FIG. 2.

(a) Focal spot in the target plane (in front of the electron spectrometer), measured using a HeNe laser. (b) Photoelectron counts in the 1b₁ liquid peak of water as the jet was translated across the focus. The FWHM of the fitted Gaussian is 22 μm. (c) Measured HeNe focal spot profiles ${\text{FWHM}}_{\text{horiz}}\sim 35\mu \mathrm{m}$, ${\text{FWHM}}_{\text{vert}}\sim 32\mu \mathrm{m}$.