1. The Angra Neutrino Detector Detector, VETO and electronics conceptual design Laudo Barbosa (May 18th, 2006) Centro Brasileiro de Pesquisas Físicas (CBPF)

2. Presentation plan The neutrino detector scheme Detector regions PMTs coverage Signal processing Trigger circuit The VETO system X&Y blocks Tile barrel Triggering logics Detector operation Calibration with VEM (Vertical Equivalent Muon) Remote data acquisition

3. The Neutrino Detector Detector regions Active region [  1m, h=1.3m] (Liquid Scintillator +  0.1% Gadolinium) Gama catcher [  1.6m, h=1.9m] (Liquid Scintillator) Buffer [  2.2m, h=2.5m] (Mineral oil)

4. 4 The Neutrino Detector PMTs coverage 6.91m 2.5m 2.2m Total area = S side + S top + S bottom  (17.28+3.8+3.8)  24.88m 2 Photocathode area = 0.038m 2 20% coverage  4.98m 2 # PMTs = 4.98/0.038  131 0.43m 0,43m 0.45m 128 PMTs implemented

5. The Neutrino Detector PMTs mounting Base + Front end Base + Front end Base + Front end InsideHalf-inside Outside

6. The Neutrino Detector Sinal Processing Front end electronics Input Buffer Amplifier & Shaper Comparator Line Driver To ADC To Trigger May be done: - Inside the front end block - At the data acquisition level (analog) - At the data acquisition level (digital)

7. The Neutrino Detector Trigger circuit Triggering criteria (Ex.): (more than n PMTs hit within  t ns) && (no VETO within  t’ ns) 128 logic signals Detector Triggering (FPGA + ADC) VETO circuit Record event (VME Bus) 128 analog signals

8. The VETO system Basics The neutrino detector is possibly NOT buried  crossed by  2000 muons/s Given a 150  s time window  0.3 cosmic particles detected Average loss of 30% of the events due to VETO, if 150  s gate applied One VEM (Vertical Equivalent Muon) has a fixed average energy loss The VEM average loss may be compared to other particle’s Cosmic muons may be used in energy calibration The waverforms are continuously sampled The VETO gate may be reduced to few  s Acquired data are handled as ‘physics’ events or ‘calibration’ events.

9. The VETO system Basics Prompt Neutron VEM/Cosmic SIGNAL TRIGGER VETO GATE 100-150  s

10. The VETO system Arrangement

11. The VETO system X&Y and Barrel Scintillators X&Y 3m long, 1cm thick, 15cm wide Readout by: optical fiber + segmented PMT or small size PMTs. Assembled as a single piece Barrel 3m long, 1.5cm thick, 60-70cm wide Readout by: small size PMTs. Fixed on a barrel structure

12. The VETO system X&Y and Barrel Scintillators Scintillator + fiber setup, built at FNAL, likely to be used at the AMIGA Project under AUGER. Multianode photomultipliers (Ex: Hamamatsu R8520 series)

13. The VETO system Triggering Logics 2x50 X channels 2x50 Y channels 14-16 Barrel channels VETO Triggering (FPGA1) VETO Event Triggering Logics (FPGA2) Neutrino VEM Interesting Record Event Detector Triggering (FPGA2)

14. Detector Operation Calibration with VEM VEM charge spectrum in a water Cerenkov detector of the Auger Project

15. 15 Detector Operation Remote data acquisition The detector continuously acquire data, recording events that may be classified as: - Neutrino events (golden) - VEM (calibration) - Other (ex: inclined muons) Data is locally (Angra) stored and sent to a central station at CBPF DAQ system DETECTOR radio link Angra Network CBPF