s We are basically concerned about the Personnel Monitoring service i.e. the dose absorbed by the radiation
personnel while working in the radiation field. As you are aware, there is some radiation which is occurring
naturally & which contributes to both general public & the radiation workers. A TLD card can not differentiate
between radiation field’s radiation & natural background radiation. Hence, to find the contribution of radiation
field’s radiation in the absorbed dose by radiation worker, contribution due to the natural background has to be
subtracted. Therefore, a control card is required to note down the contribution due to the natural background.
Accredited by BARC Govt. of India