Near Detector Readout Page

A pictoral view of the Near Electronics Readout showing which planes read out to which crates, in which racks - the readout chain is followed from phototubes to Master racks. Recently updated (Aug 2002), 8 page 538Kb PDF, easily web viewable, down-loadable, and printable.
A picture schematic of the Offline Software Plane Strip numbering conventions

Phototube Alner Boxes

One M64 phototube sits in each Alner Box. There are 5 types of Alner Box, each with different threading patterns of the mapping from fiber cables to pixels, and receiving 3 or 4 fiber cables from various combinations of modules. Alner Box Threading Patterns summarizes the 5 types (PDF doc). The pixel-to-box fiber mapping in this document is correct, however the plane strip number assignment does not match the convention used in the Offline software (see above, 3rd bullet in the readout chain summary).

The pixel numbering is ALWAYS that used by Hamamatsu. However, depending on which direction you look at the phototube face from (outside, or from it's "inside"), and depending on the orientation of the tube, the Pixel Numbers can appear "different". These Pixel Numbering Diagrams (1 page PDF) attempt to explain the various orientations used - one of which is the orientation used in the Threading Patterns document above.

The output side of an Alner Box has 4 D37 connectors, stacked horizontally, with number 1 at the top and number 4 at the bottom. Each type of Alner Box has the SAME mapping of pixel number to pin numbers on these 4 connectors. The Generic Pixel 2 Connector (1 page, PDF) diagram attempts to illustrate this mapping.

More explicit mappings are given on the following diagrams, each 2 pages PDF. Each diagram set contains mappings between the ANL module strip number, the Plane Strip number, the fiber cable "pinouts" on both the module and Alner Box ends of the cable, the Alner Box Fiber Number, the tube Pixel Number, and the Alner Box output D37 connectors.

There are specialized cables to carry the analog signal from the Box to the FE electronics (Minder boards); an inspection of the above list of mappings shows why. This Summary of Minder Cable Types lists in table form the pin assignments on each end of the cable. There are 3 basic cable types, with a single 4th cable which is a special case of the 3rd cable type. The Summary also gives the total number of each cable type required for the detector.

Near Detector Readout & Maps

Page update in progress

Summary of the Readout Chain

Phototube Alner Boxes

Mappings