A triplet polarimeter for use in the Jefferson Lab GlueX experiment

The GlueX experiment in Hall D at Jefferson Lab will utilize a polarized photon beam to help identify exotic meson states. Knowledge of the degree of polarization of the photon beam is critical for identifying those states. The use of the triplet production process (pair creation off atomic electrons) could allow for determination of polarization with high precision. A newly-constructed polarimeter will be described, preliminary results of the detector's response to alpha and electron sources will be presented, and estimates of potential performance with the Jefferson Lab Hall D photon beam will be discussed.