diff --git a/src/external/nexus/Usage.md b/src/external/nexus/Usage.md
index 1d81c66f..8b422d1b 100644
--- a/src/external/nexus/Usage.md
+++ b/src/external/nexus/Usage.md
@@ -718,7 +718,8 @@ PNeXus(const std::string& filename, bool printDebug = false);
 | Method | Description |
 |--------|-------------|
 | `GetFileName()` | Get the NeXus filename |
-| `GetHdf5Version()` / `GetHdf4Version()` | Get HDF library version |
+| `GetHdf5LibVersion()` / `GetHdf4LibVersion()` | Get HDF library version (runtime) |
+| `GetHdf5Version()` / `GetHdf4Version()` | Get HDF version from the file |
 | `GetNeXusVersion()` | Get NeXus format version |
 | `GetIdfVersion()` | Get IDF version (1 or 2) |
 
diff --git a/src/external/nexus/examples/hdf4/main.cpp b/src/external/nexus/examples/hdf4/main.cpp
index 1d3230a9..c8b16866 100644
--- a/src/external/nexus/examples/hdf4/main.cpp
+++ b/src/external/nexus/examples/hdf4/main.cpp
@@ -324,14 +324,14 @@ void h4nexus_writeTest(const nxH4::PNeXus *nxs, const std::string& outFileName,
                                       "units", std::string("picoseconds"));
 
   // spectrum_index
-  for (unsigned int i=0; i<66000; i++)
+  for (unsigned int i=0; i<16; i++)
     ival.push_back(i+1);
-  nxs_out->AddDataset<int>("/raw_data_1/instrument/detector_1/spectrum_index", ival, {66000}, nxH4::H4DataType::INT32);
+  nxs_out->AddDataset<int>("/raw_data_1/instrument/detector_1/spectrum_index", ival, {16}, nxH4::H4DataType::INT32);
   ival.clear();
 
   // dead_time
-  std::vector<float> deadTime(66000, 0.0);
-  nxs_out->AddDataset<float>("/raw_data_1/instrument/detector_1/dead_time", deadTime, {66000}, nxH4::H4DataType::FLOAT32);
+  std::vector<float> deadTime(16, 0.0);
+  nxs_out->AddDataset<float>("/raw_data_1/instrument/detector_1/dead_time", deadTime, {16}, nxH4::H4DataType::FLOAT32);
 
   // attributes dead_time
   nxs_out->AddDatasetAttribute<float>("/raw_data_1/instrument/detector_1/dead_time", "available", 0);
diff --git a/src/external/nexus/examples/hdf5/docu/Usage.md b/src/external/nexus/examples/hdf5/docu/Usage.md
index 9fa476dd..d1c7629b 100644
--- a/src/external/nexus/examples/hdf5/docu/Usage.md
+++ b/src/external/nexus/examples/hdf5/docu/Usage.md
@@ -33,6 +33,7 @@ h5nexus --fn <input_file> [options]
 | `--out <file>` | Output NeXus HDF5 file (enables write mode) |
 | `-d, --debug` | Enable debug output |
 | `-dt, --dead_time_estimate` | Calculate dead time corrections |
+| `--data idx <dout>` | Write single ASCII dataset with index `idx` to `<dout>` |
 | `-h, --help` | Show help message |
 | `-v, --version` | Show version information |
 
@@ -58,6 +59,11 @@ h5nexus --fn EMU00139040.nxs --out output.nxs
 h5nexus --fn EMU00139040.nxs --dead_time_estimate --out corrected.nxs
 ```
 
+**Extract single detector data to ASCII file:**
+```bash
+h5nexus --fn EMU00139040.nxs --dead_time_estimate --data 0 detector0.txt
+```
+
 ---
 
 ## Reading NeXus Files
@@ -520,7 +526,7 @@ NeXus uses the `NX_class` attribute to identify group types:
 |------------|----------------|-------------|
 | `/raw_data_1` | `NXentry` | Top-level entry for a measurement |
 | `/raw_data_1/instrument` | `NXinstrument` | Instrument information |
-| `/raw_data_1/detector_1` | `NXdetector` | Detector group |
+| `/raw_data_1/detector_1` | `NXdata` | Data group (IDF v2) |
 | `/raw_data_1/sample` | `NXsample` | Sample information |
 | `/raw_data_1/user_1` | `NXuser` | User information |
 
@@ -535,7 +541,7 @@ int main() {
     // Add some example data
     std::vector<int> counts(96 * 2048, 0);
     nexus.AddDataset<int>("/raw_data_1/detector_1/counts", counts,
-                          {1, 96, 2048}, H5::PredType::NATIVE_INT32);
+                          {1, 96, 2048}, H5::PredType::NATIVE_INT);
 
     // Set up proper NeXus group structure with NX_class attributes
     nexus.AddGroupAttribute("/raw_data_1", "NX_class", std::string("NXentry"));
@@ -1667,7 +1673,7 @@ int main() {
         // Add some detector data
         std::vector<int> counts(96 * 2048, 100);
         nexus.AddDataset<int>("/raw_data_1/detector_1/counts", counts,
-                             {1, 96, 2048}, H5::PredType::NATIVE_INT32);
+                             {1, 96, 2048}, H5::PredType::NATIVE_INT);
 
         // Add time information
         std::vector<float> timeAxis(2049);
@@ -1942,7 +1948,7 @@ nexus.WriteNexusFile("output.nxs");
 nxH5::PNeXus nexus;
 // Add data
 nexus.AddDataset<int>("/raw_data_1/detector_1/counts", counts, dims,
-                      H5::PredType::NATIVE_INT32);
+                      H5::PredType::NATIVE_INT);
 // Add NeXus group structure
 nexus.AddGroupAttribute("/raw_data_1", "NX_class", std::string("NXentry"));
 nexus.AddGroupAttribute("/raw_data_1/instrument", "NX_class", std::string("NXinstrument"));
diff --git a/src/external/nexus/examples/hdf5/main.cpp b/src/external/nexus/examples/hdf5/main.cpp
index 0c216454..a97637f2 100644
--- a/src/external/nexus/examples/hdf5/main.cpp
+++ b/src/external/nexus/examples/hdf5/main.cpp
@@ -415,14 +415,14 @@ void h5nexus_writeTest(const nxH5::PNeXus *nxs, const std::string& outFileName,
                                       "units", std::string("picoseconds"));
 
   // spectrum_index
-  for (unsigned int i=0; i<66000; i++)
+  for (unsigned int i=0; i<16; i++)
     ival.push_back(i+1);
-  nxs_out->AddDataset<int>("/raw_data_1/instrument/detector_1/spectrum_index", ival, {66000}, H5::PredType::NATIVE_FLOAT);
+  nxs_out->AddDataset<int>("/raw_data_1/instrument/detector_1/spectrum_index", ival, {16}, H5::PredType::NATIVE_INT);
   ival.clear();
 
   // dead_time
-  std::vector<float> deadTime(66000, 0.0);
-  nxs_out->AddDataset<float>("/raw_data_1/instrument/detector_1/dead_time", deadTime, {66000}, H5::PredType::NATIVE_FLOAT);
+  std::vector<float> deadTime(16, 0.0);
+  nxs_out->AddDataset<float>("/raw_data_1/instrument/detector_1/dead_time", deadTime, {16}, H5::PredType::NATIVE_FLOAT);
 
   // attributes dead_time
   nxs_out->AddDatasetAttribute<float>("/raw_data_1/instrument/detector_1/dead_time", "available", 0);