Born in England, PhD in Ireland, now living in the City of Angels. My passion for studying how the universe works has taken me around the world. Along the way I have spent my time enjoying the local culture - usually via bike followed by good food and beer.
I am an experimental scientist interested in how cosmic rays are produced and interact, and how we can use them to study the fundamental laws of physics. I am a member of two collaborations VERITAS and GAPS which take different approaches to this problem.
VERITAS (Very Energetic Radiation Imaging Telescope Array System) is a ground-based gamma-ray instrument operating at the Fred Lawrence Whipple Observatory (FLWO) in southern Arizona, USA. It is an array of four 12m optical reflectors for gamma-ray astronomy in the GeV - TeV energy range. These imaging Cherenkov telescopes are deployed such that they have the highest sensitivity in the VHE energy band (50 GeV - 50 TeV), with maximum sensitivity from 100 GeV to 10 TeV. This VHE observatory effectively complements the NASA Fermi mission.
I primarily use VERITAS to study galactic objects. Recently this work has focussed on the Cygnus region where I have conducted a gamma-ray survey of the region and detected emission from the gamma-ray binary PSR J2032+4127/MT91 213, only the 7th gamma-ray binary detected, the 2nd with a compact object of known type and the first with an associated extended object, TeV J2032+4130.
I am also interested in using VERITAS to search for fast transients, most notably searching for associated emission to fast radio bursts in both gamma-rays and the optical.
GAPS (General Antiparticle Spectrometer) is an experiment under development to search for the anti-deuteron particles in the cosmic rays. Astrophysically produced anti-deuterons have never been detected and so the unambiguous detection of even a single event would be very significant. Anti-deuterons could also be a tell-tale signature of dark matter annihilations.
GAPS will detect anti-deuterons with an effectively background-free method. Anti-deuterons produced by the annihilation of weakly interacting massive particles (WIMPs), a well-motivated dark matter candidate, will be captured in the GAPS target material, resulting in an exotic atom in an excited state. This exotic atom will then quickly decay, producing X-rays of precisely defined energies and a correlated pion signature from nuclear annihilation.
The method of detection uses a time-of-flight (TOF) system, which tags candidate events and particle velocities and planes of pixillated Si(Li) detectors, which serve as the target material and tracking detector. The Si(Li) detectors provide both excellent X-ray energy resolution and good particle tracking. The GAPS exotic atom detection method has already been successfully tested in an accelerator environment at KEK in 2004 and 2005. To test the hardware appropriate for GAPS, a balloon-borne prototype experiment with a TOF system and 6 Si(Li) detectors was successfully flown in June 2012 from the Taiki balloon base of the Japanese space agency JAXA.
I am primarily involved in the development of the trigger system. This requires characterising the response of the detector in flight through simulations (using GEANT4) to determine the raw rate (> 10 MHz) and then devising a scheme to reduce that rate to < 1 kHz whilst retaining as close to 100% of the rare antinucleon signal events as possible.
I have given numerous talks on my work to schools, astronomy groups and the general public, either in person or via Skype. Please contact me for more information.