G. Baldazzi

Concept for an innovative wide-field camera for x-ray astronomy

The use of large-area, fine-pitch Silicon detectors has demonstrated the feasibility of wide field imaging experiments requesting very low resources in terms of weight, volume, power and costs. The flying SuperAGILE instrument is the first such experiment, adopting large-area Silicon microstrip detectors coupled to one-dimensional coded masks. With less than 10 kg, 12 watt and 0.04 m3 it provides 6-arcmin angular resolution over >1 sr field of view. Due to odd operational conditions, SuperAGILE works in the unfavourable energy range 18-60 keV. In this paper we show that the use of innovative large-area Silicon Drift Detectors allows to design experiments with arcmin-imaging performance over steradian-wide fields of view, in the energy range 2-50 keV, with spectroscopic resolution in the range of 300-570 eV (FWHM) at room temperature. We will show the concept, design and readiness of such an experiment, supported by laboratory tests on large-area prototypes. We will quantify the expected performance in potential applications on X-ray astronomy missions for the observation and long-term monitoring of Galactic and extragalactic transient and persistent sources, as well as localization and fine study of the prompt emission of Gamma-Ray Bursts in soft X-rays.

X-ray imaging and spectroscopy performance of a large area silicon drift chamber for wide-field x-ray astronomy applications

In the context of the design of wide-field of view experiments for X-ray astronomy, we studied the response to X-rays in the range between 2 and 60 keV of a large area Silicon Drift Chamber originally designed for particle tracking in high energy physics. We demonstrated excellent imaging and spectroscopy performance of monolithic 53 cm2 detectors, with position resolution as good as 30 μm and energy resolution in the range 300-570 eV FWHM obtainable at room temperature (20 °C). In this paper we show the results of test campaigns at the X-ray facility at INAF/IASF Rome, aimed at characterizing the detector performance by scanning the detector area with highly collimated spots of monochromatic X-rays. In these tests we used a detector prototype equipped with discrete read-out front-end electronics.

High resolution X-ray Timing from a LOFT

I. Donnarumma∗a, R. Campanaa, L. Stellab, G. L. Israelb, M. Ferocia, T. Bellonic, S. Campanac, E. Costaa, E. Del Montea, Y. Evangelistaa, C. Labantid , F. Muleria, M. Rapisardaa,e, A. Rashevsky f , A. Vacchi f , G. Zampa f , N. Zampa f , P. Attinàg, G. Baldazzih, G. Bertuccioi, V. Bonvicini f , E. Bozzo j, L. Burderik, A. Corongiul, S. Covinoc, S. Dall’Ossob, D. De Martinom, T. Di Salvon, F. Fuschinod , M. Grassio, F. Lazzarottoa, P. Malcovatio, M. Marisaldid , S. Mereghettip, M. Orioq,r, A. Pellizzonil, L. Pacciania, A. Papittok,l, L. Picollio, P. Portag, A. Possentil, P. Soffittaa, R. Turollas, L. Zampierir a INAF/IASF-Roma b INAF/Osservatorio Astronomico di Roma c INAF/Osservatorio Astronomico di Brera d INAF/IASF-Bologna e ENEA-Frascati f INFN/Sezione di Trieste g Thales Alenia Space Italia Torino h Università di Bologna, Dip. di Fisica i Politecnico di Milano Dip. di Ingegneria Elettrica j ISDC

Tomographic Back‐Projection Algorithm for “Incomplete” Compton X‐Rays Detectors

A “Compton” detector finds the direction of an X‐ray by letting it interact with a gaseous, liquid or thin solid material (Tracker) and employing no collimators. This paper takes into account the case of an “incomplete” solid Tracker where the recoiling electron travels only a few dozen microns and cannot be followed. However, impact positions and incoming and outgoing energies are measured. In this situation, exploiting the Compton Scattering formula, one is only able to identify a cone whose surface the X‐ray belongs to. On the other hand, Compton tomography luckily requires only a few views (for example rotating the apparatus in just four positions around the subject), as the “electronic collimation” that takes place in each position already extracts X‐rays coming from many directions. A back‐projection algorithm that combines the reconstructed “cones” in space, weighed according to the Klein‐Nishina formula, has been applied to the special case of small animal SPECT (Single Photon Emission Computed To...

X-rays Compton detectors for Biomedical application

Collimators are usually needed to image sources emitting X‐rays that cannot be focused. Alternately, one may employ a Compton Camera (CC) and measure the direction of the incident X‐ray by letting it interact with a thin solid, liquid or gaseous material (Tracker) and determine the scattering angle. With respect to collimated cameras, CCs allow higher gamma‐ray efficiency in spite of lighter geometry, and may feature comparable spatial resolution. CCs are better when the X‐ray energy is high and small setups are required. We review current applications of CCs to Gamma Ray Astronomy and Biomedical systems stressing advantages and drawbacks. As an example, we focus on a particular CC we are developing, which is designed to image small animals administered with marked pharmaceuticals, and assess the bio‐distribution and targeting capability of these latter. This camera has to address some requirements: relatively high activity of the imaged objects; detection of gamma‐rays of different energies that may rang...