Development of digital imaging device based on the gas electron multiplier

We fabricated a gas electron multiplier (GEM) for application to digital imaging devices such as X-ray or γγ-ray detectors. Sixty-four square (3×3mm) copper pads were used to collect avalanched electron charge clusters from the GEM chamber. A 128-channel charge sensitive preamplifier, which also includes sample/hold amplifiers and a multiplexer, was used as the front end electronics of the readout circuits for data acquisition. With this system, we successfully took a two-dimensional digital image under the irradiation of the 55Fe radiation source.