Speakers
Description
We report on gaseous detector developments for hard X-ray polarimetry in space, on two complementary fronts. First, we present the status of the EXPO (Enhanced X-ray Polarimetry Observatory) payload, a proposed ESA M-class mission extending IXPE's heritage with a 2–35 keV broadband polarimetric capability. EXPO employs five GridPix photoelectric polarimeters — two Low Energy Polarimeters (Ne/DME, 1 bar) and three Medium Energy Polarimeters (Ar/DME, 3 bar) — all based on an InGrid amplification stage read out by the Timepix3 ASIC, enabling dead-time-free 3D track imaging with modulation factors of 34% at 3 keV and 49% at 17.4 keV. We also discuss the assessment of the instrumental background and the potential application, in an orbital astrophysics context, of background-rejection techniques originally developed for underground dark-matter experiments, which may prove decisive in optimizing the final detector configuration. Second, we present a wide-field Time Projection Chamber for hard X-ray polarimetry, derived from directional dark-matter search technology. The prototype (3.7 cm radius, 6 cm drift, triple-GEM + sCMOS optical readout) achieves ~15° angular and 10–15% energy resolution in the 5–50 keV band. Polarized beam calibrations yield modulation factors exceeding 0.4 at 17 keV. We outline next-generation R&D on gas mixtures, ML-based onboard data reduction, and background simulations for LEO deployment targeting GRBs, magnetar flares, and Galactic sources above ~100 mCrab.
| Name of the speaker | Davide Fiorina |
|---|---|
| Eligible for the Georges Charpak Young Scientist Award. | yes |