
Sievert
(Sv) 
A unit of radiation dose that is used
for radiation protection purposes.
When an individual is exposed to mixed sources of radiation,
the total biologically effective dose is calculated by
multiplying the physical dose (expressed in units called gray)
of each kind of radiation by a corresponding factor (called
a quality factor or Q factor) specified
for the type of radiation and its energy, after which these
amounts are added together.
The factor for gamma
rays is 1; therefore, 1 Sv = 1 Gy. The
factor for the neutrons in
atomicbomb radiation is 10; therefore, 1 Sv = 0.1
Gy.
Also see Basics
about radiation. 

