Patent ID: 6540690
Filing Date: 2003-04-01
Classification: G01J

Abstract:
A pulsed, radiation-cooled thermal infrared radiation source comprising at least one electrically conductive element made from a thin, foil-shaped material which is partially or wholly adapted to be heated from a lower temperature level To to a certain higher temperature level Tm that is maintained for a time period of duration &thgr; by means of a pulse of electric current and to be pulse-wise cooled after each of said current pulse by means of thermal radiation, and electrical means arranged to supply energy to said electrically conductive element in the form of said pulse of electric current, characterized in that the thickness of those parts of said electrically conductive element which are partially or wholly adapted to be heated to said higher temperature level Tm satisfies the relationd<2&egr;&sgr;&thgr;Tm4/C&rgr;&Dgr;T, in which &sgr;=5.67Â·10âˆ’12 W cmâˆ’2Kâˆ’4 is the Stefan-Boltzmann constant, &Dgr;T=Tmâˆ’To is the difference between said higher and said lower temperature levels and &egr;<1 is the emissivity, &rgr; is the density and C is the specific thermal capacity of said foil-shaped material, and where the sign < means â€œless thanâ€ .