arXiv subjects

R. Matsushita

Publications and source records attributed to R. Matsushita.

3 recordsLinked to original sources

arXiv2026

First Experimental Demonstration of Beam Storage by Three-Dimensional Spiral Injection Scheme for Ultra-Compact Storage Rings

Three-dimensional spiral injection enables beam storage in ultra-compact rings with nanosecond revolution periods. We report first storage of a $297 \, \mathrm{keV/}c$ electron beam in a $22 \,\mathrm{cm}$ weak-focusing ring with a $4.7\,\mathrm{ns}$ revolution period using a $140\,\mathrm{ns}$ kicker pulse. A scintillating-fiber detector observes signals $>5σ$ above noise for $\geq 1\, \mathrm{μs}$, and varying the weak-focusing field potential shifts the stored-beam region, consistent with Monte Carlo predictions, validating beam storage. This proof-of-principle opens a path to ultra-compact storage rings for next-generation precision measurements.

physics.acc-ph↗

arXiv2025

Acceleration of positive muons by a radio-frequency cavity

Acceleration of positive muons from thermal energy to $100~$keV has been demonstrated. Thermal muons were generated by resonant multi-photon ionization of muonium atoms emitted from a sheet of laser-ablated aerogel. The thermal muons were first electrostatically accelerated to $5.7~$keV, followed by further acceleration to 100 keV using a radio-frequency quadrupole. The transverse normalized emittance of the accelerated muons in the horizontal and vertical planes were $0.85 \pm 0.25 ~\rm{(stat.)}~^{+0.22}_{-0.13} ~\rm{(syst.)}~π~$mm$\cdot$mrad and $0.32\pm 0.03~\rm{(stat.)} ^{+0.05}_{-0.02} ~\rm{(syst.)}~π~$mm$\cdot$mrad, respectively. The measured emittance values demonstrated phase space reduction by a factor of $2.0\times 10^2$ (horizontal) and $4.1\times 10^2$ (vertical) allowing good acceleration efficiency. These results pave the way to realize the first-ever muon accelerator for a variety of applications in particle physics, material science, and other fields.

physics.acc-ph↗

arXiv2014

Truncated Lévy Flights and Weak Ergodicity Breaking in the Hamiltonian Mean Field Model

The dynamics of the Hamiltonian mean field model is studied in the context of continuous time random walks. We show that the sojourn times in cells in the momentum space are well described by a Lévy truncated distribution. Consequently the system in weakly non-ergodic for long times that diverge with the number of particles. For a finite number of particles ergodicity is only attained for very long times both at thermodynamical equilibrium and at quasi-stationary out of equilibrium states.

cond-mat.stat-mech↗