Fly-scan-oriented motion analyses and upgraded beamline integration architecture for the High-Dynamic Double-Crystal Monochromator at Sirius/LNLS

J Synchrotron Radiat. 2023 Jan 1;30(Pt 1):90-110. doi: 10.1107/S1600577522010724. Epub 2023 Jan 1.

Abstract

The High-Dynamic Double-Crystal Monochromator (HD-DCM) is a mechatronic system with unique control-based architecture and deep paradigm changes as compared with traditional beamline monochromators. Aiming at unprecedented inter-crystal positioning stability in vertical-bounce double-crystal monochromators (DCMs) of the order of 10 nrad RMS (1 Hz to 2.5 kHz), and not only in fixed-energy but also in fly-scan operation, it has been developed according to a `first-time right' predictive design approach for hard X-ray beamlines at Sirius, the fourth-generation light source at the Brazilian Synchrotron Light Laboratory (LNLS/CNPEM). This work explores some of the challenges that emerge with this new technology and presents the latest commissioning results that demonstrate the unparallel performances of the HD-DCM at the undulator-based EMA (Extreme Methods of Analysis) beamline at Sirius. With the enabled fast spectroscopy fly-scan possibilities, a new energy-tuning evaluation method, based on wave-propagation simulations, becomes part of a motion-oriented analysis that is carried out to derive the multi-axis non-linear positioning problem, covering not only energy selection and fixed exit in the HD-DCM but also the emission spectrum of an adjustable-phase undulator (APU). The HD-DCM control scheme and its flexible operation modes are described in detail as well. Furthermore, a new integration topology between the HD-DCM and EMA's APU, coming already close to ultimate motion levels, is described and validated.

Keywords: beamline integration; continuous energy scanning; high-performance mechatronics; synchrotron instrumentation; vertical double-crystal monochromator.

Grants and funding

This work is supported by the Brazilian Center for Research in Energy and Materials (CNPEM) under contract with the Brazilian Ministry of Science and Technology and Innovation (MCTI).