An examination is made of the possibilities of a symmetrical system of two scintillation detectors with thin polymeric plastic scintillators of various diameters for low-background measurements.
A high sensitivity is sought in serial determinations of β-activities through the utilization of a screening detector with a thin plastic scintillator connected in an anticoincidence circuit with the measuring detector.
Light reflectors and a β-particles backscatterr are applied. A minimum of radiation shielding is utilized. The method is intended for practical measurements of low-level activities in a non-specialized laboratory.