fat_null_flip_deg

pypulseqpp.sequences.fat_null_flip_deg()

Return the saturation flip angle (degrees) that nulls fat at the excitation.

In the steady state of one saturation pulse every period_s, fat is zero delay_s after the pulse when the flip a satisfies cos(a) = (1 - exp(delay/T1)) / (1 - exp(-(period - delay)/T1)), a little over 90 degrees.

Parameters:

• delay_s (float) – Time from the saturation pulse’s centre to the excitation’s (s).

• period_s (float) – Time between two saturation pulses (s).

• t1_s (float, default=FAT_T1_S) – T1 of fat (s).

Raises:

ValueError – If a time is not positive, the delay is not shorter than the period, or the fat recovers so fast that no flip leaves it at zero.

Examples

>>> from pypulseqpp.sequences import fat_null_flip_deg
>>> round(fat_null_flip_deg(5e-3, 50e-3), 1)
96.8