Instruction Manual and Experiment Guide for the PASCO scientific Model SP-9268A 012-02135F 10/03 STUDENT SPECTROMETER Copyright © January 1991 ® $7.50 better 10101 Foothills Blvd. • P.O. Box 619011 • Roseville, CA 95678-9011 USA Phone (916) 786-3800 • FAX (916) 786-8905 • email: techsupp@PASCO.
Model Name 34 012–0xxxxA
012-02135F Spectrometer Table of Contents Section Page Equipment Return ............................................................................................. ii Introduction ...................................................................................................... 1 Equipment ........................................................................................................ 2 Equipment Setup .........................................................................................
Spectrometer 012-02135F Copyright, Warranty and Equipment Return Please—Feel free to duplicate this manual subject to the copyright restrictions below. Copyright Notice Equipment Return The PASCO scientific Model SP-9268A Student Spectrometer manual is copyrighted and all rights reserved. However, permission is granted to non-profit educational institutions for reproduction of any part of this manual providing the reproductions are used only for their laboratories and are not sold for profit.
012-02135F Student Spectrometer Introduction In its simplest form, a spectrometer is nothing more than a prism and a protractor. However, because of the need for very sensitive detection and precise measurement, a real spectrometer is a bit more complicated. As shown in Figure 1, a spectrometer consists of three basic components; a collimator, a diffracting element, and a telescope. In principle, a spectrometer is the simplest of scientific instruments.
Student Spectrometer 012-02135F Equipment Spectrometer Table The PASCO scientific Model SP-9268A Student Spectrometer provides precise spectroscopic measurements using either a prism or a diffraction grating as the diffracting element. The spectrometer includes the following equipment (see Fig 2). The spectrometer table is fixed to its rotating base with a thumbscrew, so table height is adjustable. Three leveling screws on the underside of the table are used to adjust the optical alignment.
012-02135F Student Spectrometer Equipment Setup 5. Looking through the telescope, adjust the focus of NOTE: If you are using the optional Gaussian Eyepiece (SP-9285), equipment setup is somewhat simpler than described below. See the Appendix for instructions. the collimator and, if necessary, the rotation of the telescope until the slit comes into sharp focus. Do not change the focus of the telescope. 6.
Student Spectrometer 012-02135F 3. To be sure both optical units are square to the axis of rotation, follow the focusing procedure described above, adjusting the mounting pillars as necessary so the slit image is well centered in the viewing field of the telescope. 2. The mounting pillars of the telescope and collimator can be rotated by using an Allen wrench to loosen the screws that attach the pillars to their respective bases.
012-02135F Student Spectrometer Using the Diffraction Grating 5. Place a light source (preferably one with a discrete spectrum, such as a mercury or sodium lamp) approximately one centimeter from the slit. Adjust the slit width so the slit image is bright and sharp. If necessary, adjust the height of the spectrometer table so the slit image is centered in the field of view of the telescope. IMPORTANT: The Diffraction Grating is a delicate component.
Student Spectrometer 012-02135F 9. Repeat steps 6-8 until the angles for the corresponding slit images are the same to within one minute of arc. Wavelengths are determined according to the formula: Making the Reading where λ is the wavelength; a is the distance between lines on the diffraction grating l= Once the grating is aligned, do not rotate the rotating table or its base again. Diffraction angles are measured as described in the previous section, Measuring Angles of Diffraction.
012-02135F Student Spectrometer To Measure the Angle of Minimum Deviation: 4. With the prism, it is generally possible to see the refracted light with the naked eye. Locate the general direction to which the light is refracted, then align the telescope and spectrometer table base so the slit image can be viewed through the telescope. 1. Align and focus the spectrometer as described earlier. 2.
Student Spectrometer 012-02135F Maintenance Periodically clean the telescope aperture, the collimator aperture, and the prism with a nonabrasive lens paper (available at any camera store). No other regular maintenance is required. IMPORTANT: Always handle the spectrometer and its accessories with care to avoid scratching the optical surfaces and throwing off the alignment. Also, when not in use, the spectrometer should be stored in its hardwood case.
012-02135F Student Spectrometer Appendix: Using the Gaussian Eyepiece The optional Gaussian eyepiece (Model SP-9285) simplifies the task of aligning and focusing the spectrometer and aligning the diffraction grating. One Gaussian eyepiece can be used to align and focus any number of spectrometers, so only one is generally needed per lab. 5. Looking through the telescope, rotate the table until a patch of light is reflected back through the telescope from the glass surfaces of the grating.
Student Spectrometer 012-02135F Alignment Error 13. Illuminate the slit with an external light source. Rotate the telescope directly opposite the collimator and focus the collimator only (do not disturb the telescope focus) until the illuminated slit is in sharp focus. If the collimator slit is not vertical, loosen the lock ring, align the slit vertically, and then retighten the lock ring. Then align the fixed edge of the slit with the vertical cross-hair.
012-02135F Student Spectrometer Technical Support FeedBack Contacting Technical Support If you have any comments about this product or this manual please let us know. If you have any suggestions on alternate experiments or find a problem in the manual please tell us. PASCO appreciates any customer feedback. Your input helps us evaluate and improve our product.
Model Name 34 012–0xxxxA
