author = "Bernardes, D. V. and Martioli, E. and Rodrigues, Cl{\'a}udia 
          affiliation = "{Labotat{\'o}rio Nacional de Astrof{\'{\i}}sica (LNA)} and 
                         {Labotat{\'o}rio Nacional de Astrof{\'{\i}}sica (LNA)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Characterization of the SPARC4 CCDs",
              journal = "Publications of the Astronomical Society of the Pacific",
                 year = "2018",
               volume = "130",
               number = "991",
                pages = "e095002",
                month = "Sept.",
             keywords = "instrumentation: detectors, methods: data analysis, techniques: 
                         image processing.",
             abstract = "We present the photometric characterization of the four iXon Ultra 
                         888 CCD cameras of the SPARC4 instrument, which will be installed 
                         on the 1.6 m telescope of the Pico dos Dias Observatory in Brazil. 
                         We applied experimental methodologies for a systematic 
                         characterization of the read noise, electronic gain, dark current, 
                         and quantum efficiency of the CCDs. We have analyzed the 
                         statistical distribution of the read noise, and also its spatial 
                         gradient and temporal variability, where we obtained an average 
                         value of the read noise of 6.33 electrons. We applied the Janesick 
                         method to determine the electronic gain, where we obtained an 
                         average value of 3.35 e- /ADU. We have also obtained an average 
                         dark current of 0.00014 e- pix(-1) s(-1) for CCD internal 
                         temperature of -70 degrees C. We have inspected the dependency of 
                         the dark current with temperature and the spatial distribution of 
                         the dark current, where we found a variable profile in the CCD 
                         9917. We developed an experiment using a bench-mounted 
                         monochromator to obtain the spectral dependency of the quantum 
                         efficiency in the spectral range between 350 nm and 1100 nm, where 
                         we measured the quantum efficiency for each camera. The camera 
                         9915 presents the highest quantum efficiency of 95.8%. Our results 
                         are compared with those from the manufacturer. These experiments 
                         allow us to diagnose the performance of these CCD cameras, an 
                         important sub-system of the SPARC4 instrument. It also provides a 
                         systematic way for monitoring the aging of the CCDs.",
                  doi = "10.1088/1538-3873/aacb1e",
                  url = "http://dx.doi.org/10.1088/1538-3873/aacb1e",
                 issn = "0004-6280",
             language = "en",
        urlaccessdate = "04 dez. 2020"