Angular distribution of coherent bremsstrahlung

The angular distribution of the linearly polarised photon beam produced by coherent bremsstrahlung from an aligned diamond radiator has been measured at the MAMI A2 tagged photon facility. The measurements were made with a prototype position sensitive photon detector which utilises the pair production process and a double sided silicon strip detector. This polarised photon beam is used for nuclear and hadronic experiments and in their analysis the polarisation is obtained from a calculation, which matches the experimental intensity spectrum. As the polarisation is related to the photon beam angular distribution, the present measurements can be used to test this calculation. The overall agreement is found to be good although there are some regions where significant discrepancies exist.