A new technique of radioluminography for H-3 is shown, where by a spac
er is inserted between the imaging plate and the radioactive sample in
order to avoid radioactive contamination of the plate for repeated us
e. Also, elevation of the detection efficiency has been realized by im
provement in the evacuation to minimize the absorption of H-3 beta-ray
s. The technique has been studied systematically for space distance (1
spacer thickness) and for air pressure. By evacuation, the detection
sensitivity can be elevated to more than 15 times. This technique is h
ighly suitable for microplate and filter samples. (C) 1997 Elsevier Sc
ience Ltd.