Machine A was the first apparatus in the Continetti lab. It has been used in studies of the dissociative photodetachment of O4-, dissociation dynamics of the triplet states of ozone and in studies of organic anions and radicals. With a new high-efficiency photoelectron imaging detector this is currently the instrument with the highest sensitivity for the study of dissociative photodetachment processes. Machine A is currently being fitted with an Electrospray Ionization (ESI) source which will enable us to examine the dissociative properties of biofuel relevant systems that would otherwise be hard to introduce into the gas-phase.
Machine A is capable of accelerating anions created via either electron impact on a supersonic expansion of gas or ESI to up to 10keV. The ions are then mass selected by time-of-flight as they propagate to the interaction region. There, the anions of interest are photodissociated by a pulse from either an Nd:YAG or Ti:Sapphire laser system. Machine A can detect one photoelectron and up to three neutral photofragments in coincidence from each laser-ion beam crossing. Both detectors record time-of-arrival and 2D position data, from which the full three-dimensional velocity distribution of the photoelectrons and the photofragments can be recreated.
If you would like to see some references for the work done on this apparatus, please go to our publications page. For a general description of the work done on this type of machine, please read Reaction Dynamics of Transient Species.
Shown above is a picture of the A machine. The sections visible are (from right to left) the source, the acceleration region, the time of flight region. The detector region is barely visible but can be better seen in the picture below.
More photos of Machine A can be found in the photo gallery.
Last Updated March 5, 2012