Adrian McKemey. British particle physicist Adrian McKemey with one of the caesium iodide scintillat- ion crystals he has helped produce and maintain. These crystals give out pulses of light when they are hit by charged particles and radiation. Thousands of the crystals have been installed in the BaBar particle detector at the Stanford Linear Accelerator Center (SLAC), California, USA. McKemey is a visiting professor at Stanford Univ- ersity. BaBar will detect the B mesons and anti-B mesons that result from positron-electron collisions. If B mesons decay at a different rate from anti-B mesons, this may explain why there is more matter than antimatter. Photographed in 1999.