7B20.30 - ESR
This unit is a good demo due to it simple operation. Assemble the unit as shown. Set the oscilloscope to X-Y sampling. Note that the DPPH sample is permanently mounted in the coil unit. Turn on the main power and adjust the current to approximately 150 ma. You should see 4 peaks on the oscilloscope. You can adjust the phase of the coils so that two of the peaks merge with the other two peaks. The resonant frequency of the sample can be found by adjusting the R.F. Oscillator until resonance is shown on the oscilloscope. The exact resonant frequency can also be found by very careful adjustment of the R.F. Oscillator.
Additional sample material of the DPPH can be found in the demo room refrigerator.
- R. Dupree and P. K. Grannell, "A Simple ESR Spectrometer which Uses Sample Heating to Detect Magnetic Resonance", AJP, Vol. 38, #7, July 1970, p. 924.
- "Simple Electron Spin Resonance Spectrometer", Apparatus Notes, July 1965-December 1972, p. 35.
- "Electrons Spin Resonance", Alpha Scientific Laboratories.
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