MOOAB1
LANL, Los Alamos, New Mexico, USA
The MaRIE 1.0 X-FEL requires an electron beam at 12 GeV with 100pC bunch charge, 0.2 μm RMS normalized transverse emittance, and 0.15% RMS slice energy spread. These requirements place significant constraints upon the use of techniques, such as laser heaters, which have enabled other X-FELs to reach their design goals. In this paper, we present the current baseline design and performance of the MaRIE 1.0 linac, highlight current and anticipated challenges and describe potential alternate approaches for meeting our design performance goals.
TUOBB3
LANL, Los Alamos, New Mexico, USA
We propose a novel scheme for imposing strong energy slews in short electron bunches using a set of transverse deflecting cavities. Such a cavity introduces the angular divergence depending on the longitudinal position and the energy variation depending on the transverse position. Combining several cavities and vacuum drifts we first expand the beam transversally keeping x-z correlation of the distribution, then apply the energy variation, and focus the beam back. The transform matrix of the scheme is equivalent to a single chirping cavity. At the same time, the strength of the R65 element is strongly increased compared to conventional accelerating cavities. The overall energy variation along the bunch is defined by the transverse size of the beam in the middle of the beamline rather than its longitudinal size. As a result, the strength of the R65 element can be increased by 2 orders of magnitude compared to conventional design. This scheme allows for acceleration on crest increasing average accelerating gradient and reducing accelerator cost. It also allows for using weaker chicanes in compressors.