What indicates a need to replace a dosimeter?

The correct response is that a dosimeter being off-scale clearly indicates that it has reached or exceeded its measurement range for radiation exposure. When a dosimeter is off-scale, it signifies that the levels of radiation exposure that it has detected surpass the maximum limit that the device can measure accurately. This is a critical situation, as it may imply that the individual using the dosimeter has been exposed to potentially harmful levels of radiation, and the device can no longer provide reliable readings. Therefore, immediate replacement is necessary to ensure proper monitoring of ongoing exposure levels and to maintain safety protocols.

In contrast, logging low doses or recording a normal exposure would not indicate that the dosimeter needs replacement. It suggests that the dosimeter is functioning correctly within acceptable exposure limits. Similarly, if a dosimeter is less than 10% of its maximum limit, it indicates that it is still effectively monitoring exposure and does not warrant replacement.