Assembly of confocal silicon pore optics mirror modules

Silicon Pore Optics (SPO) is the mirror technology selected for the Athena X-ray observatory. SPO leads to modular optics, where the aperture is filled with mirror modules co-aligned to a common focus. SPO is produced as stacks of 38 mirror plates, which are then paired to form X-ray Optics Units (XOUs) following a modified Wolter I geometry. In the current design, a mirror module is composed of two confocal XOUs bonded in between a pair of brackets to freeze the configuration and allow interfacing to the mirror structure. Mirror modules are assembled at the XPBF2 beamline of PTB at the synchrotron radiation facility BESSY II, using pencil beam and dedicated jigs. In this paper we present the latest developments regarding the assembly of confocal mirror modules.