1. This presentation will probably involve audience discussion, which will create action items. Use PowerPoint to keep track of these action items during your presentation In Slide Show, click on the right mouse button Select “Meeting Minder” Select the “Action Items” tab Type in action items as they come up Click OK to dismiss this box This will automatically create an Action Item slide at the end of your presentation with your points entered. Levan Babukhadia D  Collaboration Meeting, January 12 - 14, 2000, Fermilab http://www-d0.fnal.gov/~blevan Level 1 FPS Algorithm Revisited SUNY at Stony Brook

2. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia FPS Readout 16 FPS 22.5 o  -sectors 4 layers of U- & V-strips Shower: 144 U- & V-strips Mip: 103 U- & V-strips Special: 72 U- & V-strips Total max ~500 analog signals per FPS  -sector Two FPS  -sectors  Two Analog Front End (AFE) boards on a single VLPC cassette. High and Low SIFT thresholds set at AFE output (~doubles the # of analog signals).

3. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia L1FPS Architecture L2PSppL2PSpp 8N 7N 6N 5N D4N DB 3N DB 2N DB 1N FPSFPS NORTHNORTH DB 6S DB 5S DB 4S DB 3S DB 2S DB 1S FPSFPS SOUTHSOUTH DB 7S DB 8S 16 N U L3 N V L3 S U L3 S V L3 L1ftp L3

4. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia Truncation in L1FPS Possible truncation problems at the Digital Daughterboard and the Collector board To address this question study cluster multiplicities in MC AFE FPS  -wedge DB DFE COL to L1 via BC Glink to L2 5 5 1 1 1 Max # of Clusters 18 for L2 Max # of Clusters 48

5. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia Cluster Occupancies from MC Dijets + 2MB MC with full detector simulation High SIFT threshold at 5 mips Excellent agreement with previous results ( DØ Note 3493 )

6. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia Cluster Occupancies Dijets + 2MB MC with full detector simulation Low SIFT threshold at 3 mips E T : 5 - 10 GeVE T : 10 - 20 GeV E T : 20 - 40 GeVE T : 40 - 500 GeV

7. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia Cluster Occupancies Dijets + 2MB MC with full detector simulation High SIFT threshold at 5 mips E T : 5 - 10 GeVE T : 10 - 20 GeV E T : 20 - 40 GeVE T : 40 - 500 GeV

8. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia Dijets MC with 6 MB Worst case: highest dijet Et 40-500 GeV and low SIFT threshold at 3 mips Also shows we are safe at the Collector board truncation

9. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia Strip Multiplicities Dijets + 2MB MC with full detector simulation Low SIFT threshold at 3 mips E T : 5 - 10 GeVE T : 10 - 20 GeV E T : 20 - 40 GeVE T : 40 - 500 GeV

10. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia Cluster Widths Dijets + 2MB MC with full detector simulation Low SIFT threshold at 3 mips E T : 5 - 10 GeVE T : 10 - 20 GeV E T : 20 - 40 GeVE T : 40 - 500 GeV

11. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia Proposed Changes in L1FPS Knowing which  -  (0.2x0.2) trigger tower the FPS cluster is associated with is one way to handle truncation without introducing physics bias. To achieve this, U- and V-signals must be handled by a single DFE DB  this requires some changes in the cable routings between AFE and DFE. Next, the trigger equations allow to do the  -  “matching” of identified U- and V-clusters. As an example, EQ8 = V8  ( U9  U10  U11 ), when true, will unambiguously identify a cluster as belonging to the trigger tower  2 -  1 V8 U11 U10 U9

12. DØ Collaboration Meeting, January 12 - 14, 2000, FermilabLevan Babukhadia Summary The MC studies indicate we do not have a problem in L1FPS DFE truncation at 18 H&L clusters. Still, the proposed modifications in: (a) cable routings between AFE and DFE to allow U-V “matching” in DFE DB & (b) L1FPS DFE algorithm to allow the determination of the  -  trigger tower assoiciation of the L1FPS cluster are to be implemented. As a result, the truncation is not expected to be a problem even in higher background environment during actual running.