Development of PGNAA facility in HANARO

A prompt gamma neutron activation analysis (PGNAA) system is being set up in HANARO, a multipurpose research reactor in the Korea Atomic Energy Research Institute. The beam is polychromatic thermal neutrons diffracted vertically by a set of pyrolytic graphite crystals at the Bragg angle of 45deg from a horizontal beam line. Prior to assembling, measurements of the neutron spectrum and gold wire activation confirmed that a sufficient neutron flux can be obtained. A tapered collimator is positioned between graphite crystals and the Teflon sample holder, being composed of alternating layers of borated plastic, lead and polyethylene. The detection system consists of a 43% n-type HPGe detector, signal electronics and a fast ACD. At present, graphite crystals and collimator with the surrounding shield on the beam line are set up and measurements of beam characteristics are progressing. Thermal neutron flux of 6.1 x 107 n/cm2s and the Cd-ratio of 364 are achieved at sample position while the reactor is operating at 24MW in November 2000. The first application of the system will be analyzing 10B in biological samples. (author)