diff --git a/Examples/BoostedBHComplexScalar/FluxExtraction.hpp b/Examples/BoostedBHComplexScalar/FluxExtraction.hpp
index c506994..d84081b 100644
--- a/Examples/BoostedBHComplexScalar/FluxExtraction.hpp
+++ b/Examples/BoostedBHComplexScalar/FluxExtraction.hpp
@@ -18,7 +18,7 @@ class FluxExtraction : public SphericalExtraction
 {
   public:
     //! The constructor
-    FluxExtraction(SphericalExtraction::params_t &a_params, double a_dt,
+    FluxExtraction(const spherical_extraction_params_t &a_params, double a_dt,
                    double a_time, bool a_first_step,
                    double a_restart_time = 0.0)
         : SphericalExtraction(a_params, a_dt, a_time, a_first_step,
@@ -30,7 +30,7 @@ class FluxExtraction : public SphericalExtraction
 
     //! The old constructor which assumes it is called in specificPostTimeStep
     //! so the first time step is when m_time == m_dt
-    FluxExtraction(SphericalExtraction::params_t a_params, double a_dt,
+    FluxExtraction(const spherical_extraction_params_t &a_params, double a_dt,
                    double a_time, double a_restart_time = 0.0)
         : FluxExtraction(a_params, a_dt, a_time, (a_dt == a_time),
                          a_restart_time)
diff --git a/Examples/KerrBHScalarField/FluxExtraction.hpp b/Examples/KerrBHScalarField/FluxExtraction.hpp
index 9f3b1fc..f198382 100644
--- a/Examples/KerrBHScalarField/FluxExtraction.hpp
+++ b/Examples/KerrBHScalarField/FluxExtraction.hpp
@@ -18,7 +18,7 @@ class FluxExtraction : public SphericalExtraction
 {
   public:
     //! The constructor
-    FluxExtraction(SphericalExtraction::params_t &a_params, double a_dt,
+    FluxExtraction(const spherical_extraction_params_t &a_params, double a_dt,
                    double a_time, bool a_first_step,
                    double a_restart_time = 0.0)
         : SphericalExtraction(a_params, a_dt, a_time, a_first_step,
@@ -30,7 +30,7 @@ class FluxExtraction : public SphericalExtraction
 
     //! The old constructor which assumes it is called in specificPostTimeStep
     //! so the first time step is when m_time == m_dt
-    FluxExtraction(SphericalExtraction::params_t a_params, double a_dt,
+    FluxExtraction(const spherical_extraction_params_t &a_params, double a_dt,
                    double a_time, double a_restart_time = 0.0)
         : FluxExtraction(a_params, a_dt, a_time, (a_dt == a_time),
                          a_restart_time)
diff --git a/Source/Background/FixedBGSimulationParametersBase.hpp b/Source/Background/FixedBGSimulationParametersBase.hpp
index 9eb0840..c631000 100644
--- a/Source/Background/FixedBGSimulationParametersBase.hpp
+++ b/Source/Background/FixedBGSimulationParametersBase.hpp
@@ -13,6 +13,9 @@
 #include "GRParmParse.hpp"
 #include "SphericalExtraction.hpp"
 
+// add this type alias here for backwards compatibility
+using extraction_params_t = spherical_extraction_params_t;
+
 //! Class to handle the simulations params that are always required in
 //! simulations with a fixed background
 class FixedBGSimulationParametersBase : public ChomboParameters
@@ -166,7 +169,7 @@ class FixedBGSimulationParametersBase : public ChomboParameters
 
     // Collection of parameters necessary for the extraction
     bool activate_extraction;
-    SphericalExtraction::params_t extraction_params;
+    spherical_extraction_params_t extraction_params;
 
     std::string data_path;
 };