An intense pulsed electrical discharge source for OH molecular beams

In this Letter we describe and characterize a pulsed DC discharge source for a molecular beam of OH radicals. The absolute line-integrated OH density has been measured by cavity ring-down spectroscopy, while the off-axis distribution of the radicals has been determined by 1-dimensional laser-induced fluorescence spectroscopy. Combining both measurements the total OH centerline flux at the maximum of the pulse was determined to be (2.2±0.1)×1017 molecules/sr s. No anomalous population distribution was found for the Λ-doublet components of the rotational ground state.