Preparing Samples for Submission

The CEN radiochronology laboratory specializes in radiocarbon dating. This is based on the principle of the degradation of the radioactive carbon isotope 14C.

The basic principle is that an organism lives in equilibrium with the ambient concentration of 14C throughout its life. Upon death, the organism ceases to ingest carbon, and the remaining 14C in its tissues decays at a known rate.

Radiocarbon dating by AMS (Accelerator Mass Spectrometry) is possible for organic samples (wood, charcoal, seeds, peat, sediments, plants, roots), shells (and carbonates) and also bones (and teeth, ivory, animal horn...). It can be carried out on very small samples (a few milligrams).

The CEN radiochronology laboratory has the equipment and expertise required to prepare samples for AMS dating, which involves two main stages:

• Sample preparation by fractionation of their carbon components, followed by CO₂ oxidation and graphitization on a target. This is a chemical step.
• Counting in a particle gas pedal is a specialized nuclear physics step.

The Radiochronology Laboratory proves its excellence at the international 14C AMS inter-laboratory comparison (SIRI)! See the results here.

1. Once the samples have been received and identified, the first stage of chemical pre-treatment is carried out.
2. The samples then undergo a combustion stage. This produces carbon dioxide (CO₂).
3. The CO₂ is then purified in a vacuum system.
4. The resulting ultra-pure carbon dioxide is sealed in a glass tube using a torch.
5. This ultra-pure CO₂ is then graphitized using a semi-automated graphitizing line (whose operations are controlled by a touch monitor).
6. The graphite produced is pressed into a target using a dedicated pneumatic press.
7. These graphite-containing targets will be sent to an affiliated laboratory with a particle gas pedal.

For a minimal additional cost, we can also measure the delta 13C of your samples using IRMS (Isotope Ratio Mass Spectrometry).

Note that each time samples of unknown age are sent to the affiliated laboratory, samples from oxalic acid transformation (international reference material for all dating laboratories), inert samples for background determination (blanks) and samples of known age (secondary standards from a calibration between several laboratories) must be added.

This ensures continuous monitoring of the quality and accuracy of the results delivered to customers.

Samples must:

• be dry.
• well identified.
• placed in plastic (or glass) vials or wrapped in aluminum foil or plastic bags (Ziploc type).

Please complete the AMS dating form (PDF) (Word) for each sample submitted. Enclose the customer's data sheet(s) with your samples.

For the customs declaration, you can indicate "Samples for scientific analysis, no commercial value".

You will be contacted by e-mail once your samples have arrived at the laboratory.

RADIOCHRONOLOGY LABORATORY
c/o Guillaume Labrecque
Laval University
Abitibi-Price Building, Room 0248
2405, Rue de la Terrasse
Quebec, QC CANADA
G1V 0A6

Guillaume Labrecque : radiocarbon@cen.ulaval.ca
Telephone : (418) 656-2131 ext. 404486