Direct observation of HO2/O-2(-) free radicals generated in water by a high-linear energy transfer pulsed heavy-ion beam

摘要

The formation and decay of HO2/O-2(-) radical from the radiolysis of water by heavy S-36(16+) ions (2.7 GeV) have been observed by time-resolved absorption spectroscopy at 260 nm. The experiment was performed at the Grand Accelerateur National d'Ions Lourds (Caen, France). In deaerated water, for a linear energy transfer (LET) of 250 eVm, the yield of HO2/O-2(-) is (6 +/- 2) x 10(-9) mol J(-1). In aerated solution, an additional formation of O-2(-) is observed due to the reaction of hydrogen atom and e(aq)(-) with oxygen. The experimental G values are compared to those obtained with light ions for the same LET. The importance of the initial velocity is discussed briefly. (C) 1998 by Radiation Research society. [References: 26]