Nondestructive elemental analysis of coins using accelerator-based thermal neutrons

Abstract EN

The accelerator-based thermal-neutron activation analysis setup at KFUPM has an adequate thermal-neutron flux that can be advantageously used for the elemental analysis of a variety of samples including archaeological ones.

The thermal neutrons are derived from the moderation of fast neutrons from the D (d, n)3He reaction which produces fast 2.5 MeV neutrons.

A maximum thermal flux of about 2.5 × 106 n / cm2-s was achieved.

For the purpose of determining the suitability of the setup for the analysis of contemporary and ancient coins, we carried out a feasibility study by irradiating a selected number of Saudi Arabian coins dating from 1958 to 1987 in the thermal-neutron flux.

The induced gamma-ray activities were then counted using a HP-GMX detector coupled to a PC-based data acquisition and analysis system.

The elements that were determined in the coins were copper (around 75 %), nickel (around 25 %), and manganese (< 0.5 %).

Calibration curves were also established for these elements.

The determined concentrations are in agreement with the data published by the Standard Catalogue of World Coins.