chap8

thesis/chapters/chap8_conclusions.tex

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+\chapter{Conclusions}
+\label{cha:conclusions}
+AlCap is an experiment proposed at PSI to study charged particles, neutrons
+and photons emitting after nuclear muon capture on aluminium. These
+measurements are important for backgrounds and hit rates estimation of the new
+generation of \mueconv experiments, COMET and Mu2e. In the first stage of the
+COMET experiment, hit rate on its main tracking detector is anticipated to be
+dominated by low energy protons following muon capture on an aluminium target,
+which has never been measured.
+
+The first run of the AlCap which aims for proton measurement has been carried
+out in 2013. Data analysis is in progress. An initial analysis on partial data
+was done with the main results are:
+\begin{enumerate}
+  \item Demonstration of the analysis chain from raw waveforms to physics
+    events;
+  \item Validation of the experimental method including: number of nuclear
+    capture muons normalisation by muonic X-ray measurement, charged particle
+    identification by specific energy loss, and unfolding of the proton energy
+    spectrum using the iterative Bayesian method;
+  \item Obtaining preliminary results on proton emission rate and spectrum:
+    the proton spectrum has a peak at \SI{4}{\MeV}, then reduces exponentially
+    with a decay constant of \SI{2.6}{\MeV}. The partial emission rate in the
+    energy range from \SIrange{4}{8}{\MeV} is $(1.7 \pm 0.1)\%$, and the total
+    emission rate assuming the shape holds for the whole spectrum is
+    $(3.5\pm0.2)$.
+\end{enumerate}
+The proton rate and spectrum have been used to optimise the planned proton
+absorber for the drift chamber of the COMET Phase-I. The resulted proton hit
+rate with the baseline configuration is very small  compared with the current
+figure. It is safe to remove the proton absorber altogether.