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Regarding the emission spectra of the considered scintillators, the best matching to
the quantum efficiency wavelength dependency of silicon photomultipliers is achieved for
BC-408 scintillator. According to Fig. 15, the highest quantum
efficiency is for around
450 nm. However, having in mind further application in the detectors relying on the signals
time
measurements, one has to carefully look also at the timing properties of the
scintilators, for which the BC-408 is the worst within the group being compared.
Cooperation
with worldwide companies, like Saint Gobain [12] or Eljen
Technology [13] indicates that even up to 40 % of purchased scintillator strips contained
optical inhomogeneities visible by the eye or when exposed to UV light.
Such defects
disturb isotropic propagation of light in scintillator material and significantly decrease the
light output. Therefore, less amount of scintillation light reaches
photoelectric converters
what makes the whole detector less efficient for the radiation and particles detection.
Scintillators containing defects need to be changed for the homogeneous ones,
however the procedure itself takes time. Moreover such method of scintillators preparation
entails a large material waste.
Therefore, the process should be optimized considering assortment of the reactor as
well as condition of polymerization to obtain a large fraction of good quality scintillators
minimizing material waste. That also decreases
costs of final product, ready for
application.
Summarizing, with the presented dissertation it
has been proven that in the
laboratory conditions it is possible to develop plastic scintillators characterized by the
parameters fulfilling the conditions for further application in J-PET/MR
tomography as
well as detectors for particle physics research.
