At the core of the AGILE scientific instrument, designed to operate on a satellite, there is the Gamma Ray
Imaging Detector (GRID) consisting of a Silicon Tracker (ST), a Cesium Iodide Mini-Calorimeter and an
Anti-Coincidence system of plastic scintillator bars. The ST needs an on-ground calibration with a γ-ray beam to
validate the simulation used to calculate the energy response function and the effective area versus the energy and
the direction of the γ rays. A tagged γ-ray beam line was designed at the Beam Test Facility (BTF) of the INFN
Laboratori Nazionali of Frascati (LNF), based on an electron beam generating γ rays through bremsstrahlung in
a position-sensitive target. The γ-ray energy is deduced by the difference with the post-bremsstrahlung electron
energy1-.2 The electron energy is measured by a spectrometer consisting of a dipole magnet and an array of
position sensitive silicon strip detectors, the Photon Tagging System (PTS). The use of the combined BTF-PTS
system as tagged photon beam requires understanding the efficiency of γ-ray tagging, the probability of fake
tagging, the energy resolution and the relation of the PTS hit position versus the γ-ray energy. This paper
describes this study comparing data taken during the AGILE calibration occurred in 2005 with simulation.
AGILE is a γ/X-ray telescope which has been in orbit since 23 April 2007. The
γ-ray detector, AGILE-GRID,
has observed Galactic and extragalactic sources, many of which were collected in the first AGILE Catalog.
We present the calibration of the AGILE-GRID using in-flight data and updated Monte Carlo simulations,
producing response matrices for the effective area, energy dispersion, and point spread dispersion as a function
of pointing direction in instrument coordinates and energy.
We performed Monte Carlo simulations in GEANT3 at different
γ-ray photon energies and incident angles,
using Kalman filter-based photon reconstruction and on-board and on-ground filters. Long integrations of in-flight observations of the Vela, Crab and Geminga sources in broad and narrow energy bands were used to validate
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.
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.
The SuperAGILE experiment is the hard X-ray monitor of the AGILE mission. It is a 2 x one-dimensional imager, with
6-arcmin angular resolution in the energy range 18 - 60 keV and a field of view in excess of 1 steradian. SuperAGILE is
successfully operating in orbit since Summer 2007, providing long-term monitoring of bright sources and prompt
detection and localization of gamma-ray bursts. Starting on October 2009 the AGILE mission lost its reaction wheel and
the satellite attitude is no longer stabilized. The current mode of operation of the AGILE satellite is a Spinning Mode,
around the Sun-pointing direction, with an angular velocity of about 0.8 degree/s (corresponding to 8 times the
SuperAGILE point spread function every second). In these new conditions, SuperAGILE continuously scans a much
larger fraction of the sky, with much smaller exposure to each region. In this paper we review some of the results of the
first 2.5 years of "standard" operation of SuperAGILE, and show how new implementations in the data analysis software
allows to continue the hard X-ray sky monitoring by SuperAGILE also in the new attitude conditions.
The X-ray sky in high time resolution holds the key to a number of observables related to fundamental physics,
inaccessible to other types of investigations, such as imaging, spectroscopy and polarimetry. Strong gravity effects, the
measurement of the mass of black holes and neutron stars, the equation of state of ultradense matter are among the
objectives of such observations. The prospects for future, non-focused X-ray timing experiments after the exciting age of
RXTE/PCA are very uncertain, mostly due to the technological limitations that need to be faced to realize experiments
with effective areas in the range of several square meters, meeting the scientific requirements. We are developing large-area
monolithic Silicon drift detectors offering high time and energy resolution at room temperature, with modest
resources and operation complexity (e.g., read-out) per unit area. Based on the properties of the detector and read-out
electronics we measured in laboratory, we built a concept for a realistic unprecedented large mission devoted to X-ray
timing in the energy range 2-30 keV. We show that effective areas in the range of 10-15 square meters are within reach,
by using a conventional spacecraft platform and launcher.
The New Hard X-Ray Imaging and Polarimetric Mission makes a synergic use of Hard X-Ray Imaging, Spectroscopy
and Polarimetry, as independent diagnostic of the same physical systems. It exploits the technology of
multi-layer optics that, with a focal length of 10 m, allow for spectroscopic and imaging, with a resolution from
15 to 20 arcseconds, on the band 0.2 - 80 keV. One of the four telescopes is devoted to polarimetry. Since the
band of a photoelectric polarimeter is not that wide, we foresee two of them, one tuned on the lower energy band
(2-10 keV) and another one tuned on higher energies (6 - 35 keV). The blurring due to the inclined penetration
of photons in the gas , thanks to the long focal length is practically negligible. In practice the polarimeters fully
exploit the resolution the telescope and NHXM can perform angular resolved simultaneous spectroscopy and
polarimetry on the band 2 - 35 keV. We are also studying the possibility to extend the band up to 80 keV by
means of a focal plane scattering polarimeter.
SuperAGILE (SA) is the hard X-ray monitor of the AGILE small satellite mission, launched on 23rd April 2007.
The monitor is based on four one-dimensional coded-mask detectors. In spite of the compactness (45×45×15 cm3)
and lightness (5 kg), the experiment has high angular resolution (6 arcmin) and point source location accuracy (<2
arcmin, for bright sources) for every position in the Field Of View (FOV). To achieve these imaging performances,
considerable efforts were made for the alignment procedures during the assembly of the experiment itself, and
with the rest of the satellite. Mechanical alignment were measured during all the assembly phases and before the
launch campaign. Moreover, a specific campaign was performed in the laboratory with radioactive calibration
sources to calibrate the imaging response on ground. A on-orbit calibration campaign was performed using the
Crab Nebula. Due to the huge satellite wobbling (1 deg) and continuous slewing (1 deg/day), a refined attitude
correction strategy has been implemented on photon-by-photon data to maintain the high imaging performances.
In this paper we summarize all the activities we performed for calibrating and optimizing the imaging capabilities,
from the assembly of the experiment to the on-orbit calibrations and we show the results achieved.
The development of micropixel gas detectors, capable to image tracks produced in a gas by photoelectrons,
makes possible to perform polarimetry of X-ray celestial sources in the focus of grazing incidence X-ray telescopes.
HXMT is a mission by the Chinese Space Agency aimed to survey the Hard X-ray Sky with Phoswich detectors, by
exploitation of the direct demodulation technique. Since a fraction of the HXMT time will be spent on dedicated
pointing of particular sources, it could host, with moderate additional resources a pair of X-ray telescopes, each
with a photoelectric X-ray polarimeter (EXP2, Efficient X-ray Photoelectric Polarimeter) in the focal plane. We
present the design of the telescopes and the focal plane instrumentation and discuss the performance of this
instrument to detect the degree and angle of linear polarization of some representative sources. Notwithstanding
the limited resources, the proposed instrument can represent a breakthrough in X-ray Polarimetry.
AGILE is an Italian Space Agency (ASI) satellite dedicated to high energy Astrophysics. It was launched successfully on 23 April 2007, and it has been operated by the AGILE Ground Segment, consisting of the Ground Station located in Malindi (Kenia), the Mission Operations Centre (MOC) and the AGILE Data Centre (ADC) established in Italy, at Telespazio in Fucino and at the ASI Science Data Centre (ASDC) in Frascati respectively. Due to the low equatorial orbit at ~ 530 Km. with inclination angle of ~ 2.5°, the satellite passes over the Ground Station every ~ 100'. During the visibility period of . ~ 12', the Telemetry (TM) is down linked through two separated virtual channels, VC0 and VC1. The former is devoted to the real time TM generated during the pass at the average rate of 50 Kbit/s and is directly relayed to the Control Centre. The latter is used to downlink TM data collected on the satellite on-board mass memory during the non visibility period. This generates at the Ground Station a raw TM file of up to 37 MByte. Within 20' after the end of the contact, both the real time and mass memory TM arrive at ADC through the dedicated VPN ASINet. Here they are automatically detected and ingested by the TMPPS pipeline in less than 5 minutes. The TMPPS archives each TM file and sorts its packets into one stream for each of the different TM layout. Each stream is processed in parallel in order to unpack the various telemetry field and archive them into suitable FITS files. Each operation is tracked into a MySQL data base which interfaces the TMPPS pipeline to the rest of the scientific pipeline running at ADC. In this paper the architecture and the performance of the TMPPS will be described and discussed.
The SuperAGILE experiment was launched on April 2007 onboard the Italian gamma-ray mission AGILE. With a field
of view of approximately one steradian and an angular resolution of 6 arcmin, SuperAGILE is imaging the X-ray sky in
two one-dimensional projections in the 18-60 keV energy range. After a ~2-month Commissioning Phase, SuperAGILE
was set in its nominal configuration at the beginning of Science Verification Phase in July 2007 and it is observing the
X-ray sky since then. In this paper we describe the in-orbit operations, the commissioning, science verification and inflight
calibration phases, and provide a brief summary of the scientific observations carried out until June 2008.
The XEUS mission incorporates two satellites: the Mirror Spacecraft with 5 m2 of collecting area at 1 keV and
2 m2 at 7 keV, and an imaging resolution of 5" HEW and the Payload Spacecraft which carries the focal plane
instrumentation. XEUS was submitted to ESA Cosmic Vision and was selected for an advanced study as a
large mission. The baseline design includes XPOL, a polarimeter based on the photoelectric effect, that takes
advantage of the large effective area which permits the study of the faint sources and of the long focal length,
resulting in a very good spatial resolution, which allows the study of spatial features in extended sources. We
show how, with XEUS, Polarimetry becomes an efficient tool at disposition of the Astronomical community.
The Italian small satellite mission AGILE has been launched the 23rd of April 2007. SuperAGILE is the solidstate
hard X-ray imager of the mission. It is a coded-mask imager, with six arcmin angular resolution, a field of
view in excess of 1 steradian, and a gross energy resolution. Ground calibration campaigns have been performed
in the last year to optimize the detector response, for the energy calibration, to obtain the effective area at
various angles for various energy bands, to study location accuracy and angular resolution. In this paper we
report the preliminary results achieved.
The AGILE satellite has just finished the first and larger part of its commissioning phase. SuperAGILE successfully
passed the commissioning tests, and it is now in its final configuration. It is observing the X-ray sky
since the end of June as a part of the Science Verification Phase. The in-flight calibrations has been started and
will ended at the end of October. We show the first data obtained with the instrument in the first months of
The Flight Model of the SuperAGILE experiment was calibrated on-ground using an X-ray generator and individual radioactive sources at IASF Rome on August 2005. Here we describe the set-up, the measurements and the preliminary results of the calibration session carried out with the X-ray generator. The calibration with omnidirectional radioactive sources are reported elsewhere. The beam was collimated using a two slits system in order to reach a rectangular spot at the detector approximately 1800 μm × 100 μm in size. The long dimension was aligned with the detector strip, so that the short dimension could fall within one single detector strip (121 μm wide). The detector was then slowly moved continuously such that the beam effectively scanned along the coding direction. This measurement was done both at detection plane level (i.e., without collimator and mask) to characterize the detector response, and at experiment level (i.e., with collimator, mask and digital electronics), to study the imaging response. Aim of this calibration is the measurement of the imaging response at 0, 10 and 20 degrees off-axis, with a parallel beam, although spatially limited to a ~2 mm long section of the coded mask.
The AGILE Mission will explore the gamma-ray Universe with a very innovative instrument combining for the first time a gamma-ray imager (sensitive in the range 30 MeV - 50 GeV) and a hard X-ray imager (sensitive in the range 15-45 keV). An optimal angular resolution and a large field of view are obtained by the use of state-of-the-art Silicon detectors integrated in a very compact instrument. AGILE will be operational at the beginning of 2007 and it will provide crucial data for the study of Active Galactic Nuclei, Gamma-Ray Bursts, unidentified gamma-ray sources, Galactic compact objects, supernova remnants, TeV sources, and fundamental physics by microsecond timing.
Development of multi-layer optics makes feasible the use of X-ray telescope at energy up to 60-80 keV: in this paper we discuss the extension of photoelectric polarimeter based on Micro Pattern Gas Chamber to high energy X-rays. We calculated the sensitivity with Neon and Argon based mixtures at high pressure with thick absorption gap: placing the MPGC at focus of a next generation multi-layer optics, galatic and extragalactic X-ray polarimetry can be done up till 30 keV.
The Flight model of SuperAGILE experiment was calibrated on-ground on August 2005 at IASF-Rome laboratories using standard radioactive X-rays sources. These omnidirectional sources were positioned at approximately 2 meters distance from the experiment. A method to correct for the beam divergence has been developed in order to use these measurements to derive information about the point spread function of the experiment for infinite distance sources. In this paper we describe the set-up of the measurements, the method to correct for the beam divergence and show preliminary results of the data analysis.
We present a concept study for a novel All Sky Monitor experiment employing very limited resources. Our experience in designing, building and testing SuperAGILE - the hard X-ray imager for the AGILE mission - has demonstrated the possibility to develop a medium-sensitivity, wide field imager, with (at launch stage) ~5.5 kg weight, 12 Watts power and 0.04 cubic meters volume. With these few resources, it can provide crossed one-dimensional images of 1/10th of the sky, with on-axis 6 arcminutes angular resolution and ~10 mCrab 1-day sensitivity in the 15-45 keV energy range. In this paper we introduce to the ASPEX (All Sky Project for Extraterrestrial X-rays) project and show how a much more efficient All Sky Monitor can now be designed using the same approach and techniques, overcoming a number of severe limitations suffered by SuperAGILE due to the context of the AGILE mission, for which it was designed. The low resources and its efficiency in localizing X-ray transients and in long-term monitoring the steady X-ray sky, make ASPEX a suitable option for several new mission concepts (e.g., PHAROS, ESTREMO, ...).
SuperAGILE is the hard X-ray (15-45 keV) imager for the gamma-ray mission AGILE, currently scheduled for
launch in early 2007. It is based on 4 Si-microstrip detectors, with a total geometric area of 1444 cm2 (max
effective area 230 cm2), equipped with 4 one-dimensional coded masks. The 4 detectors are perpendicularly
oriented, in order to provide pairs of orthogonal one-dimensional images of the X-ray sky. The field of view
of each 1-D detector is 107° x 68°, at zero response, with an overlap in the central 68° x 68° area. The angular
resolution on axis is 6 arcmin. We present here the current status of the hardware development and the scientific
In this paper we describe the instrumentation and the software tools we developed to test the SuperAGILE Front-End Electronics (SAFEE) and Interface Electronics (SAIE). The SAFEE is based on twelve XAA1.2 ASICs (produced by IDE-AS). The Test Equipment hardware is composed of commercial VME modules and laboratory developed boards. Commercial VME boards were used for data acquisition and SAFEE handling. Laboratory developed boards provide signal conditioning, pulse generation, trigger system and timing. The VME based architecture assured a stable system for a period of years and a very high acquisition rate. The choice of 'laboratory-developed' boards allowed an easy and cost effective continuous improvement of the system.
Two Linux running PC were used, one for the "System Control" and data acquisition, the other one for data reduction and archiving. The s/w for DAQ, data-reduction, and analysis also was laboratory-developed and based on well-known tools.
The AGILE gamma-ray mission is in its Phase C-D. The Engineering model of the Payload has been built and tested, and the construction of the flight model has started. We present here the status of the SuperAGILE experiment, the 15-40 keV imaging monitor, based on Silicon microstrip technology and equipped with one dimensional coded masks. We show the design of the experiment and the results of testing campaigns carried out on the engineering model of the experiment.
We show a modeling approach to describe the data involved in an astronomical space mission. The data design process is introductory to the developing of the software system for the SuperAGILE instrument on board of the Gamma ray satellite AGILE. The model will be used to simplify team coding, improve scientific return and to reinvest the results on future experiments.
AGILE is an ASI gamma-ray astrophysics space Mission which will operate in the 30 MeV - 50 GeV range with imaging capabilities also in the 10 - 40 keV range. Primary scientific goals include the study of AGNs, gamma-ray bursts, Galactic sources, unidentified gamma-ray sources, diffuse Galactic and extragalactic gamma-ray emission, high-precision timing studies, and Quantum Gravity testing. The AGILE scientific instrument is based on an innovative design of three detecting systems: (1) a Silicon Tracker, (2) a Mini-Calorimeter, and (3) an ultralight coded mask system with Si-detectors (Super-AGILE). AGILE is designed to provide: (1) excellent imaging in the energy bands 30 MeV-50 GeV (5-10 arcmin for intense sources) and 10-40 keV (1-3 arcmin); (2) optimal timing capabilities, with independent readout systems and minimal deadtimes for the Silicon Tracker, Super-AGILE and Mini-Calorimeter; (3) large field of view for the gamma-ray imaging detector (~3 sr) and Super-AGILE (~1 sr). AGILE will be the only Mission entirely dedicated to source detection above 30 MeV during the period 2004-2006.