Status of the ACS-based control system of the mid-sized telescope prototype for the Cherenkov Telescope Array (CTA)

CTA, as the next generation ground-based very-highenergy gamma-ray observatory, is defining new areas beyond those related to physics; it is also creating new demands on the control and data acquisition system. With on the order of 100 telescopes spread over a large area with numerous central facilities such as a weather monitoring system, CTA will comprise a significantly larger number of devices than any other current imaging atmospheric Cherenkov telescope experiment. A prototype for the Medium Size Telescope (MST) of 12m diameter has been installed in Berlin and is currently being commissioned. The design of the control software of this telescope incorporates the main tools and concepts under evaluation within the CTA consortium in order to provide an array control prototype for the CTA project. The readout and control system for the MST prototype is implemented within the ALMA Common Software (ACS) distributed control middleware. The interfacing to the hardware is performed via the OPen Connectivity-Unified Architecture (OPC UA). The storage system of the prototype uses two different database systems: MySQL and MongoDB. MySQL keeps configuration data, while MongoDB stores monitoring data, log messages, alarm information and CCD images. In this contribution the architecture of the MST control and data acquisition system, implementation details and first conclusions are presented. THE CHERENKOV TELESCOPE ARRAY The Cherenkov Telescope Array (CTA) project [1] is an initiative to build the next generation ground-based very high (VHE, E > 10 GeV) energy gamma-ray instrument. It will serve as an open observatory to a wide astrophysics community and will provide deep insights into the nonthermal high-energy universe. The present generation of imaging atmospheric Cherenkov telescopes (H.E.S.S. [2], MAGIC [3] and VERITAS [4]) has in recent years opened the realm of ground-based gamma-ray astronomy in the energy range above a few tens of GeV. The Cherenkov Telescope Array will explore our Universe in depth in VHE gamma rays and investigate cosmic non-thermal processes, in close cooperation with observatories operating at other wavelength ranges of the electromagnetic spectrum, and those using other messengers such as cosmic rays and neutrinos. Besides the anticipated high-energy astrophysics results, CTA will have a large discovery potential in key areas of astronomy, astrophysics and fundamental physics research. These include the study of the origin of cosmic rays and their impact on the constituents of the Universe, the investigation of the nature and variety of black hole particle accelerators, and the inquiry into the ultimate nature of matter and physics beyond the Standard Model, searching for dark matter and the effect of quantum gravity. The design foresees a factor of 5-10 improvement in sensitivity in the current very high energy gamma-ray domain of about 100 GeV to some 10 TeV, and an extension of the accessible energy range from well below 100 GeV to above 100 TeV. The CTA Observatory will consist of two sites, one in the southern hemisphere and one in the northern hemisphere, with gamma-ray telescopes of different sizes and designs. The southern hemisphere array of CTA will consist of four types of telescopes with different mirror dish sizes in order to cover the full energy range. The northern hemisphere array would consist of two telescope types. The low-energy instrumentation will consist of a few 24-metre-class telescopes (Large Size Telescopes LST) with a moderate Field of View (FoV) of the order of 4-5°. The medium energy range, from around 100 GeV to 1 TeV, will be covered by one type of telescope of the 10-12 metre class (Mid Size Telescopes MST) with a FoV of 6-8° and another type of 9-10 metre class (“Schwarzschild-Couder”) with similar FoV but better angular resolution. The high energy instruments, operating above 10 TeV, will consist of a large number of small (4-6 metre diameter) telescopes (Small Size Telescopes SST) with a FoV of around 10°. Proceedings of ICALEPCS2013, San Francisco, CA, USA WECOAAB02 Experiment Control ISBN 978-3-95450-139-7 987 C op yr ig ht c ○ 20 14 C C -B Y3. 0 an d by th e re sp ec tiv e au th or s