Chemical Yields of Ionizing Radiations in Aqueous Solutions: Effect of Energy of Alpha Particles

Integral ferric ion yields, G₀(Fe³⁺), were obtained for the Fricke dosimeter as the energy of a collimated alpha particle beam entering the solution was varied from 4.5 to 0.2 Mev by means of mica absorbers. When the energy of the alpha particle is reduced from 4.5 to 2.5 Mev, G₀(Fe³⁺) decreases from 4.79 to 4.02. Thereafter, G₀(Fe³⁺) rises to 7.10 as the energy is decreased from 2.4 to 0.06 Mev. Calculated values of the local yield, G₁(Fe³⁺), show a similar dependence on energy of the alpha particle. G₁(Fe³⁺) is 6.61 at 4.5 Mev, decreases to a minimum value of 3.35 at 1.0 Mev, and then rises to 7.10 at 0.06 Mev. With G/sub 0/(Fe³⁺) known as a function of energy for alpha particles, G₀(Fe³⁺) may be calculated for recoil atoms from some nuclear disintegration reactions involving alpha particles. Range-energy curves are also reported for alpha particles in the energy range from 4.5 to 0.2 Mev. (auth)