01 physical principles signal generation

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PHYSICAL PRINCIPLES

Signal Generation

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nuclei, protons and spins

signal generation

longitudinal relaxation T1

transverse relaxation T2

excitation and relaxation

relation between T1 and T2

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signal generation



exitation and relaxation


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ATOM

protonpositive charge

neutronno charge

electronnegative charge

hydrogen atom

protonnucleus

signal generationnuclei, protons and spins

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Proton


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electric charge+

rotation+magnetism


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N

S

electric charge+

rotation


magnetism

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X

Y

Z

summed

magnetization


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X

Y

Z


summed

magnetization

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X

Y

Z


summed

magnetization

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X

Y

Z


summed

magnetization

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0,01 Tesla

0 Kelvin = - 274 Co o


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5 ppm0,5 Tesla 1,5 Tesla

15 ppm2,3 ppm0,23 Tesla

20 Celsiuso

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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0


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B 0

Precession

Larmor frequency


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B 0f0 = x B0

f = frequency

= constant of isotope

B = magnetic field


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Nucleus f0 (0,23 T) f0 (0,5 T) f0 (1,0 T) f0 (1,5 T) f0 (3,0 T)1H 9,8 MHz 21,3 MHz 42,6 MHz 63,9 MHz 127,8 MHz19F 9,2 MHz 20,0 MHz 40,0 MHz 60,1 MHz 120,1 MHz31P 3,9 MHz 8,6 MHz 17,1 MHz 25,7 MHz 51,4 MHz

23Na 2,6 MHz 5,6 MHz 11,3 MHz 16,9 MHz 33,8 MHz13C 2,5 MHz 5,4 MHz 10,7 MHz 16,1 MHz 32,1 MHz

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NucleusMolar

Concentration (mol/l)

Relative sensitivity

1H 99,0 1,019F 0,0066 0,8331P 0,35 0,066

23Na 0,078 0,09313C 0,1 0,016

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signal generation



excitation and relaxation


Education

01 physical principles signal generation