An efficient plane-grating monochromator based on conical diffraction for continuous tuning in the entire soft X-ray...

Area of Science:

• X-ray optics
• Diffraction gratings
• Spectroscopy

Background:

• Reflection gratings with rectangular profiles exhibit high diffraction efficiency at grazing incidence for tender X-rays.
• Extreme off-plane (conical diffraction) orientation enhances grating performance.

Purpose of the Study:

• To explore the design of a conical diffraction monochromator for efficient and continuous tuning of photon energy.
• To evaluate the performance of such a monochromator for X-ray applications.

Main Methods:

• Utilizing reflection gratings in conical diffraction geometry.
• Employing a simple instrument design with a rotating plane grating and mirror.
• Incorporating a focusing mirror and exit slit for photon energy selection.

Main Results:

• The proposed monochromator scheme allows continuous tuning from below 1000 eV to 8 keV.
• High transmission is achieved as all components operate below the critical angle for total reflection.
• For tender X-rays (2-8 keV), the bandwidth is significantly larger than Si(111) double-crystal monochromators, offering higher flux.
• For soft X-rays (<1 keV), a relative spectral resolving power of approximately 10000 is achievable.

Conclusions:

• Conical diffraction monochromators offer a promising approach for high-throughput, tunable X-ray spectroscopy.
• The design provides flexibility in balancing flux and spectral bandwidth.
• This technology is suitable for both tender and soft X-ray energy ranges.