title: Novel developments in the MOSFET dosemeter for neutron dosimetry applications.
abstract: The feasibility of large-geometry Metal Oxide Semiconductor Field Effect Transistor (MOSFET) devices has been assessed for both active and passive neutron dosimetry and use in radiotherapy environments. Neutron sensitivity has been enhanced with the use of polymeric cement surrounding the gate region. Neutron activation via nuclear interaction processes is a potential problem with conventionally packaged and fabricated devices. To overcome this problem, a unique low-activation device design is described. Standard Dual in-Line devices, modified with polymeric cement and boron loaded cement have been exposed to gamma rays (60Co) and neutrons (gamma-ray shielded 252Cf) to provide neutron sensitivity estimates. The results show that the neutron sensitivity can be increased by a factor of approximately three by the use of a thin layer of polymeric cement over the gate region. Essentially zero activation is observed in the activation-reduced design compared with 1000 cps in the conventional design MOSFET when both are exposed under identical conditions to a neutron field from a gamma-ray shielded 252Cf isotopic source.
authors.affiliation: Computational and Applied Dosimetry Research Group, Physics Department, Clatterbridge Centre for Oncology, Bebington, Wirral, Merseyside CH63 4JY, UK. rprice1495@aol.com
authors.forename: Robert A
authors.initials: RA
authors.lastname: Price
authors.forename: Chris
authors.initials: C
authors.lastname: Benson
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Joyce
authors.forename: David J
authors.initials: DJ
authors.lastname: Kestell
authors.forename: Jon
authors.initials: J
authors.lastname: Silvie
mesh_terms: D004781:Environmental Exposure / Q000032:analysis; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods; D005240:Feasibility Studies; D018499:Linear Energy Transfer; D009502:Neutrons; D016273:Occupational Exposure / Q000032:analysis*; D010865:Pilot Projects; D011829:Radiation Dosage; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods; D011868:Radioisotopes / Q000032:analysis; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D014159:Transducers; D014173:Transistors, Electronic
chemical_list: D011868:Radioisotopes