ESRF Double Crystal Monochromator - Design and Working Modes
R. Baker, R. Barrett, P. Bernard, G. Berruyer, J. Bonnefoy, M. Brendike, L. Ducotté, H. Gonzalez, T. Roth, P. Tardieu
ESRF, Grenoble, France
The ESRF-Double Crystal Monochromator (ESRF-DCM) has been designed and developed in-house to enable several spectroscopy beamlines to exploit the full potential of the ESRF-EBS upgrade, implemented in 2019 - 2020. To reach concomitant beam positioning accuracy and stability, particular attention has been paid to mechanical and thermal stability, which has imposed the implementation of several innovative design concepts. To meet the extremely challenging specifications of the ESRF DCM implies not only high precision mechanical design, but also a mechatronic system enabling the active correction of the parallelism between crystals. Online metrology, associated with a controller capable of real-time signal processing have been implemented. A prototype has been partially validated and production of the first batch (two ESRF DCMs) is in progress. This presentation will give an overview of the DCM design principles and operating modes, then show how the calibration process is performed in situ on the beamline, using x-rays and associated instrumentation, and will explain the working principle of the active correction mode. To conclude, some characterisations of the DCM performances with x-rays will be presented.
Mechatronics Approach for the Development of a Nano-Active-Stabilization-System
93
T. Dehaeze, J. Bonnefoy
ESRF, Grenoble, France
C.G.R.L. Collette
ULB, Bruxelles, Belgium
Funding:This research benefited from a FRIA grant from the French Community of Belgium. With the growing number of fourth generation light sources, there is an increased need of fast positioning end-stations with nanometric precision. Such systems are usually including dedicated control strategies, and many factors may limit their performances. In order to design such complex systems in a predictive way, a mechatronic design approach also known as "model based design", may be utilized. In this paper, we present how this mechatronic design approach was used for the development of a nano-hexapod for the ESRF ID31 beamline. The chosen design approach consists of using models of the mechatronic system (including sensors, actuators and control strategies) to predict its behavior. Based on this behavior and closed-loop simulations, the elements that are limiting the performances can be identified and re-designed accordingly. This allows to make adequate choices concerning the design of the nano-hexapod and the overall mechatronic architecture early in the project and save precious time and resources. Several test benches were used to validate the models and to gain confidence on the predictability of the final system’s performances. Measured nano-hexapod’s dynamics was shown to be in very good agreement with the models. Further tests should be done in order to confirm that the performances of the system match the predicted one. The presented development approach is foreseen to be applied more frequently to future mechatronic system design at the ESRF.
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