|Our economically-priced electron
paramagnetic resonance system can be used to demonstrate EPR spectra in
a lecture, or to perform experiments in advanced lab courses.
|The system consists of a control box (left) and a magnet
box (right). The control box contains the rf oscillator, lock-in amplifier,
and a microcontroller for easy manual operation. It can also be operated
by a personal computer. The magnet box contains a 0.13 T permanent
magnet, a modulation coil for the 96-kHz lock-in amplifier, a 300 gauss
variable magnet for taking EPR spectra, and the 3.3 GHz resonator.
Measurement times between 2s and 30s are possible. A variable low-pass
filter can be used to improve the signal-to-noise ratio of the spectra.
The samples can be contained in 3-mm polystyrene straws, conventional 3-mm
EPR tubes, or quartz capillaries. The EPR sectra can be displayed
on a digital oscillsocope, or on a personal computer.
|The EPR system can be controlled, and spectra
can be read and processed, by a personal computer. Here is the EPR signal
of a powdered DDPH sample.
|Some more spectra measured with the system:
EPR spectrum of Mn in CaO.
EPR Spectrum of TEMPO in Ethanol