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

9. Status of production of J-PET plastic scintillator strips 
Because results of tests performed with small scintillator samples are satisfactory, 
the next step was to manufacture plastic scintillator strips with much larger dimensions. 
For this purpose, special furnace (DCF420/spec) was designed to enable producing long 
strips. Scintillators described in the thesis so far, have been produced using furnace of 
CZYLOK [104] which enabled synthesis of only small size samples of length less than
5 cm because of geometry and size of the chamber.
Small scintillator samples produced previously, were polymerized in the glass 
ampoule placed vertically in the furnace, as the chamber is in the shape of pipe with 
diameter of few centimeters. Glass is a very good and cheap material for the forms to bulk 
polymerization of polystyrene and polyvinyltoluene because polymer does not adhere to 
the surface of form. Additional advantage of the glass form is perfect tightness when 
closed in the flame of the burner. Having finished polymerization process, the glass form 
(ampoule) can be broken and the material can be taken out easily. 

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However it is not possible to obtain longer scintillator in respectively longer glass 
ampoule placed in pipe furnace (left panel of Fig. 35). During polymerization in such form, 
probably the pressure is too high and empty voids (bubbles) are generated in the whole 
volume of the sample. What is more, scintillators manufactured in such ampoules are 
cylindrical. Cutting the strips which are desired in the novel tomography scanner is time-
consuming and labor-intensive process, connected with large material waste. 
Because of that, cuboidal form is better for the purpose. In the new furnace
(Fig. 36), it can be placed horizontally to minimize the pressure of the liquid and monomer 
pairs (right panel of Fig. 35).