The Metrology Light Source operated as a primary source standard

Abstract

The Metrology Light Source (MLS)—the dedicated electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB), designed for metrology and technological applications in the spectral range from the far IR to the VUV—started user operation in April 2008. The MLS is used as a primary source standard from the NIR to the VUV spectral region and is therefore equipped with all the instrumentation necessary to measure with low uncertainty the storage ring parameters and the geometrical parameters needed for the calculation of the spectral photon flux according to the Schwinger theory. It can be operated at any electron beam energy between 105 MeV and 630 MeV and at electron beam currents varying from 1 pA (one stored electron) up to 200 mA, which allows conditions to be tailor-made for special applications.

A systematic neutron reflectometry study on hydrogen absorption in thin Mg1-xAlx alloy films Special issue on Neutron Scattering in Canada.

“…less than about 1000 stored electrons, N is determined unambiguously by counting the number of stored electrons via observation of the emitted SR flux which shows a step per electron provided that the SR detection system is sufficiently sensitive. This electron counting technique for providing very low photon fluxes is routinely applied by PTB at the MLS [52], at BESSY II [53] and by NIST at SURF III [58]. In addition to the source-based radiometry described above, detector-based radiometry over a wide dynamic range can also be performed at storage rings.…”

Metrology of photoluminescent materials

“…less than about 1000 stored electrons, N is determined unambiguously by counting the number of stored electrons via observation of the emitted SR flux which shows a step per electron provided that the SR detection system is sufficiently sensitive. This electron counting technique for providing very low photon fluxes is routinely applied by PTB at the MLS [52], at BESSY II [53] and by NIST at SURF III [58].…”

Predictable quantum efficient detector based onn-type silicon photodiodes

“…In general, the radiometric quantity radiant flux [5][6][7], commonly referred to as optical power, can be realized using absolute radiation sources or detectors. Source-based realization of the absolute radiant power scale can be based on Planckian radiators [6][7][8], synchrotron radiation [6,7,[9][10][11], or photon pairs produced by parametric down-conversion [7,12,13]. Standard detectors, on the other hand, can be divided into two main categories based on their operation principle: thermal detectors sense the heating effect of optical radiation and quantum detectors, such as silicon photodiodes, convert photons into detected charge carriers.…”