This document discusses different types of magnetism including paramagnetism, diamagnetism, and ferromagnetism. It describes how magnetic susceptibility determines how substances are affected by external magnetic fields based on their electron configuration. The document also discusses different types of magnets used in MRI including permanent magnets with low field strength, electromagnets, and superconducting magnets which use superconducting wires and liquid helium to generate the strongest magnetic fields.

1. MAGNETISM
BY DR NISHANT RAJ

2. INTRODUCTION
• All substances posses some form of magnetism-----Magnetic Susceptibility.
• Magnetic Susceptibility– Ability of a substance to get affected by external
magnetic field and is relate to electron configuration of the atom.

3. DEPENDING ON MAGNETIC SUSCPETIBILITY
• PARAMAGNETIC
• DIAMAGNETIC
• FERROMAGNETIC

4. PARAMAGNETISM

5. EXAMPLES: Gadolinium,Melanin and Oxygen

6. DIAMAGNETISM
EXAMPLES: Bismuth,Mercury,Copper and Carbon

8. FERROMAGNETISM
EXAMPLES: Iron, Cobalt Nickel

10. MAGNETIC FIELD STRENGTH
• Expressed by notation B
• Primary field: B0
• Secondary Field: B1
• UNITS: Gauss andTesla
• One tesla (1T) is defined as the field intensity generating one newton (N) of force per
ampere (A) of current per meter of conductor:
• 1Tesla = 1N / (1A . 1m).

12. TYPES OF MAGNET IN USE FOR CLINICAL
MRI
• PERMANENT MAGNET
• ELECTROMAGNET
• SUPERCONDUCTING MAGNET

13. PERMANENT MAGNET
• Low cost
• Open MRI
• Low magnetic field Strength: 0.2-0.5Tesla
• Low resolution

14. ELECTROMAGNET(RESISITVE MAGNET)

15. SUPERCONDUCTING MAGNET
SUPERCONDUCTOR:

17. STRUCTURE OF SUPERCONDUCTING
MAGNET
• COMPONENTS:
• 1: Superconducting Wires: of Nb/Ti Alloy
• 2.Helium:To cool the coil to -269 degree Celcius
• 3: Liquid Nitrogen and Radiation Shield: Prevents
heat exchange between helium and surrounding.

19. THANKYOU