New track interval radon exposure meters (operating principle and design).

The operating principle of innovative interval radon exposure meters INERAD (types IE-2 and IE-4) is described. The major technical features of the both models have been standardized as much as possible. The exposure meters use the LR-115 type 2 track threshold detector, which is sensitive to alpha particles.

The results of long-term simultaneous measurements of radon exhalation rate, radon concentrations in soil gas and groundwater in the fault zone.

The regular monthly radon measurements were carried out in the fault zone on the Western slope of the Beshtau magmatic massif (North Caucasus). The radon exhalation rate from the soil surface, as well as radon concentrations in soil gas at a depth of 0.5 m and in groundwater discharged at a spring located nearby have simultaneously been measured. High seasonal fluctuations in radon exhalation and radon concentration in soil gas, characterized by highs in summer and lows in winter, were registered. In summer, the radon exhalation reached 23.8 Bq m-2s-1, and the radon concentration in the soil gas reached 166 kBq m-3. In winter, both the radon exhalation and the radon concentration in the soil dropped to 0.025 Bq m-2s-1 and <3 kBq m-3, respectively. The concentration of radon in ground water varied over the year in a relatively narrow range (100-210 Bq l-1), and there were no seasonal fluctuations. A sharp increase in soil radon and radon exhalation in spring and a fall in autumn are timed to the moments when the temperature of the atmospheric air becomes, respectively, higher and lower than the temperature of the rock massif. Both the soil radon concentration and the radon exhalation show a close correlation with the temperature of atmospheric air, but in the first case the relationship is linear, and in the second - exponential. The obtained data confirm the assumption that the seasonal radon variations are caused by atmospheric air circulation in the shallow area of the fault due to the temperature difference between the atmosphere and the rock massif.

Dependence of the multiplicities of secondary particles on the impact parameter in collisions of high-energy neon and iron nuclei with photoemulsion nuclei.

A method is proposed for finding the dependence of mean multiplicities of secondaries on the nucleus-collision impact parameter from the data on the total interaction ensemble. The impact parameter has been shown to completely define the mean characteristics of an individual interaction event. A difference has been found between experimental results and the data calculated in terms of the cascade-evaporation model at impact-parameter values below 3 fm.

Target fragments in collisions of 1.8 GeV/nucleon 56Fe nuclei with photoemulsion nuclei, and the cascade-evaporation model.

Nuclear photographic emulsion is used to study the dependence of the characteristics of target-nucleus fragments on the masses and impact parameters of interacting nuclei. The data obtained are compared in all details with the calculation results made in terms of the Dubna version of the cascade-evaporation model (DCM).

Multiplicities of secondaries in interactions of 1.8 GeV/nucleon 56Fe nuclei with photoemulsion and the cascade evaporation model.

A nuclear photographic emulsion method was used to study the charge-state, ionization, and angular characteristics of secondaries produced in inelastic interactions of 56Fe nuclei at 1.8 GeV/nucleon with H, CNO, and AgBr nuclei. The data obtained are compared with the results of calculations made in terms of the Dubna version of the cascade evaporation model (DCM). The DCM has been shown to satisfactorily describe most of the interaction characteristics for two nuclei in the studied reactions. At the same time, quantitative differences are observed in some cases.

Multiplicities of secondaries in nuclear interactions, induced by 20Ne, 40Ar and 56Fe nuclei at 0.1-0.5 GeV/nucleon.

Multiplicities of various species of charged secondaries produced in inelastic interactions of 20Ne, 40Ar and 56Fe nuclei with emulsion nuclei at 0.1-0.5 GeV/nucleon have been measured. The data obtained are compared with the results for interactions of higher energy nuclei with emulsion nuclei. The dependences of the nucleus-nucleus interaction parameters on masses and energies of colliding nuclei are examined.