Radiometric comparison of the primary source standard ‘Metrology Light Source’ to a primary detector standard
| Autor: | R. Fliegauf, Alexander Gottwald, Gerhard Ulm, H. Kaser, Arne Hoehl, G. Brandt, Udo Kroth, Roman Klein, Reiner Thornagel, Mathias Richter |
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| Rok vydání: | 2011 |
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| Zdroj: | Metrologia. 48:219-225 |
| ISSN: | 1681-7575 0026-1394 |
| DOI: | 10.1088/0026-1394/48/3/017 |
| Popis: | The spectral radiant intensity of synchrotron radiation from electron storage rings can be calculated from basic electrodynamic relations (Schwinger equation). A storage ring can, thus, be used as a radiometric primary source standard. The Metrology Light Source (MLS), the dedicated electron storage ring of the Physikalisch-Technische Bundesanstalt, can be operated as a primary radiation source standard from the near infrared up to the soft x-ray region and its operational parameters can be adjusted and accurately measured in a wide range. The MLS electron beam current can be varied from 1 pA (one stored electron) up to 200 mA and, thus, the radiant intensity, being directly proportional to the stored current, can be varied by more than 11 decades. The electron energy, which has a large effect on the spectral shape of the spectrum, can be varied from 105 MeV up to 630 MeV. For the radiometric comparison, the total power irradiated into a well-defined solid angle was directly measured by a cryogenic radiometer as a primary detector standard and compared with the power calculated from the storage ring parameters. These measurements were performed for various electron energies in the range from 200 MeV to 630 MeV, thus varying the shape of the spectrum. For each electron energy setting, the power level was varied within the dynamic range of the cryogenic radiometer by a variation of the electron beam current. Good agreement was found for all parameter settings, thus validating the performance of the cryogenic radiometer and the storage ring parameter measurements within the related uncertainty budget. |
| Databáze: | OpenAIRE |
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