A new facility for the synchrotron radiation-based calibration of transfer radiation sources in the ultraviolet and vacuum ultraviolet spectral range

Abstract

The Physikalisch-Technische Bundesanstalt (PTB) has a long tradition in the calibration of radiation sources in the ultraviolet and vacuum ultraviolet spectral range, with traceability to calculable synchrotron radiation. Within this context, new instrumentation in the PTB laboratory at the Metrology Light Source (MLS) has been put into operation that opens up extended and improved calibration possibilities. A new facility for radiation source calibrations has been set up in the spectral range from 7 nm to 400 nm based on a combined normal incidence-grazing incidence monochromator. The facility can be used for the calibration of transfer sources in terms of spectral radiant intensity or mean spectral radiance, with traceability to the MLS primary source standard. We describe the design and performance of the experimental station and give examples of some commissioning results.

PTB’s radiometric scales for UV and VUV source calibration based on synchrotron radiation

“…More details of the calibration principle can be found in [16,17]. PTB operates a transfer station at the electron storage ring BESSY II, which covers the spectral range from 40 nm to 400 nm [8,13] and has been transferred from the BESSY I electron storage ring to BESSY II.…”

“…PTB operates a transfer station at the electron storage ring BESSY II, which covers the spectral range from 40 nm to 400 nm [8,13] and has been transferred from the BESSY I electron storage ring to BESSY II. A more recently constructed station is operated at the MLS, which covers the spectral range from 7 nm to 400 nm [16,17]. Table 1 summarizes the standard uncertainties obtained for the calibration of D2 transfer sources at PTB.…”

“…Later-after the closure of BESSY I-QNIM moved to the BESSY II electron storage ring. The newly set up station at the MLS [16,17] is labelled as QMP. There are two types of intercomparison: firstly, direct comparisons of the primary source standard to another primary source or detector standard by means of transfer artefacts and secondly, intercomparisons of transfer sources, calibrated by means of different transfer stations traceable to the related primary source.…”

“…These activities started at the former DESY [5] and BESSY I [6-10] synchrotron radiation facilities which are now closed. Presently, they are performed at BESSY II [11][12][13] and also at the metrology light source (MLS) [14][15][16][17], the radiometry-dedicated electron storage ring of PTB. The National Institute of Standards and Technology (NIST) has been using the electron storage ring SURF III [18] and its predecessors in a similar fashion since the 1970s.…”

A simple Peltier cold trap aperture for protection of vacuum UV optics against hydrocarbons and reliable calibration of VUV spectrometers using D2 lamps

“…As a result, the calibration procedure can be massively falsified due to the change in the emitted spectrum of the calibrated D 2 lamp and needs to be addressed. The Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany, calibrates radiometric standards in absolute units from 7 nm to 400 nm at the new electron storage ring Metrology Light Source (MLS) [7,8]. In the case of D 2 lamps a nitrogen cooled trap aperture is placed just in front of the MgF 2 window reducing the hydrocarbon flux and minimizing the intensity reduction.…”