加速器物理
The AWAKE project at CERN uses a self-modulated \SI{400}{GeV/c} proton bunch to drive GV/m wakefields in a \SI{10}{m} long plasma with an electron density of $n_{pe} = 7 \times 10^{14}\,\rm{electrons/cm}^3$. We present the upgrade of a…
Two pulsed power systems have been upgraded for the g-2 experiment at Fermilab. The Pbar Lithium Lens supply previously ran with a half sine pulsed current of 75 kA peak, 400 us duration and a repetition rate of 0.45 pps. For the g-2…
Moderate ion mobility provides a source of damping in the plasma wakefield acceleration, which may serve as an effective remedy against the transverse instability of the trailing bunch. Ion mobility in the fields of the driving and trailing…
This paper discusses the emittance growth produced by sextupole fields in conjunction with a solenoidal focusing. The sextupole emittance is derived and compared with numerical simulations using a measured sextupole field for a vacuum…
In this paper we present methods for compensating influence of solenoids, including the de-coupling of transverse motion, using quadruple lenses.
This paper traces the origins of the International Committee for Future Accelerators (ICFA), its structure and mandate, its activities and accomplishments, and its anticipated activities related to the future directions of the field of…
We propose and demonstrate a novel method to produce few-femtosecond electron beam with relatively low timing jitter. In this method a relativistic electron beam is compressed from about 150 fs (rms) to about 7 fs (rms, upper limit) with…
In recent years, modelling the evolution of beam losses in circular proton machines starting from the concept of dynamic aperture its time evolution has been the focus of intense research. Results from single-particle non-linear beam…
A six-dimensional muon ionization cooling in a helical magnet channel has been studied. The cooling performance which is analytically evaluated by solving the exact Hamiltonian is reproduced in numerical simulation. One of the key beam…
I develop the formalism that allows calculation of beam envelopes through a linear accelerator given its on-axis electric field. Space charge can naturally be added using Sacherer formalism. A complicating feature is that the reference…
We report on the development of a radio frequency (RF) linear accelerator (linac) for multiple-ion beams that is made from stacks of low cost wafers. The accelerator lattice is comprised of RF-acceleration gaps and electrostatic quadrupole…
The Isotope mass Separator On-Line DEvice (ISOLDE) facility located at CERN, produces and transports Radioactive Ion Beams (RIBs) at low or high energy through the REX/HIE-ISOLDE linear accelerator, for nuclear physics, astrophysics,…
When a resistive feedback and single-bunch wake act together, it is known that some head-tail modes may become unstable even without space charge. This feedback-wake instability, FWI, modified by space charge to a certain degree, is shown…
The short period atomic plane modulation is suggested to be applied to modify the electron channeling potential in order to make it possible to considerably increase electron channeling efficiency by the crystal structure brake ensured by…
Through an interaction of theory and optimization-guided design, we have developed a novel bunch compression scheme based on an asymmetric double emittance exchange (DEEX) with greatly reduced coherent synchrotron radiation (CSR) effects.…
We investigate beam loading and emittance preservation for a high-charge electron beam being accelerated in quasi-linear plasma wakefields driven by a short proton beam. The structure of the studied wakefields are similar to those of a…
In this paper, we present a new kind of high power and high efficiency free-electron laser oscillator based on the application of the tapering enhanced stimulated superradiant amplification (TESSA) scheme. The main characteristic of the…
This report summarizes progress made towards a new approach for enlarging the dynamic aperture of particle accelerators. Unlike prior methods which attempted to move the location of select resonances outward in phase space, our approach…
As an accelerator control system survives over several years, it is often the case that new subsystems are introduced into the original control system. The control system for the KEK electron/positron injector-linac has been using Unix…
The KEK 8-GeV electron / 3.5-GeV positron linac has been operated with very different beam specifications for downstream rings, KEKB, PF and PF-AR. For the reliable operation among these beam modes intelligent beam switching and beam…