STAR-EMC TriggerA. Vander Molen for the EMC Group

Requirements of EMC Trigger Trigger on events with

Jets Direct ’s Electrons High Et

processes Neutral Energy Isospin Ratios Calibration

and produce Luminosity bits

Signal Characteristics

Jets - Energy concentrated in 0.8x0.8 Patches Di-jets - High Et

Direct ‘s - Energy concentrated in single .05x.05 Towers Di- ‘s - High Et

Electrons -Energy concentrated in single .05x.05 Tower SMD insensitive to hadronic matter High Et - Total Energy over threshold Ratio of EMC to CTB

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

Level 0 Functionality

Convert all energy to E - Transverse Generate Etotal Generate 1.0x0.8.0 non overlapping patches (Jet

tower) Compare Etotal to 3 thresholds

Compare Etotal to 3 thresholds (Luminosity) Compare Jet tower to 3 thresholds Compare High tower to 3 thresholds Generate High tower to Trigger tower correlation.

Level 0 CTB/EMC Functionality EMC/CTB energy/multiplicity ratio

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

Electronics

35 DSM boards (30+4+1) 2 VME crates with 18 slots Modified DSMI boards

12 twisted pair differential inputs(FEE output)

128 TTL output (DSM input)

Algorithm Layer 1 of DSM boards

Transform E to E transverse High tower 3 thresholds Trigger tower 3 thresholds High tower/ Trigger tower Partial Energy Sum Output

Energy Sum 8 bits High tower 3 bits Trigger Tower 3 bits Ratio 1bit

Algorithm - continued

Layer 2 of DSM boards Form Jet patches Jet thresholds Partial Total Energy Output

Energy Sum 8 bits High tower 3 bits Trigger Tower 3 bits Ratio 1 bit Jets 3 bits

Algorithm - continued

Layer 3 of DSM boards Total Energy Total Energy thresholds Form Geometric Bit sums Generate output bits Output

Trigger bits

Day One Implementation

10% of Detector or 30-40 12 bit inputs.

(5 +1 ) DSM boards

Level 1,2 and Level 3

Level 1 Not implemented Level 2

Refined Jet finding Overlapping patches

Geometric Considerations SMD data

Level 3 Full Tracking