nuclear magnetic resonance

Examples of nuclear magnetic resonance in the following topics:

• NMR and MRIs

  • Magnetic resonance imaging is a medical imaging technique used in radiology to visualize internal structures of the body in detail.
  • Magnetic resonance imaging (MRI), also called nuclear magnetic resonance imaging (NMRI) or magnetic resonance tomography (MRT), is a medical imaging technique used in radiology to visualize internal structures of the body in detail.
  • MRI utilized the property of nuclear magnetic resonance (NMR) to image the nuclei of atoms inside the body.
  • When a person is inside the scanner's powerful magnetic field, the hydrogen protons in their body align with the direction of the field.
  • This electromagnetic field has just the right frequency (known as the resonance frequency) to become absorbed and then reverse the rotation of the hydrogen protons in the magnetic field.

• Examples and Applications

  • To achieve this, the voltage frequency must match the particle's cyclotron resonance frequency,
  • Additionally, cyclotrons are a good source of high-energy beams for nuclear physics experiments.
  • A magnetic field parallel to the filament is imposed by a permanent magnet.
  • The sizes of the cavities determine the resonant frequency, and thereby the frequency of emitted microwaves.
  • A cross-sectional diagram of a resonant cavity magnetron.

• Emission Topography

  • Positron emission tomography is a nuclear medical imaging technique that produces a three-dimensional image of processes in the body.
  • Positron emission tomography (PET) is a nuclear medical imaging technique that produces a three-dimensional image or picture of functional processes in the body.
  • PET scans are increasingly read alongside CT or magnetic resonance imaging (MRI) scans, with the combination giving both anatomic and metabolic information.

• Other Forms of Energy

  • Thermal, chemical, electric, radiant, nuclear, magnetic, elastic, sound, mechanical, luminous, and mass are forms that energy can exist in.
  • Nuclear Energy: This type of energy is liberated during the nuclear reactions of fusion and fission.
  • Examples of things that utilize nuclear energy include nuclear power plants and nuclear weapons.
  • Magnetic Energy: Technically magnetic energy is electric energy; the two are related by Maxwell's equations.
  • An example of something that stores magnetic energy is a superconducting magnet used in an MRI.

• Circular Motion

  • Magnetic forces can cause charged particles to move in circular or spiral paths.
  • Cosmic rays will follow spiral paths when encountering the magnetic field of astrophysical objects or planets (one example being Earth's magnetic field).
  • So, does the magnetic force cause circular motion?
  • (If this takes place in a vacuum, the magnetic field is the dominant factor determining the motion. ) Here, the magnetic force (Lorentz force) supplies the centripetal force
  • A particle experiencing circular motion due to a uniform magnetic field is termed to be in a cyclotron resonance.

• Zeeman Effect and Nuclear Spin

  • The picture is similar to the spin-orbit coupling except we are looking at the interaction of the total magnetic moment of the atom with the magnetic field
  • If we average over the precession of the magnetic moments around the imposed magnetic field we get the following splitting
  • that can interact with the magnetic moment of the electron.
  • The magnetic field produced by the orbiting electron is given by
  • The field of a magnetic dipole is given by

• Maxwell's Predictions and Hertz' Confirmation

  • Magnetic field lines are continuous, having no beginning or end.
  • No magnetic monopoles are known to exist.
  • A changing magnetic field induces an electromotive force (emf) and, hence, an electric field.
  • Magnetic fields are generated by moving charges or by changing electric fields .
  • Hertz used an AC RLC (resistor-inductor-capacitor) circuit that resonates at a known frequency and connected it to a loop of wire as shown in .

• Implications of Quantum Mechanics

  • Examples include the laser , the transistor (and thus the microchip), the electron microscope, and magnetic resonance imaging (MRI).

• Diffraction Revisited

  • In comparison, X-rays interact with the spatial distribution of the valence electrons, while neutrons are scattered by the atomic nuclei through the strong nuclear force.
  • In addition, the magnetic moment of the neutron is non-zero, and can thus also be scattered by magnetic fields.

• Gamma Rays

  • Some rare terrestrial natural sources that produce gamma rays that are not of a nuclear origin, are lightning strikes and terrestrial gamma-ray flashes, which produce high energy emissions from natural high-energy voltages.
  • Notable artificial sources of gamma rays include fission such as occurs in nuclear reactors, and high energy physics experiments, such as neutral pion decay and nuclear fusion.
  • Gamma radiation from radioactive materials is used in nuclear medicine.
  • Bright spots within the galactic plane are pulsars (spinning neutron stars with strong magnetic fields), while those above and below the plane are thought to be quasars (galaxies with supermassive black holes actively accreting matter).