FIELD: quantitative analysis of alpha-particle radiators in solid waste. SUBSTANCE: given invention presents counting chamber intended for detection of neutrons and having some external wall and internal space meant to position tested object. Mentioned wall is formed by first internal coat made of cadmium, internal layer of neutron moderator, intermediate coat made form cadmium, external layer of neutron moderator and external cadmium layer. Above-mentioned wall has window for passage of beam of exciting radiation. Neutron detectors with helium-3 are located in external and internal layers of neutron moderator. EFFECT: isolation of tested material subjected to irradiation from external spurious neutron medium, separation of neutron signals of different energies, diminished life time of parasitic neutrons to prevent their interference with moderated legitimate signal. 4 cl, 4 dwg
