1. ICARUS General Trigger Design Contributions from: M.Della Pietra, A.Di Cicco, P.Di Meo, G.Fiorillo, P.Parascandolo, R.Santorelli, P.Trattino B.Baboussinov, S.Centro, F.Pietropaolo, S.Ventura Work jointly conducted by Napoli and Padova groups

2. Physics considerations Events: –Cosmic rays muons –Atmospheric neutrinos –Solar neutrinos + neutrons  E ~ 5 MeV –Neutrinos from Supernova (burst)  E ~ 20 MeV –Proton decay –CNGS neutrinos  external timing –Beam muons

3. Supernova burst Specific time structure –Ex.: ~ 100 SN triggers in T300 in 1 sec Global trigger: bandwidth + storage problem –1 event = 27648 ch  2500 samples  2 bytes –~ 130 MB  13 GB total Local trigger: SN events are localized and limited to 1 crate per view –5 events per crate in COLL + IND2 views ~ 40 MB/crate –13 events per crate in IND1 view ~ 60 MB/crate  Each crate can be read-out as a separate event (See A.Rubbia presentation Sept. 02)

4. Segmentation and Selectivity Cosmic-ray shower Muon Low energy electrons

5. T600 pixel definition Rack 1 Rack 20 Rack 11Rack 13 T600 Half Module – 1 chamber viewed from cathode 1 pixel area: ~ 0.6 m 2 Total Number of Pixels ~ 80 32 x 9 Induction II wires 32 x 9 Collection wires 864 mm

6. MC simulation: low energy events ICAFLUKA, special thanks to G. Battistoni)

7. MC simulation: high energy events ICAFLUKA, special thanks to G. Battistoni)

8. Pixel definition

9. Preliminary considerations Trigger rate is dominated by physics background –Neutron capture rates expected in T600 (ICARUS/TM- 2002/13) : 2  10 -4 s -1 from natural radioactivity of the rock 0.03  0.1 s -1 from Al container Segmented trigger potentially solves bandwidth and storage problems Event pre-classification  data streams –extraction of solar neutrino data from low energy stream Test bench for T1200 low energy trigger

10. Trigger Input PMTs DAEDALUS AWS (Analog wire sum) External (beam profile chambers, cern- spill, …)

11. Basic design requirements Redundancy important to measure efficiency Global trigger: –Generated by PMTs or external –drift deadtime GLOBAL_DRIFT (1ms) –Read-out deadtime GLOBAL_BUSY (1s) vetoes new global triggers –Local triggers vetoed during GLOBAL_DRIFT Local trigger: –Generated by AWS + PMT –LOCAL_DRIFT (1ms) vetoes new local triggers

12. Trigger system architecture 1.LTCU: discriminates the 18 inputs, has one independent threshold for each input, gives two trigger proposal as output; 2.TCU: performs coincidences between LTCUs proposals, processes the fired pixels to study and label the event topology, requests global or local trigger; 3.Trigger Supervisor: monitoring of the trigger and the DAQ system, statistical functions.

13. Trigger System Architecture LTCUTCU TRIGGER SUPERVISOR DAQ CERN or any other external request 20 boards per chamber (80 boards for T600)  from v791 n-bit request v816 96 9 4 boards per T600 9 Trigger Distribution T 1 20 T 2 20 T11T11 T21T21 LTCU PMT

14. LTCU v1.0 test on Geneva prototype and LTCU v2.0

15. discriminate the inputs, coming from the v791 boards; give as output two separate trigger proposals to the next level, one for Induction II and one for Collection; remote control of all the board’s functionalities; discriminators check-control; trigger rate measurements for each input. The Local Trigger Control Unit prototype targets

16. FPGA Input stage RS232 interface 10 MHz oscillator Power supply 18 inputs Trigger outputs DAC The LTCU prototype v1.0 IN V DAC Discriminator Voltage follower RC filter OUT IN

17. The LTCU functionalities v1.8i Mask the input channels; Read the mask status; Set the thresholds; Monitor the trigger rate for each input; Discriminator test mode; Select one discriminator output put on front panel. All the board functionalities are remotely controlled via RS232 interface.

18. Trigger rate test chain LTCU inputs = 4  signals from collection plane; Trigger generated from only one  input (no FastOR); LTCU trigger output distributed to V816 module. LTCU Trigger OUT V789 LTCU  V791 IndColl IN OUT IN OUT IN Analog  OUT V816 trigger PC (RS232)

19. Trigger Rate Plateau (I) Plateau zones

20. Trigger Rate Plateau (II) Plateau zones

21. Trigger efficiency test chain LTCU inputs = 4  signals from collection plane; One LTCU IN and Trigger OUT digitalized by a modified V791; PMT trigger distributed to V816 module. PMT V789 LTCU  V791 IndColl IN OUT IN OUT IN Analog  OUT V816 trigger PC (RS232) OUT IN Modified V791

22. Test Results (I)

23. Test Results (II) ProblemsSolutions High frequency noise on input signal Band-pass filter ( f -3dB H = 2 MHz, f -3dB L = 1 kHz ); Offset for negative input isn’t a stable solution Inverter amplifier (G=1) in the input stage; More than 20mV white noise New pcb (with 8 layers) and EM/RF screening Not stable DAC threshold Stable V REF circuit

24. LTCU prototype v2.0 Power supply an filter Input stage (for one channel) or IN Band-pass filterSelectable inverter (G=1) V Test V TH OUT IN V TH DAC (for one channel) V REF V REF for DAC Filter for low noise performance Stable 259mV tension circuit V REF EM/RF Screening for input stage

25. PWR and GND distribution for LTCU v2.0 ±5A, AGND (V791 preamp. stage) +5A1, AGND1 (V791 mux stage) VCC, DGND (V791 digital stage) Four GND and two PWR planes

26. Conclusions LTCU v2.0 is being produced (5 boards); Ready to be tested on detector prototypes; Analysis of test data in progress; Article in preparation.