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Abstract We present here high angular resolution (+-1.5o) energetic particle images of the source and loss cone regions using the SEPS detector which is mounted on the despun platform of NASA's POLAR satellite. By mapping the loss and source cone fluxes in detail a better understanding is obtained of pitch angle diffusion mechanisms, wave particle interactions, and direct precipitation. The SEPS instrument consists of six pinhole cameras oriented such that an ion detector and two electron detectors point in one direction while the other three detectors point in the opposite direction. Thus, both the source and loss cones are observed simultaneously. Each camera has a pinhole aperture and a focal plane consisting of a matrix of 128 solid state sensors. The overall field of view is 48 by 24 degrees for electrons and 22 by 22 degrees for ions. Over much of the POLAR orbit the despun platform is pointed towards the earth, and during its passage through the radiation belts the SEPS field-of-view includes both the source and loss cones. Currently we are evaluating the performance of this new type of instrument and studying pitch angle distributions in and near the loss cones at various locations and under different geomagnetic conditions. |