The populations that appear to have been the most exposed to radioactive fallout as a result of nuclear weapons testing at the Semipalatinsk test site (STS) can be divided into two groups. The first group is located in the areas of the Republic of Kazakhstan in the vicinity of the STS and the second group is located in the Altai krai (i.e. Altai region) of the Russian Federation. The purpose of this paper is to estimate doses for the populations of the Republic of Kazakhstan that resided in the vicinity of the STS at the time when nuclear weapons tests were conducted in the atmosphere.The methodology that was used to estimate doses is based on the radiation measurements that were made after each test. It was developed by joint efforts of the sci-

Production of the intense accelerated Ca48 ion beam is the key problem in the experiments on synthesizing of new heavy nuclei. For this purpose an axial injection system with the electron cyclotron resonance (ECR)-4M ion source was created for the U400 cyclotron. The task was to achieve an accelerated beam with an intensity of 0.5 pμA of Ca5+48 at the Ca48 consumption of ∼0.5 mg/h. To solve this problem, a new method for the solid material feed into the ECR source was developed. The combination of a micro oven with a hot tantalum sheet inside the discharge chamber allowed the production of intense beams of ions of metals with relatively low melting point. The present article describes the method, technique, and experimental results on the production of Ca48 ion beam at the U-400 cyclotron from the ECR-4M ion source. The analysis of the working substance balance in the ion source including the ion beam extraction and material regeneration is performed. The analysis based on the experimental data has shown that the efficiency of Ca atom transformation into ion beam is close to that obtained for the gases such as Ar, and the intensity of Ca5+48 constitutes about 20% of the extracted ion beam.

The design of the electron cyclotron resonance (ECR) multicharged ion source DECRIS (Dubna ECR ion source, 14 GHz) was started at the Flerov Laboratory of Nuclear Reactions at the beginning of 1990 and in January 1992 the first plasma was ignited. A classical magnetic configuration based on the MINIMAFIOS with some "features" served as the basis for the source design. The DECRIS was installed on the ECR test bench. The tist study of the source was carried out in continuous mode of operation at strict controi of hexapole temperature. The ion source has been tested with He, N, 0, and Ar ions: The results of these initial measurements are presented.

A new compact version of the "liquid He-free" superconducting ECR ion source, to be used as an injector of highly charged heavy ions for the MC-400 cyclotron, is designed and built at the Flerov Laboratory of Nuclear Reactions in collaboration with the Laboratory of High Energy Physics of JINR. The axial magnetic field of the source is created by the superconducting magnet and the NdFeB hexapole is used for the radial plasma confinement. The microwave frequency of 14 GHz is used for ECR plasma heating. During the first tests, the source shows a good enough performance for the production of medium charge state ions. In this paper, we will present the design parameters and the preliminary results with gaseous ions.