If a modern pottery is artificially irradiated by γ-rays of 60 Co source

the modern will become ancient when the pottery is dated by the thermoluminescence technique. For distinguishing artificial irradiation a study was made. Meanwhile the "fine-grain" and "pre-dose" techniques were used respectively for measurement of the paleodose in a fine-grain sample from the same pottery. If the paleodose measured by the fine-grain technique is greater than that by the pre-dose techniques

we can affirm that the difference between two paleodoses is due to α dose and this paleodose containing α component results from natural radiation

the pottery therefore is ancient. If two paleodoses are equal approximately

i.e. α dose is not included in the paleodose

the paleodose comes from artificial γ irradiation and the pottery is an imitation.