Summary: Since the P.P.A. has a proton current of 1012, per second at 3 Bev., a careful study was made of its shielding requirements before construction began. The resulting design has been proven to possess excellent attenuation characteristics and flexibility of adaptation for varying demands by experiments. 

The personal dosimetry is based on Bonner spheres and T.T. ion chambers as well as the more conventional ones. A comparison and discussion of measurements made with the two types of detectors mentioned is made. Results of dose, particle flux and radioactivation measurements inside and outside the main shield, are presented.