Henry S. Judeikis

Isotope Effects and the Mechanism of Atom Production in Gamma‐Irradiated Ice at 4.2°K

The relative intensities of the electron spin resonance (ESR) spectra of H and D atoms were determined for mixtures of H2O and D2O which were irradiated and observed at 4.2°K. A careful analysis of the results indicates that the yield of atoms per unit irradiation dosage exhibits no isotope effect, except for the system containing trace amounts of H2O in D2O. The presence of a large isotope effect for a system of D2O containing approximately 0.1% H2O is discussed in terms of energy transfer in the solid state.

Free Radical Yields in Polytetrafluoroethylene as the Basis for a Radiation Dosimeter

Abstract : Exposure of polytetrafluoroethylene (PTFE) to ionizing radiation results in chemical degradation of the polymer and formation of long-lived free radicals. The paper describes the use of quantitative measurements of the electron spin resonance (ESR) spectra of the free radical produced in irradiated PTFE to determine radical yields and attempts to correlate these radical yields with the absorbed radiation dose. The experimental results indicate sufficient correlation over the experimental range rad to permit use of PTFE as a passive radiation dosimeter. The advantages inherent in the use of the PTFE dosimeter for the measurement of low energy electromagnetic or particulate radiation are also discussed. Energy deposition as a function of depth from the incident surface can be determined by sectioning of the polymer after irradiation. The resulting dose - depth curves can then be used to obtain spectral and profile data from polychromatic sources. (Author)