In view of an underestimation of personal dose equivalent due to ⁶⁰Co radiation when system is calibrated to ¹³⁷Cs, the effect of the atomic number of the filters used in the badge on the photon beams of 660 keV and 1250 keV was investigated. The low Z‑high Z interface created between filters and discs was found to lead to discontinuity in dose at the surface of the disc. This effect was consistently observable due to the 0.8 mm thickness of the disc. It was concluded that under‑estimation of dose due to 60Co radiation could be avoided by either reducing the thickness of the dosimeter disc or by a slight modification in the design of the filters.