Correction to the low IR spectra: “British workers later demonstrated LWIR band (8-12 µm) negative luminescence using mercury cadmium telluride diodes.”
… not sure what the difference would be at this temperature, but it could be substantial. From: H Veeder http://en.wikipedia.org/wiki/Negative_luminescence > Negative luminescence is a physical phenomenon by which an electronic device > emits less thermal radiation when an electric current is passed through it > than it does in thermal equilibrium (current off)… When viewed by a thermal > camera, an operating negative luminescent device looks colder than its > environment. This is a good find, Harry … wish it had come up earlier. It could salvage some of the Levi report, as obviously it would partly explain the color temperature variance. We need that thermocouple data. I was unaware of the phenomenon. Below is more from the entry with comments interspersed - which makes negative luminescence sound like it is expected from the “exciton” segment of our prior explanation which would be a part of” triple coherency” in laser-like device (along with photos and phonons): “Negative luminescence is most readily observed in semiconductors. Incoming infrared radiation is absorbed in the material by the creation of an electron–hole pair. An electric field is used to remove the electrons and holes from the region before they have a chance to recombine and re-emit thermal radiation. This effect occurs most efficiently in regions of low charge carrier density.” [as to the caveat that alumina is not a semiconductor, but does have low charge carrier density - it can be noted that alumina is dielectric at moderate temperature but becomes more and more conductive at elevated temperature] “Negative luminescence has also been observed in semiconductors in orthogonal electric and magnetic fields. In this case, the junction of a diode is not necessary and the effect can be observed in bulk material. A term that has been applied to this type of negative luminescence is galvanomagnetic luminescence.” “Negative luminescence might appear to be a violation of Kirchhoff's law of thermal radiation. This is not true, as the law only applies in thermal equilibrium.” “Another term that has been used to describe negative luminescent devices is "Emissivity switch", as an electric current changes the effective emissivity.” [negative luminescence would probably not effect 7 micron IR] Given that Levi did know of this phenomenon – and that it could be helpful in the context of the experiment – all he needs to do is release the thermocouple data which may not support the highest gain, but probably is more accurate than the IR calculations (thermography). Better to salvage something than have everything perceived as wrong.
