Mirrors and Multilayer Optics

Objective:

Develop and fabricate single and multilayer thin film optics, as well as experimental samples, primarily for APS beamlines and users. Staff are available for consultation regarding thin-film deposition materials selection and general optical component design or simulation. The deposition laboratories include: 1) Class 10,000 clean room that houses a large DC sputtering system and a small deposition system; 2) Class 100, 000 clean room that house a rotary deposition system and a laboratory x-ray reflectrometer for evaluation of single and multilayer thin film optics; and 3) Class 10,000 class cleanroom that is used for beamline optical system mounting and for the development of the future APS mirror/multilayer modular deposition system. These laboratories are conveniently located near 1-BM Optics and Detector Testing beamline, in the APS experiment hall floor.

Work requests can be submitted by filling the Optics Group's work request from at https://beam.aps.anl.gov/pls/apsweb/wam0002.owr_main_menu.

Figure 5: APS existing large deposition system.

Large (1.5 m) Sputter Deposition System:

Mirror substrates as large as 150 cm long, 20 cm wide, and 14 cm high can be loaded into a substrate carrier inside the vacuum system using guard rails. The substrate can be outgassed in the load lock chamber using a UV lamp. The substrate-carrier transport assembly is driven by a stepper-motor. The full length of a 1.5 m substrate can be coated using the transport assembly.

Currently four 3" diameter magnetron sputtering guns compatible with both DC and RF operations are deployed.

Small Sputter Deposition System:

Figure 6: The new small DC sputtering system. Inserts: (bottom left) R. Conely explaining the computer interface and control system, and (bottom right) the first double crystal monochromator coated using this system.

A new small profile-coating system has been commissioned and is expected to be used to explore differential-deposition techniques in order to produce more precisely-figured nanofocusing mirrors. This new system (see Figure 6) incorporates advanced features such as the ability to fabricate mirrors up 180 mm, reactive sputtering for research into new profile-coating materials, servo-based translation, and complete control system flexibility. Most importantly, this sputtering system is capable of arbitrary velocity trajectories. This feature can be utilized for thin-film thickness gradients in the axis parallel to translation, an APS first. The system was deemed fully operational in Feb. 2014.

Rotary Sputter Deposition System:

This deposition system was used to develop the first wedged multilayer Laue lenses and is used for certain types of small-area multilayer optics and experimental samples. An upgrade to add a secondary rotation axis in order to rapidly spin optics over upward-facing cathodes is planned. This upgrade will allow for intrinsically-uniform multilayer coatings on substrates up to 100mm in diameter.

Figure 7: Design concept of the APS modular mirror/multilayer deposition system.

Modular Multilayer/Mirror Deposition (MMD) System:

A unique x-ray optics processing system that will allow in-house fabrication of mirrors capable of taking full advantage of the improved coherence x-ray beams from the MBA lattice is currently being designed. This modular multilayer/mirror deposition (MDS) system will be the world's first thin-film deposition system combining in situ metrology with deposition and ion milling for 1.5-m mirrors. It will allow APS thin film experts to develop novel thin film optics to explore new science frontiers and meet the many of "Grand Challenges" highlighted in the 2013 DOE x-ray optics report.

Thin Film Laboratory Capabilities:

  • Substrates as large as 1.5m long, 20 cm wide, and 14 cm thick can be coated.
  • A variety of target materials are available.
  • Thin film stripping and substrate cleaning capability is available.
  • Short turn-around time for many types of coatings.
  • Ellipsometry, profilometry, and x-ray reflectometry are used for thin-film characterization.

X-ray mirrors, multilayers and experimental samples are fabricated on a routine basis. Thousands of thin-film based optics and samples have been supplied to the APS user community over the history of the APS. We can reliably provide high-quality thin-film and multilayer optics and experiment samples, and we are constantly improving our equipment to satisfy the demand from the APS user community. In addition, we have the expertise to fabricate complete short focal length, fixed-geometry K-B mirror assemblies.

Figure 8: Concept of MLL-based microscope.

Thin Film Research and Development

R&Din thin film optics is carried out jointly with the APS beamline scientists and user community, independently or in collaboration with other facilities to keep the group at the state-of-the art in x-ray optics. Examples include studies of new materials for mirrors, monochromators, and multilayer Laue lens; thin film stress mitigation; thin film radiation damage; etc.