4.12 Infrared radiation detection u The plancks law describes the radiation intensity distribution for an ideal radiator (blackbody ) under different temperatures W (4.131) T in which W,the energy emitted by wavelength in Wm.um the 1st radiation coefficient, CI=374.15 MWum/m2 C2-the 2nd radiation coefficient, C2=14388 umK T-the absolute temperature, in K λ- - the wavelength,inm。❑The Planck’s Law describes the radiation intensity distribution for an ideal radiator (blackbody) under different temperatures: 4.12 Infrared radiation detection       − = 1 2 5 1 T C e C W    （4.131） in which W —the energy emitted by wavelength ，in −2 −1 Wm  m ； C1 —the 1st radiation coefficient， 4 2 1 C = 374.15MWm / m ； C2 —the 2nd radiation coefficient，C2 = 14388m K ； T —the absolute temperature，in K；  —the wavelength，in m