Browsing by Author "Bradley D."

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A practical method for in-situ thickness determination using energy distribution of beta particles
(2012-01-01) Yalcin S.; Gurler O.; Gundogdu O.; Bradley D.
This paper discusses a method to determine the thickness of an absorber using the energy distribution of beta particles. An empirical relationship was obtained between the absorber thickness and the energy distribution of beta particles transmitted through. The thickness of a polyethylene radioactive source cover was determined by exploiting this relationship, which has largely been left unexploited allowing us to determine the in-situ cover thickness of beta sources in a fast, cheap and non-destructive way. © 2011 Elsevier Ltd.
Monte Carlo modelling of single and multiple Compton scattering profiles in a concrete material
(2013-04-01) Akar Tarim U.; Ozmutlu E.; Gurler O.; Yalcin S.; Gundogdu O.; Sharaf J.; Bradley D.
A Monte Carlo simulation study has been conducted of 60Co photons Compton scattered in concrete, illustrating the degraded energy spectra of gamma-ray radiation. Results are produced representing a NaI(Tl) detector model. We were able to analyse energy distributions of photons that reach the detector system after suffering several successive Compton scatterings in the target. The predicted decrease in intensity of single- and multiple-scattering peaks with increase in thickness of the target medium are in good agreement with experimental observations and findings reported by others. © 2012 Elsevier Ltd.
The energy spectrum of 662keV photons in a water equivalent phantom
(2012-01-01) Akar Tarim U.; Gurler O.; Ozmutlu E.; Yalcin S.; Gundogdu O.; Sharaf J.; Bradley D.
Investigation is made on the energy spectrum of photons originating from interactions of 662. keV primary gamma-ray photons emitted by a point source positioned at the centre of a water equivalent solid phantom of dimensions 19. cm×19. cm×24. cm. Peaks resulting from total energy loss (photopeak) and multiple and back scattering have been observed using a 51. mm×51. mm NaI(Tl) detector; good agreement being found between the measured and simulated response functions. The energy spectrum of the gamma photons obtained through the Monte Carlo simulation reveals local maxima at about 100. keV and 210. keV, being also observed in the experimental response function. Such spectra can be used as a method of testing the water equivalence of solid phantom media before their use for dosimetry measurements. © 2012 Elsevier Ltd.