Generation of Multi-Color Attosecond X-Ray Radiation Through Modulation Compression

In this paper, we propose a scheme to generate tunable multi-color attosecond coherent X-ray radiation for future light source applications. This scheme uses an energy chirped electron beam, a laser modulators, a laser chirper and two bunch compressors to generate a multi-spike prebunched kilo-Ampere current electron beam from a few tens Ampere electron beam out of a linac. Such an electron beam transports through a series of undulator radiators and bunch compressors to generate multi-color coherent X-ray radiation. As an illustration, we present an example to generate two attosecond pulses with $2.2$ nm and $3$ nm coherent X-ray radiation wavelength and more than $200$ MW peak power using a $30$ Ampere $200$ nm laser seeded electron beam

Machine learning-based direct solver for one-to-many problems of temporal shaping of electron bunches

To control the temporal profile of a charged beam to meet requirements of various accelerator applications, a widely-used technique is bunch compression via 4-dipole chicanes that may sometimes have a one-to-many map. Current approaches based on stochastic optimization or supervised learning can be limited because of the one-to-many properties. Here we demonstrate how to construct a direct and real-time solver with the aid of a semi-supervised machine learning method, the conditional generative adversarial network (CGAN), to solve one-to-many problems of temporal shaping. Unlike supervised learning that can only learn one-to-one maps, the CGAN solver can learn the one-to-many dynamics and accurately predict required longitudinal dispersion terms for a chicane to realize desired custom temporal profiles without any priori knowledge. Besides, the CGAN solver can simultaneously give multiple different solutions for a one-to-many problem, which breaks the limitation of stochastic optimization methods of finding one solution instead of many

Linac Coherent Light Source (LCLS) Bunch-Length Monitor using Coherent Radiation

The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) based on the final kilometer of the Stanford Linear Accelerator. One of the most critical diagnostic devices is the bunch length monitor (BLM), which is to be installed right after each compressor utilizing coherent radiation from the last bending magnet. We describe the components and the optical layout of such a BLM. Based on the setup geometry, we discuss some issues about the coherent radiation signal