From b042585a1b3179950edf3a24d3b0ea9d6f071a14 Mon Sep 17 00:00:00 2001 From: nam Date: Wed, 15 Oct 2014 11:39:19 +0900 Subject: [PATCH] prog saved --- thesis/chapters/chap6_analysis.tex | 58 ++++++++++++++++++++++++++++-- thesis/thesis.tex | 4 +-- 2 files changed, 58 insertions(+), 4 deletions(-) diff --git a/thesis/chapters/chap6_analysis.tex b/thesis/chapters/chap6_analysis.tex index ea806d0..3d60cdf 100644 --- a/thesis/chapters/chap6_analysis.tex +++ b/thesis/chapters/chap6_analysis.tex @@ -382,7 +382,8 @@ the cut on protons is estimated to be small compared to the statistical ones. \subsection{Corrections for the number of protons} \label{sub:corrections_for_the_number_of_protons} The protons spectra observed by the silicon detectors have been modified by -the energy loss inside the target so correction (or unfolding) is necessary. +the energy loss inside the target so correction (also called unfolding, or +reconstruction) is necessary. The unfolding, essentially, is finding a response function that relates proton's true energy and measured value. This can be done in MC simulation by generating protons with a spatial distribution as close as possible to the real @@ -413,4 +414,57 @@ method is implemented. \label{fig:al100_resp_matrices} \end{figure} After training the unfolding code is applied on the measured spectra from the -left and right arms. The unfolded proton spectra +left and right arms. The unfolded proton spectra in \cref{fig:al100_unfold} +reasonably reflect the distribution of initial protons which is off-centred to +the right arm. The path length to the left arm is longer so less protons at +energy lower than \SI{5}{\MeV} could reach the detectors. The sharp low-energy +cut off on the right arm is consistent with the Coulomb barrier for protons, +which is \SI{4.1}{\MeV} for protons emitted from $^{27}$Mg. + +Comparing the reconstructed spectra from \SIrange{5}{8}{\MeV}, the protons +yields are consistent with each other: +\begin{align} + N_{\textrm{p reco. left}} &= (110.9 \pm 2.0)\times 10^3\\ + N_{\textrm{p reco. right}} &= (110.2 \pm 2.3)\times 10^3 +\end{align} +Therefore, the number of emitted protons is taken as average value: +\begin{equation} + N_{\textrm{p reco.}} = (110.6 \pm 2.2) \times 10^3 +\end{equation} + +\begin{figure}[htb] + \centering + \includegraphics[width=0.85\textwidth]{figs/al100_unfold} + \caption{Unfolded proton spectra from the 100-\si{\um} aluminium target.} + \label{fig:al100_unfold} +\end{figure} + +\subsection{Number of nuclear captures} +\label{sub:number_of_nuclear_captures} +\begin{figure}[htb] + \centering + \includegraphics[width=0.85\textwidth]{figs/al100_ge_spec} + \caption{X-ray spectrum from the aluminium target, the characteristic + $(2p-1s)$ line shows up at 346.67~keV} +\label{fig:al100_ge_spec} +\end{figure} + +The X-ray spectrum on the germanium detector is shown on +\cref{fig:al100_ge_spec}. Fitting the double peaks on top of a first-order +polynomial gives the X-ray peak area of $5903.5 \pm 109.2$. With the same +procedure as in the case of the active target, the number stopped muons and +the number of nuclear captures are: +\begin{align} + N_{\mu \textrm{ stopped}} &= (1.57 \pm 0.05)\times 10^7\\ + N_{\mu \textrm{ nucl. cap.}} &= (9.57\pm 0.31)\times 10^6 +\end{align} +The proton emission rate in the range from \SIrange{5}{8}{\MeV} is therefore: +\begin{equation} + R_{\textrm{p}} = \frac{110.6\times 10^3}{9.57\times 10^6} = 1.16\times + 10^{-2} + \label{eq:proton_rate_al} +\end{equation} + +\subsection{Uncertainties of the emission rate} +\label{sub:uncertainties_of_the_emission_rate} + diff --git a/thesis/thesis.tex b/thesis/thesis.tex index 9aa2d7b..ac73cc3 100644 --- a/thesis/thesis.tex +++ b/thesis/thesis.tex @@ -32,8 +32,8 @@ for the COMET experiment} %\input{chapters/chap1_intro} %\input{chapters/chap2_mu_e_conv} %\input{chapters/chap3_comet} -%\input{chapters/chap4_alcap_phys} -%\input{chapters/chap5_alcap_setup} +\input{chapters/chap4_alcap_phys} +\input{chapters/chap5_alcap_setup} \input{chapters/chap6_analysis} %\input{chapters/chap7_results}