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Nicholas Bates


Postgraduate Research Student

My publications

Publications

Jafari S, Bates N, Jupp T, Abdul Sani S, Nisbet A, Bradley D (2016) Characterisation of commercial glass beads as TLDs in radiotherapy,Radiation Physics and Chemistry 137 pp. pp181-186 Elsevier
Jafari S, Bates N, Jupp T, Abdul Sani S, Nisbet A, Bradley D (2016) Commercial glass beads as TLDs in radiotherapy produced by different manufacturers,Radiation Physics and Chemistry 137 pp. pp181-186 www.elsevier.com
While commercial jewellery glass beads offer the basis of novel radiotherapy TL dosimetry (Jafari et al.
2014a,b,c, 2015a,b), detailed study of TL variation is required for the products from various manufacturers.
Investigation is made for glass beads from four manufacturers from four countries: China (Rocaille), Japan (Mill Hill), Indonesia (TOHO") and Czech Republic (Czech). Sample composition was determined using an energy-dispersive X-ray unit coupled to a scanning electron microscope. Values of mass attenuation coefficient, ¼/Á, as a function of photon energy were then calculated for photons of energy 1 keV to 10 MeV, using the National Institute of Standards and Technology XCOM program. Radiation and energy response were determined using X-rays generated at accelerating potentials from 80 kVp to 6 MV (TPR20/10¼0.670).
All bead types showed TL to be linear with dose (R240.999). Glow curve dosimetric peaks reached a
maximum value at 300 °C for the Toho and 290 °C for the Czech and Mill Hill products but was between
200?250 °C for the Rocaille product. Radiation sensitivity following mass normalisation varied within an
order of magnitude; Toho samples showed the greatest and Rocaille the least sensitivity. For the Toho,
Czech, Rocaille and Mill Hill samples the energy responses at 80 kVp were 5.0, 4.0, 3.6 and 3.3 times that
obtained at 6 MV. All four glass bead types offer potential use as TL dosimeters over doses commonly
applied in radiotherapy. Energy response variation was o1% at 6 MV but significant variation was found
for photon beam energies covering the kV range; careful characterisation is required if use at this range is
intended.