Fig. 2

Light patterns recorded with different SiPMs sizes of 13 mm thick crystals (left) and 26 mm thick crystals (right). The light patterns recorded with the SiPMs on all surfaces of the detector except the front one are shown. The top light patterns are created with a photosensitive area size of the SiPMs of 3 mm, the middle ones with 4 mm, and the bottom ones with 6 mm. The light patterns are padded such that they all have the same square shape. The red dot is the scintillation position of the gamma-ray inside the crystal projected onto each surface