1. Nuclear Magnetic Resonance
ANIMATED ILLUSTRATIONS
MS Powerpoint Presentation Files
Uses Animation Schemes as available in MS XP or MS 2003 versions
A class room educational material
File-3 Ensemble Magnetization & Relaxation
2/21/ :12:07 PM
Usic Seminar 26/09/05 Emerging trends Instrum

2. & Components of Spin Vector can be quantized
Quantization of Nuclear Spin Components An Animated Illustration
Spin Axis may be along the chosen axis also
When an axis is defined
A visualisation as to what could happen when there is NO chosen direction relevant and relatable to the SPIN AXIS
But no Quantization requirements for the Components of Spin
No well defined direction for the spin axis specified outside the spinning nucleus?
When an Axis is defined
Spin Axis
& Components of Spin Vector can be quantized
Spinning nucleus
Spin Vector Component in the presence of a chosen axis is quantized and has fixed orientation
Nucleus
has mass ‘M’
What is the Interaction by which a direction can be specified as relatable to the quantization that manifests?
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Usic Seminar 26/09/05 Emerging trends Instrum

3. Usic Seminar 26/09/05 Emerging trends Instrum
For the Quantization Effects on the Spin Angular Momentum in presence of External magnetic Field
VIEW the power point file on
“LARMOR PRECESSION.ppt”
Linked at section III.1 on the line “precession in Magnetic Fields” at URL:-
A RED ARROW (the z component) can be representative and indicate the presence of the magnetic moment.
Total (resultant) Nuclear Magnetic Moment
Z-Component
XY Component
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Usic Seminar 26/09/05 Emerging trends Instrum

4. Usic Seminar 26/09/05 Emerging trends Instrum
NET Magnetization in Magnetic Field
Now more such arrows are depicted to indicate the randomness of these vector directions -all arrows in red color now:The vectors add up to zero
A Completed-Picture of aligned Spins (?) --- Not yet (!)
When a STEADY external strong magnetic Field is turned on then these magnetic moment vectors (components) all get aligned along the LINE of the magnetic field direction in time of the order of longitudinal relaxation time
The individual magnetic moment vectors are oriented independent of others. Hence a random orientation is depicted
Some of the Vectors will be oriented opposite to the Field Direction as it would be known later. But more will be along the Field and,
a NET Magnetization along the magnetic field RESULTS
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Usic Seminar 26/09/05 Emerging trends Instrum

5. Usic Seminar 26/09/05 Emerging trends Instrum
When the Magnetic Field is applied
The previous slide tried to illustrate the salient aspects to be noted in the final picture for the magnetization growth. In this effort the time sequences of the spin alignments for the growth of the magnetization have not been shown realistically. The alignment of the spins parallel to the field direction was depicted to precede the alignment in the direction opposite to that of the field direction. In reality it would be hard to identify before hand which spin would get aligned after which other spins and whether this particular spin would align parallel to or opposite to the magnetic field direction. The final picture would have to depict more parallel alignment of the spins than the alignment opposite.
Before applying the magnetic field the spins are in a state of random distribution of the orientation
The alignment of the spins is effected and the alignment results in a NET magnetization along the Magnetic Field Direction
2/21/ :12:07 PM
Usic Seminar 26/09/05 Emerging trends Instrum

6. Time GROWTH Magnetization Strength 2/21/2019 10:12:07 PM
Usic Seminar 26/09/05 Emerging trends Instrum

7. Usic Seminar 26/09/05 Emerging trends Instrum
Relaxation Longitudinal and transverse
I h
NET Magnetization
Longitudinal T1 Relaxation
Transverse T2 Relaxation
Randomization in XY plane
π/2 pulse
2/21/ :12:07 PM
Usic Seminar 26/09/05 Emerging trends Instrum