500 Photon Detectors (IMAGE) Iowa State University Caption Iowa State University astrophysicists designed and built four of these cameras for the VERITAS gamma ray telescope system. Each camera contains 500 tube-shaped photo detectors. Credit Photo contributed by Frank Krennrich/Iowa State University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.