Accelerator Physics Papers of the Week

Start-to-end particle tracking is too slow for this and needs the full particle distribution, which an operating machine cannot measure. We address this problem for the 200-MeV transport line of the collider with two fast predictors.

We identify windows in packet sizes and bend angles for a small OAM spread and show that weak bends can produce narrow distributions with the mean OAM tilted relative to the momentum, making these states candidates for spatiotemporal vortices. For a few MeV electrons, we propose to use half-turn magnets that leave the mean OAM nearly antiparallel to the momentum while keeping its distribution narrow.

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.

Here, we propose a slit plasma wakefield acceleration (SPWA) scheme, in which a relativistic electron beam propagating through a slit channel formed by two parallel plasma slabs excites crossing plasma-electron filamentary structures within the slit, generating intense wakefields tailored to simultaneously provide longitudinal acceleration and transverse focusing for a trailing positron bunch.

Here, we demonstrate a combined strategy of phase-trajectory control and injection matching for sustained, confined acceleration.

This report examines the principal accelerator subsystems, their technical maturity, and the critical challenges that must be addressed before proceeding to a technical design.

We derive a fully quantum mechanical model of stochastic cooling valid in the strong coupling regime, finding an analytic asymptotic formula for the optimal cooled energy spread $\sigma_{E_f}\simeq0.88(\hbar\omega)^{2/3}\sigma_{E_0}^{1/3}$, with $\hbar \omega$ the cooling photon energy and $\sigma_{E_0}$ the initial energy spread.

We derive a compact analytical $6\times6$ transfer matrix about the curved reference trajectory.

LADA computes charged-particle and light-optical transfer maps by differential algebra in Python, with run-time order selection validated through order nine. It combines these established map methods with ATIMA-based stopping, straggling and scattering, the GLOBAL, CHARGE and ETACHA charge-state models, EPAX fragmentation, six-dimensional integration through measured or computed RF fields with reference-energy rebasing, and section-wise particle tracking with aperture and RF-window losses.

The short muon lifetime (\qty{2.2}{\micro\second} in the rest frame) imposes stringent constraints on the acceleration process: achieving the target luminosity requires a muon survival rate of up to \qty{70}{\percent} throughout the acceleration chain, with the full acceleration completed in approximately \qty{10}{\milli\second}. These demanding acceleration conditions raise several beam-dynamics challenges, investigated in this work.

This work develops and validates a beam model incorporating Multiple Coulomb Scattering (MCS) to estimate beam parameters.

We present the engineering development, gas diagnostics, and spectroscopy data from our hydrogen plasma.

In this paper, we adopt the foundation-model paradigm to learn general-purpose sensor representations from historical accelerator data through self-supervised pretraining.

In this work, the TFH regime in the DECRIS-PM ECR ion source is studied numerically using the NAM-ECRIS code.

Learned latent representations provide a compact domain for such optimization, but poorly supported regions of the learned manifold may decode into unrealistic physical states and yield deceptively favorable objectives. To address this challenge, we propose the Classifier-pruned Bayesian Optimization-based Latent-space Tuner (CBOL-Tuner), which performs Bayesian optimization over a temporally structured latent representation of 6D beam phase-space dynamics.