Nonproportionality of inorganic scintillators

Nonproportionality of inorganic scintillators

Khodyuk, I.V.

Dorenbos, P. (promotor)

Applied Sciences

Radiation, Radionuclides & Reactors

2013-01-15

A scintillator is a transparent material that emits a flash of light when it absorbs a ?-ray photon or an energetic particle. Scintillation crystals are widely used as spectroscopic detectors of ionizing radiation in nuclear science, space exploration, medical imaging, homeland security, etc. This thesis is about nonproportional response of inorganic scintillators to ionising radiation of different energies. Nonproportionality is the nonlinear dependence of the total light output of the scintillator on the detected amount of ionization energy, i.e., the emitted number of photons/MeV at 10 keV is not necessarily the same as at 100 keV or at 1000 keV. This dependence is due to a scintillation efficiency that depends on the density of the ionization track. The production of secondary electrons during slowing down of the primary electron inside the scintillator is a probabilistic process and may occur in different ways for the same absorbed energy. The dependence of the absolute light yield on the energy of secondary electrons and the probabilistic mechanism of their creation result in variability of the total number of photons produced inside the scintillator. This process leads to broadening of the photoabsorption peak in the pulse height spectrum measured by a scintillation detector.

scintillator
energy resolution
ionizing radiation
X-ray
nonproportionality
spectroscopy

https://doi.org/10.4233/uuid:cb4008a8-981a-4283-b213-199d41756269

Uitgeverij BOXPress

2012-12-12

9789088915536

Institutional Repository

doctoral thesis

(c) 2013 Khodyuk, I.V.