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| Paper: |
The Data Acquisition System Assessment to Support the Observation Quality System of the ASTRI Mini-Array Project |
| Volume: |
535, Astronomical Data Analysis Software and Systems XXXI |
| Page: |
369 |
| Authors: |
Conforti, V.; Gianotti, F.; Pastore, V.; Trifoglio, M.; Bulgarelli, A.; Addis, A.; Baroncelli, L.; Capalbi, M.; Fioretti, V.; Parmiggiani, N.; Sangiorgi, P.; Corpora, M.; Catalano, O. |
| Abstract: |
The ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) Project was born as a collaborative international effort led by the Italian National Institute for Astrophysics (INAF) to design and realize an end-to-end prototype of the Small-Sized Telescope (SST) of the Cherenkov Telescope Array (CTA) in a dual-mirror configuration (2M). The prototype, named ASTRI-Horn, is operative since 2014 at the INAF observing station located on Mt. Etna (Italy). The ASTRI Project is currently aimed to build a Mini-Array of nine ASTRI-Horn-like telescopes to be installed and operated at the Teide Observatory (Spain). The ASTRI software is aimed at supporting the operations of the ASTRI-Horn prototype and, eventually, of the Mini-Array. The Array Data Acquisition System (ADAS) of the ASTRI-Horn telescope acquires, packet by packet, the read-out data from the back-end electronics of the ASTRI camera. The packets are then stored locally in one raw binary file as soon as they arrive. During the acquisition, the ADAS decodes and stores data in FITS format by data type (scientific, calibration, engineering). A quick-look component, running on the same machine was also implemented, allowing the operator to display the decoded data during the acquisition. During software testing and operations performed with the ASTRI-Horn prototype, due to a CFITSIO writing method, we experienced a bottleneck in the raw-to-FITS binary data conversion when the acquisition rate was greater than about 10 Megabytes per second. Thus, we decided to apply a workaround and postpone the conversion in FITS format of the ASTRI-Horn raw data after the end of the acquisition run. The ASTRI Mini-Array software requires monitoring quality of the data as soon as data are available and this evaluation is performed by the Online Observation Quality System (OOQS). Because of this and due to the fact that the Mini-Array consists of 9 ASTRI cameras observing together, we are evaluating a solution to directly send the decoded data from the ADAS to the OOQS, strictly reducing any bottleneck. We studied a Redis-based solution to improve the data transfer efficiency from the data acquisition system to the OOQS component of the ASTRI Mini- Array. In this contribution we present the results of the comparison between two approaches: the storage in the Redis database, and the Redis asynchronous publish/subscribe paradigm. In addition, we are also compared different data formats to obtain better performance in the decoding and data transfer from the ADAS to the OOQS. |
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