data added

tetra.tex

@@ -38,6 +38,8 @@ The beam particles were identified by two plastic scintillators, which allowed t
 %For the beam particle identification and its energy determination two plastic scintillators were used. 
 The trajectories the beam projectiles were tracked by two pairs of multi-wire proportional chambers.
 The cryogenic target was filled with a deuterium gas at 27\,K of atmospheric pressure.  
+The special run with the empty target cell was conducted to estimate the background conditions, which had $\approx$16\% of the total $^8$He beam time.
+
 Detection of the charged reaction products was realized by $\Delta E$-$E$ telescopes.
 The latter allowed to identify $^6$Li with clear separation from other registered lithium isotopes.
 %The side assembly of three (20\,$\mu$m, 1\,mm and 1\,mm thick) silicon strip detector (SSD) telescope, and the front telescope made of the 1.5\,mm double side SSD coupled to the CsI(Tl) scintillator array.
@@ -74,6 +76,33 @@ We make a suggestion that these gammas are produced by the interaction of the ne
 \end{figure}
 %-------------------------------------------------------------------------------
 
+Tetranuetron was reconstructed from the recoil $^6$Li as a missing component in $^2$H($^8$He,$^6$Li) reaction.
+The total number of $^6$Li-neutron coincidences found in the recorded data was 136.
+But, due to the kinematic selection, only 108 of these events were identified as the population of 4n.
+The correlation we used for this selection is shown in Fig.\ \ref{fig:mm_4n} (b).
+This is the correlation of the neutron kinetic energy in the 4n center-of-mass frame with the reconstructed energy $E_T$.
+The fact that the most events are located below the kinematic border proves the good channel identification of the studied reaction.
+Another evidence for the 4n population is that the data collected with the empty target has zero events satisfying the used selections.
+The missing mass (MM) spectrum of 4n reconstructed after kinematic selection is shown in Fig.\ \ref{fig:mm_4n} b).
+
+%-------------------------------------------------------------------------------
+\begin{figure}
+	\centering
+	\begin{tabular}{cc}			
+		\includegraphics[width=0.5\linewidth]{figures/triangle} 
+		&
+		\includegraphics[width=0.5\linewidth]{figures/mm} \\
+		(a) & (b)
+	\end{tabular}
+	\caption{
+		(a) The dE-TAC correlation providing clear separation of gammas from neutrons.
+		(b) The ToF distribution. 
+		The set of three peaks on the left corresponds to the gammas produced in the diaphragm installed 20 cm upstream the target plane, target frame, and CsI(Tl) array.
+		Green ad red-line histograms formed by the events, identified as gamma/neutron by the dE-TAC method.
+	}
+	\label{fig:mm_4n}
+\end{figure}
+%-------------------------------------------------------------------------------
 
 \section{Conclusion}