The DUVEEL electron linac is designed to produce sub-picosecond, high brightness electron bunches for driving a short wavelength PEL. Four experiments have been commissioned to address the challenge of accurately measuring bunch lengths on this timescale. In the frequency domain, a short 12 period undulator is used to produce both off-axis coherent emission and on-axis incoherent single-shot spectra. The total coherent infrared power scales inversely with bunch length and the spectral cutoff is an indication of bunch length. The density of power spikes in the single-shot visible spectrum may also be used to estimate bunch length. In the time domain, the linac accelerating sections and a bending magnet are used to implement the RF-zero phasing method, and a sub- picosecond streak camera is also installed. Beam measurements and comparisons of these methods are reported.
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