EUROMET key Comparison on spectral responsivity

Progress Report 10.02.2012

This report corresponds to the second part of year 2011. After sending Draft A to participants on 1 June, 2011, comments and questions were received from 4 participating laboratories between 30 August and 6 October. After that, a new version of Draft A has been sent to participants on 2 February 2012, Draft A-2. Participants have been requested to confirm this draft by mid February.


a) Detector characterization.

Detectors to be used in the comparison were characterized during the first semester of 2003, including spectral responsivity, linearity and uniformity, prior to the first round of measurements. After the return of detectors, their spectral responsivity has been checked in October 2003, prior to send the batches to the second group.

b) Comparison protocol.

After approval of the method to be used in the BIPM CCPR-K2.b for determining the KC reference value, the protocol draft for this comparison was completed and approved by the members of this key comparison working group: IFA, NMi and BNM. To calculate the reference value of this key comparison the procedure used by BIPM has been adopted. Furthermore, the procedure to calculate the link to the CCPR-K2.b has been approved in the working group and included in the protocol.The final protocol was distributed to participants by November 2003.

c) Measurements

As agreed on by participants, measurements have been scheduled in two groups. The first group was formed by METAS, JV-NSL, GUM and INM-Romania. They performed the measurements between July and October. Note that the final protocol was not approved by that time, although the measurement conditions were already established. This situation was well known by all participants and has no influence on the comparison results. Detectors were sent to three laboratories of the second group (BNM, UME and SP) on December 2003. Two of them have returned the detectors already and the third have not. The other two laboratories will receive the detectors on March 2004. These laboratories asked the pilot for a delay in performing the measurements due to their particular circumstances. The pilot estimated that this delay would not negatively influence the comparison run and agreed on sending the detectors later on to them. Comparison of National scales of spectral responsivity within the 300 - 1100 nm range. Participating laboratories will have to measure the spetral responsivity of some silicon trap detectors supplied by the pilot laboratory.

Spectral measurements will be done on a monochromator basis.

Further Information

Progress report submitted in May 2004