| Author | Message | ||
     hlmark (Unregistered Guest) Unregistered guest |
Not to be argumentative, Gabi, but in the distant, prehistoric, past I'd also worked with AOTF and found that the wavelength is also subject to as many different phenomena as other technologies. Most of them, such as crystal cut, angle of incidence, polarization of the light, etc., are built in to the crystal or into the instrument design, so they don't affect the user. One phenomenon is, however, and that's the crystal temperature, so the AOTF crystal has to be temperature controlled just as most technologies require temperature control of a critical part to maintain wavelength accuracy. On the other hand that's relatively easy to do since the crystal is small and easily controlled. So in the end I agree with you. However, MPDC has brought up a point that I've been curious about myself, and I wonder if you could address it: how come nobody's implemented the theoretical ability to access wavelengths randomly. Years ago, Dave Wetzel showed that it could in fact be done, but that was done as academic research, and never seems to have made it into commercial instruments. Any thoughts? \o/ /_\ | ||
| Gabi Levin (Unregistered Guest) Unregistered guest |
Hi to everyone, Of course I am biased, and this is no secret, but the point that was raised regarding wavelength repeatability is not relevant - AOTF is a solid state, wavelength repeatability is excellent, there is nothing to wear, tear, and change. Wavelength position requires no maintenance whatsoever in years. If traditional FTNIR has any advantage is possibly resoltuion, but in NIR it offers a very limited advantage because peaks are broad anyway, and the high resolution comes at the expense of noise, a well known fact. If you write to me directly I will provide you with information on many users of AOTF in the pharmaceutical industry. Any additional information here is out of the scope of this forum and I will not abuse it, hoping I did not do so already. Many thanks, Gabi Levin, Brimrose Corp. [email protected] | ||
| MPDC (Unregistered Guest) Unregistered guest |
AOTF has evolved into a pretty stable, and VERY fast form of NIR. Especially for freespace applications and powering large (16 channel) multiplexers. The dream of completely randomly accessing wavelength has never come true, but you can select a range/interval setting which only encompasses a handfull of datapoints and in this way doe several scans per second. I have installed an application where we measured active ingredient in glass vials and did a accept/reject of several vials per second. If your application is not time critical and does not require freespace or more then 8 channels multiplexing, you might be bettter off with "traditional" FTNIR due to its great wavelength repeatability. | ||
| thomas ricour (Tricour) New member Username: Tricour Post Number: 1 Registered: 2-2006 |
Dear Sirs, I would like to know if someone uses AOTF NIR analysers in laboratory or in process, and what are his fellings and return of experiences concerning it. We are working now on discovering medical drugs by AOTF through Phy solutions in PET bags. Waiting for comments Kind regards Thomas Ricour |