Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Particle Accelerator Conference (PAC)

Experimental approach to ultra-cold ion beam at S-LSR

A. Noda, T. Shirai, Hikaru Souda, M. Tanabe, Hiromu Tongu, Masashi Ikegami, Takehiro Ishikawa, Masao Nakao, H. Fadil, M. Grieser, Igor Nikolaevich Meshkov, A. Smirnov, Koji Noda

Published Jun 1, 2007• 1 citation
Publisher

Abstract

At S-LSR, abrupt reduction of momentum spread of 7 MeV proton beam to ~2 times 10-6at proton number of -2000 has been observed, which indicates phase transition to 1 dimensional ordered state. Attained proton temperatures after transition are 26 mueV and 1 meV for longitudinal and transverse directions, respectively, which compared with the corresponding values of 20 mueV and 34 meV for electron beam, indicates the magnetization of electron. Laser cooling of24Mg+has also been started and momentum spread of ~108ions is reduced to 2 times 10-4, saturated with the momentum transfer from transverse degree of freedom by intra-beam scattering.

DOI
10.1109/pac.2007.4441137

Related papers

Latest results of experimental approach to ultra-cold beam at S-LSR

Akira Noda, Masao Nakao, Hikaru Souda +7 more

Utilizing S-LSR which has a super-periodicity of 6 and is designed to be tough against resonant perturbation to the circulating beam, we have tried to approach as low as possible temperature with laser cooled 40 keV 24Mg+ ion beam. With the use of theoretically proposed Synchro-Betatron Resonance Coupling scheme, we have experimentally demonstrated the capability of active indirect transverse laser cooling. At first, the achieved transverse cooling efficiency was limited due to heating caused by intra-beam scattering (IBS). For the purpose of reduction of IBS heating, we have established a scheme tocontrol the circulating ion beam intensity down to ~104 by scraping the outskirt of the beam with the use of a horizontally moving scraper, which enabled us to cool down the transverse beam temperatures down to 20 K and 29 K for horizontal and vertical directions, respectively for the operation tune without H-V coupling. They were modified to be 40 K and 11 K by the horizontal and vertical coupling with the difference resonance with an excitation of a solenoid of 22.5 G, which were further improved to 7.0 K and 2.1 K adding deceleration by an induction accelerator of 6 mV/m using a -26 MHz detuned laser.

•Jan 1, 2013•0 citations

Parameter optimization for Doppler laser cooling of a low-energy heavy ion beam at the storage ring S-LSR

Kazuya Osaki, H. Okamoto

S-LSR is a compact ion storage ring constructed at Kyoto University several years ago. The ring is equipped with a Doppler laser cooling system aimed at beam crystallization. Bearing in mind hardware limitations in S-LSR, we try to find an optimum set of primary experimental parameters for the production of an ultracold heavy ion beam. Systematic molecular dynamics simulations are carried out for this purpose. It is concluded that the detuning and spot size of the cooling laser should be chosen around |$-$|42 MHz and 1.5 mm, respectively, for the most efficient cooling of 40 keV |$^{24}$|Mg|$^+$| beams in S-LSR. Under the optimum conditions, the use of the resonant coupling method followed by radio-frequency field ramping enables us to reach an extremely low beam temperature on the order of 0.1 K in the transverse degrees of freedom. The longitudinal degree of freedom can be cooled to close to the Doppler limit; i.e., to the mK range. We also numerically demonstrate that it is possible to establish a stable, long one-dimensionally ordered state of ions.

Progress of Theoretical and Experimental Physics•May 14, 2014•0 citations

EXPERIMENTAL STRATEGY FOR REALIZATION OF 3-D BEAM ORDERING WITH USE OF TAPERED COOLING AT S-LSR *

A. Noda, Masashi Ikegami, Shinji Fujimoto +7 more

Experimental plan at S-LSR to realize ordered state with ultra-low temperature by application of laser cooling for 24Mg+ ions with kinetic energy of 35 keV has been surveyed. By normal mode with finite dispersion, 1 dimensional ordering and 2 dimensional zigzag structure of crystalline beam are expected if strong enough laser cooling force is applied with resonant coupling method. Three dimensional crystal is expected to be attained by the dispersion free mode with coupling cavity although limited at 1 layer level. With “tapered cooling ” utilizing Wien Filter, multi-layer 3 dimensional crystal state is expected to be realized.

•Jan 1, 2006•3 citations

Laser cooling of stored high-velocity ions by means of the spontaneous force

Wolfgang H. Petrich, M. Grieser, Rudolf Grimm +13 more

A longitudinal laser cooling of ion beams at about 5% of the velocity of light has been performed at the Heidelberg Test Storage Ring with various cooling schemes employing the spontaneous force. For a 7.29-MeV $^{9}\mathrm{Be}^{+}$ beam with an initial longitudinal temperature of 2700 K, the main characteristics of laser cooling in a storage ring are discussed. When undamped, the transverse betatron oscillations of the coasting ions limit the longitudinal temperature after laser cooling to typically 1 K. After damping the transverse motion by precooling the ions with an electron cooler, longitudinal temperatures of below 30 mK have been obtained in the subsequent laser cooling. In this case, the longitudinal ion-beam temperature can be understood as an equilibrium of the laser cooling rate with the heating rate due to intrabeam scattering. Moreover, single binary Coulomb collisions between the (still transversely hot) ions can cause such longitudinal velocity changes that ions are lost out of the critical capture range of the laser cooling force. In these two ways, intrabeam scattering imposes a substantial limit on the temperature or number of laser cooled ions in a storage ring. In our experiments, this process presently limits the ratio between the density-dependent Coulomb energy and the longitudinal thermal energy spread to a value on the order of 1, where liquid rather than gaseous behavior of the ion beam is expected to set in.

Physical Review A•Sep 1, 1993•44 citations

Application of laser-cooling to achieve an ultra-cold ion beam for FIB

Steinar H. W. Wouters, Janssen, B, G. ten Haaf +4 more

A new type of ultra-cold ion source is under development which employs transverse laser cooling and compression of a thermal atomic rubidium beam followed by photo-ionization. The resulting ultra-cold plasma is focused to a nanometer-sized spot using an existing Focused Ion Beam column and this spot can be used for the fabrication of nano-structures. Simulations of a 10 cm long laser-cooling stage and of disorder-induced heating of the resulting ion beam, predict an achievable brightness for87Rb+ of order 107 A/m2 sr eV at an longitudinal energy spread of less than 1 eV and a current of tens of pA, which is substantially better than conventional ion sources. Experimental realization of the compact ion source has recently started with the development of an efficient high-flux atom source and a 2D laser cooler. Progress on these items will be reported.

•Jan 1, 2013•0 citations

OBSERVATION OF ULTRACOLD HEAVY ION BEAMS WITH MICROMETER SIZE BY SCRAPING

M. Steck, K. Beckert, P. Béller +2 more

A method to measure the horizontal beam size of elec-tron cooled ion beams with micrometer resolution has been developed. It exploits small variations of the beam momen-tum for micrometer displacement in a dispersive section of the storage ring. The method has been applied to low in-tensity beams which are supposed to undergo a phase tran-sition to an ordered state. The measurements evidenced that the low intensity beam does not only collapse to small momentum spread, but also shrinks abruptly in the trans-verse degree of freedom. This confirms the hypothesis that a one-dimensional ordered structure is formed.

•Jan 1, 2004•0 citations
At S-LSR, abrupt reduction of momentum spread of 7 MeV proton beam to ~2 times 10-6at proton number of -2000 has been observed, which indicates phase transition to 1 dimensional ordered state. Attained proton temperatures after transition are 26 mueV and 1 meV for longitudinal and transverse directions, respectively, which compared with the corresponding values of 20 mueV and 34 meV for electron beam, indicates the magnetization of electron. Laser cooling of24Mg+has also been started and momentum spread of ~108ions is reduced to 2 times 10-4, saturated with the momentum transfer from transverse degree of freedom by intra-beam scattering.
Utilizing S-LSR which has a super-periodicity of 6 and is designed to be tough against resonant perturbation to the circulating beam, we have tried to approach as low as possible temperature with laser cooled 40 keV 24Mg+ ion beam. With the use of theoretically proposed Synchro-Betatron Resonance Coupling scheme, we have experimentally demonstrated the capability of active indirect transverse laser cooling. At first, the achieved transverse cooling efficiency was limited due to heating caused by intra-beam scattering (IBS). For the purpose of reduction of IBS heating, we have established a scheme tocontrol the circulating ion beam intensity down to ~104 by scraping the outskirt of the beam with the use of a horizontally moving scraper, which enabled us to cool down the transverse beam temperatures down to 20 K and 29 K for horizontal and vertical directions, respectively for the operation tune without H-V coupling. They were modified to be 40 K and 11 K by the horizontal and vertical coupling with the difference resonance with an excitation of a solenoid of 22.5 G, which were further improved to 7.0 K and 2.1 K adding deceleration by an induction accelerator of 6 mV/m using a -26 MHz detuned laser.
S-LSR is a compact ion storage ring constructed at Kyoto University several years ago. The ring is equipped with a Doppler laser cooling system aimed at beam crystallization. Bearing in mind hardware limitations in S-LSR, we try to find an optimum set of primary experimental parameters for the production of an ultracold heavy ion beam. Systematic molecular dynamics simulations are carried out for this purpose. It is concluded that the detuning and spot size of the cooling laser should be chosen around |−-−|42 MHz and 1.5 mm, respectively, for the most efficient cooling of 40 keV |24^{24}24|Mg|+^++| beams in S-LSR. Under the optimum conditions, the use of the resonant coupling method followed by radio-frequency field ramping enables us to reach an extremely low beam temperature on the order of 0.1 K in the transverse degrees of freedom. The longitudinal degree of freedom can be cooled to close to the Doppler limit; i.e., to the mK range. We also numerically demonstrate that it is possible to establish a stable, long one-dimensionally ordered state of ions.
Experimental plan at S-LSR to realize ordered state with ultra-low temperature by application of laser cooling for 24Mg+ ions with kinetic energy of 35 keV has been surveyed. By normal mode with finite dispersion, 1 dimensional ordering and 2 dimensional zigzag structure of crystalline beam are expected if strong enough laser cooling force is applied with resonant coupling method. Three dimensional crystal is expected to be attained by the dispersion free mode with coupling cavity although limited at 1 layer level. With “tapered cooling ” utilizing Wien Filter, multi-layer 3 dimensional crystal state is expected to be realized.
A longitudinal laser cooling of ion beams at about 5% of the velocity of light has been performed at the Heidelberg Test Storage Ring with various cooling schemes employing the spontaneous force. For a 7.29-MeV 9Be+^{9}\mathrm{Be}^{+}9Be+ beam with an initial longitudinal temperature of 2700 K, the main characteristics of laser cooling in a storage ring are discussed. When undamped, the transverse betatron oscillations of the coasting ions limit the longitudinal temperature after laser cooling to typically 1 K. After damping the transverse motion by precooling the ions with an electron cooler, longitudinal temperatures of below 30 mK have been obtained in the subsequent laser cooling. In this case, the longitudinal ion-beam temperature can be understood as an equilibrium of the laser cooling rate with the heating rate due to intrabeam scattering. Moreover, single binary Coulomb collisions between the (still transversely hot) ions can cause such longitudinal velocity changes that ions are lost out of the critical capture range of the laser cooling force. In these two ways, intrabeam scattering imposes a substantial limit on the temperature or number of laser cooled ions in a storage ring. In our experiments, this process presently limits the ratio between the density-dependent Coulomb energy and the longitudinal thermal energy spread to a value on the order of 1, where liquid rather than gaseous behavior of the ion beam is expected to set in.
A new type of ultra-cold ion source is under development which employs transverse laser cooling and compression of a thermal atomic rubidium beam followed by photo-ionization. The resulting ultra-cold plasma is focused to a nanometer-sized spot using an existing Focused Ion Beam column and this spot can be used for the fabrication of nano-structures. Simulations of a 10 cm long laser-cooling stage and of disorder-induced heating of the resulting ion beam, predict an achievable brightness for87Rb+ of order 107 A/m2 sr eV at an longitudinal energy spread of less than 1 eV and a current of tens of pA, which is substantially better than conventional ion sources. Experimental realization of the compact ion source has recently started with the development of an efficient high-flux atom source and a 2D laser cooler. Progress on these items will be reported.
A method to measure the horizontal beam size of elec-tron cooled ion beams with micrometer resolution has been developed. It exploits small variations of the beam momen-tum for micrometer displacement in a dispersive section of the storage ring. The method has been applied to low in-tensity beams which are supposed to undergo a phase tran-sition to an ordered state. The measurements evidenced that the low intensity beam does not only collapse to small momentum spread, but also shrinks abruptly in the trans-verse degree of freedom. This confirms the hypothesis that a one-dimensional ordered structure is formed.