5 research outputs found
The protoMIRAX Hard X-ray Imaging Balloon Experiment
The protoMIRAX hard X-ray imaging telescope is a balloon-borne experiment
developed as a pathfinder for the MIRAX satellite mission. The experiment
consists essentially in a coded-aperture hard X-ray (30-200 keV) imager with a
square array (1313) of 2mm-thick planar CZT detectors with a total area
of 169 cm. The total, fully-coded field-of-view is and the angular resolution is 143'. In this paper we
describe the protoMIRAX instrument and all the subsystems of its balloon
gondola, and we show simulated results of the instrument performance. The main
objective of protoMIRAX is to carry out imaging spectroscopy of selected bright
sources to demonstrate the performance of a prototype of the MIRAX hard X-ray
imager. Detailed background and imaging simulations have been performed for
protoMIRAX balloon flights. The 3 sensitivity for the 30-200 keV range
is ~1.9 10 photons cm s for an integration time
of 8 hs at an atmospheric depth of 2.7 g cm and an average zenith angle
of 30. We have developed an attitude control system for the balloon
gondola and new data handling and ground systems that also include prototypes
for the MIRAX satellite. We present the results of Monte Carlo simulations of
the camera response at balloon altitudes, showing the expected background level
and the detailed sensitivity of protoMIRAX. We also present the results of
imaging simulations of the Crab region. The results show that protoMIRAX is
capable of making spectral and imaging observations of bright hard X-ray source
fields. Furthermore, the balloon observations will carry out very important
tests and demonstrations of MIRAX hardware and software in a near space
environment.Comment: 9 pages, 13 figures, accepted for publication in Astronomy &
Astrophysic
XIPE: the X-ray Imaging Polarimetry Explorer
X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and
temporal variability measurements and to imaging, allows a wealth of physical
phenomena in astrophysics to be studied. X-ray polarimetry investigates the
acceleration process, for example, including those typical of magnetic
reconnection in solar flares, but also emission in the strong magnetic fields
of neutron stars and white dwarfs. It detects scattering in asymmetric
structures such as accretion disks and columns, and in the so-called molecular
torus and ionization cones. In addition, it allows fundamental physics in
regimes of gravity and of magnetic field intensity not accessible to
experiments on the Earth to be probed. Finally, models that describe
fundamental interactions (e.g. quantum gravity and the extension of the
Standard Model) can be tested. We describe in this paper the X-ray Imaging
Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a
small mission with a launch in 2017 but not selected. XIPE is composed of two
out of the three existing JET-X telescopes with two Gas Pixel Detectors (GPD)
filled with a He-DME mixture at their focus and two additional GPDs filled with
pressurized Ar-DME facing the sun. The Minimum Detectable Polarization is 14 %
at 1 mCrab in 10E5 s (2-10 keV) and 0.6 % for an X10 class flare. The Half
Energy Width, measured at PANTER X-ray test facility (MPE, Germany) with JET-X
optics is 24 arcsec. XIPE takes advantage of a low-earth equatorial orbit with
Malindi as down-link station and of a Mission Operation Center (MOC) at INPE
(Brazil).Comment: 49 pages, 14 figures, 6 tables. Paper published in Experimental
Astronomy http://link.springer.com/journal/1068