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DAQ System to Search for GRBs using Water Cerenkov Detectors Mario Castillo*, Gonzalo Perez*, Humberto Salazar* and L. Villaseor ** * Facultad de Ciencias FisicoMatematicas, BUAP, Puebla ** Institute of Physics and Mathematics, University of Michoacan, Morelia VII SILAFAE CAB Bariloche, Ar January, 13-21, 2009

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WCD array at Sierra Negra to search for GRBs

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4550 masl (610 g/cm2)

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4m 2 x 1.4 m Single 5 EMI flat PMT Tyvek Ultra pure (~20 microS) water

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FPGA Xilinx Spartan 2E JTAG 50 Mhz Clock VP or UT Oncore GPS Receiver 50 ns Antenna 1 PPS Serial 9600 Baud PROM 4 operation modes: Trace, Charge, Rate, Muon Decay RAM 10 bit ADC board 100-200 MHz|| Schematic of the DAQ Board (one channel upgradable to 3 channels) Languages: VHDL + Perl & AWK RS232 115200 Baud 2x-4x clock Signal from PMT

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ADC daugther boards 1 or 2 AD9214BRSZ-105 chips operating at 100MSPS.

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We use one (two) delay-locked loop (DLL) circuits to obtain 100 (200) Mhz out of 50 MHz

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Use a Motorola Oncore GPS receiver Use a Motorola Oncore GPS receiver in precise Timing Mode model UT+ Position-Hold option 1PPS Cable and antenna Delay Time RAIM option to isolate satellites with erroneous time measurements

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Trace mode, samples 30 trace points every 10 ns in real time and measures charge, amplitude, baseline and STD

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Trace Mode: Up to 180 full traces per second Bottle- neck: 115200 baud comm rate

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Charge mode: Up to 2880 Charge & Amplitude measurements per second (1920 per s if rise time is also measured)

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Measure Charge, Amplitude,T10-50,T10-90 with good precision for three different triggers. Arbitrary muons threshold of 30mV

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1.54 m diameter, 1.2 m water, one 8 PMT, tyvek 1/5 in volume of an Auger WCD

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LabView based DAS

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Rise time behaves similarly to Charge over amplitude

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Charge spectrum 2000 masl 4550 masl

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Muon decay mode: Time between consecutive pulses in a 20 microsec window and time over threshold with granularity of 5 ns

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Stopping muon at 0.1 VEM Decay electron at 0.17 VEM Crossing muon at 1.05 VEM Alarcn M. et al., NIM A 420 [1-2], 39-47 (1999).

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Rate mode: Number of pulses above 4 thresholds every 5 ms

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Conclusions DAQ system prototype tested 1-3 ADC channels at 100-200 MHz Precise timing from GPS 4 operation modes: Trace, charge, muon decay and rate To do: implement as a single board