APPENDIX A USING THE SPECTROMETER FOR AN EMISSION SPECTROSCOPY NANSLO REMOTE WEB-BASED SCIENCE LAB ACTIVITY The following provides information how to use the spectrometer controls for the Emission Spectroscopy NANSLO Remote Web-based Science Lab activity. If you would prefer, you can watch a video to see how to use the RWSL: 1. Short tutorial covering the basics: http://denverlabinfo.nanslo.org/video/emission_spectroscopy.html or you can print panel this PDF version of the instructions below. Activating the Spectrometer 1. When you first start the Emission Spectrometer control panel, you will see the Control Panel seen in Figure 11. You can gain control of the interface by right-clicking anywhere on the screen and selecting Request Control of VI. If someone else has control, you will get a message telling you that you need to wait. You will be placed in queue and will get control of the interface when the other person releases it. Figure 1 - Emission Spectrometer Control Panel Creative Commons Attribution 3.0 United States License 1
2. Click the Start button on the far left portion of the control panel to activate the spectrometer. The button will now turn yellow and say Pause. 3. In the video window on the right side of the screen, you should see four black boxes labeled A through E, and also labeled (from left-to-right) H 2, He, Ne, CO 2 and?. These are emission lamps that generate different colors of visible light, depending on the gas that is in them. In front of these lamps is a horizontal screw-drive robot with a mounted fiber optic cable that transmits the detected light to the spectrometer, where the spectrum will be digitally acquired. The spectrometer is the small box located near one end of the track. 4. The Camera Preset Positions allow you to zoom in quickly to one of the 5 lamps. Hovering over the gray area where the buttons are will give you a pop-up menu that describes where each Preset is assigned to. You can also zoom in even closer using the ZoomIn and ZoomOut buttons. Figure 2 Presets will zoom to various lamps 5. To acquire the spectrum of one of the emission lamps, first select Preset 6 so that you can see the sensor move along the track. Click on the green-colored A button on the left side of the screen. This will position the sensor in front of this tube and turn on the H 2 lamp. NOTE: because the high voltage involved in these lamps, DO NOT set the TimeTubeON field to more Creative Commons Attribution 3.0 United States License 2
than 120 seconds. The lamp status and the number of seconds it has been energized are shown in the Spectrum Status portion of the interface screen (to the right of the green lamp buttons A E). Click on Preset 1 to zoom in on the H 2 lamp once it is turned on. 6. Use the Nudge Left and Nudge Right buttons to move the fiber optic and make sure you are getting the maximum signal from the lamp. If the lamp turns off before you re finished, just click the same letter again and it will re-energize. You can also change the time that the lamp stays on (in seconds) by changing the TimeTubeON field. 7. Once you have the signal maximized, click the Pause button to hold the image so the light doesn t have to be energized while you locate the maximum peaks (Figure 3). Figure 3 Press the Pause button to freeze the spectrum 8. You will now need to zoom out on the spectrum window to view the entire spectrum properly. Here s how to zoom in and out on the spectrum: a. Click on the center button at the lower right of the graph, shown below in Figure 4. b. This brings up a small sub-menu of other buttons. The only two that are useful to you are the left-most buttons in the top and bottom rows, although you can play around Creative Commons Attribution 3.0 United States License 3
with the others if you want to. Select the left-most button in the bottom row to view the entire spectrum. Spectrum Zoom Out Figure 4 - Spectrum Zoom Out button c. Select the left-most in the top row to select specific parts of the spectrum to zoom in on and view more closely (see Figure 55). After clicking this button, you use the mouse to draw a box around the area that you want to zoom in to. Be sure you draw the box so that it includes some area past the top of the peak you are interested in, or else it will chop off the top of it in the viewing window. d. If you accidentally zoom in too far or on the wrong part of the spectrum, just zoom out and start over again. Creative Commons Attribution 3.0 United States License 4
Spectrum Zoom In Figure 5 Spectrum Zoom In button 9. Export a graph of the spectrum: a. Locate the Export to Clipboard button, but don t click on it yet. Go to the pull-down box to the right of it and set it to Graph Image. Now click the Export to Clipboard button, which will place a copy of the spectrum in your clipboard. b. Start a program like Paint or Word or Powerpoint and paste in the spectrum. Save the file with an appropriate name so you can find it later. c. You must have control of the Control Panel to do this. 10. Using the cursor to locate the most intense peaks: a. Make sure you are zoomed out to view the entire spectrum. b. Click the button labeled Enable Cursor under the left side of the graph the green light will come on and a vertical green cursor line will appear on the screen. c. Click the cursor control button indicated below in Figure 6. Creative Commons Attribution 3.0 United States License 5
d. Use the mouse to grab the cursor line by clicking on it and dragging it to the peak that you want to identify. e. If you want to zoom in on a peak for a closer look, make sure you place the cursor approximately on that peak before you click the Spectrum Zoom In button and draw a box around it. f. If you lose the cursor while zooming in on peaks, just zoom out again to find it. Cursor Control Figure 6 Enable Cursor and Cursor Control button g. There are now two fields under the graph: Wavelength (nm) and Intensity. The Wavelength field shows the current position of the cursor, and Intensity shows a relative intensity reading of wherever the cursor is located (Figure 6). h. Use the cursor to find the wavelength of each major peak in the spectrum. Creative Commons Attribution 3.0 United States License 6
i. Once you have the cursor on top of a peak, you can zoom in on it to make sure you are really on the highest part of the peak. (Sometimes they are double peaks!) If you zoom in or out, you will need to click the cursor control button again in order to move the cursor. Creative Commons Attribution 3.0 United States License 7