K-EUSO: An improved optical system for KLYPVE ultra-high energy cosmic ray space telescope

Abstract

KLYPVE is a Russian science mission to detect ultra-high energy cosmic rays (UHECRs) above 5-1019 eV. It will be attached to the Russian MRM-1 module onboard the International Space Station. The K-EUSO project is a result of the joint efforts of the JEM-EUSO collaboration to improve performance of the KLYPVE mission by employing the technologies (a corrective Fresnel lens, the focal surface detector, and a laser head) developed for the JEM-EUSO mission. The baseline design of the new KLYPVE uses a 3.4 m primary mirror, allowing large photon collection efficiency. Light from the mirror is focused by a 1.7 m diameter, double sided Fresnel lens above the focal surface. The lens enlarges the field of view to -14 and reduces aberrations thus improving the effective area by more than a factor 7. The corrective lens improves the RMS spot size to about 5 mm by using the EUSO detector technology. This paper describes details of the baseline optical system for the K (KLYPVE)-EUSO.