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


Table 12 Properties of several scintillators of Saint Gobain: BC-420, BC-404, BC-408 and the J-PET



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Table 12 Properties of several scintillators of Saint Gobain: BC-420, BC-404, BC-408 and the J-PET
scintillator [12]. 
Properties 
BC-420 
BC-404 
BC-408 
J-PET 
Light output 
[% of Anthracene] 
64 
68 
64 
64 
Rise time [ns] 
0.5 
0.7 
0.9 
0.5 
Decay time [ns] 
1.5 
1.8 
2.1 
1.9 
Maximum of emission 
wavelength [nm] 
391 
408 
425 
404 
H:C ratio 
1.102 
1.107 
1.104 
1.104 
350
400
450
500
550
600
0
20
40
60
80
100
Norm
alized
inte
nsity [
a.u
.]
Wavelength [nm]
BC-408
BC-404
BC-420
J-PET
Figure 40 Emission spectra of BC-408 (green dashed - dot line), BC-404 (red dashed line), BC-420 (black dotted 
line) and J-PET scintillator (violet solid line). 
 


77 
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. 


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