diff --git a/src/classes/PRunDataHandler.cpp b/src/classes/PRunDataHandler.cpp
index b7bb01ed..f2c2559d 100644
--- a/src/classes/PRunDataHandler.cpp
+++ b/src/classes/PRunDataHandler.cpp
@@ -4830,20 +4830,20 @@ Bool_t PRunDataHandler::WriteNexusFile(TString format, TString fln)
         return false;
       }
 
+      // set NeXus version
+      nxs->AddGroupAttribute("/", "NeXus_version", std::string("4.3.0"));
+
+      // set HDF5 version
+      nxs->AddGroupAttribute("/", "HDF_version", nxs->GetHdf5LibVersion());
+
+      // set file name
+      nxs->AddGroupAttribute("/", "file_name", std::string(fln.Data()));
+
+      // set creation time
+      std::string dt = nxs::getIso8601TimestampLocal();
+      nxs->AddGroupAttribute("/", "file_time", dt);
+
       if (fAny2ManyInfo->idf == 1) { // IDF V1
-        // set NeXus version
-        nxs->AddGroupAttribute("/", "NeXus_version", std::string("4.3.0"));
-
-        // set HDF5 version
-        nxs->AddGroupAttribute("/", "HDF_version", nxs->GetHdf5LibVersion());
-
-        // set file name
-        nxs->AddGroupAttribute("/", "file_name", std::string(fln.Data()));
-
-        // set creation time
-        std::string dt = nxs::getIso8601TimestampLocal();
-        nxs->AddGroupAttribute("/", "file_time", dt);
-
         // set IDF version
         nxs->AddDataset<int>("/run/IDF_version", {(int)fAny2ManyInfo->idf}, {1}, H5::PredType::NATIVE_INT32);
 
@@ -5037,8 +5037,150 @@ Bool_t PRunDataHandler::WriteNexusFile(TString format, TString fln)
         res = (float)(fData[0].GetTimeResolution()*fAny2ManyInfo->rebin*1.0e3)/2.0;
         nxs->AddDatasetAttribute<int>("/run/histogram_data_1/counts", "offset", res);
       } else { // IDF V2
+        nxs->AddGroupAttribute("/raw_data_1", "NX_class", std::string("NXentry"));
+
         // set IDF version
         nxs->AddDataset<int>("/raw_data_1/IDF_version", {(int)fAny2ManyInfo->idf}, {1}, H5::PredType::NATIVE_INT32);
+
+        // set beamline
+        str = *fData[0].GetBeamline();
+        nxs->AddDataset<std::string>("/raw_data_1/beamline", {str}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+
+        // set definition
+        nxs->AddDataset<std::string>("/raw_data_1/definition", {std::string("muonTD")}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+
+        // set run_number
+        nxs->AddDataset<int>("/raw_data_1/run_number", {fData[0].GetRunNumber()}, {1}, H5::PredType::NATIVE_INT32);
+
+        // set title
+        nxs->AddDataset<std::string>("/raw_data_1/title", {fData[0].GetRunTitle()->Data()}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+
+        // set start time
+        str = std::string(fData[0].GetStartDate()->Data()) + std::string("T") + std::string(fData[0].GetStartTime()->Data());
+        nxs->AddDataset<std::string>("/raw_data_1/start_time", {str}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+        nxs->AddDatasetAttribute<std::string>("/raw_data_1/start_time", "units", "ISO8601");
+
+        // set end time
+        str = std::string(fData[0].GetStopDate()->Data()) + std::string("T") + std::string(fData[0].GetStopTime()->Data());
+        nxs->AddDataset<std::string>("/raw_data_1/end_time", {str}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+        nxs->AddDatasetAttribute<std::string>("/raw_data_1/end_time", "units", "ISO8601");
+
+        // set experiment_identifier
+        str = "n/a";
+        nxs->AddDataset<std::string>("/raw_data_1/experiment_identifier", {str}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+
+        // set instrument attribute
+        nxs->AddGroupAttribute("/raw_data_1/instrument", "NX_class", std::string("NXinstrument"));
+
+        // set instrument name
+        str = *fData[0].GetInstrument();
+        nxs->AddDataset<std::string>("/raw_data_1/instrument/name", {str}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+
+        // set instrument/source attribute
+        nxs->AddGroupAttribute("/raw_data_1/instrument/source", "NX_class", std::string("NXsource"));
+
+        // set instrument/source/name
+        str = fData[0].GetLaboratory()->Data();
+        nxs->AddDataset<std::string>("/raw_data_1/instrument/source/name", {str}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+
+        // set instrument/source/type
+        TString tstr = *fData[0].GetInstrument();
+        std::string type{"n/a"};
+        if (tstr.Contains("LEM", TString::kIgnoreCase)) {
+          type = "low energy muon source";
+        } else if (tstr.Contains("GPS", TString::kIgnoreCase) || tstr.Contains("GPD", TString::kIgnoreCase) ||
+                   tstr.Contains("LTF", TString::kIgnoreCase) || tstr.Contains("FLAME", TString::kIgnoreCase) ||
+                   tstr.Contains("HAL-9500", TString::kIgnoreCase) || tstr.Contains("DOLLY", TString::kIgnoreCase) ||
+                   tstr.Contains("VMS", TString::kIgnoreCase)) {
+          type = "quasi-continous muon source";
+        } else if (tstr.Contains("EMU", TString::kIgnoreCase) || tstr.Contains("MUSR", TString::kIgnoreCase) ||
+                   tstr.Contains("HIFI", TString::kIgnoreCase)) {
+          type = "pulsed muon source";
+        }
+        nxs->AddDataset<std::string>("/raw_data_1/instrument/source/type", {type}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+
+        // set instrument/source/probe
+        str = "positive muons";
+        nxs->AddDataset<std::string>("/raw_data_1/instrument/source/probe", {str}, {1}, H5::StrType(H5::PredType::C_S1, H5T_VARIABLE));
+
+        // set instrument/detector info
+        nxs->AddGroupAttribute("/raw_data_1/instrument/detector_1", "NX_class", std::string("NXdetector"));
+
+        // set instrument/detector/spectrum_index
+        int noHistos = fData[0].GetNoOfHistos();
+        std::vector<int> spectrum_index(noHistos);
+        for (unsigned int i=0; i<spectrum_index.size(); i++)
+          spectrum_index[i] = i+1;
+        nxs->AddDataset<int>("/raw_data_1/instrument/detector_1/spectrum_index", spectrum_index, {spectrum_index.size()}, H5::PredType::NATIVE_INT32);
+
+        // set instrument/detector/raw_time (not useful for quasi-continuous sources)
+        int ival=0;
+        nxs->AddDataset<int>("/raw_data_1/instrument/detector_1/raw_time", {ival}, {1}, H5::PredType::NATIVE_INT32);
+        nxs->AddDatasetAttribute<int>("/raw_data_1/instrument/detector_1/raw_time", "available", 0);
+
+        // set instrument/detector/counts
+        // set counts
+        // feed histos
+        PRawRunDataSet *dataSet = nullptr;
+        PIntVector data;
+        UInt_t size = 0;
+        int noHisto, histoLength;
+        if (fAny2ManyInfo->rebin == 1) {
+          noHisto = fData[0].GetNoOfHistos();
+          for (UInt_t i=0; i<fData[0].GetNoOfHistos(); i++) {
+            dataSet = fData[0].GetDataSet(i, false); // i.e. the false means, that i is the index and NOT the histo number
+            if (dataSet == nullptr) { // something is really wrong
+              std::cerr << std::endl << ">> PRunDataHandler::WriteNexusFile: **ERROR** Couldn't get data set (idx=" << i << ")";
+              std::cerr << std::endl << ">>   something is really wrong!" << std::endl;
+              return false;
+            }
+            size = dataSet->GetData()->size();
+            histoLength = size;
+            for (UInt_t j=0; j<size; j++) {
+              data.push_back((UInt_t)dataSet->GetData()->at(j));
+            }
+          }
+        } else { // rebin > 1
+          UInt_t dataRebin = 0;
+          UInt_t dataCount = 0;
+          noHisto = fData[0].GetNoOfHistos();
+          for (UInt_t i=0; i<fData[0].GetNoOfHistos(); i++) {
+            dataSet = fData[0].GetDataSet(i, false); // i.e. the false means, that i is the index and NOT the histo number
+            if (dataSet == nullptr) { // something is really wrong
+              std::cerr << std::endl << ">> PRunDataHandler::WriteNexusFile: **ERROR** Couldn't get data set (idx=" << i << ")";
+              std::cerr << std::endl << ">>   something is really wrong!" << std::endl;
+              return false;
+            }
+            size = dataSet->GetData()->size();
+            dataCount = 0;
+            for (UInt_t j=0; j<size; j++) {
+              if ((j > 0) && (j % fAny2ManyInfo->rebin == 0)) {
+                dataCount++;
+                data.push_back(dataRebin);
+                dataRebin = 0;
+              }
+              dataRebin += static_cast<UInt_t>(dataSet->GetData()->at(j));
+            }
+          }
+          size = dataCount;
+        }
+        nxs->AddDataset<int>("/raw_data_1/instrument/detector_1/counts", data, {(long unsigned int)noHisto, size}, H5::PredType::NATIVE_INT32);
+        nxs->AddDatasetAttribute<int>("/raw_data_1/instrument/detector_1/counts", "axis", std::string("spectrum_index,time_bin"));
+        nxs->AddDatasetAttribute<int>("/raw_data_1/instrument/detector_1/counts", "long_name", std::string("positon counts"));
+        nxs->AddDatasetAttribute<int>("/raw_data_1/instrument/detector_1/counts", "signal", 1);
+        // t0_bin attributes
+        std::vector<int> t0_bin;
+        for (unsigned int i=0; i<fData[0].GetNoOfHistos(); i++)
+          t0_bin.push_back((int)(fData[0].GetT0Bin(i+1)/fAny2ManyInfo->rebin));
+std::cerr << std::endl;
+for (unsigned int i=0; i<fData[0].GetNoOfHistos(); i++)
+std::cerr << i << ": " << t0_bin[i] << ", ";
+std::cerr << std::endl;
+        nxs->AddDatasetAttribute<int>("/raw_data_1/instrument/detector_1/counts", "t0_bin", {t0_bin});
+        nxs->AddDatasetAttribute<int>("/raw_data_1/instrument/detector_1/counts", "units", std::string("counts"));
+
+        // set raw_data_1/detector info
+        nxs->AddGroupAttribute("/raw_data_1/detector_1", "NX_class", std::string("NXdata"));
       }
 
       int result = nxs->WriteNexusFile(fln.Data(), fAny2ManyInfo->idf);