Heavy ion radiolysis of organic materials

Radiation chemical processes induced by the passage of heavy charged particles in organic materials are discussed. An overview of the physics of energy loss processes on the subsequent chemical reactions is given. The effects of the dominant physical parameter, the linear energy transfer, (LET), on the radical and molecular products from organic compounds are examined. It is shown how the complex interaction of excited states and radical intermediates can sometimes make it difficult to predict the variation of final product yields with high LET radiation. Molecular hydrogen yields are examined in detail because of their fundamental and practical aspects. Hydrogen formation is especially interesting because it is produced by a variety of reactions with different relative LET dependences. The yield of Hz is found to be very similar for liquid organic molecules and solid polymers containing the same molecule as the side group connected to the main carbon-carbon backbone. Biradical products and cross-linking yields are also found to be comparable suggesting very similar chemistry between the liquid and solid compounds. (C) 2001 Elsevier Science Ltd. All rights reserved.