Development of silicon pore gratings for x-ray spectroscopy

X-ray reflection gratings, similar to x-ray mirrors in their use at grazing incidence, must be precisely co-aligned into stacked modules to achieve sufficient collecting area for high-resolution spectroscopy. Inspired by the silicon pore optic (SPO) technology for NewAthena, a process for stacking and bonding ribbed reflection gratings to produce “silicon pore gratings” is being developed for the Off-Plane Grating Rocket Experiment (OGRE) as proof of concept for future x-ray observatories. The process starts with substrate conformal imprint lithography (SCIL) to produce replica imprints of a master grating stamp in silica-like resist coated on wedged silicon substrates. These imprints are then diced into ribbed grating plates that match groove-free strips on each replica such that they can be bonded in a stack. With direct silicon bonding enabled by the inorganic nature of the imprint resist used in SCIL, the reflection grating plates can be stacked into modules with the same robotic arm technology used for SPOs. This presentation details the process under development and presents results from preliminary studies carried out for OGRE.