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

WCD array at Sierra Negra to search for GRBs

4550 masl (610 g/cm2)‏

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

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 MHz|| Schematic of the DAQ Board (one channel upgradable to 3 channels)‏ Languages: VHDL + Perl & AWK RS Baud 2x-4x clock Signal from PMT

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

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

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

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

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

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

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

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

LabView based DAS

Rise time behaves similarly to Charge over amplitude

Charge spectrum 2000 masl 4550 masl

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

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

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

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