The New Hard X-ray Mission (NHXM) Italian project will be operated by 2016. It is based on 4 hard X-ray optics
modules, each formed by 60 evenly spaced multilayer coated Wolter I mirror shells. For the achievement of a long focal
length (10 m) an extensible bench is used. The pseudo-cylindrical Wolter I monolithic substrates where the multilayer
coating is applied will be produced using the Ni electroforming replica approach. For three of the four mirror modules
the focal plane will host a hybrid a detector system, consisting in the combination of a Si-based low energy detector
(efficient from 0.5 up to ~ 15 keV) , on top of a high energy CdTe pixellated detector (efficient from 10 keV up to ~ 80
keV); the two cameras will be surrounded by both a passive shield and an anticoincidence shield. The total on axis
effective area of the three telescopes at 1 keV and at 30 kev is of 1500 cm2 and 350 cm2 respectively. The angular
resolution requirement is better than 20 arcsec HEW at 30 keV, while the Field of View at 50% vignetting is 12 arcmin
(diameter). The payload is finally completed with the fourth telescope module, that will have as a focal plane detector a
high sensitivity imaging photoelectric polarimetric system, operating from 2 up to 35 keV. In this paper, after an
overview of the mission configuration and its scientific goals, we report on the design and development of the multilayer
optics of the mission, based on thin replicated Ni mirror shells.
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