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ISOL@MYRRHA for Solid-State Physics and Biology

Over the last decade, ISOL facilities worldwide have invested considerable efforts in the development and optimization of setups dedicated to condensed matter and biological research. As such, a boost was given to the interdisciplinary character of radioactive ion beam applications.


Beta-NMR relies fully on highly polarized beams of radioactive ions. The beta-decay asymmetry, observed in the emission of beta particles during the beta-decay process from the polarized nuclei, is used as observable to probe resonances with an externally applied RF frequency, similarly to conventional Magnetic Resonance Imaging (MRI). ​

The main problem in conventional NMR is the need to get a high degree of polarization of the nuclei which are present in the material under investigation. High external magnetic fields are needed and a high sensitivity is needed to detect the NMR resonance signal. Not all chemical elements can be visualized by NMR due to the difficulty to polarize these nuclei inside the material.​

The benefits of the so-called beta-NMR, compared to conventional MRI are:​

  • much less polarized nuclei are needed in the sample (several orders of magnitude less);​

  • the sensitivity to resonance frequencies is much higher, due to the intrinsic higher detection efficiency of the beta particles;​

  • a wider range of isotopes can be imaged due to the external laser based polarization method.​

  • by changing the energy of the polarized ion beam (typically from a few eV to 100 keV), the implantation depth into the material is controllable and NMR resonances can be observed in strictly controlled regions of the material. ​

The last point is crucial in material science where surfaces and boundaries between materials contain important information on the material performance and characteristics.​

The beta-NMR technique is currently applied in two domains: solid state physics and biology.​


PAC measurements

From Perturbed Angular Correlation (PAC) measurements, information on local electric and magnetic fields in the sample can be inferred. 


Emission channeling

Emission channeling is a method where the crystal lattice site of and implanted “impurity” (the implanted radioactive isotope) is inferred from the emission pattern of beta-particles.​

Both experimental methods only need specific radio-isotopes to be implanted into a sample. The radioactivity emitted from the sample is subsequently measured in an offline laboratory.


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