Tuesday, June 26, 2012

Measurement Capabilities at Avian Technologies


Welcome to the Spectroscopy at Avian Technologies blog post.  Over the next few months, my colleagues and I hope to give you an idea of what we are all about when it comes to measurements- instruments, capabilities, traceability (what it is and how we are), uncertainties and anything else you would like to discuss.

First of all, we’d like to review what we have for instrument and measurement capabilities. While our instruments might be thought of as ‘old’, we like to think of them as ‘vintage’- like fine wines! They are all lovingly cared for, serviced on a regular basis, and treated in a manner befitting their status. These are/were all top-of-the-line instruments- the best available from their manufacturers.

Our ‘batterie de cuisine’ includes:

> Four Perkin-Elmer Lambda-9/Lambda-19 UV-Vis-NIR spectrophometers.
These are double beam, double monochromator instruments, the best P-E had to offer. There were about 2000 of these made, starting in 1984 and ending in 1992. They are reference instruments- typically what a national lab or major scientific research lab would have for their ‘reference’ instrument.  The Lambda-9/19’s were great because you could add all sorts of accessories to them- integrating spheres- both small (60 mm) and large (150-200 mm)-, specular accessories to measure mirrors, fiber optic accessories, and even a 0:45 accessory. We have 4 spheres, a specular accessory or two, small spot kits, and the rare 0:45 accessory (only 4 ever made- three at NMI’s and we have the fourth). These serve as our reference instruments. All of these currently reside in our NH office.

In our Rochester facility we have the following:

> Murakami GSP-1 Goniospectrophotometer-

> Gretag- Macbeth ColorEye 7000a sphere-based color spectrophotometer.*

> Byk-Gardner Color View 45:0 color spectrophotometer*

> Gretag- Macbeth ColorEye 2145 45:0 color spectrophotometer.*

> Byk-Gardner TCS Hazemeter


What measurements do we do?

• Normal Transmittance- A Lambda-9/19 spectrophotometer either with or without a 60 mm sphere accessory. This instrument is usable from roughly 220 nm to 2700 nm, but we’re only ‘traceable’ from 250-2500 nm.

• 8°/Hemispherical Reflectance Measurements:
1) Primary instrument- Lambda-19 UV-Vis-NIR double monochromator instrument with 150 mm. integrating sphere. Typically measured at 1 nm bandpass. This is our reference instrument and has been used for many years at both NRC and NPL for colour measurements. These instruments are also used for routine UV-Vis-NIR measurements of total hemispherical reflectance.
2) Macbeth ColorEye 7000a. Currently only used for fluorescent (optically brightened) materials

45:0 Radiance Factor Measurements:
1) Primary instrument- Byk-Gardner Color-View 45:0 bench top
2) Secondary instrument: Gretag-MacBeth ColorEye 2145a
3) Reference instrument: (in evaluation) Lambda-19 UV-Vis-NIR double monochromator instrument with Labsphere RSA-PE19a annular 0:45 accessory. Typically measured at 1 nm bandpass. This was the reference instrument  at both NRC and NPL for color measurements at 0:45 geometry for years. (I was one of the designers).

All of our measurements (except the goniospectrophotometric measurements) are traceable to NIST/NRC. We work closely with both scientists at NIST, NRC (Canada), and CERAM Research in the UK to assure instrument performance and keeping up on measurement techniques.

Friday, May 11, 2012

Black,black,black



We get a lot of questions about compatibility of our black coatings and surface treatments with various substrates, what is the best choice of blacks, and how they should be handled.  Most of the spectral and application data is available on- line (or by request to info@aviantechnologies.com), but here is some potentially useful information.
Avian-DS and –EP blacks are surface treatments. They are not ‘sprayed on’- they are a treatment of a metallic surface. Here is some useful information.
1) -DS black can ONLY be applied to aluminum (alloys 6061 or 1000); this is an etch-anodize process, similar in many ways to the well known (but no longer available) Martin Marietta Black. See:www.optics.arizona.edu/optomech/papers/persky%201999.pdf
2)  -EP black can be applied to any metal substrate. This is a so-called 'copper black', so a layer of copper is electrochemically deposited on the substrate and then the copper layer is blackened by an oxidative process. –EP black can be applied to just about anything as long as the copper layer can be in some way electrochemically deposited.
3) Both of these surface treatments produce a surface that is dendritic and are extremely fragile. If the surfaces have to be handled much (if at all) these are probably not appropriate for the application.
4) Each of the coatings is electrochemical. We do not do them here but send the parts out to a vendor (two separate vendors, in fact) for the treatment.
5) Neither of these surface treatments out-gas. Both have been, to some extent, been space qualified.

Avian Black-S is a coating. It is a two-part polyurethane that is extremely black over the 250 nm to 20µ range (much to my surprise- I didn’t think it would be much good in the mid-IR but some nice folks at U.S. Army Research measured the hemispherical reflectance out to 20µ and it is still VERY black!). Some other information:
1) Once cured (RT for 3 days or 60°C for 24 hours), the coating doesn’t out-gas very much at all.
2) While we recommend you spray it on, we have customers who brush it on and even some who flow coat it on. It doesn’t take much coating- 2-3 mils is fine- but the sprayed coating is much more lambertian than if applied other ways.
3) If the coating appears glossy after drying, you have not agitated Part A enough before mixing the binder. You REALLY need to assure that all the pigment particles are in suspension!

If you have questions out there about any of our coatings and materials, please post them here and we’ll be happy to try to answer them.




Welcome

Hello all!
Welcome to the Avian Technologies blog on materials, coatings, and standards. We're here to answer your questions, take your comments, and have some discussions on optical materials, etc. 
We will try to have something new for you every couple weeks or more often as needed.