Heavy ion radiolysis

In addition to the fundamental scientific aspects, many studies on the chemical effects of heavy ion radiolysis have significant practical applications. These applications range from the nuclear power industry [26,27], space radiation effects [28], medical therapy [29],... 

The dotted lines in Fig. 1 show the stopping powers for the different ions at a constant velocity in units of MeV/amu. This unit of energy is very often used in heavy ion radiolysis and it is based on the classical formula for kinetic energy, E = V2 MV, where M is the heavy ion mass. As seen in Eq. (1), the ion velocity is a dominant parameter in energy loss processes and the MeV/amu energy unit is more convenient to use than converting to absolute velocity units. Remember that MeV/amu is actually proportional to the square of the velocity. 

LaVerne JA, Araos MS. (2002) Heavy ion radiolysis of liquid benzene. J Phys Chem A 06 4 6y. 11408-11413. 

LaVerne JA, Chang Z, Araos MS. (2001) Heavy ion radiolysis of organic materials. Rad Phys Chem 60(4-5) 253-257. 

LaVerne JA, Stefanic 1, Pimblottt SM. (2005) Hydrated electron yields in the heavy ion radiolysis of water. J Phys Chem A109(42) 9393-9401. 

LaVerne JA, Tandon L, Knippel BC, Montoya VN. (2005) Heavy ion radiolysis of methylene blue. Rad Phys Chem 72(2-3) 143-147. 

The H2 yield from polystyrene irradiated with y-rays is two orders of magnitude less than that in polyethylene. The H2 yields increase with increasing LET for all the polymers shown in Fig. 2, but the increase is not linear. There is a considerably greater increase for polystyrene than polyethylene. A 5 MeV helium ion, a-particle, gives a G-value for H2 of 4.6 molecules/100 eV from polyethylene and 0.15 molecule/100 eV from polystyrene [11], The large increase in H2 yield for polystyrene suggests that this material is not as radiation inert as typically thought. The use of yields determined with y-rays for heavy ion radiolysis would clearly underestimate the production of H2 in transuranic waste materials. More experiments coupled with sophisticated models are required to predict H2 yields in other unexamined polymers and in complex mixtures. 

Chang, Z. and LaVeme, J.A., Hydrogen production in the heavy ion radiolysis of polymers. 1. Polyethylene, propylene, poly(methyhnethacrylate) and polystyrene, /. Phys. Chem. B, 104,10557,2000. 

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