Day 5

In today's staff meeting we watched a short video about imaging science at RIT, and a few people shared what they were doing in their labs; it's always so interesting to hear about the different kinds of work everyone is doing. I coded for about half an hour this morning before heading over to the lab to begin collecting sample data for calibration purposes. Our smaller camera is situated on an actuator which moves along one axis so that we can position it at the focus point of the light beam being emitted from our setup. I adjusted it using our monitor and controls until it was as in focus as our current set up allows, then I moved it backward, a little out of focus, and then back towards and past the focus point over a range of motion of about 20 microns in 0.5 micron steps, taking a picture at each step to map the transformation.

At the lunch hour, I went to attend a weekly tech talk on biomedical engineering, and various new techniques in the field. While biology isn't my area of expertise, I found the talk very interesting and insightful, and I'm very glad I went.

I spent a good deal of time today, both before and after lunchtime, running tests to determine whether or not we should collimate our light beam before sending it through the monochromator. By collimating the light, it essentially makes the light waves parallel to each other, making the beam more uniform so that the light does not spread (much) and weaken the signal, even over a larger distance. As there is already a collimating mirror inside the monochromator, we wanted to see if collimating the light before it entered would have an effect on the strength of the signal coming out the other side. So I placed a power meter in front of the exit slit of the monochromator and measured the current (in nanoAmps) across a range of wavelengths from 400 nm to 700 nm, with 50 nm intervals. In the first trial, the uncollimated light returned higher currents, but oddly enough, within the function, longer wavelengths generally returned higher currents as well. Sensing that something might be off with the collimator, we ran the test once more, this time using our much nicer (and unfortunately, as we need a second one, more expensive) collimator. The results the second time were completely the opposite and behaved more as expected with respect to wavelength differences. The collimated light generated nearly double the current as the uncollimated light. More current means a stronger signal, so unfortunately for us, that means we're going to somehow have to fit a new collimator into our budget, as the first one was quite a bit cheaper and uses a lens (less precise, more scattering) as opposed to a mirror.

We will also need a collimator on the other end of the monochromator (hence the second) so we will position it on a manual actuator which will allow us to adjust the angle and path through which light enters it. At the end of the day, we planned to set up the camera controls by creating a code using MATLAB, but the license was expired so we had to spend a fair amount of time downloading a new copy of it, but it's now ready to go tomorrow.