In order to improve the limits of quantification for trace elements, we applied the multiple gamma-ray detection method in
the prompt gamma-ray analysis (PGA). The Clover Ge detector system was constructed for multiple prompt gamma-ray analysis
(MPGA) at the neutron guide hall of the JRR-3M reactor of the Japan Atomic Energy Agency (JAEA). The MPGA system consists
of three Clover detectors and a BGO Compton suppressor. The instrumentation of the MPGA beam line and the detector system
were developed. The estimated limit of quantification of cadmium in the plastic sample is approximately 0.1 ppm. The capability
of the MPGA system could be improved by modification of the detector system, shield arrangement, software algorithm, etc.