| Author | Message | ||
     Francesco Davini (franz) Junior Member Username: franz Post Number: 8 Registered: 2-2009 |
William, you already had good answers to your question. I would like add that the original sample cups from your NIR supplier are relatively cheap and available in a range of 6 sizes, including a half depth standard diameter one, plus the (expensive) micro-mirror cup and the inexpensive disposable ones. Also, having no need for glass or quartz windows that are subject to scratches, they will last forever. Franz | ||
| Art Springsteen (artspring) Senior Member Username: artspring Post Number: 26 Registered: 2-2003 |
Hello William, Gabi is correct. You do not want to use plastic behind or you will see the spectral signature of the plastic (even something like black Acetal will show some spectral signature). So you options are something very white (like sintered PTFE) or better, stainless steel, polished or not. The sintered PTFE is theoretically the best solution but is more expensive and contaminates easily. The stainless steel is both inexpensive and practical. | ||
| Gabi Levin (gabiruth) Senior Member Username: gabiruth Post Number: 38 Registered: 5-2009 |
Hi William, The key factor is - how deep will be the layer of product when you place it on this so called spacer? If it is still deep enough to avoid having any signal from the plastic spacer - you might be OK with plastic spacer - but if this can not be guaranteed - you should use a metallic spacer - and you can use a non shiny diffuse reflecting surface which I would prefer, but some may say it is OK to use shiny reflecting surface for your spacer. All together I would prefer a metallic one - to eliminate the remote possibility of having a trace of the signature from a plastic spacer. One exception - you can use teflon type material as well, but that will probably be more expesnive than a metallic one. Gabi | ||
| William Wade (williamwade) New member Username: williamwade Post Number: 1 Registered: 6-2010 |
Hello, I have just started working with a new DA 7200 machine that has become available to our lab. However our samples are often smaller than the sample cups. Now I know that we can purchase smaller cups, but the question is can we just use a spacer in the bottom of the cups we have? For example can we place a piece of plastic in the bottom of the sample cup to raise the sample amount to the edge of the cup without changing results? Is it not actually required to be to the top edge of the cup? Or is it just needed that we spring for the smaller official sample containers? Thanks, William Wade |