Physics Lab Equipment

LEAI-13 Experimental System of Pulsed NMR

LEAI-13 Experimental System of Pulsed NMR

Features

  • 10 easy-to-use specimen tubes 


  • High homogeneous magnetic field 

  • Stable & reliable experiment data

  • Friendly software & convenient operation




Introduction


Pulsed nuclear magnetic resonance (PNMR) applies a pulsed RF field to the nuclei system and observes the response of the nuclei system. The fast Fourier transformation (FFT) technology is used to transform the time domain signal into a frequency domain signal, which is equivalent to multiple single-frequency continuous wave nuclear magnetic resonance (CW-NMR) spectrometers at the same time. Therefore, the nuclear magnetic resonance phenomenon can be observed in a larger range, and the signal amplitude is twice as large as the CW ones.


LEAI-13 PNMR Apparatus uses DDS digital synthesis technology for the transmitting pulse source and PID control technology for the temperature control of the magnet. The experimental data is stable and reliable, the operation is convenient, and the experiment contents are rich, which can be used in advanced physics labs in colleges and universities. 


LEAI-13 PNMR Apparatus consists of a Constant Temperature Unit (including magnet and temperature control device), a RF Transmitting Unit (including power supply of modulation field), and a Signal Receiving Unit (including power supply of homogenous field and temperature display). A computer is also required for running the program of experiments.


Using this instrument, the following experimental objectives can be achieved:

 

1. Understand the basic physical theory and experimental configuration of a PNMR system. Learn to explain related physical phenomena in PNMR using classical vector model.

2. Learn to use signals of spin echo (SE) and free induction decay (FID) to measure T2 (spin-spin relaxation time). Analyze the influence of magnetic field homogeneity on NMR signal. 

3. Learn to measure T1 (spin-lattice relaxation time) using reverse recovery.

4. Qualitatively understand the relaxation mechanism, observe the effect of paramagnetic ions on nuclear relaxation time. 

5. Measure T2 of copper sulfate solution at different concentrations. Determine the relationship of T2 with the change of concentration. 

6. Measure the relative chemical displacement of the specimen.


The instruction manual contains comprehensive materials including experimental configurations, principles and step-by-step instructions. Please click Experiment Theory and Contents to find more information about this apparatus.


Specifications

DescriptionSpecifications
Power supply of modulation fieldmaximum current 0.5 A, voltage regulation 0 - 6.00 V
Power supply of homogenous fieldmaximum current 0.5 A, voltage regulation 0 - 6.00 V
Oscillator frequency20 MHz 
Magnetic field strength0.470 T
Magnetic pole diameter100 mm
Magnetic pole distance20 mm
Magnetic field homogeneity20 ppm (10 mm × 10 mm × 10 mm)
Controlled temperature36.500 °C
Magnetic field stability4 hours warm to be stabilized, Larmor frequency drift less than 5 Hz per minute.


Parts List

DescriptionQtyNote
Constant Temperature Unit1including magnet and temperature control device
RF Transmitting Unit1including power supply of modulation field
Signal Receiving Unit1including power supply of homogenous field and temperature display
Power Cord1

Various Cable12
Specimen Tubes10
Instructional Manual1


    LEAI-13-1.jpg

Energy level splitting in a magnetic field (H-nuclei)

LEAI-13-2.jpg

FID signal

LEAI-13-3.jpg

Spin echo signal

LEAI-13-4.jpg

Acquired signal

LEAI-13-5.jpg

Calculation of transversal relaxation time T2

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