Radiation dosimetry using three-dimensional optical random access memories

Three-dimensional optical random access memories (3D ORAMs) are a new gener ation of high-density data storage devices. Binary information is stored an d retrieved via a light induced reversible transformation of an ensemble of bistable photochromic molecules embedded in a polymer matrix. This paper d escribes the application of 3D ORAM materials to radiation dosimetry. It is shown both theoretically and experimentally, that ionizing radiation in th e form of heavy charged particles is capable of changing the information or iginally stored on the ORAM material. The magnitude and spatial distributio n of these changes are used as a measure of the absorbed dose. particle typ e and energy. The effects of exposure on 3D ORAM materials have been invest igated for a variety of particle types and energies, including protons. alp ha particles and C-12 ions. The exposed materials are observed to fluoresce when exposed to laser light. The intensity and the depth of the fluorescen ce is dependent on the type and energy of the particle to which the materia ls were exposed. It is shown that these effects can be modeled using Monte Carlo calculations. The model provides a better understanding of the proper ties of these materials. which should prove useful for developing systems f or charged particle and neutron dosimetry/detector applications. (C) 2001 P ublished by Elsevier Science B.V.