ABSTRACT
Isotopes are divided into two groups — stable and unstable, i.e., radioactive. The neutron generators provide less neutron flux than fission reactors, so that the quantity of radionuclides obtainable with these accelerators is small and their main application is in the neutron therapy and activation analysis. While the natural sources of radionuclides are of general interest and of considerable importance in many fields; the vast majority of radionuclides used in laboratories are manmade. Most of the manmade radionuclides created by charged particles are produced by a cyclotron or other type of accelerator. There are many different possibilities of arrangements of the external targets on the cyclotron irradiation facility. The production of reactor radionuclides depends on the available neutron flux and the frequency and length of reactor operation time. Radionuclide production in a cyclotron requires the solution of a number of special problems. Gas targets are especially advantageous in the production of short-lived radionuclides used in applications in nuclear medicine.
