cal/cal/blackbody.cal

{
        Plank's formula for black body radiation spectrum
}

{ Required constants }

k : 8.617e-5;           { Boltzmann constant (eV/K) }
h : 4.136e-15;          { Plank constant (eV-sec) }
e : 1.602e-19;          { elemetary charge (Coulombs) }
c : 2.998e8;            { speed of light (m/sec) }

{
        The following distribution is in units of Joules/meter^4,
        i.e., energy per radiating volume per wavelength
        lmb (lambda) is expected in nm (10^-9 meter)
        and T must be given in degrees Kelvin
}

u(lmd,T) : 8*PI*h*e*c*(lmd*1e-9)^-5 / (exp(h*c/(lmd*1e-9*k*T)) - 1);
Revision:	1.1
Committed:	Sat Feb 22 02:07:21 2003 UTC (21 years, 2 months ago) by greg
Branch:	MAIN
CVS Tags:	rad3R5, rad3R6, rad3R6P1
Log Message:	Changes and check-in for 3.5 release Includes new source files and modifications not recorded for many years See ray/doc/notes/ReleaseNotes for notes between 3.1 and 3.5 release
#	User	Rev	Content
1	greg	1.1	{
2			Plank's formula for black body radiation spectrum
3			}
4
5			{ Required constants }
6
7			k : 8.617e-5; { Boltzmann constant (eV/K) }
8			h : 4.136e-15; { Plank constant (eV-sec) }
9			e : 1.602e-19; { elemetary charge (Coulombs) }
10			c : 2.998e8; { speed of light (m/sec) }
11
12			{
13			The following distribution is in units of Joules/meter^4,
14			i.e., energy per radiating volume per wavelength
15			lmb (lambda) is expected in nm (10^-9 meter)
16			and T must be given in degrees Kelvin
17			}
18
19			u(lmd,T) : 8PIhec(lmd1e-9)^-5 / (exp(hc/(lmd1e-9kT)) - 1);