diff --git a/src/graphnet/models/graphs/nodes/__init__.py b/src/graphnet/models/graphs/nodes/__init__.py
index 2eebef4be..540752e64 100644
--- a/src/graphnet/models/graphs/nodes/__init__.py
+++ b/src/graphnet/models/graphs/nodes/__init__.py
@@ -10,4 +10,5 @@
     NodesAsPulses,
     NodesAsDOMTimeSeries,
     PercentileClusters,
+    NodesAsRefoldedDOM,
 )
diff --git a/src/graphnet/models/graphs/nodes/nodes.py b/src/graphnet/models/graphs/nodes/nodes.py
index e5a226168..30ec2fa04 100644
--- a/src/graphnet/models/graphs/nodes/nodes.py
+++ b/src/graphnet/models/graphs/nodes/nodes.py
@@ -13,8 +13,13 @@
 from graphnet.models.graphs.utils import (
     cluster_summarize_with_percentiles,
     identify_indices,
+    lex_sort,
+    pulse_template,
+    spe_atwd_old,
+    pulseseries_to_wf,
 )
 from copy import deepcopy
+import numpy as np
 
 
 class NodeDefinition(Model):  # pylint: disable=too-few-public-methods
@@ -145,6 +150,7 @@ def __init__(
         id_columns: List[str] = ["dom_x", "dom_y", "dom_z"],
         time_index: str = "dom_time",
         charge_index: str = "charge",
+        max_activations: Optional[int] = None,
     ) -> None:
         """Construct nodes as DOMs with time series of pulses.
 
@@ -153,6 +159,7 @@ def __init__(
             id_columns: List of columns that uniquely identify a DOM.
             time_index: Name of the column that contains the time index.
             charge_index: Name of the column that contains the charge.
+            max_activations: Maximum number of activations to keep per DOM.
         """
         assert isinstance(keys, type(id_columns))
 
@@ -160,9 +167,14 @@ def __init__(
         self._id_columns = [self._keys.index(key) for key in id_columns]
         self._time_index = self._keys.index(time_index)
         self._charge_index = self._keys.index(charge_index)
-
+        self._max_activations = max_activations
         super().__init__()
 
+    def _define_output_feature_names(
+        self, input_feature_names: List[str]
+    ) -> List[str]:
+        return input_feature_names
+
     def _sort_by_n_pulses(
         self, time_series: List[torch.Tensor]
     ) -> torch.Tensor:
@@ -177,42 +189,64 @@ def _sort_by_n_pulses(
 
     def _construct_nodes(self, x: torch.Tensor) -> Data:
         """Construct nodes from raw node features ´x´."""
+        # cast to numpy
+        x = x.numpy()
         # sort by time
-        x = x[x[:, self._time_index].sort().indices]
+        x = x[np.argsort(x[:, self._time_index])]
         # undo log10 scaling since we want to sum up charge
-        x[:, self._charge_index] = torch.pow(10, x[:, self._charge_index])
+        x[:, self._charge_index] = np.power(10, x[:, self._charge_index])
         # shift time to positive values with a small offset
-        x[:, self._time_index] += -min(x[:, self._time_index])
+        x[:, self._time_index] += -np.min(x[:, self._time_index])
         # Group pulses on the same DOM
-        dom_index = _group_identical(x[:, self._id_columns])
+        x = lex_sort(x, self._id_columns)
 
-        val, ind = dom_index.sort(stable=True)
-        counts = torch.concat(
-            [torch.tensor([0]), val.bincount().cumsum(-1)[:-1]]
+        unique_sensors, counts = np.unique(
+            x[:, self._id_columns], return_counts=True, axis=0
+        )
+        # sort DOMs and pulse-counts
+        sort_this = np.concatenate(
+            [unique_sensors, counts.reshape(-1, 1)], axis=1
+        )
+        sort_this = lex_sort(x=sort_this, cluster_columns=self._id_columns)
+        unique_sensors = sort_this[:, 0 : unique_sensors.shape[1]]
+        counts = sort_this[:, unique_sensors.shape[1] :].flatten().astype(int)
+
+        time_series = np.split(
+            x[:, [self._charge_index, self._time_index]], counts.cumsum()[:-1]
         )
-        unique_doms = x[:, self._id_columns + [self._time_index]][ind][counts]
 
-        time_series = [
-            x[dom_index == index_key][
-                :, [self._charge_index, self._time_index]
-            ]
-            for index_key in dom_index.unique()
-        ]
         # add total charge to unique dom features and apply log10 scaling
-        charge = torch.stack(
-            [torch.log10(image[:, 0].sum()) for image in time_series]
+        time_charge = np.stack(
+            [
+                (image[0, 1], np.arcsinh(5 * image[:, 0].sum()) / 5)
+                for image in time_series
+            ]
         )
-        x = torch.column_stack([unique_doms, charge])
+        x = np.column_stack([unique_sensors, time_charge])
+
+        # time_series, sort_ind = self._sort_by_n_pulses(time_series)
+        # cutter = torch.tensor([len(ts) for ts in time_series])
+        # x = x[sort_ind]
+        if self._max_activations is not None:
+            counts[counts > self._max_activations] = self._max_activations
+            time_series = [
+                image[: self._max_activations] for image in time_series
+            ]
+        time_series = np.concatenate(time_series)
+        # apply inverse hyperbolic sine to charge values (handles zeros unlike log scaling)
+        time_series[:, 0] = np.arcsinh(5 * time_series[:, 0]) / 5
 
-        time_series, sort_ind = self._sort_by_n_pulses(time_series)
-        cutter = torch.tensor([len(ts) for ts in time_series])
-        x = x[sort_ind]
-        time_series = torch.concat(time_series)
-        return Data(x=x, time_series=time_series, cutter=cutter, n_doms=len(x))
+        return Data(
+            x=torch.tensor(x),
+            time_series=torch.tensor(time_series),
+            cutter=torch.tensor(counts),
+            n_doms=len(x),
+        )
 
 
 @torch.jit.script
 def log10powsum(tensor: torch.Tensor) -> torch.Tensor:
+    """Convert to power of 10 and sum and convert back to log10."""
     return torch.log10(torch.sum(torch.pow(10, tensor)))
 
 
@@ -236,6 +270,15 @@ def pad_charge(tensor: torch.Tensor, time_range: torch.Tensor) -> torch.Tensor:
 
 @torch.jit.script
 def return_closest(tt: torch.Tensor, tr: torch.Tensor) -> torch.Tensor:
+    """Return closest index of time range to time tensor.
+
+    Args:
+        tt: pulse time of shape (num_pulses,1).
+        tr: time range of shape (len(time_range),1).
+
+    Returns:
+        tensor: binned time index of shape (num_pulses,1).
+    """
     return torch.argmin(abs(tt - tr.unsqueeze(1)), dim=0)
 
 
@@ -243,7 +286,7 @@ def return_closest(tt: torch.Tensor, tr: torch.Tensor) -> torch.Tensor:
 def sum_charge(
     x: torch.Tensor,
     dom_index: torch.Tensor,
-    id_columns: list[int],
+    id_columns: List[int],
     time_index: int,
     charge_index: int,
 ) -> torch.Tensor:
@@ -273,11 +316,11 @@ def sum_charge(
 def create_time_series(
     x: torch.Tensor,
     dom_index: torch.Tensor,
-    id_columns: list[int],
+    id_columns: List[int],
     time_index: int,
     charge_index: int,
     time_range: torch.Tensor,
-) -> list[torch.Tensor]:
+) -> List[torch.Tensor]:
     """Create time series.
 
     Args:
@@ -313,33 +356,44 @@ def create_time_series(
     return [unique_doms, time_series]
 
 
-@torch.jit.script
-def get_unique_dom_features(
-    x: torch.Tensor,
-    dom_index: torch.Tensor,
-    id_columns: list[int],
-    time_index: int,
-    charge_index: int,
-    time_range: torch.Tensor,
-) -> torch.Tensor:
-    unique_doms = []
-    for index_key in torch.unique(dom_index):
-        unique_doms.append(
-            torch.hstack(
-                [
-                    x[dom_index == index_key][0][id_columns],
-                    x[dom_index == index_key][0][time_index],
-                    x[dom_index == index_key][:, charge_index].max(),
-                ]
-            )
-        )
-    unique_doms = torch.vstack(unique_doms)
-    return unique_doms
+# @torch.jit.script
+# def get_unique_dom_features(
+#     x: torch.Tensor,
+#     dom_index: torch.Tensor,
+#     id_columns: List[int],
+#     time_index: int,
+#     charge_index: int,
+#     time_range: torch.Tensor,
+# ) -> torch.Tensor:
+#     """Get unique dom features.
+
+#     Args:
+#         tensor: padded charge tensor of shape )"""
+#     unique_doms = []
+#     for index_key in torch.unique(dom_index):
+#         unique_doms.append(
+#             torch.hstack(
+#                 [
+#                     x[dom_index == index_key][0][id_columns],
+#                     x[dom_index == index_key][0][time_index],
+#                     x[dom_index == index_key][:, charge_index].max(),
+#                 ]
+#             )
+#         )
+#     unique_doms = torch.vstack(unique_doms)
+#     return unique_doms
 
 
 def create_sparse_charge_series(
     dom_index: torch.Tensor, time_index: torch.Tensor, values: torch.Tensor
 ) -> torch.Tensor:
+    """Create sparse charge series.
+
+    Args:
+        dom_index: indexing of doms for grouping.
+        time_index: indexing of time bins for grouping.
+        values: values to be summed up.
+    """
     i = torch.vstack([dom_index, time_index])
     v = values
     s = torch.sparse_coo_tensor(
@@ -386,6 +440,7 @@ def __init__(
             id_columns: List of columns that uniquely identify a DOM.
             time_index: Name of the column that contains the time index.
             charge_index: Name of the column that contains the charge.
+            granularity: Number of time bins to use.
         """
         assert isinstance(keys, type(id_columns))
 
@@ -546,3 +601,141 @@ def _construct_nodes(self, x: torch.Tensor) -> Data:
             raise AttributeError
 
         return Data(x=torch.tensor(array))
+
+
+class NodesAsRefoldedDOM(NodeDefinition):
+    """Represent each node as DOM a with a time series of pulses."""
+
+    def __init__(
+        self,
+        keys: List[str] = [
+            "dom_x",
+            "dom_y",
+            "dom_z",
+            "dom_time",
+            "charge",
+            "atwd",
+            "width",
+        ],
+        id_columns: List[str] = ["dom_x", "dom_y", "dom_z"],
+        time_index: str = "dom_time",
+        charge_index: str = "charge",
+        atwd_index: str = "atwd",
+        width_index: str = "width",
+        max_activations: Optional[int] = None,
+    ) -> None:
+        """Construct nodes as DOMs with time series of pulses.
+
+        Args:
+            keys: List of node feature names.
+            id_columns: List of columns that uniquely identify a DOM.
+            time_index: Name of the column that contains the time index.
+            charge_index: Name of the column that contains the charge.
+            atwd_index: Name of the column that contains the atwd.
+            width_index: Name of the column that contains the width.
+            max_activations: Maximum number of activations to keep per DOM.
+        """
+        assert isinstance(keys, type(id_columns))
+
+        self._keys = keys
+        self._id_columns = [self._keys.index(key) for key in id_columns]
+        self._time_index = self._keys.index(time_index)
+        self._charge_index = self._keys.index(charge_index)
+        self._atwd_index = self._keys.index(atwd_index)
+        self._width_index = self._keys.index(width_index)
+        self._max_activations = max_activations
+        super().__init__()
+
+    def _define_output_feature_names(
+        self, input_feature_names: List[str]
+    ) -> List[str]:
+        return input_feature_names + ["n_pulses"]
+
+    def _sort_by_n_pulses(
+        self, time_series: List[torch.Tensor]
+    ) -> torch.Tensor:
+        """Sort time series by number of pulses."""
+        sort_index = (
+            torch.tensor([len(ts) for ts in time_series])
+            .sort(descending=True)
+            .indices
+        )
+        sorted_time_series = [time_series[i] for i in sort_index]
+        return sorted_time_series, sort_index
+
+    def _construct_nodes(self, x: torch.Tensor) -> Data:
+        """Construct nodes from raw node features ´x´."""
+        # cast to numpy
+        x = x.numpy()
+        # sort by time
+        x = x[np.argsort(x[:, self._time_index])]
+        # undo log10 scaling since we want to sum up charge
+        # x[:, self._charge_index] = np.power(10, x[:, self._charge_index])
+        # shift time to positive values with a small offset
+        x[:, self._time_index] += -np.min(x[:, self._time_index])
+        # find largest charge bin in time
+        _counts, edges_ = np.histogram(
+            x[:, self._time_index], bins=1000, weights=x[:, self._charge_index]
+        )
+        largest_charge_time = (
+            0.5 * (edges_[:-1] + edges_[1:])[np.argmax(_counts)]
+        )
+
+        # weigthed_mean_time = np.average(x[:, self._time_index],weights=x[:, self._charge_index])
+        # Group pulses on the same DOM
+        x = lex_sort(x, self._id_columns)
+
+        unique_sensors, counts = np.unique(
+            x[:, self._id_columns], return_counts=True, axis=0
+        )
+        # sort DOMs and pulse-counts
+        sort_this = np.concatenate(
+            [unique_sensors, counts.reshape(-1, 1)], axis=1
+        )
+        sort_this = lex_sort(x=sort_this, cluster_columns=self._id_columns)
+        unique_sensors = sort_this[:, 0 : unique_sensors.shape[1]]
+        counts = sort_this[:, unique_sensors.shape[1] :].flatten().astype(int)
+
+        time_series = np.split(
+            x[
+                :,
+                [
+                    self._charge_index,
+                    self._time_index,
+                    self._atwd_index,
+                    self._width_index,
+                ],
+            ],
+            counts.cumsum()[:-1],
+        )
+
+        # add total charge to unique dom features and apply log10 scaling
+        time_charge_n = np.stack(
+            [
+                (image[0, 1], np.log10(image[:, 0].sum()), len(image))
+                for image in time_series
+            ]
+        )
+        x = np.column_stack([unique_sensors, time_charge_n])
+
+        # perform refolding
+        ts = []
+        time_range = np.linspace(
+            largest_charge_time - 1600, largest_charge_time + 3200, 1000
+        )
+        for ind, time_series in enumerate(time_series):
+            charge_series = pulseseries_to_wf(
+                time_series, spe_atwd_old, time_range, 1
+            ).astype(np.float16)
+            ts.append(charge_series)
+        ts = np.array(ts)
+        # time_series = np.concatenate(time_series)
+        x = np.column_stack([x, ts])
+
+        return Data(
+            x=torch.tensor(x),
+            time_series=torch.tensor(ts),
+            time_range=time_range,
+            cutter=torch.tensor(counts),
+            n_doms=len(x),
+        )
diff --git a/src/graphnet/models/graphs/utils.py b/src/graphnet/models/graphs/utils.py
index ccd861783..114a35a3d 100644
--- a/src/graphnet/models/graphs/utils.py
+++ b/src/graphnet/models/graphs/utils.py
@@ -1,6 +1,6 @@
 """Utility functions for construction of graphs."""
 
-from typing import List, Tuple
+from typing import List, Tuple, Callable
 import numpy as np
 
 
@@ -158,3 +158,50 @@ def cluster_summarize_with_percentiles(
         )
 
     return array
+
+
+class pulse_template:
+    """SPE shape for DOMs."""
+
+    def __init__(self, args: List[float]):
+        """Initialize SPE shape for DOMs.
+
+        Args:
+            args: List of parameters for the SPE shape. (c, x0, b1, b2)
+        """
+        self.args = args
+
+    def __call__(self, time: np.ndarray) -> np.ndarray:
+        """SPE shape implementation for DOMs."""
+        c, x0, b1, b2 = self.args
+        t = time - 11.5
+        func = c * (np.exp(-(t - x0) / b1) + np.exp((t - x0) / b2)) ** -8
+        return func
+
+
+def spe_atwd_old(time: np.ndarray) -> np.ndarray:
+    """SPE shape for ATWD."""
+    t = time - 11.5  # causality
+    c = 15.47 / 13.292860653948139
+    x0 = -3.929 - 5
+    b1 = 4.7
+    b2 = 39.0
+    return c * (np.exp(-(abs(t - x0)) / b1) + np.exp((abs(t - x0)) / b2)) ** -8
+
+
+def pulseseries_to_wf(
+    pulses: np.ndarray,
+    template: Callable,
+    times: np.ndarray,
+    norm: float = 1.0,
+) -> np.ndarray:
+    """Convolve pulses with SPE shape."""
+    wf = (
+        np.sum(
+            pulses[:, 0]
+            * template(times[..., None] - pulses[:, 1][None, ...]),
+            axis=1,
+        )
+        * norm
+    )
+    return wf
diff --git a/src/graphnet/models/rnn/__init__.py b/src/graphnet/models/rnn/__init__.py
index 63e29d3b2..830fbd56a 100644
--- a/src/graphnet/models/rnn/__init__.py
+++ b/src/graphnet/models/rnn/__init__.py
@@ -2,3 +2,4 @@
 
 from .node_rnn import Node_RNN
 from .dom_window_rnn import Dom_Window_RNN
+from .node_transformer import Node_Transformer