Microwave cavity search for paraphotons

In this proceeding we report the first results of a microwave cavity search for hidden sector photons. Using a pair of isolated resonant cavities we look for 'light shining through a wall' from photon--hidden sector photon oscillations. Our prototype experiment consists of two cylindrical, copper cavities stacked axially inside a single vacuum chamber. At a hidden sector photon mass of 39.58 μeV we place an upper limit on the kinetic mixing parameter χ at 7.8x10-6. Whilst this result is inside already established limits our experiment has great scope for improvement.