For which traditional unit of measure are all ions of either sign collected and measured?

• A. Gy
• B. rad
• C. rem
• D. Roentgen

Answer: (D)

The traditional unit of measure where all ions of either sign are collected and measured is the Roentgen. This unit specifically quantifies the amount of ionization produced in air by X-rays or gamma radiation. The fundamental concept behind the Roentgen is based on the measurement of ion pairs formed in a specified volume of air due to radiation exposure. It is used to evaluate the exposure to radiation, emphasizing the ionization of both positive and negative charges in the air.

In contrast, the other units listed refer to different aspects of radiation measurement. The Gray (Gy) is a unit of absorbed dose that measures the energy deposited in a material. The rad is an older unit similar to the Gray but used in the context of absorbed doses. The rem is a unit that accounts for the biological effect of radiation, weighing the absorbed dose based on the type of radiation and its impact on health. Thus, while these units are integral to understanding radiation and its effects, they do not involve the direct measurement of ion pairs like the Roentgen does.