Performance of the XL-Calibur hard X-ray telescope before and after the 2022 stratospheric flight

Le résumé fourni par la source

We report on the performance of the hard X-ray telescope (HXT) onboard the XL-Calibur balloon-borne mission, before and after its 2022 long duration balloon (LDB) flight. XL-Calibur aims to achieve high-sensitivity hard X-ray polarization observations, with the HXT providing the large effective area essential for this mission. The HXT was developed in Japan; its initial performance measurement was conducted at SPring-8 BL20B2 in June 2021. Subsequently, XL-Calibur completed its first flight in July 2022. In preparation for the second XL-Calibur flight in 2024, we conducted a similar characterization at BL20B2 to assess whether the HXT maintained its performance after recovery. We observe that the on-axis effective area of the HXT increases from 276.4−0.4+0.5 to 288.2±0.6 cm2 (20 keV) and that the half-power diameter degrades from 1.8±0.1 arcmin to 2.0±0.1 arcmin (20 keV). Detailed analysis shows that in the part of the HXT that experienced the maximum change, reflectors tilt up to 0.4 arcmin, with a focal distance shift of ∼22 cm (a ∼2% change). Despite these changes, the performance of the HXT remains well within the tolerances required to meet the scientific requirements.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.