I am looking to be able to heat a sample of material, typically less than 500mg and sitting in a fused silica sample holder about 10mm diameter. Wondering about using (say) a 5W LED with narrow emission angle. The overall sample chamber of the machine is quite small, so ideally I need a small source, possibly with a light pipe. I certainly do not want the thermal mass of something like a halogen bulb. So, the questions…
Does this seem feasible?
What type of LED (in terms of wavelength) is the most efficient?
Does wavelength matter in terms of heating the sample? [Typically the archetypal "white powder"]
Now, I expect you to ask me what sort of temperature I want to get. The answer is "not sure", but probably 80 degC would be adequate. It is to drive off moisture.
The only cooling I have is a small ambient temperature airflow. Other possibilities (that I have not yet examined in detail) are low power uwaves and maybe changing the pan from silica to steel and using induction heating.
Best Answer
It really depends on what kind of sample you want to heat up, but the most common way would be to use IR LEDs, like these. I'd use a small lens to focus the beam on the sample (could be tuned precisely enough using visible light from red LED). Make sure you protect your eyes when you power up the IR LED though - its emission is invisible and doesn't make your iris contract or your eyes hurt, so it has potential to burn your retina when visible light would be mostly harmless.