diff --git a/src/picongpu/include/particles/ionization/byField/ADK/AlgorithmADK.hpp b/src/picongpu/include/particles/ionization/byField/ADK/AlgorithmADK.hpp
index 8ec590275e..44b816d8f4 100644
--- a/src/picongpu/include/particles/ionization/byField/ADK/AlgorithmADK.hpp
+++ b/src/picongpu/include/particles/ionization/byField/ADK/AlgorithmADK.hpp
@@ -84,12 +84,17 @@ namespace ionization
                                     * math::exp(float_X(-2.0) * util::cube(protonNumber) / (float_X(3.0) * util::cube(nEff) * eInAU));
 
             /* simulation time step in atomic units */
-            const float_X DELTA_T_AU = float_X(DELTA_T / ATOMIC_UNIT_TIME);
+            const float_X timeStepAU = float_X(DELTA_T / ATOMIC_UNIT_TIME);
             /* ionization probability
              *
              * probability = rate * time step
+             * --> for infinitesimal time steps
+             *
+             * the whole ensemble should then follow
+             * P = 1 - exp(-rate * time step) if the laser wavelength is
+             * sampled well enough
              */
-            float_X probADK     = rateADK * DELTA_T_AU;
+            float_X probADK     = rateADK * timeStepAU;
 
             /* ionization condition */
             if (randNr < probADK && chargeState < protonNumber)