Key comparison on gauge block measurement by interferometry

Project Description

An MRA key comparison on measurement of gauge blocks by interferometry (or similar high accuracy technique). Gauge blocks anticipated to cover the range from ~1 mm to 500 mm. The comparison will link with the CCL-K1.n01 comparison also being organised at the same time through common participants.

Progress Report 2026-08-17

The first (EU) circulation loop was completed at the end of 2024 with the gauges being returned to the pilot.
The second (ATA Carnet) loop has now been completed but with a delay which caused the Carnet to expire.
The gauges are back with the pilot and are being calibrated prior to starting loop 3.

Two participants originally planned for loop 2 have been added to loop 3, which is about to be re-planned.
Circulation is expected to end in early 2027.

AzMi (Azerbaijan Institute of Metrology) is no longer taking part in this project.

Progress Report 2025-10-06

The first (EU) circulation loop was completed at the end of 2024 with the gauges being returned to the pilot. The second (ATA Carnet) loop is now underway.
One EU participant had to delay until loop 3 and another EU participant is also likely to delay until loop 3.

Circulation is spected end of 2026 or early 2027.

Progress Report 2023-09-28

The pilot laboratory pre-measurements have been completed. The comparison started in July 2023 with NPL making their official measurements as a participant. The gauges were then shipped to SMD Belgium (for customs reasons) and SMD then shipped the gauges to the next participant, CEM. Thus, the first loop circulation has started. This EU loop is planned to end in November 2024 when the gauges will be returned to the pilot laboratory for check measurements prior to starting the circulation loop involving an ATA Carnet in 2025. The items are finally expected back at the pilot laboratory at the end (December) of 2025.