DC Monochromator
Brazilian Synchrotron Light Source (LNLS, CNPEM), Campinas, Brazil
An innovative scanning Double Crystal Monochromator (DCM) was developed and built with the ability to accurately select a defined wavelength.
A double crystal monochromator selects a narrow band from a broad wavelength source by two parallel silicon crystals. The wavelength selection is defined by the angle with the incoming beam and the crystal The pointing of the beam is defined by the parallelism of the two crystals. As the sample can be at a large distance (> 30m), pointing accuracy and stability are crucial.
Challenges
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Control bragg angle variations 2 – 60 deg during fly scan within pointing stability of < 5 nm
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LN2 cooling of the first crystal (< 70° K)
Cooperation
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Cooperation with LNLS for specifications, assembly, test and optimization
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LNLS beamline engineers participated in system integration as part of the knowledge transfer process
Key Competences
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System dynamics
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Thermal system analysis and management
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Cryogenics
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Precision mechanics
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Motion control