noun (plural same)
A unit of effective absorbed dose of ionizing radiation in human tissue, loosely equivalent to one roentgen of X-rays.
- The modern international system of units includes the Gray, the Sievert, and the Becquerel (Bq); these replace the rad, rem, and Curie, respectively.
- According to Badhwar, the total increase in cosmonaut exposure was about 6 or 7 rem, a dose equivalent to 100 to 150 days of additional radiation exposure.
- The rem takes account of a ‘quality factor’, which for the more dangerous alpha particles is 10.
1940s: acronym from roentgen equivalent man.