LENA Conversion Foils Using Single-Layer Graphene

Implementing graphene foils in existing neutral atom detector designs will increase their angular and energy resolution, and also improve their mass discrimination and usable energy range. Graphene atomic uniformity and low mass density offer natural advantages over amorphous carbon foils in time-of-flight instruments. We expect that Phase II will yield flight-ready prototype foils available for rocket or pathfinder missions with substantial improvements in instrument performance. Graphene foils can also enable improved designs, for instance with lower mass or lower power consumption. Graphene is potentially useful in very low energy neutral atom detection, e.g. E4cm2) -SLG on nanohole arrays with hole coverage of >99% -a method for attaching single-layer graphene to mesh without adhesive -bilayer graphene membranes with >95% coverage on commercial mesh -Lyman alpha blocking of 99.8% using aluminum nanohole arrays Our Phase II effort will continue to improve microgrids, nanogrids and graphene for LENA detectors. In particular, we will 1. Fabricate bilayer graphene (BLG) on microgrids as a better-performing foil for existing LENA instrument designs. 2. Fabricate pristine SLG on nanogrids, extending TOF detectors to <200eV. 3. Investigate surface modification of graphene to enable detection of <10eV neutral atoms. 4. Make prototype samples for other NASA and non-NASA applications. Compared with existing foils, our proposed SLG structure reduces scattering, improves low energy signal, and improves energy resolution. The structure reduces the serial losses and increases the effective collection area.