Comparison between (n–γ), (γ–γ) and natural γ-ray activity techniques for ash measurement of coal samples

A comparison between neutron capture gamma (n–γ), compton backscattering gamma ray (γ–γ) and natural radioactivity techniques was performed to measure the ash content of coal samples from coal mines in the north of Iran. The results proved that the neutron–gamma technique is superior to the other two techniques. The standard deviation between the chemical assays and the neutron–gamma, gamma–gamma and natural gamma predictions are 1.44, 5.68 and 1.71% ash, respectively.