a novel structure for a small , inexpensive , and easily replaced infrared source having near blackbody emission over a spectrum of 2 - 20 micron wavelengths is disclosed . the source element is self - starting and has a life expectancy in excess of 1000 hours at 1700 degrees k , which requires only 22 watts of power to maintain . because the source is energy efficient , there is no need of auxilliary cooling or added thermal isolation from adjacent components when the source is used in an instrument such as a spectrophotometer .