Which unit is commonly displayed on high-range RADIAC scales to express exposure?

Which unit is commonly displayed on high-range RADIAC scales to express exposure?

• A. Rem
• B. Roentgen
• C. Sievert
• D. Gray

Answer: (B)

High-range RADIAC scales are designed to show exposure, not absorbed dose or dose equivalent. Exposure is the amount of ionization produced in air by radiation, and the roentgen is the unit historically used to quantify that ionization level in air. RADIACs used in field or high-range readings typically display exposure values in roentgens (or exposure rate in R per hour) because that directly reflects the amount of ionizing radiation present in the surrounding air. The other units describe different concepts. Rem and Sievert measure dose equivalent, which accounts for biological effect; Gray measures absorbed dose, which is energy deposited in matter. Since the instrument is indicating how much radiation is present in the environment (exposure in air), roentgen is the appropriate unit for these high-range scales.

High-range RADIAC scales are designed to show exposure, not absorbed dose or dose equivalent. Exposure is the amount of ionization produced in air by radiation, and the roentgen is the unit historically used to quantify that ionization level in air. RADIACs used in field or high-range readings typically display exposure values in roentgens (or exposure rate in R per hour) because that directly reflects the amount of ionizing radiation present in the surrounding air.

The other units describe different concepts. Rem and Sievert measure dose equivalent, which accounts for biological effect; Gray measures absorbed dose, which is energy deposited in matter. Since the instrument is indicating how much radiation is present in the environment (exposure in air), roentgen is the appropriate unit for these high-range scales.