InversionPreparation

class pypulseqpp.sequences.InversionPreparation

Bases: RfModule

Non-selective adiabatic inversion, followed by an optional crusher.

The acquisition loop supplies the inversion-time delay.

Parameters:

• system (pypulseqpp.Opts) – System limits.

• duration_s (float, default=0.01) – Inversion pulse duration (s). Shorter durations increase the required sweep rate and may violate the adiabatic condition.

• spoiling_cycles (float, default=4.0) – Dephasing of the crusher, in cycles across voxel_size_m. Zero omits the crusher.

• voxel_size_m (float, default=0.001) – Length the dephasing is counted over (m) — the smallest voxel dimension, since that is the one that has to be spoiled.

• axis ({'z', 'x', 'y'}, default='z') – Crusher axis.

• pulse_type (str, default='hypsec') – Adiabatic sweep family.

• bandwidth_hz (float, default=40000.0) – Frequency width of the sweep (Hz).

• adiabaticity (int, default=4) – Sweep-rate margin over the adiabatic condition.

• labels (sequence of str, default=None) – Counters emitted on the inversion block, which starts each shot. The module creates the label events; the acquisition loop assigns their per-shot values.

Attributes:

• rf_prep (RfEvent) – The inversion pulse.

• gz_spoil (GradEvent) – The crusher, when spoiling_cycles is nonzero.

• prep_labels (LabelSetEvent or list of LabelSetEvent) – One per name in labels, in order. Absent when labels is empty, and a bare event rather than a list when there is one.

Raises:

ValueError – If voxel_size_m is not positive, spoiling_cycles is negative, or axis is not a gradient channel.

Examples

>>> import pypulseqpp.sequences as design
>>> import pypulseqpp as pp
>>> prep = design.InversionPreparation(pp.Opts(), duration_s=8e-3)
>>> len(prep.blocks)
2

>>> len(design.InversionPreparation(pp.Opts(), spoiling_cycles=0).blocks)
1

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Methods

init_module	Build the module's block layout; implemented by the subclass.
publish	Publish events from the caller's locals and register keyword aliases.
register	Publish named events without requiring prior block registration.
sim_rf	Simulate this module's pulse across off-resonance.

Attributes

blocks	Return block tuples in play order, retaining the original event objects.
duration	Duration of the module in seconds.
seq	Sequence holding the module's construction-time block layout.