Through-flow sensors with silicon semiconductor detectors for measuring alpha activity in solutions

Several types of functionally and operationally tested through-flow sensors are described. The measuring chamber, which may be dismountable or non-dismountable, contains a silicon semiconductor detector of the N type. The liquid sample flows in the measuring chamber through a labyrinth of glass bars. The measuring chamber is sealed with the detector which is cemented to it. The effective area of the detector is within the range of 1.5 to 3 cm2. The detection properties of the equipment may be restored by decontamination with a 0.1 to 1 M HNO3 solution and demineralized water or by regeneration of the surface by etching the surface layer of SiO2. The advantages and disadvantages of different types of measuring chambers are discussed. (M.D.)