Feasibility of beam crystallization in a cooler storage ring

We report the first observation of indirect resonantly enhanced transverse laser cooling of a bunched, stored ion beam of 40 keV 24 Mg þ . The longitudinal velocity distribution and the horizontal beam size of the laser-cooled 24 Mg þ ion beam with 280 nm laser light were simultaneously observed by the use of standard fluorescence-based techniques. Keeping the operation point at (2.068, 1.105), the synchrotron tune ( s ) was changed from 0.0376 to 0.1299. A strong decrease in the cooled horizontal beam size and a corresponding increase in the equilibrium cooled momentum spread were observed at the expected synchrobetatron resonance coupling condition of s ¼ 0:068, which is the first observation of a resonantly induced coupling for enhanced indirect transverse laser cooling of an ion beam, and is an important step towards creating a crystalline ground state of the beam.

“…The horizontal phase advance ($ 124:1 ) is twice higher, but it still satisfies the maintenance condition [12]. Refer to [28] in detail.…”

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Resonance coupling induced enhancement of indirect transverse cooling in a laser-cooled ion beam

Nakao

T.Hiromasa

Souda

et al. 2012

“…(1) that the longitudinal average velocity of each particle is linearly proportional to the horizontal coordinate x in the final equilibrium state reached by the tapered force. The tapered cooling can thus realize all kinds of crystalline configurations if the ring lattice satisfies the conditions mentioned above [16]. The ideal tapering factor is, however, not constant but varies along the beam orbit.…”

Section: Introductionmentioning

confidence: 99%

Crystalline beams in dispersion-free storage rings

Ikegami

Okamoto

Yuri

2006

Self Cite

Generating a multidimensional crystalline beam in a storage ring has been known to be difficult without a special cooling force, i.e., tapered cooling, because of the momentum dispersion induced by bending magnets. It is, however, possible to eliminate the dispersion all around the ring by adding an electric dipole field in each magnetic bending region. A storage ring with such unique deflectors should enable us to reach multidimensional crystalline states with an ordinary untapered cooling force. In order to verify this expectation, molecular dynamics simulations are performed to study beam crystallization in several dispersion-free storage rings including the S-LSR at Kyoto University. The present results show that various crystalline states can be established without relying on the tapered force.

“…[39] has confirmed the existence of these second-and third-order coherent resonances. The importance of such coherent parametric resonances is also addressed in connection with cooler storage rings [1,2,10] and next-generation high-power rings [40].…”

Section: B High Density Regimementioning

confidence: 99%

“…As the beam density increases in phase space, the tune shift becomes larger and can eventually reach the magnitude of the initial bare tune at the ultralowemittance limit. Such a unique situation is expected to occur in advanced cooling experiments if several necessary conditions are satisfied [1,2]. Another good example is nonscaling fixed field alternating gradient (FFAG) accelerators [3].…”

Section: Introductionmentioning

confidence: 99%

Experimental study of resonance crossing with a Paul trap

Takeuchi

Fukushima

Ito

et al. 2012

The effect of resonance crossing on beam stability is studied systematically by employing a novel tabletop experimental tool and a multiparticle simulation code. A large number of ions are confined in a compact linear Paul trap to reproduce the collective beam behavior. We can prove that the ion plasma in the trap is physically equivalent to a charged-particle beam propagating through a strong focusing channel. The plasma confinement force is quickly ramped such that the trap operating point traverses linear and nonlinear resonance stop bands. Assuming a nonscaling fixed field alternating gradient accelerator composed of many identical FODO cells, we measure how much ion losses occur under diverse conditions. It is experimentally and numerically demonstrated that too slow resonance crossing leads to significant ion losses as expected. Particular attention must be paid to the linear coherent resonance excited at a quarter-integer tune. When the beam intensity is high, this type of linear stop band can seriously affect the beam quality even for rather fast resonance crossing. A scaling law is given of the emittance growth caused by the quarter-integer resonance crossing.