title: Experimental determination of the diffusion coefficient in two-dimensions in ferrous sulphate gels using the finite element method.
abstract: A novel two-dimensional finite element method for modelling the diffusion which occurs in Fricke or ferrous sulphate type radiation dosimetry gels is presented. In most of the previous work, the diffusion coefficient has been estimated using simple one-dimensional models. This work presents a two-dimensional model which enables the diffusion coefficient to be determined in a much wider range of experimental situations. The model includes the provision for the determination of a drift parameter. To demonstrate the technique comparative diffusion measurements between ferrous sulphate radiation dosimetry gels, with and without xylenol orange chelating agent and carbohydrate additives have been undertaken. Diffusion coefficients of 9.7 +/- 0.4, 13.3 +/- 0.6 and 9.5 +/- 0.8 10(-3) cm2h-1 were determined for ferrous sulphate radiation dosimetry gels with and without xylenol orange and with xylenol orange and sucrose additives respectively.
authors.affiliation: Centre for Medical and Health Physics, School of Physical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane Q 4001. c.baldock@qut.edu.au
authors.forename: C
authors.initials: C
authors.lastname: Baldock
authors.forename: P J
authors.initials: PJ
authors.lastname: Harris
authors.forename: A R
authors.initials: AR
authors.lastname: Piercy
authors.forename: B
authors.initials: B
authors.lastname: Healy
mesh_terms: D002614:Chelating Agents; D004058:Diffusion; D005296:Ferrous Compounds; D020342:Finite Element Analysis; D005782:Gels; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D011874:Radiometry / Q000379:methods*; D012996:Solutions; D013395:Sucrose
chemical_list: D002614:Chelating Agents; D005296:Ferrous Compounds; C075364:Fricke solution; D005782:Gels; D012996:Solutions; D013395:Sucrose