diff --git a/src/simfmri/handlers/acquisition/workers.py b/src/simfmri/handlers/acquisition/workers.py
index f899806..961ca29 100644
--- a/src/simfmri/handlers/acquisition/workers.py
+++ b/src/simfmri/handlers/acquisition/workers.py
@@ -230,24 +230,25 @@ def acq_noncartesian(
     if nufft_backend == "stacked":
         kwargs["z_index"] = "auto"
     logger.debug("extra kwargs %s", kwargs)
-    if "gpunufft" in nufft_backend:
-        from mrinufft.operators.interfaces.gpunufft import make_pinned_smaps
-
-        smaps = make_pinned_smaps(sim.smaps)
-    else:
-        smaps = sim.smaps
     op_kwargs = dict(
         shape=sim.shape,
         n_coils=sim.n_coils,
         density=False,
         backend_name=nufft_backend,
     )
+    if "gpunufft" in nufft_backend:
+        logger.debug("Using gpunufft, pinning smaps")
+        from mrinufft.operators.interfaces.gpunufft import make_pinned_smaps
+
+        op_kwargs["pinned_smaps"] = make_pinned_smaps(sim.smaps)
+        op_kwargs["smaps"] = None
+    else:
+        op_kwargs["smaps"] = sim.smaps
     scheduler = kspace_bulk_shot(trajectory_gen, sim.n_frames, n_shot_sim_frame)
     with Parallel(n_jobs=n_jobs, backend="loky", mmap_mode="r") as par:
         par(
             delayed(_single_worker)(
                 sim_frame,
-                smaps,
                 shot_batch,
                 shot_pos,
                 op_kwargs,
@@ -287,7 +288,6 @@ def work_generator(sim: SimData, kspace_bulk_gen: Generator) -> Generator[tuple]
 
 def _single_worker(
     sim_frame: np.ndarray,
-    smaps: np.ndarray,
     shot_batch: np.ndarray,
     shot_pos: tuple[int, int],
     op_kwargs: Mapping[str, Any],
@@ -302,17 +302,7 @@ def _single_worker(
             category=UserWarning,
             module="mrinufft",
         )
-        if "gpunufft" in [
-            op_kwargs.get("backend_name", None),
-            op_kwargs.get("nufft_backend", None),
-        ]:
-            fourier_op = get_operator(
-                samples=shot_batch,
-                pinned_smaps=smaps,
-                **op_kwargs,
-            )
-        else:
-            fourier_op = get_operator(samples=shot_batch, smaps=smaps, **op_kwargs)
+        fourier_op = get_operator(samples=shot_batch, **op_kwargs)
         kspace = fourier_op.op(sim_frame)
     L = shot_batch.shape[1]