here is another graph
On Fri, Oct 10, 2014 at 10:03 PM, Axil Axil <[email protected]> wrote: > [image: figure 6] > > From the graph, 1300C looks like a 2micron wave length, this corresponds > to a transmittance of about .85, > > > On Fri, Oct 10, 2014 at 9:10 PM, Jed Rothwell <[email protected]> > wrote: > >> A correspondent wrote to me (not an exact quote): >> >> a quick look a the literature scrub shows transmissivity of alumina >> quickly drops to zero past ~7 micron wavelength. Much of the data seems to >> be in relation to the crystalline variant (e.g sapphire) vs >> non-crystalline. >> >> >> http://www.janis.com/Libraries/Window_Transmissions/Sapphire_Al2O3_TransmissionCurveDataSheet.sflb.ashx >> >> Notice the Ecat report clearly states on page 4 “The spectral range for >> both cameras is from 7.5 to 13 μm.” That seems to indicate that any >> transmitted IR through the alumina wouldn’t be detected by the IR cameras. >> > >
