The electrochemical etching, because of its complexity, is of interest when it makes it possible to achieve detection characteristics which are not encountered with the chemical etching. These unique characteristics can be found for example for the personal dosimetry of low-energy neutrons around nuclear reactors and for the detection of both low- and high-energy cosmic-ray neutrons at civil aviation altitudes. In particular sufficiently large signal-to-noise ratios for cosmic ray neutron measurements can be achieved by using stack of polycarbonate- and/or CR-39-detectors, since the electrochemical etching processes make it possible: (a) the rapid scanning of large detector areas, and (b) the counting of coincidence events in paired detectors induced by a-few-microns long tracks. The detection of the radon decay products is hindered by the fact that their concentrations are altered in the vicinity of detector surface during the measurement. Polycarbonate detectors may be useful in solving these problems both because they register radon-decay products far away from the plated-out surface and they can be manufactured with any possible geometry and/or shape. However, it is possible to use several combinations of chemical and electrochemical etching steps which implies the possibility of new applications of track detectors for the registration of neutrons, cosmic rays and radon decay products.