compared to electron cooling. For ion currents exceeding 10 µA intrabeam-scattering losses could not be compensated by the narrow band laser system presently in use. Yet, no unexpected problems occurred encouraging the envisaged extension of the laser cooling to highly relativistic beams. At ESR, especially the combination with modest electron cooling provided three-dimensionally cold beams in the plasma parameter range of unity, where ordering effects can be expected and a still unexplained signal reduction of the Schottky signal is observed.
Cooling of molecular ion beams
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2004
An overview of the use of stored ion beams and phase space cooling (electron cooling) is given for the field of molecular physics. Emphasis is given to interactions between molecular ions and electrons studied in the electron cooler: dissociative recombination and, for internally excited molecular ions, electron-induced ro-vibrational cooling. Diagnostic methods for the transverse ion beam properties and for the internal excitation of the molecular ions are discussed, and results for phase space cooling and internal (vibrational) cooling are presented for hydrogen molecular ions.
Density Limitations in a Stored Laser-Cooled Ion Beam
Physical Review Letters, 1999
We present a new technique for transverse beam profile diagnostics of a stored ion beam, imaging the fluorescence light from a laser-excited ion beam onto a high resolution charge-coupled device detector. This technique has much higher sensitivity and spatial resolution than conventional techniques. Using this method we have obtained evidence for space-charge-dominated behavior of a stored, laser-cooled beam of 24 Mg 1 ions. However, the transverse size of the longitudinally cooled beam is larger than that expected for a space-charge limited beam. This seems to confirm expectations from molecular dynamics simulations, showing that to reach a crystalline beam, other techniques have to be applied.
Laser-acceleration and Laser-cooling for Ion Beams
2004
Cooling and acceleration of ions by lasers has gained increasing attention over the last years. The common interest is to further increase the luminosity of ion beams, either by shrinking the phase space occupied by the beam, or simply via increasing the number of particles. Recently, laser cooling has demonstrated ion beam crystallization as the ultimate reduction of the beam temperature. On the other hand, acceleration of ions by ultra-intense lasers resulted in the generation of ion beams of unprecedented quality, both in terms of beam power and beam emittance.
Limitations of Ion Beam Brightness with Electron Cooling - Theory and Experiment
AIP Conference Proceedings, 2002
Electron cooling is used for damping both single particle and coherent oscillations of ion beams. The extremely high phase space density of the cooled ion beam can become a source of stability problems ("electron heating"). For storage rings such as CELSIUS, COSY and the Indiana Cooler, this is a serious problem that limits the use of the electron cooling in physical experiments. Proper design of the electron cooler can improve the stability of the cooled ion beam. 3. M. Steck, "Beam accumulation with the SIS Electron Cooler", Nuclear Instruments and Methods in Physics Research A 441 (200) 175-182. 4. D. Reistad, "Measurements of Electron Cooling and Electron Heating at CELSIUS", to appear in Proceedings of the workshop on Beam Cooling 2001, Bad Honeff, Germany. 5. E.I. Antohin. V.N.Bocharov, "Conceptual Project of an Electron Cooling System at an Energy of Electrons of 350 keV", Nuclear Instruments and Methods in Physics Research A 441 (2000) 87-91.
Beam Dynamics Study in a Dual Energy Storage Ring for Ion Beam Cooling
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), 2021
A dual energy storage ring designed for beam cooling consists of two closed rings with significantly different energies: the cooling and damping rings. These two rings are connected by an energy recovering superconducting RF structure that provides the necessary energy difference. In our design, the RF acceleration has a main linac and harmonic cavities both running at crest that at first accelerates the beam from low energy 𝐸 to high energy 𝐸 and then decelerates the beam from 𝐸 to 𝐸 in the next pass. The purpose of the harmonic cavities is to extend the bunch length in a dual energy storage ring as such a longer bunch length may be very useful in a cooling application. Besides these cavities, a bunching cavity running on zerocrossing phase is used outside of the common beamline to provide the necessary longitudinal focusing for the system. In this paper, we present a preliminary lattice design along with the fundamental beam dynamics study in such a dual energy storage ring.
All-Optical Ion Beam Cooling and Online Diagnostics at Relativistic Energies
The workshop on beam cooling and related topics, COOL 2009, was organized by Institute of Modern Physics, IMP, in succession to several precursor workshops on beam cooling and related techniques. It was held in the Ningwozhuang Hotel of Lanzhou, China, between August 31 and 4 September, 2009. The workshop was attended by 48 participants from 8 countries in Europe, America, and Asia. About 33 contributions were presented in talk, 12 on poster. The workshop was structured in 12 sessions with 3 oral presentations each, two sessions in the morning and two sessions in the afternoon. One afternoon was reserved for the poster presentations. The contributions gave a rather complete overview of recent developments in the field of beam cooling, but also some planned new projects and ideas for advanced cooling concepts were discussed. The presentations covered the range from high intensity antiproton stacking accumulated by stochastic cooling and now also supplemented by electron beam, down to low intensity crystalline beams achieved by means of electron and laser cooling. Beyond these well-established techniques, more advanced concepts like muon cooling and a stochastic cooling scheme based on the use of an electron beam were discussed. A possibility to relax from the workshop and enjoy the vicinity was given on an excursion that took the participants to the Ta'er Lamasery in Qinghai. The excursion, as well as the reception and banquet near the Yellow River, gave plenty of time for intense and extended discussions. The organizers would like to thank IMP, National Natural Science Foundation of China, Chinese Academy of Sciences and Kansai Electronics (Suzhou) Co. Ltd for sponsoring this workshop. Special thanks should be given to the conference secretaries Qiang
Laser Cooling of Relativistic C3+ Ion Beams with a Large Initial Momentum Spread
We present results on laser cooling of stored relativistic C 3+ ion beams at the Experimental Storage Ring (ESR) in Darmstadt. For the first time, laser cooling of bunched relativistic ion beams using a continuous-wave UV-laser that was widely tunable over a large frequency range has been demonstrated. This new scheme allows to address the complete, initially broad momentum distribution of the ion beam without the need of additional electron cooling. Most importantly, this new method can be directly adopted to future high-energy ion storage rings where a previous scheme, based on varying the bunching frequency, can no longer be employed. As conventional beam diagnostics reach their limit at the ultra-low momentum spreads achievable with laser cooling, we show that with in-vacuo detectors the fluorescence emitted by the laser-cooled ions can be used instead for optical beam diagnostics.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017
We report on an experiment that was conducted in preparation of laser cooling experiments at the heavy-ion storage ring CSRe. The lifetimes of ion beams made up of 12 C 3+ and 16 O 4+ ions stored at an energy of 122 MeV/u in the CSRe were determined by two independent methods, firstly via a DC current transformer (DCCT) and secondly via a Schottky resonator. Using electron-cooling, the signals of the 12 C 3+ and 16 O 4+ ions could be separated and clearly observed in the Schottky spectrum. The obtained individual lifetimes of the 12 C 3+ and 16 O 4+ components were 23.6 s and 17.8 s, respectively. The proportion of 12 C 3+ ions in the stored ion beam was measured to be more than 70% at the beginning of the injection and increasing as a function of time. In addition to these measurements, the operation and remote control of a pulsed laser system placed directly next to the storage ring was tested in a setup similar to the one envisaged for future laser experiments.