The Bristol & Oxford Chemical Dynamics Group

Velocity-map and spatial-map imaging using new designs of high-resolution ion optics

The detailed design of an ion optics assembly can be an important factor in determining the velocity and/or spatial resolution achieved in recorded images. The various participating groups already have considerable local expertise in designing such assemblies but the optimal design will often be application dependent; a design optimised for studying molecular photodissociation processes will differ from that used in studying ion-molecule or neutral-neutral reactions, and is likely to be very different from the ideal ion optics for any surface map imaging study.

Several complementary developments are planned within this Programme Grant. These include: (i) continuing to build on a successful Knowledge Transfer Partnership with Dr Orla Kelly and colleagues at Photek Ltd. that has already delivered new and improved ion optics assembly designs for conventional and slice VMI applications; (ii) promulgating these improvements amongst other group members, and more widely, thereby encouraging their adoption in future imaging spectrometers, and (iii) applying similarly detailed simulations and analysis to the design of ion optics for spatial mapping.

Cross section of the new, improved VMI ion optics developed in collaboration with Photek Ltd, showing electrode geometries and calculated lines of equipotential (calculated using SIMION).

Comparison of the optimum resolutions achievable with the new VMI ion optics compared with those used previously, as predicted from SIMION modelling of Cl+ ions with a range of starting velocities.

Further Information