Cover the end of a light guide with a white paper rectangular sheet (130 mm x 12 mm) and fix it with small pieces of transparent adhesive strip.
Cover the PMT with a white paper rectangular sheet (150 mm x 83 mm) and close with transparent adhesive strip.
Cover the PMT with black insulating adhesive strip (20 mm) starting from the blue plastic connector up to the photocathode.
Insert the optical coupling disc (organic Scintillator) between the PMT and the light guide.
While pushing the PMT towards the light guide, wrap the black insulating adhesive strip (20 mm) two or three times around the junction, in order to join the two parts.
While pushing the PMT towards the light guide, wrap with the black insulating adhesive strip (10 mm) the zones of discontinuity.
Insert the cylindrical muff around the PMT pressing it to touch the light guide.
Place the two aluminum stirrups and screw, without fastening, all the M4 and M3 screws.
Fasten the 4 M4 screws of the stirrups, checking that they are well placed.
Fasten the 4 M3 screws to pull the PMT in position.
Wrap with adhesive black strip (10 mm) the coupling region between the PMT connector and the PVC muff, with 2 or 3 turns.
Place the labels on the light guide and on the Scintillator.
