diff --git a/docs/source/usage/examples.rst b/docs/source/usage/examples.rst
index 426881b7f..100139584 100644
--- a/docs/source/usage/examples.rst
+++ b/docs/source/usage/examples.rst
@@ -70,6 +70,16 @@ Beam Distributions
 
    examples/distgen/README
 
+
+Channels & Rings
+----------------
+
+.. toctree::
+   :maxdepth: 1
+
+   examples/fodo_channel/README.rst
+
+
 Lattice Design & Optimization
 -----------------------------
 
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index d33221240..528eb8290 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -219,6 +219,23 @@ add_impactx_test(FODO.py.MPI
     examples/fodo/plot_fodo.py
 )
 
+# FODO Channel ################################################################
+#
+add_impactx_test(FODO_channel
+        examples/fodo_channel/input_fodo.in
+        OFF  # ImpactX MPI-parallel
+        examples/fodo_channel/analysis_fodo.py
+        examples/fodo_channel/plot_fodo.py
+)
+add_impactx_test(FODO_channel.py
+        examples/fodo_channel/run_fodo.py
+        OFF  # ImpactX MPI-parallel
+        examples/fodo_channel/analysis_fodo.py
+        examples/fodo_channel/plot_fodo.py
+)
+label_impactx_test(FODO_channel slow)
+label_impactx_test(FODO_channel.py slow)
+
 # Chicane #####################################################################
 #
 add_impactx_test(chicane
diff --git a/examples/fodo_channel/README.rst b/examples/fodo_channel/README.rst
new file mode 100644
index 000000000..eeaa9a8e1
--- /dev/null
+++ b/examples/fodo_channel/README.rst
@@ -0,0 +1,74 @@
+.. _examples-fodo-channel:
+
+FODO Channel
+============
+
+A 300m channel of 100 stable FODO cells (3m each) with a zero-current phase advance of 67.8 degrees.
+
+The matched Twiss parameters at entry are:
+
+* :math:`\beta_\mathrm{x} = 2.82161941` m
+* :math:`\alpha_\mathrm{x} = -1.59050035`
+* :math:`\beta_\mathrm{y} = 2.82161941` m
+* :math:`\alpha_\mathrm{y} = 1.59050035`
+
+We use a 2 GeV electron beam with initial unnormalized rms emittance of 2 nm.
+
+The second moments of the particle distribution after the FODO cell should coincide with the second moments of the particle distribution before the FODO cell, to within the level expected due to noise due to statistical sampling.
+
+In this test, the initial and final values of :math:`\lambda_x`, :math:`\lambda_y`, :math:`\lambda_t`, :math:`\epsilon_x`, :math:`\epsilon_y`, and :math:`\epsilon_t` must agree with nominal values.
+This test also demonstrates the ``cycle_intervals`` capability of our beam monitor diagnostics, only creating output every 10th FODO cell
+
+
+Run
+---
+
+This example can be run **either** as:
+
+* **Python** script: ``python3 run_fodo.py`` or
+* ImpactX **executable** using an input file: ``impactx input_fodo.in``
+
+For `MPI-parallel <https://www.mpi-forum.org>`__ runs, prefix these lines with ``mpiexec -n 4 ...`` or ``srun -n 4 ...``, depending on the system.
+
+.. tab-set::
+
+   .. tab-item:: Python: Script
+
+       .. literalinclude:: run_fodo.py
+          :language: python3
+          :caption: You can copy this file from ``examples/fodo/run_fodo.py``.
+
+   .. tab-item:: Executable: Input File
+
+       .. literalinclude:: input_fodo.in
+          :language: ini
+          :caption: You can copy this file from ``examples/fodo/input_fodo.in``.
+
+
+Analyze
+-------
+
+We run the following script to analyze correctness:
+
+.. dropdown:: Script ``analysis_fodo.py``
+
+   .. literalinclude:: analysis_fodo.py
+      :language: python3
+      :caption: You can copy this file from ``examples/fodo/analysis_fodo.py``.
+
+
+Visualize
+---------
+
+You can run the following script to visualize the beam evolution over time:
+
+.. dropdown:: Script ``plot_fodo.py``
+
+   .. literalinclude:: plot_fodo.py
+      :language: python3
+      :caption: You can copy this file from ``examples/fodo/plot_fodo.py``.
+
+.. figure:: https://gist.githubusercontent.com/ax3l/8ae7dcb9e07c361e002fa56d6b16cb16/raw/cc952670bb946cd7a62282bc7aa3f03f3d5faa16/fodo_channel.png
+   :alt: preserved emittance in the FODO channel.
+
+   FODO transversal emittance evolution (preserved)
diff --git a/examples/fodo_channel/analysis_fodo.py b/examples/fodo_channel/analysis_fodo.py
new file mode 100755
index 000000000..127a4af0a
--- /dev/null
+++ b/examples/fodo_channel/analysis_fodo.py
@@ -0,0 +1,105 @@
+#!/usr/bin/env python3
+#
+# Copyright 2022-2023 ImpactX contributors
+# Authors: Axel Huebl, Chad Mitchell
+# License: BSD-3-Clause-LBNL
+#
+
+
+import numpy as np
+import openpmd_api as io
+from scipy.stats import moment
+
+
+def get_moments(beam):
+    """Calculate standard deviations of beam position & momenta
+    and emittance values
+
+    Returns
+    -------
+    sigx, sigy, sigt, emittance_x, emittance_y, emittance_t
+    """
+    sigx = moment(beam["position_x"], moment=2) ** 0.5  # variance -> std dev.
+    sigpx = moment(beam["momentum_x"], moment=2) ** 0.5
+    sigy = moment(beam["position_y"], moment=2) ** 0.5
+    sigpy = moment(beam["momentum_y"], moment=2) ** 0.5
+    sigt = moment(beam["position_t"], moment=2) ** 0.5
+    sigpt = moment(beam["momentum_t"], moment=2) ** 0.5
+
+    epstrms = beam.cov(ddof=0)
+    emittance_x = (sigx**2 * sigpx**2 - epstrms["position_x"]["momentum_x"] ** 2) ** 0.5
+    emittance_y = (sigy**2 * sigpy**2 - epstrms["position_y"]["momentum_y"] ** 2) ** 0.5
+    emittance_t = (sigt**2 * sigpt**2 - epstrms["position_t"]["momentum_t"] ** 2) ** 0.5
+
+    return (sigx, sigy, sigt, emittance_x, emittance_y, emittance_t)
+
+
+# initial/final beam
+series = io.Series("diags/openPMD/monitor.h5", io.Access.read_only)
+last_step = list(series.iterations)[-1]
+initial = series.iterations[1].particles["beam"].to_df()
+final = series.iterations[last_step].particles["beam"].to_df()
+
+# compare number of particles
+num_particles = 10000
+assert num_particles == len(initial)
+assert num_particles == len(final)
+
+# compare beamline length: 300m
+assert np.isclose(
+    300.0, series.iterations[last_step].particles["beam"].get_attribute("z_ref")
+)
+# compare beam monitor outputs: 10 (every 10th FODO element + 1)
+assert len(series.iterations) == 11
+
+print("Initial Beam:")
+sigx, sigy, sigt, emittance_x, emittance_y, emittance_t = get_moments(initial)
+print(f"  sigx={sigx:e} sigy={sigy:e} sigt={sigt:e}")
+print(
+    f"  emittance_x={emittance_x:e} emittance_y={emittance_y:e} emittance_t={emittance_t:e}"
+)
+
+atol = 0.0  # ignored
+rtol = 2.2 * num_particles**-0.5  # from random sampling of a smooth distribution
+print(f"  rtol={rtol} (ignored: atol~={atol})")
+
+assert np.allclose(
+    [sigx, sigy, sigt, emittance_x, emittance_y, emittance_t],
+    [
+        7.5451170454175073e-005,
+        7.5441588239210947e-005,
+        9.9775878164077539e-004,
+        1.9959540393751392e-009,
+        2.0175015289132990e-009,
+        2.0013820193294972e-006,
+    ],
+    rtol=rtol,
+    atol=atol,
+)
+
+
+print("")
+print("Final Beam:")
+sigx, sigy, sigt, emittance_x, emittance_y, emittance_t = get_moments(final)
+print(f"  sigx={sigx:e} sigy={sigy:e} sigt={sigt:e}")
+print(
+    f"  emittance_x={emittance_x:e} emittance_y={emittance_y:e} emittance_t={emittance_t:e}"
+)
+
+atol = 0.0  # ignored
+rtol = 2.2 * num_particles**-0.5  # from random sampling of a smooth distribution
+print(f"  rtol={rtol} (ignored: atol~={atol})")
+
+assert np.allclose(
+    [sigx, sigy, sigt, emittance_x, emittance_y, emittance_t],
+    [
+        7.4790118496224206e-005,
+        7.5357525169680140e-005,
+        9.9775879288128088e-004,
+        1.9959539836392703e-009,
+        2.0175014668882125e-009,
+        2.0013820380883801e-006,
+    ],
+    rtol=rtol,
+    atol=atol,
+)
diff --git a/examples/fodo_channel/input_fodo.in b/examples/fodo_channel/input_fodo.in
new file mode 100644
index 000000000..5126f9336
--- /dev/null
+++ b/examples/fodo_channel/input_fodo.in
@@ -0,0 +1,60 @@
+###############################################################################
+# Particle Beam(s)
+###############################################################################
+beam.npart = 10000
+beam.units = static
+beam.kin_energy = 2.0e3
+beam.charge = 1.0e-9
+beam.particle = electron
+beam.distribution = waterbag_from_twiss
+beam.alphaX = -1.5905003499999992
+beam.alphaY = 1.5905003499999992
+beam.alphaT = 0.0
+beam.betaX = 2.8216194100262637
+beam.betaY = 2.8216194100262637
+beam.betaT = 0.5
+beam.emittX = 2e-09
+beam.emittY = 2e-09
+beam.emittT = 2e-06
+
+
+###############################################################################
+# Beamline: lattice elements and segments
+###############################################################################
+lattice.elements = monitor drift1 quad1 drift2 quad2 drift3
+lattice.nslice = 5
+lattice.periods = 101  # FODO channel of 101 periods
+
+monitor.type = beam_monitor
+monitor.cycle_intervals = 10
+monitor.backend = h5
+
+drift1.type = drift
+drift1.ds = 0.25
+
+quad1.type = quad
+quad1.ds = 1.0
+quad1.k = 1.0
+
+drift2.type = drift
+drift2.ds = 0.5
+
+quad2.type = quad
+quad2.ds = 1.0
+quad2.k = -1.0
+
+drift3.type = drift
+drift3.ds = 0.25
+
+
+###############################################################################
+# Algorithms
+###############################################################################
+algo.particle_shape = 2
+algo.space_charge = false
+
+
+###############################################################################
+# Diagnostics
+###############################################################################
+diag.slice_step_diagnostics = false
diff --git a/examples/fodo_channel/plot_fodo.py b/examples/fodo_channel/plot_fodo.py
new file mode 100755
index 000000000..5ec2b6715
--- /dev/null
+++ b/examples/fodo_channel/plot_fodo.py
@@ -0,0 +1,132 @@
+#!/usr/bin/env python3
+#
+# Copyright 2022-2023 ImpactX contributors
+# Authors: Axel Huebl, Chad Mitchell
+# License: BSD-3-Clause-LBNL
+#
+
+import argparse
+import glob
+import re
+
+import matplotlib.pyplot as plt
+import openpmd_api as io
+import pandas as pd
+from matplotlib.ticker import MaxNLocator
+from scipy.stats import moment
+
+
+def get_moments(beam):
+    """Calculate standard deviations of beam position & momenta
+    and emittance values
+
+    Returns
+    -------
+    sigx, sigy, sigt, emittance_x, emittance_y, emittance_t
+    """
+    sigx = moment(beam["position_x"], moment=2) ** 0.5  # variance -> std dev.
+    sigpx = moment(beam["momentum_x"], moment=2) ** 0.5
+    sigy = moment(beam["position_y"], moment=2) ** 0.5
+    sigpy = moment(beam["momentum_y"], moment=2) ** 0.5
+    sigt = moment(beam["position_t"], moment=2) ** 0.5
+    sigpt = moment(beam["momentum_t"], moment=2) ** 0.5
+
+    epstrms = beam.cov(ddof=0)
+    emittance_x = (sigx**2 * sigpx**2 - epstrms["position_x"]["momentum_x"] ** 2) ** 0.5
+    emittance_y = (sigy**2 * sigpy**2 - epstrms["position_y"]["momentum_y"] ** 2) ** 0.5
+    emittance_t = (sigt**2 * sigpt**2 - epstrms["position_t"]["momentum_t"] ** 2) ** 0.5
+
+    return (sigx, sigy, sigt, emittance_x, emittance_y, emittance_t)
+
+
+def read_file(file_pattern):
+    for filename in glob.glob(file_pattern):
+        df = pd.read_csv(filename, delimiter=r"\s+")
+        if "step" not in df.columns:
+            step = int(re.findall(r"[0-9]+", filename)[0])
+            df["step"] = step
+        yield df
+
+
+def read_time_series(file_pattern):
+    """Read in all CSV files from each MPI rank (and potentially OpenMP
+    thread). Concatenate into one Pandas dataframe.
+
+    Returns
+    -------
+    pandas.DataFrame
+    """
+    return pd.concat(
+        read_file(file_pattern),
+        axis=0,
+        ignore_index=True,
+    )  # .set_index('id')
+
+
+# options to run this script
+parser = argparse.ArgumentParser(description="Plot the FODO benchmark.")
+parser.add_argument(
+    "--save-png", action="store_true", help="non-interactive run: save to PNGs"
+)
+args = parser.parse_args()
+
+
+# initial/final beam
+series = io.Series("diags/openPMD/monitor.h5", io.Access.read_only)
+last_step = list(series.iterations)[-1]
+initial = series.iterations[1].particles["beam"].to_df()
+final = series.iterations[last_step].particles["beam"].to_df()
+ref_particle = read_time_series("diags/ref_particle.*")
+
+# scaling to units
+millimeter = 1.0e3  # m->mm
+mrad = 1.0e3  # ImpactX uses "static units": momenta are normalized by the magnitude of the momentum of the reference particle p0: px/p0 (rad)
+# mm_mrad = 1.e6
+nm_rad = 1.0e9
+
+
+# select a single particle by id
+# particle_42 = beam[beam["id"] == 42]
+# print(particle_42)
+
+
+# steps & corresponding z
+steps = list(series.iterations)
+
+z = list(map(lambda step: ref_particle[ref_particle["step"] == step].z.values, steps))
+# print(f"z={z}")
+
+
+# beam transversal size & emittance over steps
+moments = list(
+    map(
+        lambda step: (
+            step,
+            get_moments(series.iterations[step].particles["beam"].to_df()),
+        ),
+        steps,
+    )
+)
+# print(moments)
+emittance_x = list(map(lambda step_val: step_val[1][3] * nm_rad, moments))
+emittance_y = list(map(lambda step_val: step_val[1][4] * nm_rad, moments))
+
+# print(sigx, sigy)
+
+
+# print beam transversal size over steps
+f = plt.figure(figsize=(9, 4.8))
+ax1 = f.gca()
+im_emittance_x = ax1.plot(z, emittance_x, ".-", label=r"$\epsilon_x$")
+im_emittance_y = ax1.plot(z, emittance_y, ".-", label=r"$\epsilon_y$")
+
+ax1.legend()
+ax1.set_xlabel(r"$z$ [m]")
+ax1.set_ylabel(r"$\epsilon_{x,y}$ [nm]")
+ax1.set_ylim([1.98, 2.03])
+ax1.xaxis.set_major_locator(MaxNLocator(integer=True))
+plt.tight_layout()
+if args.save_png:
+    plt.savefig("fodo_lambda.png")
+else:
+    plt.show()
diff --git a/examples/fodo_channel/run_fodo.py b/examples/fodo_channel/run_fodo.py
new file mode 100755
index 000000000..483cbd783
--- /dev/null
+++ b/examples/fodo_channel/run_fodo.py
@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+#
+# Copyright 2022-2024 ImpactX contributors
+# Authors: Axel Huebl, Chad Mitchell, Marco Garten
+# License: BSD-3-Clause-LBNL
+#
+# -*- coding: utf-8 -*-
+
+from impactx import ImpactX, distribution, elements, twiss
+
+sim = ImpactX()
+
+# set numerical parameters and IO control
+sim.particle_shape = 2  # B-spline order
+sim.space_charge = False
+# sim.diagnostics = False  # benchmarking
+sim.slice_step_diagnostics = True
+
+# domain decomposition & space charge mesh
+sim.init_grids()
+
+# load a 2 GeV electron beam with an initial
+# unnormalized rms emittance of 2 nm
+kin_energy_MeV = 2.0e3  # reference energy
+bunch_charge_C = 1.0e-9  # used with space charge
+npart = 10000  # number of macro particles
+
+#   reference particle
+ref = sim.particle_container().ref_particle()
+ref.set_charge_qe(-1.0).set_mass_MeV(0.510998950).set_kin_energy_MeV(kin_energy_MeV)
+
+#   particle bunch
+distr = distribution.Waterbag(
+    **twiss(
+        beta_x=2.8216194100262637,
+        beta_y=2.8216194100262637,
+        beta_t=0.5,
+        emitt_x=2e-09,
+        emitt_y=2e-09,
+        emitt_t=2e-06,
+        alpha_x=-1.5905003499999992,
+        alpha_y=1.5905003499999992,
+        alpha_t=0.0,
+    )
+)
+sim.add_particles(bunch_charge_C, distr, npart)
+
+# add beam diagnostics
+monitor = elements.BeamMonitor("monitor", backend="h5", cycle_intervals=10)
+
+# design the accelerator lattice)
+ns = 5  # number of slices per ds in the element
+fodo = [
+    monitor,
+    elements.Drift(ds=0.25, nslice=ns),
+    elements.Quad(ds=1.0, k=1.0, nslice=ns),
+    elements.Drift(ds=0.5, nslice=ns),
+    elements.Quad(ds=1.0, k=-1.0, nslice=ns),
+    elements.Drift(ds=0.25, nslice=ns),
+]
+# assign a fodo segment
+sim.lattice.extend(fodo)
+
+# FODO channel of 101 periods
+sim.periods = 101
+
+# run simulation
+sim.evolve()
+
+# clean shutdown
+sim.finalize()