Velocity map imaging of a slow beam of ammonia molecules inside a quadrupole guide

摘要: Velocity map imaging inside an electrostatic quadrupole guide is demonstrated. By switching the voltages that are applied to rods, can be used for guiding Stark decelerated molecules and extracting ions. The extraction field homogeneous along axis of quadrupole, while it defocuses ions in direction perpendicular both ion optics. To compensate this astigmatism, a series planar electrodes with horizontal vertical slits used. A velocity resolution 35 m s−1 obtained. It shown signal due thermal background eliminated, resulting detection slow increased signal-to-noise ratio. As illustration resolving power we have system characterize phase-space distribution ammonia beam.