BME/EECS458 Biomedical Instrumentation and Design Laboratory
PNMR Lab
Post-Lab
Remember to include your Team Evaluations with the post-lab.
Also be sure to specify which member did which job.
For your Results and Discussions, using the data / graphs you obtained, answer the questions from the lab handout, and give a conclusion of the results. This shouldn’t be more than one or two type written pages. Also address the following:
1. Provide a figure of the pulse programmer output. This can be sketched by hand but be neat, label the axes, indicate amplitudes, widths etc...
2. Using the resonant frequency recorded from step 4 of the procedure calculate the magnetic field using the equation:
ΩR = γBo
where γ = 4.257711 MHz per kGauss
Compare this to the specification of the magnet given by Teachspin of 3500 Gauss (Give %Error), and also if you use the frequency obtained in step 5.
3. Give the widths of the π/2, π, and 3π/2 pulses in a Table comment on any relationships you can determine.
4. Show the FID signal you obtained (provide a figure, not a hand sketch)
5. From the FID signal calculate the constant T2* if the signal decays at y=A*exp(-t/ T2*)
6. Provide a figure of the spin echo signal when using 1 B pulse
7. Using this figure calculate the constant T2 assuming the spin echo decays at y=A*exp (-t/ T2).
8. Provide a figure of the spin echo with 40 B pulses and again calculate T2 using the Carr –Purcell method (the amplitudes of the spin echo should decay with the y=A*exp (-t/ T2).
9. Compare the T2 values you obtain.
10. Using your data from step 9 of the procedure fit it to a curve y=Mo(1-2*exp(-t/ T1)) and calculate T1 (spin-lattice relaxation time)
11. Using the values of T2 and T2* comment on the homogeneity of the magnetic field.
12. Pulsed NMR obtains data that is used to make an image (MRI). Propose an explanation of how the time constants T1 (spin-lattice relaxation time) and T2 (spin-spin relaxation time) could be used to give information on a sample subjected to the magnetic field. Your explanation should include what these time constants tell you as well as what a FFT of an FID signal could also tell you. There are a few pages in the book in Chapter 12 that may help as well you may want to do a little research on the web.
Individual Group Member Questions:
· Each member of your group should answer 1 question.
· No members of the group should answer the same question.
· These will be graded based on content and thoroughness.
· The answers should be at least ½ page and no more than 2 pages. Going outside this range will be penalized.
· Please include graphs, pictures, and references as appropriate. These do not count toward the length, but do not include information that is irrelevant or does not satisfy your goal.
For this post-lab, you will make up your own questions to answer. You should have different questions from your other group members – please try to be creative. The difficulty of your question will definitely be taken into account for your grade.
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