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Synchrotron Radiation Sources

Working Group 7.22


The group is responsible for the operation and usage of the electron storage rings BESSY II and Metrology Light Source (MLS) as national radiometric source standards in a wide spectral range from the near infra red up to the X-ray range. The group operates all equipment that is necessary for the determination of all parameters need for the calculation of the spectral radiant intensity of the synchrotron radiation with low uncertainty.

At both electron storage rings a beamline for the usage of the un-dispersed, calculable synchrotron radiation is available. Here, the radiation from the respective electron storage ring is used for the characterization of energy-dispersive detectors or wavelength-dispersive spectrometers, e.g. for space missions. For the latter task a large vacuum vessel is available that allows to accommodate an entire space spectrograph.

The calibration of radiation sources in terms of spectral radiant intensity and spectral radiance is performed traceable to the respective national standards BESSY II and MLS. Therefore, both at BESSY II and at the MLS facilities for the calibration of radiation sources are available, at BESSY II for the spectral range 35 nm to 400 nm and at the MLS for the extended spectral range from 7 nm to 400 nm.

Moreover, the group is responsible for the operation of the undulator U125 at the MLS and the undulator U49 at BESSY II and the usage of the respective white light beamlines. The group also deploys a 7 T wavelength shifter as a source of calculable radiation in the hard x-ray spectral range.

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  • Source-based characterization of space instruments, spectrometers and energy-dispersive detectors.
  • Development and spectral characterization of transfer standard sources.
  • Characterization of radiation sources in the spectral range from 7 nm to 400 nm.
  • Usage of the flexible operation mode of the electron storage rings, especially of the MLS, in terms of reduced electron beam current or electron beam energy for research.
  • Research on steady-state-micro-bunching at electron storage rings.

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Calibration of radiation sources in terms of spectral radiant intensity or radiance traceable to the national standards BESSY II and MLS in the spectral range from 115 nm to 400 nm, especially of deuterium lamps.

Calibration of energy-dispersive or wavelength dispersive instruments with direct, calculable synchrotron radiation

Provision of the values of the storage ring parameters with low uncertainty for other PTB groups engaged at the MLS or BESSY II, especially of the electron beam current.

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