diff --git a/opengate/tests/src/test022_half_life_test.py b/opengate/tests/src/test022_half_life_test.py
new file mode 100755
index 000000000..67ab204dc
--- /dev/null
+++ b/opengate/tests/src/test022_half_life_test.py
@@ -0,0 +1,139 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+import opengate as gate
+from opengate.tests import utility
+import uproot
+import sys
+import math
+
+
+def test022_half_life(n_threads=1):
+    paths = utility.get_default_test_paths(__file__, output_folder="test022")
+
+    # create the simulation
+    sim = gate.Simulation()
+
+    # main options
+    sim.g4_verbose = False
+    sim.visu = False
+    sim.number_of_threads = 1
+    sim.random_seed = 12344321
+    sim.output_dir = paths.output
+    print(sim)
+
+    # units
+    m = gate.g4_units.m
+    cm = gate.g4_units.cm
+    mm = gate.g4_units.mm
+    nm = gate.g4_units.nm
+    keV = gate.g4_units.keV
+    Bq = gate.g4_units.Bq
+    sec = gate.g4_units.s
+    d = gate.g4_units.d
+
+    # set the world size like in the Gate macro
+    sim.world.size = [1 * m, 1 * m, 2 * m]
+
+    # waterbox (not really used here)
+    waterbox = sim.add_volume("Box", "waterbox")
+    waterbox.size = [10 * cm, 10 * cm, 10 * cm]
+    waterbox.translation = [0 * cm, 0 * cm, 0 * cm]
+    waterbox.material = "G4_AIR"
+
+    # detector
+    detector = sim.add_volume("Box", "detector")
+    detector.size = [80 * cm, 80 * cm, 1 * nm]
+    detector.translation = [0, 0, 30 * cm]
+    detector.material = "G4_BGO"
+    detector.color = [1, 0, 0, 1]
+
+    # physics
+    sim.physics_manager.physics_list_name = "QGSP_BERT_EMZ"
+    sim.physics_manager.enable_decay = True
+    sim.physics_manager.global_production_cuts.all = (
+        1 * mm
+    )  # all means: protons, electrons, positrons, gammas
+
+    # source #1
+    source1 = sim.add_source("GenericSource", "source1")
+
+    # source1.particle = "gamma"
+    # spectrum = gate.sources.utility.get_spectrum("Lu177", "gamma", database="icrp107")
+    # source1.energy.type = "spectrum_discrete"
+    # source1.energy.spectrum_energies = spectrum.energies
+    # source1.energy.spectrum_weights = spectrum.weights
+    # source1.activity = 10 * Bq
+
+    source1.particle = "ion 71 177"
+    source1.activity = 0.1 * Bq
+    source1.half_life = 6.647 * d
+    # source1.user_particle_life_time = 6.647 * d / math.log(2.0)
+    source1.user_particle_life_time = 0
+
+    source1.position.type = "disc"
+    source1.position.radius = 2 * cm
+    source1.position.translation = [0, 0, -10 * cm]
+    source1.direction.type = "focused"
+    source1.direction.focus_point = [0, 0, 0]
+    # source1.energy.mono = 100 * keV
+
+    # add stat actor
+    stats = sim.add_actor("SimulationStatisticsActor", "Stats")
+    stats.track_types_flag = True
+
+    # hit actor
+    ta = sim.add_actor("PhaseSpaceActor", "PhaseSpace")
+    ta.attached_to = "detector"
+    ta.attributes = ["KineticEnergy", "GlobalTime"]
+    ta.output_filename = f"test022_half_lifev_{n_threads}.root"
+    ta.steps_to_store = "first"
+    f = sim.add_filter("ParticleFilter", "f")
+    f.particle = "gamma"
+    f.policy = "accept"
+    ta.filters.append(f)
+
+    # timing
+    sim.run_timing_intervals = [[0 * sec, 1e6 * sec]]
+    # sim.run_timing_intervals = [[1e6 * sec, 2e6 * sec]]
+
+    # start simulation
+    sim.run(start_new_process=True)
+
+    # get result
+    print(stats)
+
+    # read phsp
+    with uproot.open(ta.get_output_path()) as root:
+        branch = root["PhaseSpace"]["GlobalTime"]
+        time = branch.array(library="numpy") / d
+
+    # plot debug
+    import matplotlib.pyplot as plt
+
+    fig, ax = plt.subplots(ncols=1, nrows=1, figsize=(5, 5))
+    a = ax
+    a.hist(
+        time,
+        bins=100,
+        label="decay source",
+        histtype="stepfilled",
+        alpha=0.5,
+        density=True,
+    )
+    a.legend()
+    a.set_xlabel("time (d)")
+    a.set_ylabel("detected photon")
+    # plt.show()
+
+    fn = paths.output / "test022_half_life_fit.png"
+    print("Figure in ", fn)
+    plt.savefig(fn)
+
+
+def main():
+    test022_half_life(n_threads=1)
+
+
+if __name__ == "__main__":
+    main()