Magnetic Resonance Demonstrator




Our economically-priced magnetic resonance system can be used to demonstrate free-induction decays, spin echos and CPMG sequences in a lecture, or to perform experiments in advanced lab courses.  The system can be extended to also perform NQR measurements. 


The system consists of a control box (left) and a magnet box (right). The control box contains the pulse transmitter, receiver, and a microcontroller for easy manual operation.  It can also be operated by a personal computer.  The magnet box contains a 0.4T magnet and the resonant receiver and transmitter coil.  The coil can be tuned by a variable capacitor, allowing for measuring hydrogen and fluorine samples. Conventional 5-mm NMR tubes can be used. 

The receiver and transmitter frequencies can be selected separately, allowing for an intermediate-frequency display of the MR response of the sample.  The amplitudes of the first (pi/2) and second (pi) pulse can be varied independently.  The pulse lengths and the duration between first and second pulse can be varied between 10 microseconds and 10 milliseconds.  A trigger pulse is generated a presettable time after the first pulse.  To improve the signal-to-noise ratio, a tunable low-pass filter  is integrated.  The pulse repetition time can be selected between 60ms and 30s.

The MR signal can be displayed on a digital or an analog oscillsocope.

The NMR signal can be read and processed also by a personal computer. Here is a CPMG sequence from a mineral oil sample.

In addition to the intermediate frequency detector, an envelope detector is available for easier characterization of more complex signals (e.g., CPMG sequences).

The system can be extended for NQR measurements (FID and Spin Echo).  Here is the time trace of a chlorine NQR FID.

ez SQUID Mess- und Analysegeräte Dr. Hans-Michael Mück, Herborner Strasse 9, 35764 Sinn, Germany