diff --git a/analysis/fillChain.cxx b/analysis/fillChain.cxx
index 06a8ece4ac5482ddbc12c6f1646fe4cf8718ba1b..787ec59350d301eea41b1b4e14652063c20af74d 100644
--- a/analysis/fillChain.cxx
+++ b/analysis/fillChain.cxx
@@ -40,7 +40,6 @@ Double_t GetClusterPositionMWPC(unsigned short n, unsigned short *x, Float_t pla
 	return position;
 } //--------------------------------------------------------------------
 
-
 void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents = 0) {
 
 	TString inFile;
@@ -62,16 +61,28 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 	cout << "Input file: " << inFile << endl;
 	cout << "Output file: " << outFile << endl;
 
+	///////////////////////////////////////////////////
+	// Input file initialization
+	///////////////////////////////////////////////////
+
 	TFile *fr = new TFile(inFile);
 	TTree *tr = (TTree*)fr->Get("AnalysisxTree");
 
 	TNeEvent *revent = new TNeEvent();
-
 	tr->SetBranchAddress("NeEvent.", &revent);
 
+
+	///////////////////////////////////////////////////
+	// Output file initialization
+	///////////////////////////////////////////////////
+
 	TFile *fw = new TFile(outFile, "RECREATE");
 	TTree *tw = new TTree("cal", "Calibrated information");
 
+	///////////////////////////////////////////////////
+	// Output tree variables
+	///////////////////////////////////////////////////
+
 	Int_t trigger;
 
 	Float_t SQ20E[16];
@@ -127,12 +138,8 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 
 	//left 1 mm position
 	Float_t x1mm, y1mm;
-	const Float_t z1mm = 230.;
 
 	Float_t xThin, yThin;
-	const Float_t zThin = 230.-53.6;
-
-	const Float_t xThinOffset = -3., yThinOffset = -1.8;
 
 	Int_t mapXbin, mapYbin;
 
@@ -140,6 +147,10 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 	TVector3 vNorm(0.,0.,1.);
 	Double_t angleLeft;
 
+	///////////////////////////////////////////////////
+	// Output tree branches initialization
+	///////////////////////////////////////////////////
+
 	tw->Branch("trigger",&trigger,"trigger/I");
 
 	tw->Branch("angleLeft",&angleLeft,"angleLeft/D");
@@ -223,6 +234,11 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 	else nevents = noevents;
 	if (nevents > tr->GetEntries()) nevents = tr->GetEntries();
 
+	///////////////////////////////////////////////////
+	// calibration coefficients and thickness map
+	///////////////////////////////////////////////////
+
+
 //	TNeDet16 *pSQX_L_EC = new TNeDet16("SQX_L_EC");
 //	TNeDet16 pSQX_L_EC("../SQX_L_EC");
 	TNeDet16 pSQX_L_EC("./SQX_L");
@@ -240,10 +256,6 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 	TNeDet16 pSQ20_EC("./sq20_58");
 	pSQ20_EC.ReadData();
 
-//	for (Int_t i = 0; i < 32; i++) {
-//		cout << pSQX_L_EC.Energy(1, i) << endl;
-//	}
-
 	Float_t energy = 0;
 
 	cout << nevents << " entries will be treated." << endl;
@@ -254,26 +266,48 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 	TH2F *hThickness = new TH2F(*(TH2F*)fThickness.Get("hTh"));
 //	hThickness->Draw("col");
 
-//	std::cout << std::setprecision(1) << std::fixed;
+
+	///////////////////////////////////////////////////
+	// Parameters related to geometry
+	///////////////////////////////////////////////////
+
+
+	//MWPC //todo: convert to minus
+	const Float_t l12 = 546.;	//z coordinate of the center of MWPC1
+	const Float_t lt = 270.;	//z coordinate of the center of MWPC2
+
+	//offsets taken from S. Krupko
+	const Float_t MWPC1_X_offset = -1.0;
+	const Float_t MWPC1_Y_offset = -2.1375;
+	const Float_t MWPC2_X_offset = 0.2;
+	const Float_t MWPC2_Y_offset = -1.125;
+
+	//left telescope
+	const Float_t z1mm = 230.;
+	const Float_t zThin = 230.-53.6;
+	const Float_t xThinOffset = -3.;
+	const Float_t yThinOffset = -1.8;
 
 
+	//todo: add sign taking into account direction of numbering
 	const Int_t kSQL_X_strips = 32;
 	const Int_t kSQL_Y_strips = 16;
 	const Int_t kSQL_20_strips = 16;
 
-//	const Double_t kSQLY_energy_thr = 1.;
-//	const Double_t kSQLX_energy_thr = 1.;
-//	const Double_t kSQL20_energy_thr = 1.2;
-
+	//thin detector
 	const Double_t kSQ20_norm_thickness = 20.;
 
-//	for (Int_t yi = 0; yi < kSQL_Y_strips; yi++) {
-//		cout << "y bin: " << yi+1 << "\t\t";
-//		for (Int_t xi = 0; xi < kSQL_X_strips; xi++) {
-//			cout << hThickness->GetBinContent(xi+1, yi+1) << "\t";
-//			if (xi == kSQL_X_strips-1) cout << endl;
-//		}
-//	}
+	const Double_t thinXoffset = 1.;
+	const Double_t thinYoffset = -1.8;
+
+
+	//left CsI detectors
+	const UShort_t CsIleftThr = 180;
+
+	///////////////////////////////////////////////////
+	// Individual thresholds
+	///////////////////////////////////////////////////
+
 
 	Float_t timeCorr[16] = {0, -2, 0, 2,
 							-2.5, 5, -6, 4,
@@ -345,18 +379,6 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 		460, 460, 460, 453
 	};
 
-	const UShort_t CsIleftThr = 180;
-
-	const Double_t thinXoffset = 1.;
-	const Double_t thinYoffset = -1.8;
-
-	const Float_t MWPC1_X_offset = -1.0;
-	const Float_t MWPC1_Y_offset = -2.1375;
-	const Float_t MWPC2_X_offset = 0.2;
-	const Float_t MWPC2_Y_offset = -1.125;
-
-
-
 	fw->cd();
 
 	//////////////////////////////////
@@ -365,18 +387,12 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 
 	for (Int_t eventNo = 0; eventNo < nevents; eventNo++) {
 
-//		cout << eventNo << endl;
-
 		tr->GetEvent(eventNo);
 
 		trigger = revent->trigger;
 
 		if (trigger != 3) continue;
 
-//		cout << eventNo << endl;
-//		cout << revent->SQX_L[0] << endl;
-//		SQLXE[0] = revent->SQX_L[0];
-
 		SQ20Esum = 0.;
 		SQLXEsum = 0.;
 		SQLYEsum = 0.;
@@ -394,7 +410,6 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 
 		SQ20timeMult = 0;
 		SQLXtimeMult = 0;
-//		SQLXtimeSum = 0;
 		SQLYtimeMult = 0;
 
 		CsI_L_veto = kFALSE;
@@ -422,8 +437,7 @@ void fillTree(const TString beam = "he", Int_t nofile = 0, const Int_t noevents
 			TOF = ( (revent->tF5[0]+revent->tF5[1]+revent->tF5[2]+revent->tF5[3]) - (revent->tF3[0]+revent->tF3[1]+revent->tF3[2]+revent->tF3[3]) )/4.*0.125+89.165;
 		}
 
-		const Float_t l12 = 546.;
-		const Float_t lt = 270.;
+		if (TOF<166. || TOF>181.) continue;
 
 			///////////////////////////////////////////////
 			//MWPC's