Lab Assignment: Nuclear Magnetic Resonance

In this lab, you will explore nuclear magnetic resonance with the Teachspin Pulsed/CW NMR Spectrometer.

Part A. Find the Free Induction Decay in mineral oil

Before you begin you will need to familiarize yourself with the equipment by carefully reading the manual provided below. You are encouraged to read the theory and experimental apparatus description thoroughly before you turn on the spectrometer. It may also be beneficial to read through and understand qualitatively how an oscilloscope works. For this lab, you will be using the new Tektronix oscilloscopes in the locked cabinet, the Tektronix DPB 2024B. I

Part B. Find the relaxation times T1 and T2 in a sample of mineral oil

The PS_NMR.pdf file linked below has a nice description of how to perform the measurement. Ask if you have questions.

The manual for the spectrometer is available PS2_Manual_1.41.pdf: Teachspin PS2-A NMR manual

Laboratory procedure:

1. Inspect the equipment to check if indeed all of the blue coaxial cable are connected and connected properly. Most likely you won't have to do anything here but be aware that someone may have inadvertently left something connected improperly. Knowing where all the wires go will also help you familiarize yourself with the equipment.
2. Use the NMR probe to check that the spectrometer is properly calibrated. This part is described in the "Getting Started" section. PLEASE DO NOT adjust the capacitors until you've obtained the signal shown on page II-19 of the manual and you have consulted with the instructor. This calibration step will be discussed during the orientation presented by the instructor. Also, it is relatively easy to break the fragile capacitors which will render the equipment useless. Note the voltage readings during the orientation and make sure they are within expectations.
3. Replace the probe with the sample of mineral oil and attempt to find the FID signal on the scope. A nice signal is illustrated on page III-7 of the PS-2 manual. Record the voltage and time sweep on the oscilloscope. Do you understand what these mean? Are they as expected for the sample at hand?
4. During the search for the FID signal play with the spectrometer settings and look through the questions on page III-7. Try to answers them as you progress through the experiment. At first they may not make sense but by the end of the experiment most of them should be clear. Don't worry about answering them on your report. But if you'd like to comment on them on the report please feel free to do so.
5. During the experiment, if you feel compelled to include a particular scope display, say the FID, spin echo or anything else that catches your eye you can do so in one of two ways: the simplest way is to just a take a photo of the scope screen with your phone. Or you can, with our new Tektronix scope also has a USB port you can use to record the output of the scope, in a supported image format.

Some useful links:

• Youtube video on Magnetic Resonance using earth-field NMR experiment. The technology employed is different but the discussion is, particularly the theoretical description is appropriate to the Teachspin device http://www.youtube.com/user/magritek
• This online book by Joseph P. Hornak, Ph.D. is something worthwhile to peruse http://www.cis.rit.edu/htbooks/nmr/inside.htm
• A nice simulation from the UF's Center for Safety, Simulation and Advanced Learning Technologies. It provides you with a better visual of how NMR works. You'll need an Adobe Shockwave so you iPad/iPhone may not work and or you'll need to add it to you browser. http://vam.anest.ufl.edu/simulations/nuclearmagneticresonance.php

• PS2_Conceptual_Introduction_to_the_Experiment.pdf: Nice summary of the physics and measurement of T1 and T2 with the PS2-A.
• PS2_Manual_1.41.pdf: Revised Teachspin PS2-A manual. It supersedes the old manual and a great improvement.
• Pulsed_NMR.pdf: Document that features the PS1A experiment, a precursor to the one you will be using, but with an excellent and clear description of the physics, the experimental setup and measurement of two relaxation times T1 and T2. A good supplement to the new manual
• PS2_Aliasing_on_the_Digital_Oscilloscope_Rev_2.0.pdf: A note on scope usage that may be a worthwhile read.