Rad- Unit
of absorbed dose measuring the energy imparted by ionizing radiation to matter
(1 rad = .01 Joule/kilogram or 100 ergs/gm)"
Radian- A unit
of angular measure; one radian is that angle with an intercepted arc on a circle
equal in length to the radius of the circle. (Thus, pie radians equals
180°)
Rankine- A
traditional unit of absolute temperature; 1°Rankine represents the same
temperature difference as 1°Fahrenheit, but the zero point of the scale is set
at absolute zero, so the Rankine temperature is 459.67° plus the Fahrenheit
temperature; 1°Rankine is equal to exactly 5/9 kelvin (the unit is named for the
British physicist and engineer William Rankine, 1820-1872)
Ryleigh- A CGS
unit of light intensity used in astronomy and physics to measure the brightness
of the night sky, auroras, and planetary objects (one rayleigh represents the
light intensity of one million photons of light emitted in all directions per
square centimeter of receiver per second, or, in SI units, 795.775 x 106 per
square meter per steradian)
Rem- The unit
of dose equivalent (DE) is expressed as rem (roentgen equivalent man) and
defined as the product of absorbed dose (D) in radians and other necessary
modifying factors
Roentgen- Unit
of exposure measuring the ionizing ability of g radiation; one roentgen produces
one electric charge (1.6´10-19 C) per 10 6 m 3 of dry air at 0° C and
atmospheric pressure. This corresponds to an energy loss of 0.0877 joule per
kilogram in air
