Temporal characterization of laser plasma accelerated electron bunches by CTR

Laser driven plasma accelerators offer the prospect of a new source of relativistic electron beams. One of the key parameters to be determined is the temporal profile of the electron bunch. Available experimental data show bunch lengths <30 fs, however, best estimates still rely on particle-in-cell simulations predicting durations of ∝10 fs. We report on progress towards measuring the temporal profile of electron bunches from a laser-wakefield accelerator, based on the detection of coherent THZ radiation emitted at a metal-vacuum boundary. The construction of a broadband (2-40 μm) spectrometer based on pyroelectric detectors as well as a numerical assessment of its capabilities are presented.