Title

Data acquisition architecture and online processing system for the HAWC gamma-ray observatory

Authors

A. U. Abeysekara, The University of Utah
R. Alfaro, Universidad Nacional Autónoma de México
C. Alvarez, Universidad Autónoma de Chiapas
J. D. Álvarez, Universidad Michoacana de San Nicolás de Hidalgo
R. Arceo, Universidad Autónoma de Chiapas
J. C. Arteaga-Velázquez, Universidad Michoacana de San Nicolás de Hidalgo
H. A. Ayala Solares, Michigan Technological University
A. S. Barber, The University of Utah
B. M. Baughman, University of Maryland
N. Bautista-Elivar, Universidad Politécnica de Pachuca
J. Becerra Gonzalez, University of Maryland
E. Belmont-Moreno, Universidad Nacional Autónoma de México
S. Y. BenZvi, University of Rochester
D. Berley, University of Maryland
M. Bonilla Rosales, Instituto Nacional de Astrofisica Optica y Electronica
J. Braun, University of Wisconsin-Madison
R. A. Caballero-Lopez, Universidad Nacional Autónoma de México
K. S. Caballero-Mora, Universidad Autónoma de Chiapas
A. Carramiñana, Instituto Nacional de Astrofisica Optica y Electronica
M. Castillo, Universidad Michoacana de San Nicolás de Hidalgo
U. Cotti, Universidad Michoacana de San Nicolás de Hidalgo
J. Cotzomi, Benemerita Universidad Autonoma de Puebla
E. de la Fuente, Universidad de Guadalajara
C. De León, Benemerita Universidad Autonoma de Puebla
T. DeYoung, Michigan State University
J. Diaz-Cruz, Benemerita Universidad Autonoma de Puebla
R. Diaz Hernandez, Instituto Nacional de Astrofisica Optica y Electronica
J. C. Díaz-Vélez, University of Wisconsin-Madison
B. L. Dingus, Los Alamos National Laboratory
M. A. DuVernois, University of Wisconsin-Madison
R. W. Ellsworth, University of Maryland
D. W. Fiorino, University of Maryland

Document Type

Article

Publication Date

4-21-2018

Abstract

© 2018 Elsevier B.V. The High Altitude Water Cherenkov observatory (HAWC) is an air shower array devised for TeV gamma-ray astronomy. HAWC is located at an altitude of 4100 m a.s.l. in Sierra Negra, Mexico. HAWC consists of 300 Water Cherenkov Detectors, each instrumented with 4 photomultiplier tubes (PMTs). HAWC re-uses the Front-End Boards from the Milagro experiment to receive the PMT signals. These boards are used in combination with Time to Digital Converters (TDCs) to record the time and the amount of light in each PMT hit (light flash). A set of VME TDC modules (128 channels each) is operated in a continuous (dead time free) mode. The TDCs are read out via the VME bus by Single-Board Computers (SBCs), which in turn are connected to a gigabit Ethernet network. The complete system produces ≈500 MB/s of raw data. A high-throughput data processing system has been designed and built to enable real-time data analysis. The system relies on off-the-shelf hardware components, an open-source software technology for data transfers (ZeroMQ) and a custom software framework for data analysis (AERIE). Multiple trigger and reconstruction algorithms can be combined and run on blocks of data in a parallel fashion, producing a set of output data streams which can be analyzed in real time with minimal latency ( < 5 s). This paper provides an overview of the hardware set-up and an in-depth description of the software design, covering both the TDC data acquisition system and the real-time data processing system. The performance of these systems is also discussed.

Publication Title

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

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