加速器物理
A novel geometrical configuration to form a magnetic field perpendicular to an aperture, created by an asymmetric current distribution, within a single layer, and using a continuous ideal current line, named the uni-layer magnet, is here…
Dynamic aperture (DA) is an important nonlinear property of a storage ring lattice, which has a dominant effect on beam injection efficiency and beam lifetime. Generally, minimizing both resonance driving terms (RDTs) and amplitude…
A summary of numerical modeling capabilities regarding high power cyclotrons and fixed field alternating gradient machines is presented. This paper focuses on techniques made available by the OPAL simulation code.
Electron beam quality is paramount for X-ray pulse production in free-electron-lasers (FELs). State-of-the-art linear accelerators (linacs) can deliver multi-GeV electron beams with sufficient quality for hard X-ray-FELs, albeit requiring…
Compact H$^-$ cyclotrons are used all across the globe to produce medical isotopes. Machines with external ion sources have demonstrated average extracted currents on the order of a few mA, although reported operational numbers are…
In this paper we demonstrate that cyclotrons can be made to have precisely constant betatron tunes over wide energy ranges. In particular, we show that the horizontal tune can be made constant and does not have to follow the Lorentz factor…
Stripping extraction of hydrogen molecular ions has gained interest in the cyclotron industry due to its high extraction efficiency. However, the magnetic field could result in undesired Lorentz dissociation of the hydrogen anion/molecular…
An accurate and detailed field map is important for cyclotron beam dynamics studies. During the long history of cyclotron studies, many techniques have been developed by cyclotron pioneers for the treatment of median plane field map. In…
Existing analytical models for transverse beam dynamics in isochronous cyclotrons are often not valid or not precise for relativistic energies. The main difficulty in developing such models lies in the fact that cross-terms between…
A high-level beam background is a crucial challenge to future upgrades to the BEPCII collider. We report on the first separate measurement of the main beam background components at BEPCII. The separation measurement enables the beam…
We evaluate the neutron and muon fluxes produced in the ILC beam dumps by Monte Carlo simulations and discuss their potential use in irradiation fields. We show that the beam dumps can provide high-intensity neutron and muon fluxes with…
A superconducting radio-frequency (SRF) photo injector is in operation at the electron linac for beams with high brilliance and low emittance (ELBE) radiation center and generates continuous wave (CW) electron beams with high average…
We improve the algorithm to noninvasively update the response matrix using information from the orbit-feedback system, described in [1]. The new version is capable of adapting to slow changes of the lattice, albeit at the expense of…
The multiplexing capabilities of superconducting X-ray free-electron lasers (FELs) have gained much attention in recent years. The demanding requirements for photon properties from multiple undulator lines necessitate more flexible beam…
Unforeseen particle accelerator interruptions, also known as interlocks, lead to abrupt operational changes despite being necessary safety measures. These may result in substantial loss of beam time and perhaps even equipment damage. We…
Metal photocathodes are an important source of high-brightness electron beams, ubiquitous in the operation of both large-scale accelerators and table-top microscopes. When the surface of a metal is nano-engineered with patterns on the order…
A prototype of ion beam transport module has been developed at the Institut Pluridisciplinaire Hubert Curien (IPHC) and used as a test bed to investigate key issues related to the efficient transport of ion beams. This includes the…
A new frequency converter, operating at significantly higher power and efficiency than previous devices, is described in this paper. The proposed device is implemented as a klystron structure where a new design principle is used. New…
One of the decisive issues in the design and operation of cyclotrons is the choice of the beam extraction method. Typical methods are extraction by electrostatic extractors and by stripping. The former method requires DC high voltage…
The current and future need for high-energy neutrons has been a subject of increasing discussion and concern. Immediate applications for such an intense neutron source include medical isotope production, high-energy physics (HEP) research,…