The Glasgow International Radiocarbon Inter-comparison (GIRI)

The next global radiocarbon inter-comparison is now underway with samples currently being dispatched by courier.

We have sourced a rich set of materials (thank you to everyone who has helped with this) - all samples are natural (wood, bone, peat and grain), some are known-age, and overall their age spans approx. 40,000BP to modern.are now ready to dispatch the samples (at last). Some samples have been pre-treated (cellulose and humic), but others will require pre-treatment and we ask that you provide some detail about your method of pre-treatment when reporting the results.

We have designed a study with two groups of samples.  The first group is typical of the samples provided in SIRI, where the volume of material being provided will be sufficient to make a few repeat measurements.  In the second group, we will provide a quantity of material, sufficient to allow AMS labs to run (and report) multiple measurements from different wheels/batches over the space of the six months experimental phase.  It is intended that sufficient material will remain to allow labs to use these as internal quality assurance samples.

If you have not already done so and you are interested in receiving samples, then please email or

This exercise is for AMS facilities, but we will endeavour, to send a smaller number of radiometric -size samples.

Reporting Results

Results for these samples should be returned by end of March 2022. A short report will then be prepared and sent to you by end of 2022.  We intend as in past inter-comparisons to create a more detailed, individualised report.

Results should be reported using the files below:

GIRI Participant Form

GIRI Results Table - AMS

GIRI Results Table - Radiometric

Please do not change the column order or labels, but if you are making multiple targets for a given sample, please insert rows to report individual results, not the average.

Send your completed results table and participant form to our specific mailbox: