Alpha-X

Introduction: Alpha-X, Advanced Laser-Plasma High-energy Accelerators towards X-rays, is a 4-year program to develop a laser-plasma accelerator and produce coherent short-wavelength radiation in a free-electron laser. Apart from Strathclyde University, where construction of the final beamline has started, the project involves several other UK research groups. 

The project basically consists of three main components: A high-brightness rf-photogun tailor made for the production of ultra-short electron bunches. A plasma wakefield accelerator to accelerate these short bunches to high energy. An undulator to use the bunches to produce coherent short-wavelength radiation.

Our contribution to this project includes:
Assistance with the development of the rf-photogun.
Detailed GPT simulations from cathode to plasma entrance.
Assist with implementation and simulations of a simple (linear) plasma model.
Study of the FEL processes in the undulator for a variety of scenarios.

[ RF-photogun] [ Start to end simulations ] [ Home page of this project ]

RF-photogun: Based on the experience gained during our design of the TU/e 2.6 cell rf-photogun, we finalized the design of the Strathclyde rf-photogun in July 2004.

RF-photogun under construction

Two significant differences with the 2.6 cell rf-photogun designed for the DC/RF scheme of Eindhoven University are:

The new design incorporates elliptical irises to reduce the field on the cavity walls and thus reduce breakdown problems.

Left plot shows the field-distribution near the new elliptical irises. Right plot shows a typical BNL profile.

The structure is 2.5 instead of 2.6 cell. This reduces arrival time sensitivity to rf-phase jitter, at the cost of a slight reduction in output energy.

Start to end simulations: The flexibility of the GPT code makes is ideally suited for start-to-end simulations, including FEL processes. All components for such a simulation have been developed, including a simple (electrostatic) model for the plasma accelerator.

Three snapshots of full start-to-end GPT simulation result of the bunching process in the alpha-x plasma accelerator. Particles are color-coded on final energy to assist interpretation of the simulation results.

Collaboration: This project is commissioned by the Strathclyde University, Department of Physics, Glasgow, UK.