PHEMOS UV Imager Summary

Status on Tasks COM DEV and U of C signed a contract in December Provided feedback on science requirements Started to look at optical design – Investigation into design concepts – Reviewed some of the U of C optical designs generated on another program Started to investigate image intensifier

Summary of Issues/Questions Can U of C provide zemax design files for their designs? Environmental requirements? What are the Performance Assurance requirements? (reference section of PHEMOS SOW) What is the life requirement? Which way is 40 degree offset from nadir? In the orbit plane? Why is it there? Is it constant? Solar illumination angles

Image Intensifier Trades include; Diameter 25 mm vs 40 mm – 25 mm smaller volume, 40 mm better SNR and better resolution/lower risk – Material, MgF 2 vs BaF 2 Photocathode material – ”Solar Blind” has better efficiency ~ 30 %, but poor vis rejection – Cesium Iodide very good visible rejection above 190 nm but low efficiency ~ 2% (cuts off quickly, so LBH-Low may have 3%) – KBr on MCP, better performance but would need likely development Photocathode to MCP gap – 100 microns is performance limit, best spatial resolution – 200 microns lower vibration risk, but higher blurring

Image Intensifier Trades include; Phosphor material, likely P43 but others will be investigated – P43 has good efficiency, fast enough MCP details – single stage vs double stage – Thickness, pore size, bias angle, voltage range Number of fibre optic elements – 1, 2 or 3 – Impacts on risk and subcontract structure

Summary Requirements have been defined Optical engineering team is engaged and ready to move ahead with optical design Developing Image Intensifier conceptual design CCD/CMOS selection will begin soon