摘要 |
The sensor material has at least one permitted intermediate energy level (5,6) between its excited (7) and excited (8) states, and the resulting energy gaps (6-7, 6-5, 5-8) correspond to the max. permitted phonon energy in it, so that energy relaxation has, via fluorescence (4) and phonon emission (9,10,11) comparable probability in the actual temp. range. The material is placed in optical connection with the one end surface of the optic fibre, and at least two of its surfaces are brightly polished or similarly treated to provide total reflection of beams within a specific angle interval. It has a reflective lining on the main part of its surface directed towards the ambiance, and can be in powder form, enclosed in a tubular capsule provided with at least one reflecting lining. |