Shown is the bottom mount plate (580×230mm) and the assembly that holds the single-chip modules. The window in the leftmost grey unit shows the approximate chip active area (13×31mm).

1. This is the single-chip PC board, 70×70mm plus connector space. It slides into a slot.
2. This tray holds the source. The source is a 2" cylinder. The tray slides out, and can be positioned at different heights.
3. These are the boxes that hold the PMTs. On the left you can see the profile drawn on the back board of the top of the tube, and the light guide.
   Dismount the box, thread the cables through both holes, and slide the PMT into place. The bottom of the tube fits into a cutout at the bottom. The fit is supposed to be snug. If it is too tight, rub the edge of the hole with the stick (6) - this will open it up a little.
   (The boxes are not quite identical left and right).
4. After the tube/lightguide/scintillator is fit into the holder box, slide it over the alignment block 4, and down until it clicks. Secure it with the two rubber bands.
5. This block ensures that the scintillator squares are aligned with centerline of the source, MAPS chip and PMTs, which runs 35mm from the back board.