Development of new type gaseous gamma camera with GEM

We are developing a new gaseous detector with Gas Electron Multiplier (GEM) as a gamma camera for biomolecular analysis and medical applications. Our system consists of the gamma conversion layers (gold) and the amplification layers. In order to know the performance of the prototype gamma camera, gamma-ray irradiation test was performed with radioactive source of ^99mTc (141 keV). 2D images were obtained using a pinhole collimator.