Measurements of the Distribution of Ionization Losses Along the Track of a $${}^{{210}}$$Pb Recoil Nucleus Using a Matrix End-Cap Proportional Counter

The paper presents the results of measuring the distribution of ionization losses along the track of a recoil nucleus ( $${}^{210}$$ Pb) with an initial energy of 146.5 keV from the decay of $${}^{214}$$ Po. The measurements were carried out using a multi-cell matrix ( $$3\times 3$$ ) end-cap proportional counter (MCPC). Each cell is an end-face proportional counter $$d=5$$ mm with a ring anode $$d=0.7$$ mm. The MTPC was filled with a mixture of $$96.3\%\textrm{Ar}+3.7\%\textrm{Xe}$$ at a pressure of 62 Torr. Recoil nuclei were emitted from the source surface in the central part of the drift electrode. The sour electric field of daughter products of $${}^{222}$$ Rn decay from an auxiliary xenon carrier gas. Calibration was carried out using the energy releases of $$\alpha$$ -particles from the same source at a distance between the drift electrode and the recording plane. It was determined that the amplitude of pulses from recoil nuclei at the peak of the spectrum corresponds to an energy of $$63.1\pm 2.9$$ keV.