Development of novel plastic scintillators based on polyvinyltoluene for the hybrid j-pet/mr tomograph

Figure 9 Temperature schedule of the plastic scintillators polymerization [68]. 
Scintillators are prepared by dissolving scintillating additives in liquid monomer: 
styrene or vinyltoluene. As the primary fluor 2,5-diphenyloxazole (PPO) or p-terphenyl 
(PTP) were used in an amount of 2 wt. %. As a wavelength shifter
2-(4-styrylphenyl)benzoxazole was applied. The concentration of the novel wavelength 
shifter was optimized as it is described in Chapter 10: Light output of J-PET scintillators. 
The reaction mixture was poured into glassy ampoules, inert gas purged and then 
tightly sealed in the flame of the burner. Such prepared samples had been placed in the 
tube furnace and then polymerization was started according to the schedule shown in
Fig. 9. To minimize the risk of explosion, the mixture occupies the half of the ampoule 
volume at maximum. Photographs of obtained scintillators are shown in Fig. 10. 

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Figure 10 J-PET plastic scintillators in UV light. Left and centre: scintillators removed from the glass ampoule. 
Right from the top: scintillator cut and polished, exposed to UV in daylight, in the dark and scintillator wrapped 
in light tight foil in the dark. 
7. Optical, spectral and timing properties of J-PET scintillator 
7.1. Optical properties of J-PET scintillator 
In order to characterize properties of the scintillator containing the novel 
wavelength shifter, and check if it is matched to spectral properties of silicon 
photomultipliers, absorption and emission spectra of the wavelength shifter:
2-(4-styrylphenyl)benzoxazole and emission spectra of the scintillator were registered. 
Absorption and emission spectra of 4.2*10
-8 
M 2-(4-styrylphenyl)benzoxazole 
solution in toluene were registered. They are shown in Fig. 11. Maximum of absorption 
lies at 349 nm, while the emission spectrum is characterized by the maximum in 402 nm. 

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novel WLS absorption
novel WLS emission