A crossed molecular beam apparatus using high-resolution ion imaging

A new crossed molecular beam apparatus with a high-resolution ion imaging detector is described. Two pulsed supersonic molecular beams are crossed at right angles in a vacuum of 10 −7 Torr. The collision region is irradiated with a tunable laser pulse that ionizes the scattered particles state selectively. The generated ions are accelerated by stacked electrodes in a two-dimensional (2D) space focusing mode that increases the velocity resolution of the apparatus. A cylindrical hexapole deflector is placed in the middle of the time-of-flight mass spectrometer to compensate the center-of-mass velocity of the ions and to direct them to the center of the 2D imaging detector. Real-time image processing of the charge coupled device camera signal eliminates blurring of the image detector. The performance of the apparatus was examined by observing the inelastic scattering of NO+Ar at a collision energy of 66 meV. The observed multiple rainbow peaks clearly demonstrate the high performance of the apparatus.