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Assumptions:

1. Numbers start from 0 not 1.
2. Addresses go in the direction of
   • increasing z (south to north along the beamline)
   • increasing azimuthal angle (phi) starting from phi=0 (=west)
   • increasing radial distance from beam (R)

Barrel Addresses:

• Z direction: panel 0 through 11 as z increases from south to north within a panel, strips 0 through 255 moving south to north
  
• phi direction: row 0 through 5, with row 0 being the row at phi = 0
  
• R direction: inner shell is 0, outer shell is 1
  
• a single strip number is identified by a shell (0=inner, 1=outer in R)
  • row (0-5 in phi)
  • panel (0-11 in z)
  • strip (0-255 in z)

Pad Addresses:

• Z direction: the south end is 0, the north end is 1
• phi direction: There are twelve wedges in each end, wedge addresses 0-11 start at phi=0 and increase as phi increases

  Within each wedge, there are 12 columns, numbered 0-11 in the direction of increasing phi.

• R direction: There are 21 rows in a wedge, assigned addresses 0 - 20 as R increases
• a single pad is identified by its end (0=south, 1=north in z)
  • wedge (0-11 in phi)
  • column (0-11 in phi)
  • row (0-20 in R)

Proposed Format for Addresses in the Barrel:

bit: 16 15 14 13	12 11 10 9	8 7 6 5 4 3 2 1
use:shell <- row ->	<-- panel --->	<- strip number within a panel ->
0/1 0 to 5	address	from 0 to 255
	from 0 to 11

Proposed format for addresses in the pads:

• bits 1- 8 : row and column encoded as NCOLUMN*21 + NROW where NROW is the row number (0-20 in R) and NCOLUMN is the column number (0-11 in phi) In the ideal world, this numbering system would be used in the readout of the individual wedges.
• bits 9-12 : wedge number (0-11 in phi)
• bit 13 : end number (0-1 in z)
• bits 14-15 : flag (both bits on = 11) which allows the pad addresses to be distinguished from the strips because if bits 13-15 are interpreted as a panel number for the strips, it corresponds to 6 or 7, which does not exist in the barrel.
• bit 16 : not needed

Figure 1. Proposed MVD Nomenclature

Figure 2. MVD Wedge Nomenclature