diff --git a/artisoptions_christinenonthermal.h b/artisoptions_christinenonthermal.h
index 96a1d4ed3..f27fd6157 100644
--- a/artisoptions_christinenonthermal.h
+++ b/artisoptions_christinenonthermal.h
@@ -147,5 +147,7 @@ constexpr bool EXPANSIONOPACITIES_ON = false;
 
 constexpr bool EXPANSION_OPAC_SAMPLE_KAPPAPLANCK = false;
 
+constexpr bool USE_XCOM_GAMMAPHOTOION = false;
+
 // NOLINTEND(modernize*,misc-unused-parameters)
 #endif  // ARTISOPTIONS_H
\ No newline at end of file
diff --git a/artisoptions_classic.h b/artisoptions_classic.h
index 0c860af99..6d154e174 100644
--- a/artisoptions_classic.h
+++ b/artisoptions_classic.h
@@ -143,5 +143,7 @@ constexpr bool EXPANSIONOPACITIES_ON = false;
 
 constexpr bool EXPANSION_OPAC_SAMPLE_KAPPAPLANCK = false;
 
+constexpr bool USE_XCOM_GAMMAPHOTOION = false;
+
 // NOLINTEND(modernize*,misc-unused-parameters)
 #endif  // ARTISOPTIONS_H
\ No newline at end of file
diff --git a/artisoptions_doc.md b/artisoptions_doc.md
index 82cc9693a..2d8f2dda2 100644
--- a/artisoptions_doc.md
+++ b/artisoptions_doc.md
@@ -220,5 +220,7 @@ constexpr bool KEEP_ALL_RESTART_FILES;
 // multiply bound-free cooling coefficient by upper level population instead of the upper ion target level population
 constexpr bool BFCOOLING_USELEVELPOPNOTIONPOP;
 
+// Use XCOM data for gamma photoionisation instead of Si+Fe Equation 2 of Ambwani & Sutherland (1988), Veigele (1973)
+constexpr bool USE_XCOM_GAMMAPHOTOION;
 
 ```
\ No newline at end of file
diff --git a/artisoptions_kilonova_lte.h b/artisoptions_kilonova_lte.h
index 27bfe9013..6afca1f50 100644
--- a/artisoptions_kilonova_lte.h
+++ b/artisoptions_kilonova_lte.h
@@ -142,5 +142,7 @@ constexpr bool EXPANSIONOPACITIES_ON = false;
 
 constexpr bool EXPANSION_OPAC_SAMPLE_KAPPAPLANCK = false;
 
+constexpr bool USE_XCOM_GAMMAPHOTOION = false;
+
 // NOLINTEND(modernize*,misc-unused-parameters)
 #endif  // ARTISOPTIONS_H
diff --git a/artisoptions_nltenebular.h b/artisoptions_nltenebular.h
index 958fe948d..86aeaf40f 100644
--- a/artisoptions_nltenebular.h
+++ b/artisoptions_nltenebular.h
@@ -150,5 +150,7 @@ constexpr bool EXPANSIONOPACITIES_ON = false;
 
 constexpr bool EXPANSION_OPAC_SAMPLE_KAPPAPLANCK = false;
 
+constexpr bool USE_XCOM_GAMMAPHOTOION = false;
+
 // NOLINTEND(modernize*,misc-unused-parameters)
 #endif  // ARTISOPTIONS_H
\ No newline at end of file
diff --git a/artisoptions_nltewithoutnonthermal.h b/artisoptions_nltewithoutnonthermal.h
index baffe8f8a..dfe3dbfc9 100644
--- a/artisoptions_nltewithoutnonthermal.h
+++ b/artisoptions_nltewithoutnonthermal.h
@@ -146,5 +146,7 @@ constexpr bool EXPANSIONOPACITIES_ON = false;
 
 constexpr bool EXPANSION_OPAC_SAMPLE_KAPPAPLANCK = false;
 
+constexpr bool USE_XCOM_GAMMAPHOTOION = false;
+
 // NOLINTEND(modernize*,misc-unused-parameters)
 #endif  // ARTISOPTIONS_H
\ No newline at end of file
diff --git a/gammapkt.cc b/gammapkt.cc
index 8067186ac..3f3c2a012 100644
--- a/gammapkt.cc
+++ b/gammapkt.cc
@@ -27,8 +27,6 @@
 namespace gammapkt {
 // Code for handing gamma rays - creation and propagation
 
-constexpr bool USE_XCOM_GAMMAPHOTOION = true;
-
 struct gamma_line {
   double energy{};  // in erg
   double probability{};