Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · physics/0206003

Intrabeam scattering analysis of measurements at KEK's ATF damping ring

K. L. F. Bane·H. Hayano·K. Kubo·T. Naito·T. Okugi·J. Urakawa
View original source ↗Read source document ↗Export metadata ↓

Abstract

We derive a simple relation for estimating the relative emittance growth in x and y due to intrabeam scattering (IBS) in electron storage rings. We show that IBS calculations for the ATF damping ring, when using the formalism of Bjorken-Mtingwa, a modified formalism of Piwinski (where eta squared divided by beta has been replaced by the dispersion invariant), or a simple high-energy approximate formula all give results that agree well. Comparing theory, including the effect of potential well bunch lengthening, with a complete set of ATF steady-state beam size vs. current measurements we find reasonably good agreement for energy spread and horizontal emittance. The measured vertical emittance, however, is larger than theory in both offset (zero current emittance) and slope (emittance change with current). The slope error indicates measurement error and/or additional current-dependent physics at the ATF; the offset error, that the assumed Coulomb log is correct to within a factor of 1.75.

Explore related subjects

physics.acc-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

K. L. F. Bane, H. Hayano, K. Kubo, T. Naito, T. Okugi, J. Urakawa. 2002-06-01. Intrabeam scattering analysis of measurements at KEK's ATF damping ring. https://doi.org/10.1103/physrevstab.5.084403

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Impedance of multilayer cylindrical structures with a material-filled beam region

Beam-coupling impedances in material media are relevant for ionization-cooling channels of a future muon collider, where the beam propagates in matter rather than vacuum. We extend the cylindrical field-matching formalism for multilayer structures to the case of a material-filled beam region surrounded by external layers with arbitrary electromagnetic properties. Relative to the vacuum formulation, the usual factor $1/γ^2$ is replaced by the material-dependent factor $F=1/\varepsilon_1-μ_1β^2$, and the radial propagation constant is modified accordingly. Analytical expressions are obtained for the monopolar longitudinal and dipolar transverse impedances, with the surrounding structure encoded through reflection coefficients determined by field matching. The formalism reduces to the known vacuum and perfectly conducting limits in the appropriate cases. Representative calculations are presented for absorber-relevant configurations, illustrating the dependence on the material properties of both the beam region and the surrounding layers. In particular, a finite beam-region conductivity can generate a real impedance component and reverse the sign of the imaginary space-charge impedance, while sufficiently high permittivity can give rise to resonant structures associated with oscillatory radial fields. The effect of finite-conductivity surroundings is also examined, showing the approach towards the perfectly conducting limit as the external conductivity is increased. The applicability of the infinite-length approximation is also discussed by comparison with finite-length mode-matching results.

physics.acc-ph↗
arXiv2026

Brilliance for adaptive computational research in accelerator physics

Computational research requires repeated decisions about models, calculations and the interpretation of results. We introduce Brilliance, an agent that combines large language models, reusable physics expertise and numerical simulation to construct and revise investigations in accelerator physics. Starting from a detailed expert-specified request, Brilliance develops an ideal storage-ring lattice meeting the specified emittance ceiling and sampled nonlinear-acceptance criteria after revising optics that fail particle-tracking tests. Further scientist-guided exploration produces a candidate with a natural emittance of 6.51 pm rad and millimeter-scale transverse acceptance, while exposing unresolved momentum-acceptance limitations. Using measured responses from the High Energy Photon Source, Brilliance also performs offline optics calibration consistent with an independent specialist analysis. An expert-module ablation examines how reusable domain knowledge influences research choices and outcomes. Here, we demonstrate a practical route to scientist-agent collaboration in sustained numerical research.

physics.acc-ph↗
arXiv2026

High-transformer-ratio plasma-based afterburner for extending X-ray free-electron laser photon energies to $\gtrsim$50 keV

Bright coherent X-rays in the $\gtrsim$50 keV range are highly desirable for applications in materials science, high-energy-density physics, and nuclear physics, but are difficult to obtain from present X-ray free-electron laser (XFEL) facilities. Plasma-based afterburners offer a compact route to increasing the electron-beam energy, yet high transformer ratio (TR) operation is vulnerable to hosing instability, which can severely degrade the witness beam quality. We propose using a transversely elliptical driver beam to excite an elliptical nonlinear plasma wake with an axially varying focusing gradient, thereby suppressing the witness beam hosing through betatron decoherence. Three-dimensional particle-in-cell simulations show that, for a 3 kA driver and a 2.35 kA witness beam with an rms length of 4 $\mathrmμ$m and a beam separation of 94 $\mathrmμ$m (TR $\approx 3$), this scheme can accelerate an 8 GeV witness beam to $\sim30$ GeV while nearly half of the electrons meet the XFEL requirements. Start-to-end simulations show that the resulting beam can drive $\gtrsim50$ keV XFEL radiation with peak powers of $\sim10$ GW and durations of $\sim10$ fs, even when quantum diffusion is included, offering a compact route to extend existing XFEL facilities to higher photon energies.

physics.acc-ph↗