New CsI Crystal Calorimeter Nomenclature

J. Koglin

A new numbering system was developed for the CsI calorimeter during the process of implementing the correct geometry for the GEANT simulation in the fall of 1996.  Currently a lookup table is used in GEANT to convert this new numbering system into the system described in Katevi's thesis.  The new numbering system described below has been implemented for the 1998 run.  Additionally, information for both the trigger and delay cabling is given.

Crystal Numbering System

The calorimeter can be divided into 10 groups of 24 crystals each.  These ten groups and the crystal type form the basis of the naming system for the clusters and superclusters as well as the crystals themselves.  The last digit of the crystal number designates the group in which it is located.  The calorimeter can be divided into two hemispheres.  The upstream crystals end in digits 0 to 4 while the downstream crystals end in digits 5 to 9, such that opposite crystals differ by 5 digits (an exception to this rule is the half-D's and veto crystals which have opposite crystals differing by 15 digits). The crystal map shown below contains the serial numbers for the crystals.  In this map, the crystal types (P, A, B, C, D, H, and V) are also appended to the crystal number. (Postscript File)

(There is also a Postscript File available of a different version of the Crystal Map without serial numbers.)

Cable Grouping:  Both the trigger and delayed cables for the crystals are grouped in 15 bunches of 16 cables each. (Text File)


Cluster Definitions:  Each cluster can be comprised of up to nine crystals.  The highlighted numbers show the crystals that could be left out of the clusters with only a small effect on event recognition.
(Postscript File, Text File)


Super Cluster Definitions: (Postscript File, Text File)


Trigger SplittersBelow is the organization for the trigger splitters.  Six splitter units have two rows of twenty 3x-splitters.   The split signals go to the cluster units via 5ns limo cables according to the Cluster Definition table above.  Each cluster unit has inputs for four clusters.  The cluster units have two high threshold and two low threshold 10 pin ribbon cable outputs.  (Postscript File, Excel Spreadsheet) (Note:  half-D splitters revised on January 23, 1999)

Delayed SplittersBelow is the organization for the slitters for the delayed cables.  The signals going to ADC's and TDC's are ordered sequentially by crystal number.  The splitters, grouped in units of sixteen, have special ribbon cable outputs which go to the ADC's.  They also have limo outputs which go via 5ns limo cables to discriminators and subsequently to TDC's.  This numbering system has the effect of separating neighbor crystals whereby a normal single arm event cause hits in two or less crystals from a group of 16 (four or less hits in a group of 32).  This is very important for efficient readout of the Domino Sampling Chips. (Postscript File)

J. Koglin, April 28th, 1998 (Updated July 6, 1998)