diff --git a/CHECLabPy/core/io/simtel.py b/CHECLabPy/core/io/simtel.py
index fdc695b..404b69d 100644
--- a/CHECLabPy/core/io/simtel.py
+++ b/CHECLabPy/core/io/simtel.py
@@ -48,7 +48,7 @@ def __init__(self, path, max_events=None):
         )
         self.seeker = EventSeeker(reader)
 
-        first_event = self.seeker[0]
+        first_event = self.seeker.get_event_index(0)
         tels = list(first_event.r0.tels_with_data)
         self.tel = tels[0]
         shape = first_event.r0.tel[self.tel].waveform.shape
@@ -62,7 +62,7 @@ def __init__(self, path, max_events=None):
         self.mapping = get_clp_mapping_from_tc_mapping(tc_mapping)
         n_rows = self.mapping.metadata['n_rows']
         n_columns = self.mapping.metadata['n_columns']
-        camera_geom = first_event.inst.subarray.tel[tels[0]].camera
+        camera_geom = reader.subarray.tel[tels[0]].camera.geometry
         engineering_frame = EngineeringCameraFrame(n_mirrors=2)
         engineering_geom = camera_geom.transform_to(engineering_frame)
         pix_x = engineering_geom.pix_x.value
@@ -84,7 +84,7 @@ def __init__(self, path, max_events=None):
     def _build_waveform(self, event):
         self._fill_event_containers(event)
         samples = event.r1.tel[self.tel].waveform[self.pixel_order]
-        mc_true = event.mc.tel[self.tel].photo_electron_image[self.pixel_order]
+        mc_true = event.mc.tel[self.tel].true_image[self.pixel_order]
         waveform = SimtelWaveform(
             samples,
             iev=self._iev,
@@ -95,7 +95,7 @@ def _build_waveform(self, event):
         return waveform
 
     def _get_event(self, iev):
-        event = self.seeker[iev]
+        event = self.seeker.get_event_index(iev)
         return self._build_waveform(event)
 
     def __iter__(self):
@@ -119,8 +119,8 @@ def is_compatible(path):
 
     def _fill_event_containers(self, event):
         self._iev = event.count
-        self._t_cpu = pd.to_datetime(event.trig.gps_time.value, unit='s')
-        self.run_id = event.r0.obs_id
+        self._t_cpu = pd.to_datetime(event.trigger.tel[self.tel].time.value, unit='s')
+        self.run_id = event.index.obs_id
 
         self.mc = dict(
             iev=self._iev,
diff --git a/CHECLabPy/utils/mapping.py b/CHECLabPy/utils/mapping.py
index a0dfd14..b013ff2 100644
--- a/CHECLabPy/utils/mapping.py
+++ b/CHECLabPy/utils/mapping.py
@@ -1,5 +1,8 @@
 import warnings
 import numpy as np
+from ctapipe.instrument import SubarrayDescription, TelescopeDescription, \
+    CameraDescription, CameraReadout, OpticsDescription
+from astropy import units as u
 
 
 def get_clp_mapping_from_tc_mapping(tc_mapping):
@@ -169,11 +172,25 @@ def get_ctapipe_camera_geometry(mapping):
         pix_area=None,
         pix_type='rectangular',
         frame=EngineeringCameraFrame(n_mirrors=2),
-        sampling_rate=u.Quantity(1, u.GHz),
     )
     return camera
 
 
+def get_ctapipe_subarray(mapping):
+    tel_id = 0
+    geom = get_ctapipe_camera_geometry(mapping)
+    camera = CameraDescription("CHEC", geom, CameraReadout.from_name("CHEC"))
+    optics = OpticsDescription.from_name("SST-ASTRI")
+    subarray = SubarrayDescription(
+        "test array",
+        tel_positions={tel_id: np.zeros(3) * u.m},
+        tel_descriptions={
+            tel_id: TelescopeDescription("SST-ASTRI_CHEC", "SST", optics, camera)
+        },
+    )
+    return subarray, tel_id
+
+
 def get_row_column(pix_x, pix_y):
     """
     Get the row and column of rectangular pixels of a camera that are
diff --git a/CHECLabPy/waveform_reducers/ctapipe_integrators.py b/CHECLabPy/waveform_reducers/ctapipe_integrators.py
index 1d14832..5734309 100644
--- a/CHECLabPy/waveform_reducers/ctapipe_integrators.py
+++ b/CHECLabPy/waveform_reducers/ctapipe_integrators.py
@@ -1,5 +1,6 @@
 from CHECLabPy.core.reducer import WaveformReducer, column
-from CHECLabPy.utils.mapping import get_ctapipe_camera_geometry
+from CHECLabPy.utils.mapping import get_ctapipe_subarray
+import numpy as np
 
 
 class CtapipeLocalPeakIntegrator(WaveformReducer):
@@ -69,20 +70,21 @@ def __init__(self, n_pixels, n_samples, mapping=None, **kwargs):
                    .format(self.__class__.__name__, self.columns))
             raise ImportError(msg)
 
-        camera = get_ctapipe_camera_geometry(mapping)
-
+        subarray, self._tel_id = get_ctapipe_subarray(mapping)
+        n_pixels = subarray.tel[self._tel_id].camera.geometry.n_pixels
+        self.channel = np.zeros(n_pixels, dtype=int)
         self.window_size = self.kwargs.get("window_size", 6)
         self.window_shift = self.kwargs.get("window_shift", 3)
         self.integrator = NeighborPeakWindowSum(
             window_shift=self.window_shift,
             window_width=self.window_size,
             lwt=0,
+            subarray=subarray,
         )
-        self.integrator.neighbors = camera.neighbor_matrix_where
 
     def _prepare(self, waveforms):
         super()._prepare(waveforms)
-        charge, pulse_time = self.integrator(waveforms)
+        charge, pulse_time = self.integrator(waveforms, self._tel_id, self.channel)
 
         self.t = pulse_time
         self.charge = charge