diff --git a/PreAnalyzer.C b/PreAnalyzer.C
index af887b0..eb3bb55 100644
--- a/PreAnalyzer.C
+++ b/PreAnalyzer.C
@@ -1,12 +1,14 @@
 #define PreAnalyzer_cxx
 
-#include "PreAnalyzer.h"
 #include <TStyle.h>
 #include <TMath.h>
-
 #include <stdio.h>
 
 
+#define TREESTRUCT  1 // if 0 = multi, 1 = array.
+
+#include "PreAnalyzer.h"
+
 //############################################ BEGIN
 void PreAnalyzer::Begin(TTree * tree){
 
@@ -153,19 +155,32 @@ Bool_t PreAnalyzer::Process(Long64_t entry){
    //################ Gamma-Paritcle 
    for( int i = 0 ; i < NCLOVER; i++){
       if( gamma[i] > 0  ) {
-         gammaID[multi_N] = i;
-         gamma_N[multi_N] = gamma[i];
-         gamma_t[multi_N] = gammaTime[i];
-         multi_N++;
+         
+         if( TREESTRUCT == 0 ){
+            gammaID[multi_N] = i;
+            gamma_N[multi_N] = gamma[i];
+            gamma_t[multi_N] = gammaTime[i];
+         }else{
+            gamma_N[i] = gamma[i];
+            gamma_t[i] = gammaTime[i];
+         }
+         multi_N++; 
       }
    }
    
   for ( int i = 0 ; i < NGAGG ; i++){   
     if( count[i] == 2 ){
-      gaggID[multiGagg_N] = i;
-      gagg_tail[multiGagg_N] = (tail[i][0]+tail[i][1])/2.;
-      gagg_peak[multiGagg_N] = (peak[i][0]+peak[i][1])/2.;
-      gagg_t[multiGagg_N]    = gaggTime[i];
+      
+      if ( TREESTRUCT == 0 ){
+         gaggID[multiGagg_N] = i;
+         gagg_tail[multiGagg_N] = (tail[i][0]+tail[i][1])/2.;
+         gagg_peak[multiGagg_N] = (peak[i][0]+peak[i][1])/2.;
+         gagg_t[multiGagg_N]    = gaggTime[i];
+      }else{
+         gagg_tail[i] = (tail[i][0]+tail[i][1])/2.;
+         gagg_peak[i] = (peak[i][0]+peak[i][1])/2.;
+         gagg_t[i]    = gaggTime[i];
+      }
       multiGagg_N++;
     }
   }
@@ -186,9 +201,10 @@ void PreAnalyzer::Terminate(){
 
    saveFile->cd(); //set focus on this file
    newTree->Write(); 
+   Long64_t nEntries = newTree->GetEntries();
    saveFile->Close();
 
-   printf("-------------- done, saved in %s.\n", saveFileName.Data());
+   printf("-------------- done, saved in %s. number of entry : %lld\n", saveFileName.Data(), nEntries);
 
    gROOT->ProcessLine(".q");
 
diff --git a/PreAnalyzer.h b/PreAnalyzer.h
index 7330138..dc85b3e 100644
--- a/PreAnalyzer.h
+++ b/PreAnalyzer.h
@@ -141,14 +141,18 @@ void PreAnalyzer::Init(TTree *tree)
    eCorr = LoadCorrectionParameters("correction_e.dat"); 
    
    ///======================== open a new file
-   saveFileName = "haha.root";
-   
+   //TODO, if it is TChain, then we can get file name, else, use option
+   if( option == "" ){
+      saveFileName = "haha.root";
+   }else{
+      saveFileName = option;
+   }
    saveFile = new TFile( saveFileName,"recreate");
    
    TMacro e_corr("correction_e.dat");
    e_corr.Write("correction_e");
    
-   newTree = new TTree("tree", "tree");
+   newTree = new TTree("tree", saveFileName);
    
    eventID = -1;
    runID = 0;
@@ -156,18 +160,27 @@ void PreAnalyzer::Init(TTree *tree)
    multi_N = 0;
    multiGagg_N = 0;
    
-   newTree->Branch("eventID",       &eventID, "eventID/l");
-   newTree->Branch("runID",         &runID_N, "runID/I");
-   newTree->Branch("multi",         &multi_N, "multi/I"); 
-   newTree->Branch("multiGagg", &multiGagg_N, "multiGagg/I"); 
-   newTree->Branch("gammaID",        gammaID, "gammaID[multi]/S");
-   newTree->Branch("gamma",          gamma_N, "gamma[multi]/D");
-   newTree->Branch("gamma_t",        gamma_t, "gamma_t[multi]/l");
-   newTree->Branch("gaggID",          gaggID, "gaggID[multiGagg]/I");
-   newTree->Branch("gaggP",        gagg_peak, "gaggP[multiGagg]/D");
-   newTree->Branch("gaggT",        gagg_tail, "gaggT[multiGagg]/D");
-   newTree->Branch("gagg_t",          gagg_t, "gagg_t[multiGagg]/l");
-   
+   if( TREESTRUCT ==  0 ){
+      newTree->Branch("eventID",       &eventID, "eventID/l");
+      newTree->Branch("runID",         &runID_N, "runID/I");
+      newTree->Branch("multi",         &multi_N, "multi/I"); 
+      newTree->Branch("multiGagg", &multiGagg_N, "multiGagg/I"); 
+      newTree->Branch("gammaID",        gammaID, "gammaID[multi]/S");
+      newTree->Branch("gamma",          gamma_N, "gamma[multi]/D");
+      newTree->Branch("gamma_t",        gamma_t, "gamma_t[multi]/l");
+      newTree->Branch("gaggID",          gaggID, "gaggID[multiGagg]/I");
+      newTree->Branch("gaggP",        gagg_peak, "gaggP[multiGagg]/D");
+      newTree->Branch("gaggT",        gagg_tail, "gaggT[multiGagg]/D");
+      newTree->Branch("gagg_t",          gagg_t, "gagg_t[multiGagg]/l");
+   }else{
+      newTree->Branch("eventID",       &eventID, "eventID/l");
+      newTree->Branch("runID",         &runID_N, "runID/I");
+      newTree->Branch("gamma",          gamma_N, Form("gamma[%d]/D", NCLOVER));
+      newTree->Branch("gamma_t",        gamma_t, Form("gamma_t[%d]/l", NCLOVER));
+      newTree->Branch("gaggP",        gagg_peak, Form("gaggP[%d]/D", NGAGG));
+      newTree->Branch("gaggT",        gagg_tail, Form("gaggT[%d]/D", NGAGG));
+      newTree->Branch("gagg_t",          gagg_t, Form("gagg_t[%d]/l", NGAGG));
+   }
    printf("======================== Start processing....\n");
    StpWatch.Start();
 
diff --git a/armory/EventBuilder.cpp b/armory/EventBuilder.cpp
index 2bdf006..c174946 100644
--- a/armory/EventBuilder.cpp
+++ b/armory/EventBuilder.cpp
@@ -80,7 +80,7 @@ int main(int argn, char **argv){
   printf(">>> Create output tree\n");
   TFile * saveFile = new TFile(outFileName, "recreate");
   saveFile->cd();
-  TTree * newtree = new TTree("tree", "tree");
+  TTree * newtree = new TTree("tree", outFileName);
 
   Int_t eventID = 0 ;  
   Int_t multi = 0; /// this is total multipicilty for all detectors
diff --git a/armory/to2root.cpp b/armory/to2root.cpp
index 88d92c3..e11b96a 100644
--- a/armory/to2root.cpp
+++ b/armory/to2root.cpp
@@ -77,7 +77,7 @@ int main(int argc, char **argv) {
 
   TFile * outRootFile = new TFile(outFileName, "recreate");
   outRootFile->cd();
-  TTree * tree = new TTree("tree", "tree");
+  TTree * tree = new TTree("tree", outFileName);
 
   unsigned long long          evID = 0;
   int                        multi = 0;