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

Figure 13 Absorption and emission spectra of 2,5-diphenyloxazole (PPO) are marked with green solid line and 
green dashed line. Spectra are taken from [69]. Absorption and emission spectra of 2-(4-styrylphenyl)benzoxazole 
(novel WLS) are marked with blue dotted line and pink dashed-dotted line, respectively. 
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PTP emission
novel WLS absorption
novel WLS emission
Figure 14 Absorption and emission spectra of p-terphenyl (PTP) are marked with green solid line and red dashed 
line, respectively. Spectra are taken from [69]. Absorption and emission spectra of 2-(4-styrylphenyl)benzoxazole 
(novel WLS) are marked with blue dotted line and pink dashed-dotted line, respectively. 
Emission spectra of J-PET and BC-420 scintillator were registered with
FluoroLog-3 (Horiba Jobin-Yvon) in reflecting mode using PMT R928P and continuous 
wave xenon source. The obtained emission spectrum of the J-PET scintillator is indicated 
as green solid line in Fig. 14. It is clearly visible that J-PET spectrum is broader than

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BC-420 (red dashed line). This means that photons are emitted by the J-PET scintillator in 
larger wavelength range than photons emitted by BC-420. 
In Fig. 15 quantum efficiency of vacuum and silicon photomultipliers are presented 
as well. Broadening of J-PET scintillator spectrum towards longer wavelengths enables 
more effective registration of its scintillation light by SiPMs. Emission spectrum of J-PET 
scintillator overlaps the region of larger SiPMs quantum efficiency in comparison to
BC-420. Quantum efficiency of SiPMs is larger than quantum efficiency of vacuum 
photomultipliers and it increases significantly with the increasing wavelength (up to about 
450 nm) as indicated by pink dashed-dotted line in Fig. 15. 
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Vacuum R4998 photomultiplier
Silicon S12572-100P photomultiplier