For our apparatus, we used the Nd-YAG laser, dye laser, and heat pipes that were previously used by Tim and Emmett. Instead of using the Cesium heat pipe, we used the Sodium pipe. The light that came out of the pipe (be it transmitted or emitted) was then passed along an optical path using mirrors and prisms into a spectrometer. Our first experiment intended to pass the light into a spectrometer calibrated for IR light and then into an IR detector. We later used a spectrometer that had a grating for visible light installed which output to a Photo-Multiplier Tube.
The IR detector would have been passed through an amplifier and into a Boxcar, so it would have taken the place of the PMT in the above diagram.
The boxcar integrator takes data over a short, timed period that is modeled by a square pulse. This pulse can be seen by connecting the boxcar to an oscilloscope. By then connecting the amplified input (in this case, the output from the PMT) to the other channel of the scope, we could adjust the delay of the boxcar so that the brief pulse enclosed an intense and uniform portion of the curve for the incident light. We triggered the boxcar with the YAG laser, so we took data for every pulse.
The data taken by the boxcar was then integrated over a user-specified number of pulses (we used 5-10) and exported to a computer.
Jim Nolen had been using the spectrometer and computer for his independent research project earlier this semester. In the process of taking his own data, Jim had created a LabView program that scanned the spectrometer grating over an adjustable range of wavelengths, graphed the boxcar data, and allowed the export of that data to a file for analysis with Excel. After a couple of lessons from Jim, we became adept enough at using his program to take our own data in a timely fashion.