Ultra-high Field Gradient Research Articles

ARIES – Development of Accelerator Technology in Europe 2017-2020: Global and Local Consequences

Abstract The article describes chosen, yet key parts of newly established European, infrastructural research and development project ARIES (2017-2020) - Accelerator Research and Innovation for European Science and Society, to be realized inside the framework of the H2020 programme. Two institutions from Poland participate in ARIES – these are Warsaw University of Technology and Institute of Nuclear Chemistry and Technology. ARIES is a topical continuation of the previous infrastructural accelerator projects realized uninterruptedly since 2003 – FP6 CARE – Coordinated Accelerator Research in Europe and FP7 TIARA – Test Infrastructure and Accelerator Research Area, EuCARD – European Coordination for Accelerator Research and Development, and EuCARD2. The article is simultaneously a part of a series of papers concerning the participation of Polish doctoral students and young researchers, especially from the Warsaw University of Technology, in large European and world experiments of the discovery class, including building large research infrastructures like: FLASH and EXFEL, ESS, ITER and DEMO, IFMIF, but also satellites built by the ESA, etc. ARIES embraces, among others, the following subjects: energy efficiency and management, cost lowering, miniaturization and ultra-high field gradients, promotion innovation, industrial applications, societal implications, new materials and components, new methods of particles acceleration including laser-plasma-particles interaction, and building new generations of systems.

Longitudinal wake field for an electron beam accelerated through an ultrahigh field gradient

Electron accelerators with higher and higher longitudinal field gradients are desirable, as they allow for the production of high-energy beams by means of compact and cheap setups. Laser-plasma acceleration technique appears to constitute the more promising breakthrough in this direction, delivering unprecedent field gradients up to TV/m. In this article we give a quantitative description of the impact of longitudinal wake fields on the electron beam. Our paper is based on the solution of Maxwell's equations for the longitudinal field. Our conclusions are valid when the acceleration distance is much smaller than the overtaking length, that is the length that electrons travel as a light signal from the tail of the bunch overtakes the head of the bunch. This condition is well verified for laser-plasma devices. We calculate a closed expression for the impedance and the wake function that may be evaluated numerically. It is shown that the rate of energy loss in the bunch due to radiative interaction is equal to the energy emitted through coherent radiation in the far zone. Furthermore, an expression is found for the asymptotic limit of a large distance of the electron beam from the accelerator compared with the overtaking length. Such expression allows us to calculate analytical solutions for a Gaussian transverse and longitudinal bunch shape. We describe an application of our analytical asymptote by studying the feasibility of a table-top free-electron laser based on laser-plasma driver. Numerical estimations presented in this paper indicate that the effects of the time-dependent energy change induced by the longitudinal wake pose a serious threat to the operation of this device.

Development status of PRISM FFAG ring and phase rotation simulation

PRISM is a project to produce a high quality, high purity and high intensity muon beam by the phase rotation technique in FFAG synchrotron using ultra-high field gradient RF systems. To achieve ultra-high field gradient, we construct a test RF system and we have done several test with the system. And a research for the phase rotation with simulation is also being advanced and a construction of the FFAG ring has been started.

Ultra-High Field Gradient RF for Bunch Rotation

An ultra-high field gradient RF system has been designed for the PRISM project. This paper will report the status of R&D.