The Advanced Photon Source
a U.S. Department of Energy Office of Science User Facility

Crystal Optics

 

"

Expertise includes:

  1. Designing crystal optics with X-ray dynamical-theory calculations and modeling to achieve desired resolution, efficiency, acceptance, etc., In-house dynamical theory software HXRD is available upon request.
  2. Fabricating and refurbishing ultrahigh-quality crystal optics (Si, Ge, quartz, sapphire, diamond), from precise orienting, cutting/dicing, grinding, etching, to strain-free polishing
  3. X-ray characterization and testing of crystal optics using X-ray topography and double-crystal rocking curve imaging.

Work requests can be submitted by filling the Optics Group's work request from.

 

The crystal optics facilities are described below.

                           ​

Dicing/Cutting Laboratory (COF2)

The lab is equipped with two dicing saws for precision cutting of wafers and plates up to 10mm thick, and a diamond-wire saw for slicing crystal boules of Si and Ge up to 8 inches in diameter and length. All slicing and cutting processes have been optimized to minimize the induced crystalline damage.

Etching Laboratory (Bldg. 401/L0104)

This facility is used to etch crystals using wet chemical methods (mainly HF and HNO3) to remove surface layers that have stresses/strains/damages induced by machining processes.

Polishing Lab (COF3)

The Polishing Laboratory utilizes the following lappers/polishers

Hyprez LM28 Lapping Machine (Engis)

Conventional lapping machine is used for planarization and thinning of optical components up to 300mm diameter on composite copper lapping plate or hard pad.

Strasbaugh 6DF-1 Precision Polishmaster

This versatile overarm polisher can be outfitted with variety of plates and pads to perform intermediate and fine polishing steps, using diamond or colloidal silica slurries.

C-CHiRP 400 Channel Cut Polishing Machine

In-house developed and patented method for automated polishing of channel-cut crystal monochromators. Polishing of the inner diffracting surfaces reduces helps preserve coherence of the beam, and is critical for taking advantage of APS-U beam characteristics."

Inspection Equipment

The Fabrication Laboratory is equipped with DIC microscope for immediate inspection during polishing process. Optics requiring more detailed inspection and accurate measurements are sent to the Metorology Laboratory.

Other Equipment (in collaboration with the ANL Central Shops)

Two high-precision grinders; Blanchard precise grinder; several overarm polishers; core drill press; and Ultrasound mill.

X-ray Laboratory (Bldg. 401/L0111 and 401/L0120)

This laboratory is equipped with three main instruments:

  1. Two-axis Rigaku diffractometer (with Cu or Mo x-ray tube) for precisely orienting single crystals along required lattice planes with precision ≤0.1°.
  2. Back-reflection Laue camera (with Cu or Mo x-ray tube) for identification/verification of crystal orientations, equipped with the LauePt simulation software (developed in-house by Xianrong Huang) for studying the orientations of any single crystals with high precision up to 0.1°.
  3. Topo Unit, consisting of 18kW rotating-anode X-ray generator and a double-crystal diffractometer, can measure high-resolution (strain sensitivity better than 10-6) double-crystal rocking curves of silicon, germanium, diamond, etc. and take topography images (with a CCD detector) on each point of the rocking curve. The X-ray beam size can be up to four inches in diameter, allowing to reveal macroscopic strains of large crystals (including X-ray monochromators mounted on fixtures). A ultrahigh-precision stage is under development for orienting crystals with precision toward 0.01o.

"

Advanced X-ray characterization of crystal optics is carried out at the 1-BM Optics and Detectors Test Beamline.

Crystal Optics Research and Development

R&D in crystal optics is carried out either independently, or jointly with the APS beamline scientists and user community, or in collaboration with other facilities to keep the group at the state-of-the art in x-ray optics. Examples include designing and development of high-to ultrahigh- resolution crystal monochromators and analyzers (from sub-10 meV to sub-meV) for IXS/RIXS, strain-free crystal polishing with roughness toward 1A, automated machine polishing of channel-cut crystals, quartz-based X-ray optics, diamond optics, SiC optics, etc.

"

Development of novel sub-10-meV RIXS system with a flat quartz analyzer (in collaboration with IXN Group, Kim et al., Scientific Reports 8, 1598 (2018).

 

 

 

09.03.2021