diff --git a/core-buffer/include/SFWriter.hpp b/core-buffer/include/SFWriter.hpp
index b8fd593..fca8b4b 100644
--- a/core-buffer/include/SFWriter.hpp
+++ b/core-buffer/include/SFWriter.hpp
@@ -6,6 +6,14 @@
 #include <H5Cpp.h>
 #include "RingBuffer.hpp"
 
+struct DetectorFrame
+{
+    uint64_t pulse_id;
+    uint64_t frame_index;
+    uint32_t daq_rec;
+    uint16_t n_received_packets;
+};
+
 class SFWriter {
 
     const size_t n_frames_;
@@ -26,7 +34,7 @@ public:
             const size_t n_frames,
             const size_t n_modules);
     ~SFWriter();
-    void write(std::shared_ptr<DetectorFrame> metadata, char* data);
+    void write(const DetectorFrame* metadata, const char* data);
     void close_file();
 };
 
diff --git a/core-buffer/src/SFWriter.cpp b/core-buffer/src/SFWriter.cpp
index a7bd827..958aa3e 100644
--- a/core-buffer/src/SFWriter.cpp
+++ b/core-buffer/src/SFWriter.cpp
@@ -75,7 +75,7 @@ void SFWriter::close_file()
     file_.close();
 }
 
-void SFWriter::write(shared_ptr<DetectorFrame> metadata, char* data) {
+void SFWriter::write(const DetectorFrame* metadata, const char* data) {
     auto pulse_id = metadata->pulse_id;
     auto frame_index = metadata->frame_index;
     auto daq_rec = metadata->daq_rec;