Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Bilateral NIST-PTB Comparison of Spectral Responsivity in the VUV



Uwe Arp, Ping-Shine Shaw, Zhigang Li, Alexander Gottwald, Mathias Richter


To compare the calibration capabilities for the spectral responsivity in the vacuum-ultraviolet spectral region between 135 nm and 250 nm, PTB and NIST agreed on a bilateral comparison. Calibrations of semiconductor photodiodes as transfer detectors were performed using mono¬chromatized synchrotron radiation and cryogenic electrical substitution radiometers as primary detector standards. Great importance was attached to the selection of suitable transfer detector standards due to their critical issues in that wavelength regime. The uncertainty budgets were evaluated in detail. The comparison showed a reasonable agreement between the participants. However, it got obvious that the uncertainty level for this comparison cannot easily be further reduced due to the lack of sufficiently radiation-hard and long-term stable transfer standard detectors.


vacuum-ultraviolet, absolute cryogenic radiometer, synchrotron radiation, responsivity


Arp, U. , Shaw, P. , Li, Z. , Gottwald, A. and , M. (2011), Bilateral NIST-PTB Comparison of Spectral Responsivity in the VUV, Metrologia, [online], (Accessed June 21, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created January 20, 2011, Updated February 19, 2017