1. STAR-EMC Trigger A. Vander Molen for the EMC Group

2. Requirements of EMC Trigger n Trigger on events with u Jets u Direct  ’s u Electrons u High E t processes u Neutral Energy u Isospin Ratios u Calibration n and produce u Luminosity bits

3. Signal Characteristics n Jets - Energy concentrated in 0.8x0.8 Patches u Di-jets - High E t n Direct  ‘s - Energy concentrated in single.05x.05 Towers u Di-  ‘s - High E t n Electrons -Energy concentrated in single.05x.05 Tower n SMD insensitive to hadronic matter n High E t - Total Energy over threshold n Ratio of EMC to CTB

4. Input Signals To Level 0 n 300 6 bit Barrel PMT trigger towers (.2 x.2) n 300 6 bit Barrel PMT highest tower (.05 x.05)

5. Level 0 Functionality n Convert all energy to E - Transverse n Generate E total n Generate 1.0x0.8.0 non overlapping patches (Jet tower) n Compare E total to 3 thresholds n Compare E total to 3 thresholds (Luminosity) n Compare Jet tower to 3 thresholds n Compare High tower to 3 thresholds n Generate High tower to Trigger tower correlation.

6. Level 0 CTB/EMC Functionality n EMC/CTB energy/multiplicity ratio

7. Interim Output Bits n Total E total 3 bit(1 bit/threshold) n Jet tower 6 bits (2 bit counter/threshold) n High tower 6 bits (2 bit counter/threshold) n High /trigger tower 2 bits(2 bit counter) n Luminosity 3 bits Barrel (1 bit/threshold) n Patch energy 8 bits

8. Electronics n 35 DSM boards (30+4+1) n 2 VME crates with 18 slots n Modified DSMI boards u 12 twisted pair differential inputs(FEE output) u 128 TTL output (DSM input)

10. Algorithm n Layer 1 of DSM boards u Transform E to E transverse u High tower 3 thresholds u Trigger tower 3 thresholds u High tower/ Trigger tower u Partial Energy Sum u Output F Energy Sum 8 bits F High tower 3 bits F Trigger Tower 3 bits F Ratio 1bit

11. Algorithm - continued n Layer 2 of DSM boards u Form Jet patches u Jet thresholds u Partial Total Energy u Output F Energy Sum 8 bits F High tower 3 bits F Trigger Tower 3 bits F Ratio 1 bit F Jets 3 bits

12. Algorithm - continued n Layer 3 of DSM boards u Total Energy u Total Energy thresholds u Form Geometric Bit sums u Generate output bits u Output F Trigger bits

13. Day One Implementation n 10% of Detector or 30-40 12 bit inputs. n (5 +1 ) DSM boards

14. Level 1,2 and Level 3 n Level 1 Not implemented n Level 2 u Refined Jet finding F Overlapping patches u Geometric Considerations u SMD data n Level 3 u Full Tracking