Grazing incidence imaging from 10 to 40 keV

Area of Science:

• X-ray astronomy
• Grazing incidence optics
• Materials science

Background:

• Grazing incidence optics are crucial for focusing X-rays in astronomical imaging.
• Current mirror technologies face limitations in reflectivity and performance at higher X-ray energies.
• Explorer class missions require advanced optics for high-energy observations.

Purpose of the Study:

• To explore the feasibility of imaging X-rays at 10-40 keV using grazing incidence optics.
• To review the scientific rationale and existing laboratory measurements for high-energy X-ray optics.
• To evaluate potential mirror materials for improved reflectivity and performance.

Main Methods:

• Reviewed scientific literature and laboratory measurements on grazing incidence optics.
• Measured reflectivity of iridium-coated float glass and gold-coated mirrors at various grazing angles and X-ray energies (8, 17, 26 keV).
• Assessed mirror performance against theoretical predictions.

Main Results:

• Iridium-coated float glass demonstrated improved reflectivity over gold, aligning with theoretical predictions.
• Both materials exhibited lower absolute reflectivity than theoretically expected, potentially due to deposition methods affecting layer density.
• High reflectivity (>50%) was achieved with iridium-coated glass at grazing angles up to 33, 16, and 11 arcmin at 8, 17, and 26 keV, respectively.

Conclusions:

• Iridium-coated float glass is a viable material for high-energy X-ray imaging optics.
• Measured reflectivity values are close to theoretical predictions, indicating the potential for effective high-energy X-ray telescopes.
• A design for an Explorer class high-energy imaging telescope utilizing these optics is presented.