Browsing by Author "Cornelius, IM"

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Characterisation of a ΔE–E particle telescope using the ANSTO heavy ion microprobe
    (Elsevier, 2007-07) Siegele, R; Reinhard, MI; Prokopovich, DA; Ionescu, M; Cohen, DD; Rosenfeld, AB; Cornelius, IM; Wroe, A; Lerch, MLF; Fazzi, A; Pola, A; Agosteo, S
    Semiconductor planar processing technology has spurned the development of novel radiation detectors with applications in space, high energy physics, medical diagnostics, radiation protection and cancer therapy. The ANSTO heavy ion microprobe, which allows a wide range of ions to be focused into spot sizes of a few micrometers in diameter, has proven to be an essential tool for characterising these detectors using the Ion Beam Induced Charge (IBIC) imaging technique. The use of different ions and the wide range of available energies on the heavy ion microprobe, allows the testing of these devices with ionising particles associated with different values of linear energy transfer (LET). Quadruple coincidence measurements have been used to map the charge collection characteristics of a monolithic ΔE-E telescope, This was done through simultaneous measurement of the spatial coordinates of the microbeam relative to the sample and the response of both detector elements. The resulting charge collection maps were used to better understand the functionality of the device as well as to ascertain ways in which future device designs could be modified to improve performance. © 2007, Elsevier Ltd.
  • Thumbnail Image
    Item
    Cylindrical silicon-on-insulator microdosimeter: charge collection characteristics.
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2007-11-22) Ziebell, AL; Lim, WH; Reinhard, MI; Cornelius, IM; Prokopovich, DA; Siegele, R; Dzurak, AS; Rosenfeld, AB
    At present there exists a need, in both medical physics and radiation protection, for a portable microdosimeter that can be used in determining the radiobiological effectiveness (RBE) of different mixed radiation fields.
  • No Thumbnail Available
    Item
    Cylindrical silicon-on-insulator microdosimeter: design, fabrication and TCAD modeling
    (Institute of Electrical and Electronics Engineers (IEEE), 2009-04) Lim, WH; Ziebell, AL; Cornelius, IM; Reinhard, MI; Prokopovich, DA; Dzurak, AS; Rosenfeld, AB
    A novel silicon-on-insulator (SOI) microdosimeter has been designed and fabricated using planar processing techniques to realise a device with a micron-scale well-defined sensitive volume. Cylindrical structures were employed to allow for an improved definition of the average chord length of the sensitive volume over that of previous elongated parallelepiped solid-state detector designs. The structures were manufactured on individual silicon mesas situated on top of a buried oxide insulating layer. The mesa design eliminated lateral charge diffusion. Two kinds of test structures were designed with sensitive region widths of 2 mum and 10 mum. In addition, an array of 900 cylindrical diodes was fabricated to increase the charge collection statistics. TCAD (Technology Computer Aided Design) modeling of the electrostatic potential and electric field profile of the cylindrical microdosimeter was carried out to obtain 3D potential and electric field profiles. The modeling revealed a radial electric field within the cylindrical-shaped sensitive volume with a 1/r dependence. While the electric field at the core of the cylindrical microdosimeter was not sufficiently high to induce avalanche signal multiplication, the higher electric field at the core should still assist in the measurement of low linear-energy transfer (LET) events. © 2009, Institute of Electrical and Electronics Engineers (IEEE)
  • No Thumbnail Available
    Item
    Geant4 simulation of the CERN-EU high-energy reference field (CERF) facility
    (Oxford University Press (OUP), 2010-09) Prokopovich, DA; Reinhard, MI; Cornelius, IM; Rosenfeld, AB
    The CERN-EU high-energy reference field facility is used for testing and calibrating both active and passive radiation dosemeters for radiation protection applications in space and aviation. Through a combination of a primary particle beam, target and a suitable designed shielding configuration, the facility is able to reproduce the neutron component of the high altitude radiation field relevant to the jet aviation industry. Simulations of the facility using the GEANT4 (GEometry ANd Tracking) toolkit provide an improved understanding of the neutron particle fluence as well as the particle fluence of other radiation components present. The secondary particle fluence as a function of the primary particle fluence incident on the target and the associated dose equivalent rates were determined at the 20 designated irradiation positions available at the facility. Comparisons of the simulated results with previously published simulations obtained using the FLUKA Monte Carlo code, as well as with experimental results of the neutron fluence obtained with a Bonner sphere spectrometer, are made. © 2010, Oxford University Press (OUP)
  • No Thumbnail Available
    Item
    Ion beam induced charge collection time imaging of a silicon microdosimeter
    (Elsevier, 2003-03-04) Cornelius, IM; Orlić, I; Siegele, R; Rosenfeld, AB; Cohen, DD
    The ion beam induced charge (IBIC) collection time imaging of a silicon microdosimeter was discussed. The zero-crossing time parameter was found to increase as a function of the distance of ion strike from the pn junction. The measurements were used with a pulse shape discrimination technique to render the microdosimeter insensitive to ion strikes outside the ideal sensitive volume. © 2003 Elsevier B.V.