Salvatore Scuderi

Response analysis in the 300- to 2500-Å spectral range of ultraviolet-enhanced charge-coupled devices

The measurements of the ultraviolet response by some UV-enhanced CCDs have been realized. In particular, the quantum efficiency of coronene- and lumigen-coated and of back-illuminated ion-implanted CCDs have been measured in the 300 to 2500-A spectral range. Very interesting performances have been found, mainly for one ion-implanted CCD with quantum efficiency values of more than 60% at 304 A. Also some measurements of the CCD uniformity response and spatial resolution capability in this spectral region have been performed. The obtained results are very promising for the possibility of using these semiconductor detectors in the ultraviolet spectral region also with very good performance.

The ASTRI camera for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) foresees, in its southern site (Chile), the implementation of up to 70 small-sized telescopes (SSTs), which will extend the energy coverage up to hundreds of TeV. It has been proposed that one of the first set of CTA SSTs will be represented by the ASTRI mini-array, which includes (at least) nine ASTRI telescopes. The endto-end prototype of such telescopes, named the ASTRI SST-2M, is installed in Italy and it is now completing the overall commissioning and entering the science verification phase. ASTRI telescopes are characterized by an optical system based on a dual-mirror Schwarzschild-Couder design and a camera at the focal plane composed of silicon photomultiplier sensors managed by a fast read-out electronics specifically designed. Based on a custom peak-detector mode, the ASTRI camera electronics is designed to perform Cherenkov signal detection, trigger generation, digital conversion of the signals and data transmission to the camera server. In this contribution we will describe the main features of the ASTRI camera, its performance and results obtained during the commissioning phase of the ASTRI SST-2M prototype in view of the ASTRI mini-array implementation.

Comparison between the EUV performances of cryogenically cooled CCDs and a MAMA detector

The results of some measurements to characterize the performance of various cryogenically cooled CCDs and of a Multi Anode Microchannel Array detector in the Extreme UltraViolet region (EUV) are presented. A performance comparison between the two different types of detector was made: from these measurements some indications can be obtained which say in what conditions and for what applications one detector is preferable to the other. This can have some important implications, for example in choosing a detector for a space mission.

Characterization of SPAD Arrays: First Results

SPAD detectors are very promising for astrophysical applications. Large arrays are crucial to cover as much of the focal plane as possible. STMicroelectronics has developed various monolithic arrays of SPAD. At present, the manufacturing of 5×5 arrays (each with an active area of 40 μm and pitch between adjacent pixels of 240 μm) is completed and improvements in terms of pixels and technology are under study and development. An appropriate cryogenic system to host the packaged SPAD arrays and detection electronics to drive them have been designed and realized. Electro-optical characteristics of various arrays in different operating conditions have been measured and the obtained results are presented herein.

AIR WATCH: air-induced fluorescence by radiation laboratory experiments

We report preliminary measurements of the air UV fluorescence light yield as a function of pressure using as a stimulus hard x-rays. For comparison measurements in pure nitrogen are also reported. Knowledge of the air UV fluorescence light yield induced by hard x-rays is needed in order to evaluate the capability to detect, in an AIRWATCH FROM SPACE experiment, Gamma Ray Burst (GRB) events. The experiment was carried out a the LAX x-ray facility in Palermo, by using an high flux collimated x-ray photon beam. The experimental result indicate that the fluorescence yield is inversely proportional to the filling pressure. At pressures below 30 mbar, corresponding to the value for the upper atmospheric layers in which the X and gamma ray photons of the GRBs are absorbed, about 0.1 percent of the total energy of a GRB is transformed in UV photons. This makes possible the observation of the GRBs with the technique proposed in the AIRWATCH FROM SPACE experiment.

GIANO-B online data reduction software at the TNG

GIANO-B is the high resolution near-infrared (NIR) spectrograph of the Telescopio Nazionale Galileo (TNG), which started its regular operations in October 2017. Here we present GIANO-B Online Data Reduction Software (DRS) operating at the Telescope. GIANO-B Online DRS is a complete end-to-end solution for the spectrograph real-time data handling. The Online DRS provides management, processing and archival of GIANO-B scientific and calibration data. Once the instrument control software acquires the exposure ramp segments from the detector, the DRS ensures the complete data flow until the final data products are ingested into the science archive. A part of the Online DRS is GOFIO software, which performs the reduction process from ramp-processed 2D spectra to extracted and calibrated 1D spectra. A User Interface (UI) developed as a part of the Online DRS provides basic information on the final reduced data, thus allowing the observer to take decisions in real-time during the night and adjust the observational strategy as needed.

Introducing GOFIO: a DRS for the GIANO-B near-infrared spectrograph

The NIR echelle spectrograph GIANO-B at the Telescopio Nazionale Galileo is equipped with a fully automated online DRS: part of this pipeline is the GOFIO reduction software, that processes all the observed data, from the calibrations to the nodding or stare images. GOFIO reduction process includes bad pixel and cosmic removal, flat-field and blaze correction, optimal extraction, wavelength calibration, nodding or stare group processing. An offline version of GOFIO will allow the users to adapt the reduction to their needs, and to compute the radial velocity using telluric lines as a reference system. GIANO-B may be used simultaneously with HARPS-N in the GIARPS observing mode to obtain high-resolution spectra in a wide wavelength range (383-2450 nm) with a single acquisition. In this framework, GOFIO, as part of the online DRS, provides fast and reliable data reduction during the night, in order to compare the infrared and visible observations on the fly.

Ultraviolet Italian Sky Surveyor (UVISS) on the International Space Station (ISS): study report

A Mission into Hot Phenomena in the Universe is proposed by means of a small telescope of 50 cm aperture accommodated on the International Space Station. Two operating modes are envisaged: 3 angstrom dispersion imaging spectroscopy in the 90 - 320 nm range (1st priority) or wide field (1 degree) medium bandwidth imaging in the same range but Ly-(alpha) (2nd priority). It will use a pointing platform attached to an Express Pallet Adapter available to the Italian Space Agency (ASI) more than 4 - 6 months per year. During a life time of 6 yr focal plane instruments may be changed when on-ground refurbishment occurs. With reasonable exposure times hot thermal sources as faint as V equals 19 - 2 can be observed in the spectroscopy mode at 110 nm and active chromospheres on cool stars as faint as V equals 15 at 250 nm can be monitored. Assessment of FUV imaging is underway, possibly providing observations of hot sources as faint as V equals 21 - 22. Nominal uplift to ISS is set in Autumn 2005.