Digital Control of an FFC NMR Relaxometer Power Supply

  • Rúben J. A. Lopes
  • Pedro J. Sebastião
  • Duarte M. Sousa
  • António RoqueEmail author
  • Elmano Margato
Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 604)


The fast field cycling (FFC) experimental technique allows to overcome a technical difficulty associated with the nuclear magnetic resonance (NMR) signal-to-noise ratio (SNR) at low frequency spin-lattice relaxation measurements when using conventional NMR spectrometers. Constituting a step forward than the classical analog approaches, in this paper, a digital control system for an FFC-NMR relaxometer power supply was developed. The hardware and software were designed to allow for the modulation of the Zeeman field as required by this technique. Experimental results show that under digital control the system performs fast transitions between the high and low magnetic flux density levels, i.e., the switching times obtained are in the millisecond range, and, assures a good stability of the field during the steady states. Comparative proton relaxometry measurements in two compounds (liquid crystal 5CB and ionic liquid [BMIM]BF4) were made to assess the digital control system performance.


Digital control Nuclear magnetic resonance Digital PID 



This work was supported by national funds through Instituto Politécnico de Setúbal, ISEL/Instituto Politécnico de Lisboa, Fundação para a Ciência e a Tecnologia (FCT) with reference UID/CEC/50021/2019 and UID/CTM/04540/2019.


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Copyright information

© Springer Nature Switzerland AG 2020

Authors and Affiliations

  • Rúben J. A. Lopes
    • 1
  • Pedro J. Sebastião
    • 1
  • Duarte M. Sousa
    • 2
  • António Roque
    • 3
    Email author
  • Elmano Margato
    • 4
  1. 1.Department of Physics, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
  2. 2.Department of Electrical and Computer Engineering, Instituto Superior Técnico & INESC-IDUniversidade de LisboaLisbonPortugal
  3. 3.Department of Electrical EngineeringEscola Superior de Tecnologia de Setúbal/Instituto Politécnico de SetúbalSetúbalPortugal
  4. 4.CEI, ISEL-Instituo Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, andINESC-IDLisbonPortugal

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