Consider a 2-D object consisting of two triangle compartments, as shown in Figure P9.4. Suppose a solution containing a 511 KeV gamma ray emitting radionuclide with concentration f = 0.5….
Derive a more general formula for MZ (t). You can assume that the transverse magnetization has completely dephased before each RF pulse, that is, Mxy(TR) = 0.
The following equations from Example 12.4 give the components of M after an α pulse (assuming the system is in equilibrium just before the α pulse):
Suppose that we now excite the sample with a train of α pulses, separated by a time TR. The equilibrium condition is true when TR is long compared with T1 and we can assume that MZ just before the pulse is equal to
Mo. Derive a more general formula for MZ (t). You can assume that the transverse magnetization has completely dephased before each RF pulse, that is, Mxy(TR) = 0. (Hint: In this more general formula, MO will be replaced with the steady-state value of the longitudinal magnetization. Define MZ after the (n + 1)th pulse to be , and MZ after the nth pulse to be . Relate these two quantities with an equation. Derive another (very simple) equation from the steady-state condition. You now have enough information to solve the problem.)