Product yields in water radiolysis with heavy ions relevant to track structures

Radiolysis of neutral water with high-energy heavy ions has been investigated since FY 2002. It has been purposed to clarify track structure and its dynamics. Until the end of FY 2007, following 3 things has been accomplished. (A) primary yields, which are defined as yields approximately at 100 ns after radiation passage, of main products have widely been determined, (B) Temporal behavior of water decomposition radicals during ns-μs has been investigated, and (C) a sensitive method to determine Hydroxyl radical OH yield has also been developed and applied to heavy ion irradiations. In FY 2008, (A) and (C) are extended to higher linear energy transfer (LET) regions by using energy absorber at the upstream or by taking heavier ions, Kr and Xe. In addition, (C) was also applied in (D) challenge to scrutinize Hydroxyl radical OH yield near and at the Bragg peak. (author)