My principal research interest is measuring energetic particle radiation in space. This includes Galactic cosmic rays which fill the Galaxy and are probably accelerated by supernovae shocks; Solar energetic particles which are accelerated by events on the Sun and by shocks in interplanetary space; and the anomalous cosmic rays, which are believed to be interstellar neutral atoms that drift into the Solar System, become ionized and are carried by the Solar wind out to the termination shock (a shock formed where the Solar wind becomes sub-sonic) where they undergo acceleration.
A non-research interest is nuclear science, technology and policy. I teach an Inquiry Course for non-majors on the subject, “Myths and Misconceptions about Nuclear Science.”
I am deeply involved in the Energetic Heavy Ion Sensor (EHIS) for the Geostationary Operational Environmental Satellite (GOES-R) Program (https://www.goes-r.gov/spacesegment/seiss.html). EHIS instruments are now flying on GOES-16 and GOES-17 with two more waiting for launch (GOES-T and -U).
Much of my research involves the development of new and innovative instrumentation. The exigencies of space flight mean that instruments have to be very low in mass and power usage, and be extremely reliable. New instrument concepts include my Angle Detecting Inclined Sensors (ADIS) system. The EHIS are ADIS instruments. Other instrument development projects include the Positron Identification by Coincident Annihilation Photons (PICAP) and, more recently, a project to develop a synthetic diamond Cherenkov detector.
Scientifically, most of my work has been detailed measurements of the isotopic and elemental composition of Galactic cosmic rays using data from our High Energy Telescope (HET), on the Ulysses spacecraft. I have also been involved in the study of cosmic ray modulation by the Solar wind, particularly the three dimensional structure of the Heliosphere, again mainly using data from Ulysses.
