Protection instruments such as survey monitors must be calibrated in terms of what?

The correct choice, dose equivalent, is fundamental in radiation protection because it measures the biological effect of ionizing radiation on human tissue. Calibration of survey monitors in terms of dose equivalent is essential as it provides a consistent framework for assessing the potential biological impact of radiation exposure. This is particularly important for ensuring that safety standards are met and to protect individuals from harmful effects.

By calibrating survey monitors to measure dose equivalent, the instruments can effectively gauge the risk associated with different types and levels of radiation. This ensures that appropriate safety measures are implemented based on the actual biological risk rather than just the physical measurement of radiation, which might not accurately reflect the potential for harm.

While the other options—air kerma, exposure, and energy levels—are important in the context of radiation measurement, they do not directly correspond to the biological effects of radiation in the same way dose equivalent does. Air kerma relates to the kinetic energy transferred to air and does not account for the biological significance. Exposure measures the ionization in the air, and energy levels refer to the type and characteristics of the radiation but do not provide a measure of its biological impact. Thus, dose equivalent serves as the most relevant measure for calibrating protection instruments such as survey monitors.