D2AM, a beamline with a high-intensity point-focusing fixed-exit monochromator for multiwavelength anomalous...

Area of Science:

• Synchrotron Radiation
• Crystallography
• Materials Science

Background:

• The D2AM beamline at the European Synchrotron Radiation Facility (ESRF) is a versatile French CRG (Collaborative Research Group) facility.
• It is designed for both biological macromolecule crystallography and materials science, utilizing X-rays from a bending magnet.

Purpose of the Study:

• To detail the technical specifications and capabilities of the D2AM beamline.
• To highlight its suitability for single-wavelength and multiwavelength anomalous diffraction (MAD) studies.
• To emphasize its advanced optical system for high-intensity, focused X-ray beams.

Main Methods:

• Utilizes an Si[111] two-crystal monochromator for X-ray energy selection (6.5–17 keV).
• Employs a focusing system with two curved mirrors and a sagittally focusing monochromator crystal.
• Features automated alignment for mirrors and monochromator, enabling rapid wavelength changes for MAD experiments.

Main Results:

• Achieves a spot size of 0.3 x 0.1 mm (FWHM) at the sample position.
• Delivers beam intensity of approximately 10(11) photons/s on a 0.3 x 0.3 mm area.
• Provides excellent harmonic rejection (>10(-5)) and high energy resolution (0.5 eV stability/reproducibility).

Conclusions:

• The D2AM beamline's stable, high-intensity, and focused X-ray beam is well-suited for demanding crystallographic and materials science applications.
• Its automated features and rapid wavelength switching capabilities optimize experimental efficiency, particularly for MAD studies.
• The beamline's performance characteristics make it a valuable resource for researchers in structural biology and condensed matter physics.