Observation of radiation effects on three-dimensional optical random-access-memory materials for use in radiation dosimetry

The first experimental investigation has been performed of radiation effect s on three-dimensional optical random-access-memory materials. Thin films o f poly(methyl methacrylate) doped with spirobenzopyran were irradiated with uniform fluxes of protons, alpha-particles and C-12(+3) ions, at fixed ene rgies per nucleon from 0.5 to 2.5 MeV and fluences from 10(10) to 10(14) cm (-2). The exposed films were examined under a confocal laser scanning micro scopy system which is capable of optically sectioning the materials. The ir radiation resulted in a permanent change in the materials from a nonfluores cent form to a form which is fluorescent under both 488 and 514 nm excitati on. Profiles were measured of fluorescent intensity versus depth, and of in tensity versus dose. It was found that both the particle energy and the dos e can be obtained from measuring the width of the depth profile and the flu orescent intensity. These properties are very promising for dosimetry appli cations since they allow calculation of an accurate dose equivalent. (C) 19 99 Elsevier Science Ltd. All rights reserved.