The on-ground calibrations of SuperAGILE: I. X-ray pencil beam

Abstract

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.

Imaging x-ray sources at a finite distance in coded-mask instruments

“…The shrinking procedure was demonstrated to be a powerful tool to use diverging beam sources at finite distance to calibrate coded-mask systems. In this section we present how the shrinking procedure has been used during the calibrations of the SuperAGILE experiment, currently flying on-board the AGILE space mission (see [5] and [8] for the first calibrations of this instrument performed in 2005).…”