title: Ferrous-Ferric Ion exchange dosemeter.
abstract: In this work a three-dimensional ferrous-ferric ion exchange dosemeter is proposed and the dose response measured. The dosemeter consists of strong acid cation exchange resin beads in the H form in water. Amberlyst 15 Wet beads with a harmonic mean diameter of 0.600-0.850 mm were prepared by soaking them in an aqueous solution of ferrous ammonium sulphate to exchange ferrous ions for H(+) ions. The beads were rinsed with distilled water and packed in glass vials. Sets of samples with ferrous ion concentrations of 0.5 and 1.0 mM were dosed with 6 MV X rays from a Varian 2100C linac. The spin-lattice relaxation time constants (T1) for the samples were measured using an Apollo spectrometer (Tecmag, Houston, TX) interfaced to a 1.5 T magnet (Magnex, Abingdon, UK). Each sample had two T1 values; a long T1 at 1200 ms that did not significantly change with dose and a short T1 that ranged from 56 ms at 0 Gy to 36 ms at 100 Gy. The R1 vs. dose responses were linear with slopes of 0.066 and 0.079 s(-1) Gy(-1).
authors.affiliation: Department of Biophysical Sciences and Medical Physics, University of Minnesota, 420 Delaware Street, MMC 292, Minneapolis, MN 55455, USA. bauh0002@umn.edu
authors.forename: John A
authors.initials: JA
authors.lastname: Bauhs
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Hammer
mesh_terms: D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007474:Ion Exchange; D007477:Ions / Q000737:chemistry / Q000528:radiation effects; D007501:Iron / Q000737:chemistry* / Q000528:radiation effects*; D008422:Materials Testing; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation* / Q000379:methods
chemical_list: D007477:Ions; D007501:Iron