Nuclear Reactions Used for Isotope Production

An overview of the cross sections and their energy dependence will be given to enable suitable reactions to be selected for the production of the desired radionuclides. 

In Table 1/10 the cross sections are listed for (n,y) reactions with thermal neutrons. The cross sections are given in barn (1 b = 10 m2). The advantages of using thermal neutrons are the rather high flux of projectiles available In nuclear reactors and the rather 

Cross Sections for (n, y) Reactions Induced by Thermal Neutrons [3]. 

The uncertainties given in parentheses refer always to the right most digits. 

Neutron-excess isotopes of Ru, Rh, and Pd are mostly produced via fission of heavy nuclides. In Fig, 1-17 the formation cross sections, i.e., cumulative fission yields multiplied by fission cross section of are shown for the relevant isotopes of Ru, Rh, and Pd. The cumulative fission yields were obtained from the evaluation prepared by Crouch [7]. For the fission cross section the following values were used in the calculations 235u(nth,f)a = 582.6(11)b [8] and 235u(n 4. f) a = 2.085(23) b [9]. As can be seen in Fig. 1-17 the use of 14 MeV neutrons is less favorable. However, in special cases they might be advantageous because the relative yield of the heavier nuclides increases considerably and the necessary (chemical) separation will therefore be easier. 

---