Modification of shirt buttons for retrospective radiation dosimetry after a radiological event

Abstract

Preliminary results are presented for a personal radiation dosimeter in the form of a clothing button to provide gamma-ray dose estimation for clinically-significant external radiation exposures to the general public due to a radiological incident, such as use of a radiological dispersal device. Rods of thermoluminescent material (LiF:Mg,Ti and LiF:Mg,Cu,P) were encapsulated in plastic "buttons," attached to shirts, and subjected to three cycles of home or commercial laundering or dry cleaning, including ironing or pressing. The buttons were subsequently exposed to doses of 137Cs gamma rays ranging from 0.75 to 8.2 Gy. The rods were removed from the buttons and their light output compared to their responses when bare or to the responses of a set of calibration rods of the same type and from the same manufacturer. In all three of the comparisons for LiF:Mg,Ti rods, the relative responses of the rods in buttons changed by 2-6% relative to the same rods before cleaning. In both comparisons for LiF:Mg,Cu,P rods, the response of laundered rods was 1-3% lower than for the same rods before cleaning. Both these materials are potential candidates for button dosimeters.

Fig. 1

Photograph of the TLD “buttons”. L-R: top disc; bottom disc with slots for three TLD rods; bottom disc with TLD rods; bottom disc with TLD rods and holes for attaching the button to a shirt.

Fig. 2

Light readings for LiF:Mg,Ti rods without application of ECCs before and after two methods of cleaning and for the calibration set when irradiated with the buttons. The data was fitted to second order polynomials due to the supralinear response of LiF:Ti,Mg at high doses. The first three curves listed in the legend are for Test 2 (Harshaw) and the second three curves are for Test 3 (Rexon). Error bars are the standard deviations of the readings.

Fig. 3

Light readings for LiF:Mg,Cu,P rods without application of ECCs before and after two methods of cleaning, for the calibration set when irradiated with the buttons and for a group of rods from the same batch (cohort). The lines are linear least squares fits to the data. The first two curves listed in the legend are for Test 2 (Harshaw) and the bottom three curves are for Test 3 (Rexon). Error bars are the standard deviations of the readings.