Machine A

More photos of Machine A can be found here.

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 capable of accelerating anions created via electron impact on a supersonic expansion of gas to up to 10keV. These 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 of this type of machine, go to the Machines A and C page.

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..

Those who currently work on this spectrometer include Qichi Hu, Jon Oakman, and Chris Johnson. Their contact information can be found on the group members page.