2. History x-y mechanics Needs mapping to r- trigger towers Optimised Any-5 Swiss cross Current

3. Endcap Map In ORCA ee_map_133.dat Text file format –Supercrystal number –crystal number –phi tower –Eta tower http://www.phy.bris.ac.uk/research/ppp ages/numbering/numbering.htm Top right hand quadrant of positive z endcap as seen from the back i.e. looking towards the interaction point.

4. Sides meet here at a right angle 510152025 49141924 38131823 27121722 16111621 Numbering within supercrystal 56 46 18 1

5. Generating other quadrants Supercrystal rotation is rotated in each quadrant Trigger pattern is rotated ORCA implementation is not quite correct.

7. Generating second Dee With respect to the trigger tower definition the two dees would look identical if place side by side. i.e. one dee is obtained from the other by rotating about the y=0 axis. Code to plot both endcaps from ORCA in the standard colours has been developed but is not yet in the ORCA release

8. Numbering Schemes Purpose –For construction? –For reconstruction? For construction –Needs to reflect the mechanics For reconstruction –Simple navigation from one super-crystal to the next

9. Construction v Reconstruction Different demands may require that we have two numbering schemes Where is the interface?

10. Numbering within supercrystal At the initial construction stage all supercrystals look the same –They dont know which way up they will be installed. At the construction stage the crystal numbering within supercrystals should be the same. In preliminary discussions in the UK it was felt that SC numbering within the supercrystal should be consistent at all stages.

11. Construction Biased SC Numbering Scheme This proposed scheme is based on the 100 channel boxes Supercrystals with adjacent numbers are connected into the same box Partials which fill in spare slots have large numbers. Partials 149(10) 33 150(10) 29 151(10) 58 152(5) 58 152(1) ) 29 6665 7473 43 50 57 15 1 58 15 26 7 13 11 10 9 3 4 14 15 16 59 2524 1817 2021 30 37 44 5152 22 19 68 60 45 38 31 23 69 61 53 46 39 32 26 727170 62 54 47 40 34 27 55 6463 4241 4849 56 28 3635 33 149 150 29 67 12 8 152

12. Reconstruction Biased Numbering Scheme Use the x-y grid Last year I suggested numbering out from the beam pipe in x and y with negative numbers. Similar proposal from Jeremy Mans but with crystals numbered from 1-100 across the entire endcap and negative numbers indicating negative endcap.

13. Conclusion We may well need more than on numbering scheme We need to define the interface and make sure it is properly validated –ORCA has been slightly wrong for a long time