| 摘要 |
<p>A method and apparatus for detecting radiation in a relatively narrow wavelength band within radiation having a wide range of wavelengths. The method comprises detecting radiation in a first wavelength band including said narrow wavelength band and other wavelengths; detecting radiation in a second wavelength band which comprises substantially only said other wavelengths; and comparing the levels of detected radiation to determine the presence of radiation in the said narrow wavelength band.</p> |
