Berkeley Lab

TREX Staging Beamline

A modular approach to attaining high energies with LPAs

The staging beamline (top) in Cave A.

The staging beamline (top) in Cave A

For high energy physics colliders, the ability to accelerate the particle beam in many sequential stages, each boosting beam energy, is crucial to achieve the required energies. The area between stages does not accelerate the beam, and hence should be kept short to minimize system length. Such “staged” systems are also important for photon source applications, where the second stage can be used to decelerate the electron beam after photon production to reduce radiation production.

diagnostics for the electron and optical beams, around the Staging Target Chamber.

Diagnostics for the electron and optical beams, around the Staging Target Chamber

Research on sequential LPAs is conducted using the staging beamline, where the TREX laser, after compression, is split into two independently controllable laser beams, each of which excites a separate LPA. A tape drive based plasma mirror is used in order to couple the laser for the second stage while keeping the distance between stages short. The beamline is equipped with multiple optical and electron diagnostics, independent target controls (hexapods), and a single-shot magnetic spectrometer to measure the beams from each stage.

A successful demonstration of staging is described in S. Steinke, J. van Tilborg, C. Benedetti, C.G.R. Geddes, C.B. Schroeder, J. Daniels, K.K. Swanson, A.J. Gonsalves, K. Nakamura, N.H. Matlis, B. H. Shaw, E. Esarey, and W.P. Leemans, “Multistage coupling of independent laser plasma accelerators,” Nature, available online 1 February 2016,