The milli-arc-second structure imager (MASSIM): a new concept for a high angular resolution x-ray telescope

Abstract

MASSIM, the Milli-Arc-Second Structure Imager, is a mission that has been proposed for study within the context of NASA's Astrophysics Strategic Mission Concept Studies program. It uses a set of achromatic diffractiverefractive Fresnel lenses on an optics spacecraft to focus 5-11 keV X-rays onto detectors on a second spacecraft flying in formation 1000 km away. It will have a point-source sensitivity comparable with that of the current generation of major X-ray observatories (Chandra, XMM-Newton) but an angular resolution some three orders of magnitude better. MASSIM is optimized for the study of jets and other phenomena that occur in the immediate vicinity of black holes and neutron stars. It can also be used for studying other astrophysical phenomena on the milli-arc-second scale, such as those involving proto-stars, the surfaces and surroundings of nearby active stars and interacting winds.We describe the MASSIM mission concept, scientific objectives and the trade-offs within the X-ray optics design. The anticipated performance of the mission and possible future developments using the diffractiverefractive optics approach to imaging at X-ray and gamma-ray energies are discussed.

Multiband imaging at the diffraction limit using Fresnel x-ray telescopes

“…Nevertheless, its combination with refractive lens components made of Be likely marks the most attractive type of all hybrid optics as discussed so far under the criterion of technical feasibility. A similar approach was also proposed for the MASSIM mission, 7 and it might be worthwhile to investigate the performance of this heterogeneous implementation. For the data in the right column ("Be-PC") of Table 15, the Be Fresnel lens from the monolithic scheme (summarized in Table 14) is simply replaced by the polycarbonate device as described above.…”

“…Be will probably serve as the more practical alternative for short-term proof-of-concept "pathfinder" studies and also full-size missions. 7 Despite its worse transmission, the higher density and refractive power enables a more relaxed lens design in terms of the aspect ratio. Moreover, its greater hardness and stability compared to Li should ease the precise fabrication of the Fresnel grooves.…”

“…Hybrid optics, designed for a specific energy on behalf of an additional refractive component, 2,6 extend the bandwidth to a few 10 2 eV. In the recent past, a preliminary mission concept 7 found its way to the community and even experimental results on scaled-down versions of Si Fresnel lenses have been published. 8,9 Despite their impressive optical capabilities with respect to resolution as well as sensitivity, all those telescopic arrangements are restricted to a specific energy band.…”

“…Its high stiffness and excellent suitability for low-temperature, even cryogenic applications, 23 mark it as the likely material of choice for the realization of a mid-term mission for energies beyond about 4.5 keV. 7 …”

Toward the diffraction limit with transmissive x-ray lenses in astronomy

“…Almost one decade ago, Skinner [7,8] proposed diffractive/refractive lenses for next-generation spaceborne telescopes beyond current mirror-based observatories such as XMM-Newton and Chandra. Despite advancements such as possible arrangements [9,10], integrated mission concepts [11], and instructive reviews [12,13], a selfcontained theory of their optical components in prospect is still missing.…”