chap5, chap6 work with siunitx
This commit is contained in:
@@ -2,10 +2,40 @@
|
|||||||
\label{cha:the_alcap_run_2013}
|
\label{cha:the_alcap_run_2013}
|
||||||
\thispagestyle{empty}
|
\thispagestyle{empty}
|
||||||
The first run of the AlCap experiment was performed at the $\pi$E1 beam line
|
The first run of the AlCap experiment was performed at the $\pi$E1 beam line
|
||||||
area, PSI (Figure~\ref{fig:psi_exp_hall_all}) from November 26 to December 23,
|
area, PSI from November 26 to December 23,
|
||||||
2013. The goal of the run was to measure protons rate and spectrum following
|
2013. The goal of the run was to measure protons rate and spectrum following
|
||||||
muon capture on aluminium.
|
muon capture on aluminium.
|
||||||
|
|
||||||
|
\section{Experimental set up}
|
||||||
|
\label{sec:experimental_set_up}
|
||||||
|
The low energy muons from the $\pi$E1 beam line were stopped in thin aluminium
|
||||||
|
and silicon targets, and charged particles emitted were measured by two pairs
|
||||||
|
of silicon detectors inside of a vacuum vessel
|
||||||
|
(\cref{fig:alcap_setup_detailed}). A stopped muon event is defined by
|
||||||
|
a group of upstream detectors and a muon veto plastic scintillator.
|
||||||
|
The number of stopped muons is monitored by a germanium detector placed outside
|
||||||
|
of the vacuum chamber. In addition, several plastic scintillators were used to
|
||||||
|
provide veto signals for the silicon and germanium detectors. Two liquid
|
||||||
|
scintillators for neutron measurements were also tested in this run.
|
||||||
|
\begin{figure}[btp]
|
||||||
|
\centering
|
||||||
|
\includegraphics[width=0.55\textwidth]{figs/alcap_setup_detailed}
|
||||||
|
\caption{AlCap detectors: two silicon packages inside the vacuum vessel,
|
||||||
|
muon beam detectors including plastic scintillators and a wire chamber,
|
||||||
|
germanium detector and veto plastic scintillators.}
|
||||||
|
\label{fig:alcap_setup_detailed}
|
||||||
|
\end{figure}
|
||||||
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
|
\subsection{Muon beam and vacuum chamber}
|
||||||
|
Muons in the $\pi$E1 beam line are decay products of pions created
|
||||||
|
as a \SI{590}{\mega\electronvolt} proton beam hits a thick carbon target
|
||||||
|
(E-target in \cref{fig:psi_exp_hall_all}). The beam line was designed to
|
||||||
|
deliver muons with momenta ranging from
|
||||||
|
\SIrange{10}{500}{\mega\electronvolt\per\cc} and
|
||||||
|
momentum spread from \SIrange{0.26}{8.0}{\percent}. These parameters can be
|
||||||
|
selected by changing various magnets and slits shown in
|
||||||
|
\cref{fig:psi_piE1_elements}~\cite{Foroughli.1997}.
|
||||||
|
|
||||||
\begin{figure}[p]
|
\begin{figure}[p]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[height=0.85\textheight]{figs/psi_exp_hall_all}
|
\includegraphics[height=0.85\textheight]{figs/psi_exp_hall_all}
|
||||||
@@ -15,37 +45,7 @@ muon capture on aluminium.
|
|||||||
\label{fig:psi_exp_hall_all}
|
\label{fig:psi_exp_hall_all}
|
||||||
\end{figure}
|
\end{figure}
|
||||||
|
|
||||||
\section{Experimental set up}
|
\begin{figure}[btp]
|
||||||
\label{sec:experimental_set_up}
|
|
||||||
The low energy muons from the $\pi$E1 beam line were stopped in thin aluminium
|
|
||||||
and silicon targets, and charged particles emitted were measured by two pairs
|
|
||||||
of silicon detectors inside of a vacuum vessel
|
|
||||||
(Figure~\ref{fig:alcap_setup_detailed}). A stopped muon event is defined by
|
|
||||||
a group of upstream detectors and a muon veto plastic scintillator.
|
|
||||||
The number of stopped muons is monitored by a germanium detector placed outside
|
|
||||||
of the vacuum chamber. In addition, several plastic scintillators were used to
|
|
||||||
provide veto signals for the silicon and germanium detectors. Two liquid
|
|
||||||
scintillators for neutron measurements were also tested in this run.
|
|
||||||
\begin{figure}[htbp]
|
|
||||||
\centering
|
|
||||||
\includegraphics[width=0.65\textwidth]{figs/alcap_setup_detailed}
|
|
||||||
\caption{AlCap detectors: two silicon packages inside the vacuum vessel,
|
|
||||||
muon beam detectors including plastic scintillators and a wire chamber,
|
|
||||||
germanium detector and veto plastic scintillators.}
|
|
||||||
\label{fig:alcap_setup_detailed}
|
|
||||||
\end{figure}
|
|
||||||
|
|
||||||
\subsection{Muon beam and vacuum chamber}
|
|
||||||
Muons in the $\pi$E1 beam line are decay products of pions created
|
|
||||||
as a 590~\mega\electronvolt\ proton beam hit a thick carbon target
|
|
||||||
(E-target in Figure~\ref{fig:psi_exp_hall_all}). The beam line was designed to
|
|
||||||
deliver muons with momenta ranging from 10 to 500~\mega\electronvolt\per\cc\
|
|
||||||
and
|
|
||||||
momentum spread from 0.26 to 8.0\%. These parameters can be selected by
|
|
||||||
changing various magnets and slits shown in
|
|
||||||
Figure~\ref{fig:psi_piE1_elements}~\cite{Foroughli.1997}.
|
|
||||||
|
|
||||||
\begin{figure}[htb]
|
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.7\textwidth]{figs/psi_piE1_elements}
|
\includegraphics[width=0.7\textwidth]{figs/psi_piE1_elements}
|
||||||
\caption{The $\pi$E1 beam line}
|
\caption{The $\pi$E1 beam line}
|
||||||
@@ -54,16 +54,17 @@ Figure~\ref{fig:psi_piE1_elements}~\cite{Foroughli.1997}.
|
|||||||
|
|
||||||
One of the main requirements of the AlCap experiment was a low energy muon beam
|
One of the main requirements of the AlCap experiment was a low energy muon beam
|
||||||
with narrow momentum bite in order to achieve a high fraction of stopping muons
|
with narrow momentum bite in order to achieve a high fraction of stopping muons
|
||||||
in the very thin targets. In this Run 2013, muons from 28 to
|
in the very thin targets. In this Run 2013, muons from
|
||||||
45~\mega\electronvolt\per\cc\ and momentum spread of 1\% and 3\%were used.
|
\SIrange{28}{45}{\mega\electronvolt\per\cc} and momentum spread of 1\% and
|
||||||
|
3\%were used.
|
||||||
|
|
||||||
For part of the experiment the target was replaced with one of the silicon
|
For part of the experiment the target was replaced with one of the silicon
|
||||||
detector packages allowed an accurate momentum and range calibration
|
detector packages allowed an accurate momentum and range calibration
|
||||||
%(via range-energy relations)
|
%(via range-energy relations)
|
||||||
of the beam at the target. Figure~\ref{fig:Rates} shows the measured muon rates
|
of the beam at the target. \Cref{fig:Rates} shows the measured muon rates
|
||||||
as a function of momentum for two different momentum bites.
|
as a function of momentum for two different momentum bites.
|
||||||
Figure~\ref{fig:Beam} shows an example of the resulting energy spectra.
|
\Cref{fig:Beam} shows an example of the resulting energy spectra.
|
||||||
\begin{figure}[htbp]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.6\textwidth]{figs/Rates.png}
|
\includegraphics[width=0.6\textwidth]{figs/Rates.png}
|
||||||
\caption{Measured muon rate (kHz) at low momenta. Momentum bite of 3 and 1 \%
|
\caption{Measured muon rate (kHz) at low momenta. Momentum bite of 3 and 1 \%
|
||||||
@@ -71,18 +72,18 @@ Figure~\ref{fig:Beam} shows an example of the resulting energy spectra.
|
|||||||
\label{fig:Rates}
|
\label{fig:Rates}
|
||||||
\end{figure}
|
\end{figure}
|
||||||
|
|
||||||
\begin{figure}[htbp]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.9\textwidth]{figs/beam.pdf}
|
\includegraphics[width=0.9\textwidth]{figs/beam.pdf}
|
||||||
\caption{Energy deposition at 36.4 MeV/c incident muon beam in an
|
\caption{Energy deposition at \SI{36.4}{/c} incident muon beam in an
|
||||||
1500-\micron-active
|
\SI{1500}{\micro\meter}-thick active target. The peak at low energy is due
|
||||||
target. The peak at low energy is due to beam electrons, the
|
to beam electrons, the peaks at higher energies are due to muons. Momentum
|
||||||
peaks at higher energies are due to muons. Momentum bite of 1 and 3\% FWHM
|
bite of 1 and 3\% FWHM on left and right hand side, respectively.}
|
||||||
on left and right hand side, respectively.} \label{fig:Beam}
|
\label{fig:Beam}
|
||||||
\end{figure}
|
\end{figure}
|
||||||
|
|
||||||
The targets and charged particle detectors are installed inside the vacuum
|
The targets and charged particle detectors are installed inside the vacuum
|
||||||
chamber as shown in Figure~\ref{fig:alcap_setup_detailed}. The muon beam enters
|
chamber as shown in \cref{fig:alcap_setup_detailed}. The muon beam enters
|
||||||
from the right of the image and hits the target, which is placed at the
|
from the right of the image and hits the target, which is placed at the
|
||||||
centre of the vacuum chamber and orientated at 45 degrees to the beam axis.
|
centre of the vacuum chamber and orientated at 45 degrees to the beam axis.
|
||||||
The side walls and bottom flange of the vessel provide several
|
The side walls and bottom flange of the vessel provide several
|
||||||
@@ -91,7 +92,7 @@ scintillator detectors inside the chamber.
|
|||||||
In addition, the chamber is equipped with several lead collimators
|
In addition, the chamber is equipped with several lead collimators
|
||||||
%so that muons that are not captured in the target would quickly decay.
|
%so that muons that are not captured in the target would quickly decay.
|
||||||
to quickly capture muons that do not stop in the actual target.
|
to quickly capture muons that do not stop in the actual target.
|
||||||
%\begin{figure}[htbp]
|
%\begin{figure}[btp]
|
||||||
%\centering
|
%\centering
|
||||||
%\includegraphics[width=0.55\textwidth]{figs/SetupOverview.jpg}
|
%\includegraphics[width=0.55\textwidth]{figs/SetupOverview.jpg}
|
||||||
%\caption{Vacuum chamber in beam line}
|
%\caption{Vacuum chamber in beam line}
|
||||||
@@ -102,22 +103,25 @@ to quickly capture muons that do not stop in the actual target.
|
|||||||
%a silicon detector in the low vacuum region of $10^{-3}$ mbar.
|
%a silicon detector in the low vacuum region of $10^{-3}$ mbar.
|
||||||
%An interlock mechanism was installed to prevent the bias of the
|
%An interlock mechanism was installed to prevent the bias of the
|
||||||
%silicon detectors from being applied before the safe vacuum level.
|
%silicon detectors from being applied before the safe vacuum level.
|
||||||
For a safe operation of the silicon detector, a vacuum of $<10^{-4}$\,mbar was
|
For a safe operation of the silicon detector, a vacuum of \SI{e-4}{\milli\bar}
|
||||||
necessary. With the help of the vacuum group of PSI, we could consistently
|
was necessary. With the help of the vacuum group of PSI, we could consistently
|
||||||
reach $10^{-4}$\,mbar within 45 minutes after closure of the chamber's top
|
reach the required vacuum level within 45 minutes after closure of the
|
||||||
flange.
|
chamber's top flange.
|
||||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
|
|
||||||
\subsection{Silicon detectors}
|
\subsection{Silicon detectors}
|
||||||
The main detectors for proton measurement in the Run 2013 were four large area
|
The main detectors for proton measurement in the Run 2013 were four large area
|
||||||
silicon detectors. The silicon detectors were grouped into two detector
|
silicon detectors. The silicon detectors were grouped into two detector
|
||||||
packages located symmetrically at 90 degrees of the nominal muon beam path, SiL
|
packages located symmetrically at 90 degrees of the nominal muon beam path, SiL
|
||||||
and SiR in Figure~\ref{fig:alcap_setup_detailed}. Each arm consists of: one
|
and SiR in \cref{fig:alcap_setup_detailed}. Each arm consists of: one
|
||||||
$\Delta$E counter, a 65-\micro\meter-thick silicon detector, divided into
|
$\Delta$E counter, a \SI{65}{\micro\meter}-thick silicon detector, divided into
|
||||||
4 quadrants; one E counter made from 1500-\micron-thick silicon; and one
|
4 quadrants; one E counter made from \SI{1500}{\micro\meter}-thick silicon; and
|
||||||
plastic scintillator to identify electrons or high energy protons that pass
|
one plastic scintillator to identify electrons or high energy protons that
|
||||||
through the silicon. The area of each of these silicon detectors and the
|
pass through the silicon. The area of each of these silicon detectors and the
|
||||||
scintillators is $50\times50 \textrm{mm}^2$.
|
scintillators is $50\times50 \textrm{mm}^2$. There is a dead layer of
|
||||||
|
\SI{0.5}{\micro\meter} on each side of the silicon detectors according to the
|
||||||
|
manufacturer Micron Semiconductor
|
||||||
|
\footnote{\url{http://www.micronsemiconductor.co.uk/}}.
|
||||||
|
|
||||||
The detectors were named according to their positions relative to the muon
|
The detectors were named according to their positions relative to the muon
|
||||||
view: the SiL package contains the thin
|
view: the SiL package contains the thin
|
||||||
@@ -129,11 +133,11 @@ SiR1-4.
|
|||||||
Bias for the four silicon detectors was supplied by an ORTEC 710 NIM module,
|
Bias for the four silicon detectors was supplied by an ORTEC 710 NIM module,
|
||||||
which has a vacuum interlock input to prevent biasing before the safe vacuum
|
which has a vacuum interlock input to prevent biasing before the safe vacuum
|
||||||
level has been reached. Typical voltage to fully depleted the detectors were
|
level has been reached. Typical voltage to fully depleted the detectors were
|
||||||
-300~\volt\ and -10~\volt\ for the thick and thin silicon detectors
|
\SI{-300}{\volt} and \SI{-10}{\volt} for the thick and thin silicon detectors
|
||||||
respectively. The leakage currents at the operating voltages are less than
|
respectively. The leakage currents at the operating voltages are less than
|
||||||
1.5~\micro\ampere\ for the thick detectors, and about 0.05~\micro\ampere\
|
\SI{1.5}{\micro\ampere} for the thick detectors, and about
|
||||||
for the thin ones (see Figure~\ref{fig:si_leakage}).
|
\SI{0.05}{\micro\ampere} for the thin ones (see \cref{fig:si_leakage}).
|
||||||
\begin{figure}[htb]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.85\textwidth]{figs/si_leakage}
|
\includegraphics[width=0.85\textwidth]{figs/si_leakage}
|
||||||
\caption{Leakage currents of the silicon detectors under bias.}
|
\caption{Leakage currents of the silicon detectors under bias.}
|
||||||
@@ -146,8 +150,8 @@ output
|
|||||||
pulse height on an oscilloscope. One would expect that the maximum pulse height
|
pulse height on an oscilloscope. One would expect that the maximum pulse height
|
||||||
increases as the bias is raised until the voltage of fully depleted. The effect
|
increases as the bias is raised until the voltage of fully depleted. The effect
|
||||||
can also be seen on the pulse height spectrum as in
|
can also be seen on the pulse height spectrum as in
|
||||||
Figure~\ref{fig:sir2_bias_alpha}.
|
\cref{fig:sir2_bias_alpha}.
|
||||||
\begin{figure}[htb]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.75\textwidth]{figs/sir2_bias_alpha}
|
\includegraphics[width=0.75\textwidth]{figs/sir2_bias_alpha}
|
||||||
\caption{$^{241}\textrm{Am}$ spectra in cases of fully depleted (top), and
|
\caption{$^{241}\textrm{Am}$ spectra in cases of fully depleted (top), and
|
||||||
@@ -195,12 +199,12 @@ Figure~\ref{fig:sir2_bias_alpha}.
|
|||||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
\subsection{Upstream counters}
|
\subsection{Upstream counters}
|
||||||
\label{sub:upstream_counters}
|
\label{sub:upstream_counters}
|
||||||
The upstream detector consists of three counters: a 500~$\mu$m thick
|
The upstream detector consists of three counters: a \SI{500}{\micro\meter}-thick
|
||||||
scintillator muon trigger counter ($\mu$SC); a muon anti-coincidence counter
|
scintillator muon trigger counter (\Pmu{}SC); a muon anti-coincidence counter
|
||||||
($\mu$SCA) surrounding the trigger counter with a hole
|
(\Pmu{}SCA) surrounding the trigger counter with a hole
|
||||||
of 35 \milli\meter\ in diameter to define the beam radius; and a multi-wire
|
of 35 \si{\milli\meter}\ in diameter to define the beam radius; and a multi-wire
|
||||||
proportional chamber ($\mu$PC) that uses 24 X wires and 24 Y wires at
|
proportional chamber (\Pmu{}PC) that uses 24 X wires and 24 Y wires at
|
||||||
2~\milli\meter~intervals.
|
2~\si{\milli\meter}~intervals.
|
||||||
|
|
||||||
The upstream detectors provide signal of an incoming muon as coincident hits on
|
The upstream detectors provide signal of an incoming muon as coincident hits on
|
||||||
the muon trigger and the wire chamber in anti-coincident with the muon
|
the muon trigger and the wire chamber in anti-coincident with the muon
|
||||||
@@ -214,7 +218,7 @@ ready to be used in our run without any modification.
|
|||||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
|
|
||||||
\subsection{Germanium detector}
|
\subsection{Germanium detector}
|
||||||
%\begin{figure}[htbp]
|
%\begin{figure}[btp]
|
||||||
%\centering
|
%\centering
|
||||||
%\includegraphics[width=0.9\textwidth]{figs/neutron.png}
|
%\includegraphics[width=0.9\textwidth]{figs/neutron.png}
|
||||||
%\caption{Setup of two
|
%\caption{Setup of two
|
||||||
@@ -225,9 +229,9 @@ We used a germanium detector to normalise the number of stopped muons by
|
|||||||
measuring characteristics muon X-rays from the target material. The primary
|
measuring characteristics muon X-rays from the target material. The primary
|
||||||
X-rays of interest are the 346.828~keV line for aluminium targets, and the
|
X-rays of interest are the 346.828~keV line for aluminium targets, and the
|
||||||
400.177 line for silicon targets. The energies and intensities of the X-rays
|
400.177 line for silicon targets. The energies and intensities of the X-rays
|
||||||
listed in Table~\ref{tab:xray_ref} follow measurement results from
|
listed in \cref{tab:xray_ref} follow measurement results from
|
||||||
Measday and colleagues~\cite{MeasdayStocki.etal.2007}.
|
Measday and colleagues~\cite{MeasdayStocki.etal.2007}.
|
||||||
\begin{table}[htb]
|
\begin{table}[btp]
|
||||||
\begin{center}
|
\begin{center}
|
||||||
\begin{tabular}{c l l l l }
|
\begin{tabular}{c l l l l }
|
||||||
\toprule
|
\toprule
|
||||||
@@ -250,11 +254,11 @@ The germanium detector is
|
|||||||
a GMX20P4-70-RB-B-PL, n-type, coaxial high purity germanium detector produced
|
a GMX20P4-70-RB-B-PL, n-type, coaxial high purity germanium detector produced
|
||||||
by ORTEC. The detector was optimised for low energy gamma and X-rays
|
by ORTEC. The detector was optimised for low energy gamma and X-rays
|
||||||
measurement with an ultra-thin entrance window of 0.5-mm-thick beryllium and
|
measurement with an ultra-thin entrance window of 0.5-mm-thick beryllium and
|
||||||
a 0.3-\micron-thick ion implanted contact (Figure~\ref{fig:ge_det_dimensions}).
|
a 0.3-\si{\micro\meter}-thick ion implanted contact (\cref{fig:ge_det_dimensions}).
|
||||||
This detector is equipped with a transistor reset preamplifier which,
|
This detector is equipped with a transistor reset preamplifier which,
|
||||||
according to the producer, enables it to work in an ultra-high rate environment
|
according to the producer, enables it to work in an ultra-high rate environment
|
||||||
up to $10^6$ counts\per\second~ at 1~\mega\electronvolt.
|
up to $10^6$ counts\si{\per\second} at \SI{1}{\mega\electronvolt}.
|
||||||
\begin{figure}[htb]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.9\textwidth]{figs/ge_det_dimensions}
|
\includegraphics[width=0.9\textwidth]{figs/ge_det_dimensions}
|
||||||
\caption{Dimensions of the germanium detector}
|
\caption{Dimensions of the germanium detector}
|
||||||
@@ -288,12 +292,12 @@ carried out.
|
|||||||
\section{Front-end electronics and data acquisition system}
|
\section{Front-end electronics and data acquisition system}
|
||||||
The front-end electronics of the AlCap experiment was simple since we employed
|
The front-end electronics of the AlCap experiment was simple since we employed
|
||||||
a trigger-less read out system with waveform digitisers and flash ADCs
|
a trigger-less read out system with waveform digitisers and flash ADCs
|
||||||
(FADCs). As shown in Figure~\ref{fig:alcapdaq_scheme}, all plastic
|
(FADCs). As shown in \cref{fig:alcapdaq_scheme}, all plastic
|
||||||
scintillators signals were amplified by PMTs, then fed into the digitisers. The
|
scintillators signals were amplified by PMTs, then fed into the digitisers. The
|
||||||
signals from silicon and germanium detectors were preamplified, and
|
signals from silicon and germanium detectors were preamplified, and
|
||||||
subsequently shaped by spectroscopy amplifiers and timing filter amplifiers
|
subsequently shaped by spectroscopy amplifiers and timing filter amplifiers
|
||||||
(TFAs) to provide energy and timing information.
|
(TFAs) to provide energy and timing information.
|
||||||
\begin{figure}[htbp]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.99\textwidth]{figs/alcapdaq_scheme}
|
\includegraphics[width=0.99\textwidth]{figs/alcapdaq_scheme}
|
||||||
\caption{Schematic diagram of the electronics and DAQ used in the Run 2013}
|
\caption{Schematic diagram of the electronics and DAQ used in the Run 2013}
|
||||||
@@ -304,21 +308,21 @@ The germanium detector has its own transistor reset preamplifier
|
|||||||
installed very close to the germanium crystal. Two ORTEC Model 142
|
installed very close to the germanium crystal. Two ORTEC Model 142
|
||||||
preamplifiers were used for the thick silicon detectors. The timing outputs of
|
preamplifiers were used for the thick silicon detectors. The timing outputs of
|
||||||
the preamplifiers were fed into three ORTEC Model 579 TFAs.
|
the preamplifiers were fed into three ORTEC Model 579 TFAs.
|
||||||
We used an ORTEC Model 673 to shape the germanium signal with 6~\micro\second
|
We used an ORTEC Model 673 to shape the germanium signal with 6~\si{\micro\second}
|
||||||
shaping time.
|
shaping time.
|
||||||
|
|
||||||
A more modern-style electronics was used for thin silicon detectors where the
|
A more modern-style electronics was used for thin silicon detectors where the
|
||||||
preamplifier, shaping and timing amplifiers were implemented on one compact
|
preamplifier, shaping and timing amplifiers were implemented on one compact
|
||||||
package, namely a Mesytec MSI-8 box. This box has 8 channels, each channel
|
package, namely a Mesytec MSI-8 box. This box has 8 channels, each channel
|
||||||
consists of one preamplifier board and one shaper-and-timing filter board which
|
consists of one preamplifier board and one shaper-and-timing filter board which
|
||||||
can be fine-tuned independently. The shaping time was set to 1~\micro\second\
|
can be fine-tuned independently. The shaping time was set to 1~\si{\micro\second}\
|
||||||
for all channels.
|
for all channels.
|
||||||
|
|
||||||
The detector system produced signals that differs significantly in time scale,
|
The detector system produced signals that differs significantly in time scale,
|
||||||
ranging from very fast (about 40~\nano\second\ from scintillators) to very slow
|
ranging from very fast (about 40~\si{\nano\second}\ from scintillators) to very slow
|
||||||
(several \micro\second\ from shaping outputs of semiconductor detectors). This
|
(several \si{\micro\second}\ from shaping outputs of semiconductor detectors). This
|
||||||
lead to the use of several sampling frequencies from 17~\mega\hertz\ to
|
lead to the use of several sampling frequencies from 17~\si{\mega\hertz}\ to
|
||||||
250~\mega\hertz, and three types of digitisers were employed:
|
250~\si{\mega\hertz}, and three types of digitisers were employed:
|
||||||
\begin{itemize}
|
\begin{itemize}
|
||||||
\item custom-built 12-bit 170-MHz FADCs which was designed for the
|
\item custom-built 12-bit 170-MHz FADCs which was designed for the
|
||||||
MuCap experiment. Each FADC board has dimensions the same as those of
|
MuCap experiment. Each FADC board has dimensions the same as those of
|
||||||
@@ -328,10 +332,10 @@ lead to the use of several sampling frequencies from 17~\mega\hertz\ to
|
|||||||
Ethernet-level protocol. The protocol only allows detecting
|
Ethernet-level protocol. The protocol only allows detecting
|
||||||
incomplete data transfers but no retransmitting is possible due to the
|
incomplete data transfers but no retransmitting is possible due to the
|
||||||
limited size of the module's output buffer. The FADCs accept clock signal
|
limited size of the module's output buffer. The FADCs accept clock signal
|
||||||
at the frequency of 50~\mega\hertz\ then multiply that internally up to
|
at the frequency of 50~\si{\mega\hertz}\ then multiply that internally up to
|
||||||
170~\mega\hertz. Each channel on one board can run at different sampling
|
170~\si{\mega\hertz}. Each channel on one board can run at different sampling
|
||||||
frequency not dependent on other channels. The FADC has 8 single-ended
|
frequency not dependent on other channels. The FADC has 8 single-ended
|
||||||
LEMO inputs with 1~\volt pp dynamic range.
|
LEMO inputs with 1~\si{\volt} pp dynamic range.
|
||||||
\item a 14-bit 100-MS/s CAEN VME FADC waveform digitiser model V1724. The
|
\item a 14-bit 100-MS/s CAEN VME FADC waveform digitiser model V1724. The
|
||||||
module houses 8 channels with 2.25~Vpp dynamic range on single-ended MCX
|
module houses 8 channels with 2.25~Vpp dynamic range on single-ended MCX
|
||||||
coaxial inputs. The digitiser features an optical link for transmission of
|
coaxial inputs. The digitiser features an optical link for transmission of
|
||||||
@@ -347,7 +351,7 @@ lead to the use of several sampling frequencies from 17~\mega\hertz\ to
|
|||||||
proprietary binary drivers and libraries.
|
proprietary binary drivers and libraries.
|
||||||
\end{itemize}
|
\end{itemize}
|
||||||
All digitisers were driven by external clocks which were derived from the same
|
All digitisers were driven by external clocks which were derived from the same
|
||||||
500-\mega\hertz\ master clock, a high precision RF signal generator Model SG382
|
500-\si{\mega\hertz}\ master clock, a high precision RF signal generator Model SG382
|
||||||
of Stanford Research System.
|
of Stanford Research System.
|
||||||
|
|
||||||
The silicon detectors were read out by FADC boards feature network-based data
|
The silicon detectors were read out by FADC boards feature network-based data
|
||||||
@@ -355,14 +359,14 @@ readout interface. To maximize the data throughput, each of the four FADC
|
|||||||
boards was read out through separate network adapter.
|
boards was read out through separate network adapter.
|
||||||
The CAEN digitisers were used to read out
|
The CAEN digitisers were used to read out
|
||||||
the germanium detector (timing and energy, slow signals) or scintillator
|
the germanium detector (timing and energy, slow signals) or scintillator
|
||||||
detectors (fast signals). For redundancy, all beam monitors ($\mu$SC, $\mu$SCA
|
detectors (fast signals). For redundancy, all beam monitors (\Pmu{}SC, \Pmu{}SCA
|
||||||
and $\mu$PC) were also read out by a CAEN time-to-digital converter (TDC)
|
and \Pmu{}PC) were also read out by a CAEN time-to-digital converter (TDC)
|
||||||
model V767 which was kindly provided by the MuSun experiment.
|
model V767 which was kindly provided by the MuSun experiment.
|
||||||
|
|
||||||
The Data Acquisition System (DAQ) of the AlCap experiment, so-called AlCapDAQ,
|
The Data Acquisition System (DAQ) of the AlCap experiment, so-called AlCapDAQ,
|
||||||
provided the readout of front-end electronics, event assembling, data logging,
|
provided the readout of front-end electronics, event assembling, data logging,
|
||||||
hardware monitoring and control, and the run database of the experiment
|
hardware monitoring and control, and the run database of the experiment
|
||||||
(Figure~\ref{fig:alcapdaq_pcs}). It was based on MIDAS framework~\footnote{
|
(\cref{fig:alcapdaq_pcs}). It was based on MIDAS framework~\footnote{
|
||||||
MIDAS is a general purpose DAQ software system developed at PSI and TRIUMF:\\
|
MIDAS is a general purpose DAQ software system developed at PSI and TRIUMF:\\
|
||||||
\url{http://midas.triumf.ca}} and consisted of two circuits, {\em i})
|
\url{http://midas.triumf.ca}} and consisted of two circuits, {\em i})
|
||||||
a detector circuit for synchronous data readout from the front-end electronics
|
a detector circuit for synchronous data readout from the front-end electronics
|
||||||
@@ -375,7 +379,7 @@ running Linux operating system and connected into a private subnetwork.
|
|||||||
|
|
||||||
%\hl{TODO: storage and shift monitor}
|
%\hl{TODO: storage and shift monitor}
|
||||||
|
|
||||||
\begin{figure}[htb]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.95\textwidth]{figs/alcapdaq_pcs}
|
\includegraphics[width=0.95\textwidth]{figs/alcapdaq_pcs}
|
||||||
\caption{AlCapDAQ in the Run 2013. The {\ttfamily fe6} front-end is
|
\caption{AlCapDAQ in the Run 2013. The {\ttfamily fe6} front-end is
|
||||||
@@ -397,10 +401,10 @@ correlation between detectors would be established in the analysis stage.
|
|||||||
|
|
||||||
At the beginning of each block, the time counter in each digitiser is reset to
|
At the beginning of each block, the time counter in each digitiser is reset to
|
||||||
ensure time alignment across all modules. The period of 110~ms was chosen to be:
|
ensure time alignment across all modules. The period of 110~ms was chosen to be:
|
||||||
{\em i} long enough compares to the time scale of several \micro\second\ of the
|
{\em i} long enough compares to the time scale of several \si{\micro\second}\ of the
|
||||||
physics of interest, {\em ii} short enough so that there is no timer rollover
|
physics of interest, {\em ii} short enough so that there is no timer rollover
|
||||||
on any digitiser (a FADC runs at its maximum speed of 170~\mega\hertz\ could
|
on any digitiser (a FADC runs at its maximum speed of \SI{170}{\mega\hertz} could
|
||||||
handle up to about 1.5 \second\ with its 28-bit time counter).
|
handle up to about \SI{1.5}{\second} with its 28-bit time counter).
|
||||||
|
|
||||||
To ease the task of handling data, the data collecting period was divided into
|
To ease the task of handling data, the data collecting period was divided into
|
||||||
short runs, each run stopped when the logger had recorded 2 GB of data.
|
short runs, each run stopped when the logger had recorded 2 GB of data.
|
||||||
@@ -431,14 +435,14 @@ different targets were carried out for silicon targets:
|
|||||||
|
|
||||||
As the emitted protons deposit a significant amount of energy in the target
|
As the emitted protons deposit a significant amount of energy in the target
|
||||||
material, thin targets and thus excellent momentum resolution of the low energy
|
material, thin targets and thus excellent momentum resolution of the low energy
|
||||||
muon beam are critical. Aluminium targets of 50-\micro\meter\ and
|
muon beam are critical. Aluminium targets of 50-\si{\micro\meter}\ and
|
||||||
100~\micron\ thick were used. Although a beam with low momentum spread of
|
100~\si{\micro\meter}\ thick were used. Although a beam with low momentum spread of
|
||||||
1\% is preferable, it was used for only a small portion of the run due to the
|
1\% is preferable, it was used for only a small portion of the run due to the
|
||||||
low beam rate (see Figure~\ref{fig:Rates}). The beam momentum for each target
|
low beam rate (see \cref{fig:Rates}). The beam momentum for each target
|
||||||
was chosen to maximise the number of stopped muons. The collected data sets are
|
was chosen to maximise the number of stopped muons. The collected data sets are
|
||||||
shown in Table~\ref{tb:stat}.
|
shown in \cref{tb:stat}.
|
||||||
|
|
||||||
\begin{table}[htb!]
|
\begin{table}[btp!]
|
||||||
\begin{center}
|
\begin{center}
|
||||||
\vspace{0.15cm}
|
\vspace{0.15cm}
|
||||||
\begin{tabular}{l c c c}
|
\begin{tabular}{l c c c}
|
||||||
@@ -446,16 +450,16 @@ shown in Table~\ref{tb:stat}.
|
|||||||
\textbf{Target} &\textbf{Momentum} & \textbf{Run time} & \textbf{Number}\\
|
\textbf{Target} &\textbf{Momentum} & \textbf{Run time} & \textbf{Number}\\
|
||||||
\textbf{and thickness}&\textbf{scaling factor} & \textbf{(h)} &\textbf{of muons}\\
|
\textbf{and thickness}&\textbf{scaling factor} & \textbf{(h)} &\textbf{of muons}\\
|
||||||
\midrule
|
\midrule
|
||||||
Si 1500 \micro\meter& 1.32& 3.07& $2.78\times 10^7$\\
|
Si 1500 \si{\micro\meter}& 1.32& 3.07& $2.78\times 10^7$\\
|
||||||
& 1.30& 12.04& $2.89 \times 10^8$\\
|
& 1.30& 12.04& $2.89 \times 10^8$\\
|
||||||
& 1.10& 9.36& $1.37 \times 10^8$ \\
|
& 1.10& 9.36& $1.37 \times 10^8$ \\
|
||||||
\midrule
|
\midrule
|
||||||
Si 62 \micro\meter & 1.06& 10.29& $1.72 \times 10^8$\\
|
Si 62 \si{\micro\meter} & 1.06& 10.29& $1.72 \times 10^8$\\
|
||||||
\midrule
|
\midrule
|
||||||
Al 100 \micro\meter& 1.09& 14.37&$2.94 \times 10^8$\\
|
Al 100 \si{\micro\meter}& 1.09& 14.37&$2.94 \times 10^8$\\
|
||||||
& 1.07& 2.56& $4.99 \times 10^7$\\
|
& 1.07& 2.56& $4.99 \times 10^7$\\
|
||||||
\midrule
|
\midrule
|
||||||
Al 50 \micro\meter m & 1.07& 51.94& $8.81 \times 10^8$\\
|
Al 50 \si{\micro\meter} m & 1.07& 51.94& $8.81 \times 10^8$\\
|
||||||
\bottomrule
|
\bottomrule
|
||||||
\end{tabular}
|
\end{tabular}
|
||||||
\end{center}
|
\end{center}
|
||||||
@@ -473,11 +477,11 @@ Since the AlCapDAQ is a trigger-less system, it stored all waveforms of the
|
|||||||
hits occured in 100-ms-long blocks without considering their physics
|
hits occured in 100-ms-long blocks without considering their physics
|
||||||
significance The analysis code therefore must be able to extract parameters of
|
significance The analysis code therefore must be able to extract parameters of
|
||||||
the waveforms, then organises the pulses into physics events correlated to
|
the waveforms, then organises the pulses into physics events correlated to
|
||||||
stopped muons (Figure~\ref{fig:muon_event}). In addition, the analyser is
|
stopped muons (\cref{fig:muon_event}). In addition, the analyser is
|
||||||
intended to be usable as a real-time component of a MIDAS DAQ, where simple
|
intended to be usable as a real-time component of a MIDAS DAQ, where simple
|
||||||
analysis could be done online for monitoring and diagnostic during the run.
|
analysis could be done online for monitoring and diagnostic during the run.
|
||||||
|
|
||||||
\begin{figure}[htb]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.9\textwidth]{figs/muon_event.pdf}
|
\includegraphics[width=0.9\textwidth]{figs/muon_event.pdf}
|
||||||
\caption{Concept of the AlCap analysis code: pulses from individual detector
|
\caption{Concept of the AlCap analysis code: pulses from individual detector
|
||||||
@@ -520,7 +524,7 @@ algorithm that takes the pulse parameters from the peak of the waveform. In
|
|||||||
parallel, a pulse finding and template fitting code is being developed because
|
parallel, a pulse finding and template fitting code is being developed because
|
||||||
it would provide more accurate pulse information. The first iteration of this
|
it would provide more accurate pulse information. The first iteration of this
|
||||||
code has been completed and is being tested.
|
code has been completed and is being tested.
|
||||||
\begin{figure}[htb]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.85\textwidth]{figs/analysis_scheme}
|
\includegraphics[width=0.85\textwidth]{figs/analysis_scheme}
|
||||||
\caption{Concept of the analysis framework in \rootana{}}
|
\caption{Concept of the analysis framework in \rootana{}}
|
||||||
@@ -545,7 +549,7 @@ detectors. These particle hits are still stored in the time-ordered tree
|
|||||||
corresponds to the 110 ms block length from the AlCapDAQ. By iterating through
|
corresponds to the 110 ms block length from the AlCapDAQ. By iterating through
|
||||||
the tree to find stopped muons and taking any hits within a certain window
|
the tree to find stopped muons and taking any hits within a certain window
|
||||||
around this muon from every detector, a stopped-muon-centred tree shown in
|
around this muon from every detector, a stopped-muon-centred tree shown in
|
||||||
Figure~\ref{fig:muon_event} can be produced. This will make it much easier to
|
\cref{fig:muon_event} can be produced. This will make it much easier to
|
||||||
look for coincidences and apply cuts, thereby bringing the end
|
look for coincidences and apply cuts, thereby bringing the end
|
||||||
goal of particle numbers and energy distributions.
|
goal of particle numbers and energy distributions.
|
||||||
|
|
||||||
@@ -558,8 +562,8 @@ The online analyser was developed and proved to be very useful during the run.
|
|||||||
A few basic modules were used to produce plots for diagnostic purposes
|
A few basic modules were used to produce plots for diagnostic purposes
|
||||||
including: persistency view of waveforms, pulse height
|
including: persistency view of waveforms, pulse height
|
||||||
spectra, timing correlations with respect to the upstream counters. The
|
spectra, timing correlations with respect to the upstream counters. The
|
||||||
modules and their purposes are listed in Table~\ref{tab:online_modules}.
|
modules and their purposes are listed in \cref{tab:online_modules}.
|
||||||
\begin{table}[htb]
|
\begin{table}[btp]
|
||||||
\begin{center}
|
\begin{center}
|
||||||
\begin{tabular}{l p{6cm}}
|
\begin{tabular}{l p{6cm}}
|
||||||
\toprule
|
\toprule
|
||||||
@@ -604,7 +608,7 @@ groups such as upstream counters, silicon arms. It could also periodically
|
|||||||
update the plots to reflect real-time status of the detector system.
|
update the plots to reflect real-time status of the detector system.
|
||||||
%Screen
|
%Screen
|
||||||
%shots of the {\ttfamily online-display} with several plots are shown in
|
%shots of the {\ttfamily online-display} with several plots are shown in
|
||||||
%Figure~\ref{fig:online_display}.
|
%\cref{fig:online_display}.
|
||||||
|
|
||||||
%\hl{Screen shots}
|
%\hl{Screen shots}
|
||||||
\subsection{Offline analyser}
|
\subsection{Offline analyser}
|
||||||
@@ -612,15 +616,15 @@ update the plots to reflect real-time status of the detector system.
|
|||||||
Some offline analysis modules has been developed during the beam time and could
|
Some offline analysis modules has been developed during the beam time and could
|
||||||
provide quick feedback in confirming and guiding the decisions at the time. For
|
provide quick feedback in confirming and guiding the decisions at the time. For
|
||||||
example, the X-ray spectrum analysis was done to confirm that we could observe
|
example, the X-ray spectrum analysis was done to confirm that we could observe
|
||||||
the muon capture process (Figure~\ref{fig:muX}), and to help in choosing optimal
|
the muon capture process (\cref{fig:muX}), and to help in choosing optimal
|
||||||
momenta which maximised the number of stopped muons.
|
momenta which maximised the number of stopped muons.
|
||||||
\begin{figure}[htbp]
|
\begin{figure}[btp]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.7\textwidth]{figs/muX.png}
|
\includegraphics[width=0.7\textwidth]{figs/muX.png}
|
||||||
\caption{Germanium
|
\caption{Germanium
|
||||||
detector spectra in the range of 300 - 450 keV with different setups: no
|
detector spectra in the range of 300 - 450 keV with different setups: no
|
||||||
target, 62-\micron-thick silicon target, and 100-\micron-thick aluminium
|
target, 62-\si{\micro\meter}-thick silicon target, and
|
||||||
target. The ($2p-1s$) lines from
|
100-\si{\micro\meter}-thick aluminium target. The ($2p-1s$) lines from
|
||||||
aluminium (346.828 keV) and silicon (400.177 keV) are clearly visible,
|
aluminium (346.828 keV) and silicon (400.177 keV) are clearly visible,
|
||||||
the double peaks at 431 and 438 keV are from the lead shield, the peak at
|
the double peaks at 431 and 438 keV are from the lead shield, the peak at
|
||||||
351~keV is a background gamma ray from $^{211}$Bi.}
|
351~keV is a background gamma ray from $^{211}$Bi.}
|
||||||
|
|||||||
@@ -4,7 +4,7 @@
|
|||||||
\section{Analysis modules}
|
\section{Analysis modules}
|
||||||
\label{sec:analysis_modules}
|
\label{sec:analysis_modules}
|
||||||
A full analysis has not been completed yet, but initial analysis
|
A full analysis has not been completed yet, but initial analysis
|
||||||
based on the existing modules (Table~\ref{tab:offline_modules}) is possible
|
based on the existing modules (\cref{tab:offline_modules}) is possible
|
||||||
thanks to the modularity of the analysis framework.
|
thanks to the modularity of the analysis framework.
|
||||||
|
|
||||||
\begin{table}[htb]
|
\begin{table}[htb]
|
||||||
@@ -30,16 +30,16 @@ thanks to the modularity of the analysis framework.
|
|||||||
\end{table}
|
\end{table}
|
||||||
|
|
||||||
The MakeAnalysedPulses module takes a raw waveform, calculates the pedestal
|
The MakeAnalysedPulses module takes a raw waveform, calculates the pedestal
|
||||||
from a predefined number of first samples, subtracts this pedestal, takes
|
from a predefined number of first samples, subtracts this pedestal taking
|
||||||
pulse polarity into account, then calls another module to extract pulse
|
pulse polarity into account, then calls another module to extract pulse
|
||||||
parameters. At the moment, the simplest module, so-called MaxBinAPGenerator,
|
parameters. At the moment, the simplest module, so-called MaxBinAPGenerator,
|
||||||
for pulse information calculation is in use. The module looks for the
|
for pulse information calculation is in use. The module looks for the
|
||||||
sample that
|
sample that
|
||||||
has the maximal deviation from the baseline, takes the deviation as pulse
|
has the maximal deviation from the baseline, takes the deviation as pulse
|
||||||
amplitude and the time stamp of the sample as pulse time. The procedure is
|
amplitude and the time stamp of the sample as pulse time. The procedure is
|
||||||
illustrated on Figure~\ref{fig:tap_maxbin_algo}. This module could not detect
|
illustrated on \cref{fig:tap_maxbin_algo}. This module could not detect
|
||||||
pile up or double pulses in one \tpulseisland{} in
|
pile up or double pulses in one \tpulseisland{} in
|
||||||
Figure~\ref{fig:tap_maxbin_bad}.
|
\cref{fig:tap_maxbin_bad}.
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.85\textwidth]{figs/tap_maxbin_algo}
|
\includegraphics[width=0.85\textwidth]{figs/tap_maxbin_algo}
|
||||||
@@ -82,7 +82,7 @@ the beam rate was generally less than \SI{8}{\kilo\hertz}.
|
|||||||
%candidate: a prompt hit on the target in $\pm 200$ \si{\nano\second}\ around the
|
%candidate: a prompt hit on the target in $\pm 200$ \si{\nano\second}\ around the
|
||||||
%time of the $\mu$Sc pulse. The number comes from the observation of the
|
%time of the $\mu$Sc pulse. The number comes from the observation of the
|
||||||
%time correlation between hits on the target and the $\mu$Sc
|
%time correlation between hits on the target and the $\mu$Sc
|
||||||
%(Figure~\ref{fig:tme_sir_prompt_rational}).
|
%(\cref{fig:tme_sir_prompt_rational}).
|
||||||
%\begin{figure}[htb]
|
%\begin{figure}[htb]
|
||||||
%\centering
|
%\centering
|
||||||
%\includegraphics[width=0.85\textwidth]{figs/tme_sir_prompt_rational}
|
%\includegraphics[width=0.85\textwidth]{figs/tme_sir_prompt_rational}
|
||||||
@@ -97,7 +97,7 @@ rate, time correlation to hits on $\mu$Sc, \ldots on each channel during the
|
|||||||
data collecting period. Runs with significant difference from the nominal
|
data collecting period. Runs with significant difference from the nominal
|
||||||
values were further checked for possible causes, and would be discarded if such
|
values were further checked for possible causes, and would be discarded if such
|
||||||
discrepancy was too large or unaccounted for. Examples of such trend plots are
|
discrepancy was too large or unaccounted for. Examples of such trend plots are
|
||||||
shown in Figure~\ref{fig:lldq}.
|
shown in \cref{fig:lldq}.
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.47\textwidth]{figs/lldq_noise}
|
\includegraphics[width=0.47\textwidth]{figs/lldq_noise}
|
||||||
@@ -131,15 +131,10 @@ During data taking period, electrons in the beam were were also used for energy
|
|||||||
calibration of thick silicon detectors where energy deposition is large enough.
|
calibration of thick silicon detectors where energy deposition is large enough.
|
||||||
The muons at different momenta provided another mean of calibration in the beam
|
The muons at different momenta provided another mean of calibration in the beam
|
||||||
tuning period.
|
tuning period.
|
||||||
%Typical pulse height spectra of the silicon detectors are shown
|
|
||||||
%in Figure~\ref{fig:si_eg_spectra}.
|
|
||||||
|
|
||||||
According to Micron Semiconductor
|
The alpha particles from the source would deposit
|
||||||
\footnote{\url{http://www.micronsemiconductor.co.uk/}}, the
|
about 66~keV in the \SI{0.5}{\micro\meter}-thick dead layer, and the peak would
|
||||||
manufacturer of the silicon detectors, the nominal thickness of the dead layer on
|
appear at 5418~keV (\cref{fig:toyMC_alpha}).
|
||||||
each side is 0.5~\si{\micro\meter}. The alpha particles from the source would deposit
|
|
||||||
about 66~keV in this layer, and the peak would appear at 5418~keV
|
|
||||||
(Figure~\ref{fig:toyMC_alpha}).
|
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.6\textwidth]{figs/toyMC_alpha}
|
\includegraphics[width=0.6\textwidth]{figs/toyMC_alpha}
|
||||||
@@ -149,7 +144,7 @@ about 66~keV in this layer, and the peak would appear at 5418~keV
|
|||||||
\end{figure}
|
\end{figure}
|
||||||
|
|
||||||
The calibration coefficients for the silicon channels are listed in
|
The calibration coefficients for the silicon channels are listed in
|
||||||
Table~\ref{tab:cal_coeff}.
|
\cref{tab:cal_coeff}.
|
||||||
\begin{table}[htb]
|
\begin{table}[htb]
|
||||||
\begin{center}
|
\begin{center}
|
||||||
\begin{tabular}{l c r}
|
\begin{tabular}{l c r}
|
||||||
@@ -183,7 +178,7 @@ source\footnote{Energies and intensities of gamma rays are taken from the
|
|||||||
X-ray and Gamma-ray Decay Data Standards for Detector Calibration and Other
|
X-ray and Gamma-ray Decay Data Standards for Detector Calibration and Other
|
||||||
Applications, which is published by IAEA at \\
|
Applications, which is published by IAEA at \\
|
||||||
\url{https://www-nds.iaea.org/xgamma_standards/}}, the
|
\url{https://www-nds.iaea.org/xgamma_standards/}}, the
|
||||||
recorded pulse height spectrum is shown in Figure~\ref{fig:ge_eu152_spec}. The
|
recorded pulse height spectrum is shown in \cref{fig:ge_eu152_spec}. The
|
||||||
source was placed at the target position so that the absolute efficiencies can
|
source was placed at the target position so that the absolute efficiencies can
|
||||||
be calibrated. The relation between pulse height in ADC count and energy is
|
be calibrated. The relation between pulse height in ADC count and energy is
|
||||||
found to be:
|
found to be:
|
||||||
@@ -197,7 +192,7 @@ worse at 3.1~\si{\kilo\electronvolt}~for the annihilation photons at
|
|||||||
|
|
||||||
The absolute efficiencies for the $(2p-1s)$ lines of aluminium
|
The absolute efficiencies for the $(2p-1s)$ lines of aluminium
|
||||||
(346.828~\si{\kilo\electronvolt}) and silicon (400.177~\si{\kilo\electronvolt}) are
|
(346.828~\si{\kilo\electronvolt}) and silicon (400.177~\si{\kilo\electronvolt}) are
|
||||||
presented in Table~\ref{tab:xray_eff}. In the process of efficiency calibration,
|
presented in \cref{tab:xray_eff}. In the process of efficiency calibration,
|
||||||
corrections for true coincidence summing and self-absorption were not applied.
|
corrections for true coincidence summing and self-absorption were not applied.
|
||||||
The true coincidence summing probability is estimated to be very
|
The true coincidence summing probability is estimated to be very
|
||||||
small, about \sn{5.4}{-6}, thanks to the far geometry of the calibration. The
|
small, about \sn{5.4}{-6}, thanks to the far geometry of the calibration. The
|
||||||
@@ -263,7 +258,7 @@ polyethylene is less than \sn{4}{-4} for a 100~\si{\kilo\electronvolt}\ photon.
|
|||||||
%detector was placed perpendicular to the nominal beam path, after an oval
|
%detector was placed perpendicular to the nominal beam path, after an oval
|
||||||
%collimator. The beam momentum scaling factor was scanned from 1.10 to 1.60,
|
%collimator. The beam momentum scaling factor was scanned from 1.10 to 1.60,
|
||||||
%muon momenta and energies in the measured points are listed in
|
%muon momenta and energies in the measured points are listed in
|
||||||
%Table~\ref{tab:mu_scales}.
|
%\cref{tab:mu_scales}.
|
||||||
%\begin{table}[htbp]
|
%\begin{table}[htbp]
|
||||||
%\begin{center}
|
%\begin{center}
|
||||||
%\begin{tabular}{c c c c}
|
%\begin{tabular}{c c c c}
|
||||||
@@ -301,7 +296,7 @@ polyethylene is less than \sn{4}{-4} for a 100~\si{\kilo\electronvolt}\ photon.
|
|||||||
\label{sec:charged_particles_from_muon_capture_on_silicon_thick_silicon}
|
\label{sec:charged_particles_from_muon_capture_on_silicon_thick_silicon}
|
||||||
This analysis was done on a subset of the active target runs 2119 -- 2140
|
This analysis was done on a subset of the active target runs 2119 -- 2140
|
||||||
because of the problem of wrong clock frequency found in the data quality
|
because of the problem of wrong clock frequency found in the data quality
|
||||||
checking shown in Figure~\ref{fig:lldq}. The data set contains \sn{6.43}{7}
|
checking shown in \cref{fig:lldq}. The data set contains \sn{6.43}{7}
|
||||||
muon events.
|
muon events.
|
||||||
%64293720
|
%64293720
|
||||||
|
|
||||||
@@ -316,7 +311,7 @@ Because of the active target, a stopped muon would cause two coincident hits on
|
|||||||
the muon counter and the target. The energy of the muon hit on the active
|
the muon counter and the target. The energy of the muon hit on the active
|
||||||
target is also well-defined as a narrow momentum spread beam was used. The
|
target is also well-defined as a narrow momentum spread beam was used. The
|
||||||
correlation between the energy and timing of all the hits on the active target
|
correlation between the energy and timing of all the hits on the active target
|
||||||
is shown in Figure~\ref{fig:sir2f_Et_corr}. The most intense spot at zero time
|
is shown in \cref{fig:sir2f_Et_corr}. The most intense spot at zero time
|
||||||
and about 5 MeV energy corresponds to stopped muons in the thick target. The
|
and about 5 MeV energy corresponds to stopped muons in the thick target. The
|
||||||
band below 1 MeV is due to electrons, either in the beam or from muon decay in
|
band below 1 MeV is due to electrons, either in the beam or from muon decay in
|
||||||
orbits, or emitted during the cascading of muon to the muonic 1S state. The
|
orbits, or emitted during the cascading of muon to the muonic 1S state. The
|
||||||
@@ -341,7 +336,7 @@ particles from the stopped muons:
|
|||||||
It can be seen that there is a faint stripe of muons in the time larger than
|
It can be seen that there is a faint stripe of muons in the time larger than
|
||||||
1200~ns region, they are scattered muons by other materials without hitting the
|
1200~ns region, they are scattered muons by other materials without hitting the
|
||||||
muon counter. The electrons in the beam caused the constant band below 1 MeV and
|
muon counter. The electrons in the beam caused the constant band below 1 MeV and
|
||||||
$t > 5000$ ns (see Figure~\ref{fig:sir2_1us_slices}).
|
$t > 5000$ ns (see \cref{fig:sir2_1us_slices}).
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.85\textwidth]{figs/sir2_sir2f_amp_1us_slices}
|
\includegraphics[width=0.85\textwidth]{figs/sir2_sir2f_amp_1us_slices}
|
||||||
@@ -401,8 +396,8 @@ hits:
|
|||||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
\subsection{Number of charged particles with energy above 2~MeV}
|
\subsection{Number of charged particles with energy above 2~MeV}
|
||||||
\label{sub:number_of_charged_particles_with_energy_from_8_10_mev}
|
\label{sub:number_of_charged_particles_with_energy_from_8_10_mev}
|
||||||
As shown in Figure~\ref{fig:sir2_1us_slices} and illustrated by MC simulation
|
As shown in \cref{fig:sir2_1us_slices} and illustrated by MC simulation
|
||||||
in Figure~\ref{fig:sir2_mc_pdfs}, there are several components in
|
in \cref{fig:sir2_mc_pdfs}, there are several components in
|
||||||
the energy spectrum recorded by the active target:
|
the energy spectrum recorded by the active target:
|
||||||
\begin{enumerate}
|
\begin{enumerate}
|
||||||
\item charged particles from nuclear muon capture, this is the signal we are
|
\item charged particles from nuclear muon capture, this is the signal we are
|
||||||
@@ -484,7 +479,7 @@ The number of nuclear captures can be inferred from the number of recorded
|
|||||||
muonic X-rays. The reference values of the parameters needed for the
|
muonic X-rays. The reference values of the parameters needed for the
|
||||||
calculation taken from Suzuki et al.~\cite{SuzukiMeasday.etal.1987} and Measday
|
calculation taken from Suzuki et al.~\cite{SuzukiMeasday.etal.1987} and Measday
|
||||||
et al.~\cite{MeasdayStocki.etal.2007} are
|
et al.~\cite{MeasdayStocki.etal.2007} are
|
||||||
listed in Table~\ref{tab:mucap_pars}.
|
listed in \cref{tab:mucap_pars}.
|
||||||
\begin{table}[htb]
|
\begin{table}[htb]
|
||||||
\begin{center}
|
\begin{center}
|
||||||
\begin{tabular}{l l l}
|
\begin{tabular}{l l l}
|
||||||
@@ -505,7 +500,7 @@ listed in Table~\ref{tab:mucap_pars}.
|
|||||||
\end{table}
|
\end{table}
|
||||||
|
|
||||||
The muonic X-ray spectrum emitted from the active target is shown in
|
The muonic X-ray spectrum emitted from the active target is shown in
|
||||||
Figure~\ref{fig:sir2_xray}. The $(2p-1s)$ line is seen at
|
\cref{fig:sir2_xray}. The $(2p-1s)$ line is seen at
|
||||||
399.5~\si{\kilo\electronvolt}, 0.7~\si{\kilo\electronvolt}\ off from the
|
399.5~\si{\kilo\electronvolt}, 0.7~\si{\kilo\electronvolt}\ off from the
|
||||||
reference value of 400.177~\si{\kilo\electronvolt}. This discrepancy is within our
|
reference value of 400.177~\si{\kilo\electronvolt}. This discrepancy is within our
|
||||||
detector's resolution, and the calculated efficiency is
|
detector's resolution, and the calculated efficiency is
|
||||||
@@ -552,7 +547,7 @@ corrected for several effects:
|
|||||||
pulse time, and (b) the reset pulses of the transistor reset preamplifier.
|
pulse time, and (b) the reset pulses of the transistor reset preamplifier.
|
||||||
The effects of the two dead time could be calculated by examining the
|
The effects of the two dead time could be calculated by examining the
|
||||||
interval between two consecutive pulses on the germanium detector in
|
interval between two consecutive pulses on the germanium detector in
|
||||||
Figure~\ref{fig:sir2_ge_deadtime}.
|
\cref{fig:sir2_ge_deadtime}.
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.85\textwidth]{figs/sir2_ges_self_tdiff}
|
\includegraphics[width=0.85\textwidth]{figs/sir2_ges_self_tdiff}
|
||||||
@@ -592,7 +587,7 @@ corrected for several effects:
|
|||||||
\end{itemize}
|
\end{itemize}
|
||||||
|
|
||||||
The number of X-rays after applying all above corrections is 3293.5. The X-ray
|
The number of X-rays after applying all above corrections is 3293.5. The X-ray
|
||||||
intensity in Table~\ref{tab:mucap_pars} was normalised to the number of stopped
|
intensity in \cref{tab:mucap_pars} was normalised to the number of stopped
|
||||||
muons, so the number of stopped muons is:
|
muons, so the number of stopped muons is:
|
||||||
|
|
||||||
\begin{align}
|
\begin{align}
|
||||||
@@ -602,9 +597,9 @@ muons, so the number of stopped muons is:
|
|||||||
&= 9.03\times10^6 \nonumber
|
&= 9.03\times10^6 \nonumber
|
||||||
\end{align}
|
\end{align}
|
||||||
where $\epsilon_{(2p-1s)}$ is the calibrated absolute efficiency of the
|
where $\epsilon_{(2p-1s)}$ is the calibrated absolute efficiency of the
|
||||||
detector for the 400.177~keV line in Table~\ref{tab:xray_eff}, and
|
detector for the 400.177~keV line in \cref{tab:xray_eff}, and
|
||||||
$I_{(2p-1s)}$ is the probability of emitting this X-ray per stopped muon
|
$I_{(2p-1s)}$ is the probability of emitting this X-ray per stopped muon
|
||||||
(80.3\% from Table~\ref{tab:mucap_pars}).
|
(80.3\% from \cref{tab:mucap_pars}).
|
||||||
|
|
||||||
Taking the statistical uncertainty of the peak area, and systematic
|
Taking the statistical uncertainty of the peak area, and systematic
|
||||||
uncertainties from parameters of muon capture, the number of stopped muons
|
uncertainties from parameters of muon capture, the number of stopped muons
|
||||||
@@ -621,7 +616,7 @@ The number of nuclear captured muons is:
|
|||||||
\label{eqn:sir2_Ncapture}
|
\label{eqn:sir2_Ncapture}
|
||||||
\end{equation}
|
\end{equation}
|
||||||
where the $f_{\textrm{cap.Si}}$ is the probability of nuclear capture per
|
where the $f_{\textrm{cap.Si}}$ is the probability of nuclear capture per
|
||||||
stopped muon from Table~\ref{tab:mucap_pars}.
|
stopped muon from \cref{tab:mucap_pars}.
|
||||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
\subsection{Emission rate of charged particles}
|
\subsection{Emission rate of charged particles}
|
||||||
\label{sub:emission_rate_of_charged_particles}
|
\label{sub:emission_rate_of_charged_particles}
|
||||||
@@ -633,7 +628,7 @@ nuclear muon capture in~\eqref{eqn:sir2_Ncapture}:
|
|||||||
= \frac{149.9\times10^4}{7.25\times10^6} = 0.252
|
= \frac{149.9\times10^4}{7.25\times10^6} = 0.252
|
||||||
\end{equation}
|
\end{equation}
|
||||||
Uncertainties of this rate calculation are listed in
|
Uncertainties of this rate calculation are listed in
|
||||||
Table~\ref{tab:sir2_uncertainties}, including:
|
\cref{tab:sir2_uncertainties}, including:
|
||||||
\begin{itemize}
|
\begin{itemize}
|
||||||
\item uncertainties from number of charged particles, both statistical and
|
\item uncertainties from number of charged particles, both statistical and
|
||||||
systematic (from spectrum shape and fitting) ones are absorbed in the
|
systematic (from spectrum shape and fitting) ones are absorbed in the
|
||||||
@@ -690,7 +685,7 @@ So, the emission rate is:
|
|||||||
%\label{fig:sobottka_spec}
|
%\label{fig:sobottka_spec}
|
||||||
%\end{figure}
|
%\end{figure}
|
||||||
%The spectrum measured by Sobottka and Wills~\cite{SobottkaWills.1968} is
|
%The spectrum measured by Sobottka and Wills~\cite{SobottkaWills.1968} is
|
||||||
%reproduced in Figure~\ref{fig:sobottka_spec}, the spectral integral in the
|
%reproduced in \cref{fig:sobottka_spec}, the spectral integral in the
|
||||||
%energy region from 8 to 10~\si{\mega\electronvolt}\ is $2086.8 \pm 45.7$.
|
%energy region from 8 to 10~\si{\mega\electronvolt}\ is $2086.8 \pm 45.7$.
|
||||||
%The authors obtained the spectrum in a 4~\si{\micro\second}\ gate period which began
|
%The authors obtained the spectrum in a 4~\si{\micro\second}\ gate period which began
|
||||||
%1~\si{\micro\second}\ after a muon stopped, which would take 26.59\% of the emitted
|
%1~\si{\micro\second}\ after a muon stopped, which would take 26.59\% of the emitted
|
||||||
@@ -769,11 +764,11 @@ within a coincidence window of $\pm 0.5$~\si{\micro\second}\ around the thick
|
|||||||
silicon hit, the two hits are considered to belong to one particle with
|
silicon hit, the two hits are considered to belong to one particle with
|
||||||
$\Delta$E being the energy of the thin hit, and total E being the sum energy of
|
$\Delta$E being the energy of the thin hit, and total E being the sum energy of
|
||||||
the two hits. Particle identification is done using correlation between
|
the two hits. Particle identification is done using correlation between
|
||||||
$\Delta$E and E. Figure~\ref{fig:si16p_dedx_nocut} shows clearly visible banding
|
$\Delta$E and E. \cref{fig:si16p_dedx_nocut} shows clearly visible banding
|
||||||
structure. No cut on energy deposit or timing with respect to muon hit are
|
structure. No cut on energy deposit or timing with respect to muon hit are
|
||||||
applied yet.
|
applied yet.
|
||||||
|
|
||||||
With the aid from MC study (Figure~\ref{fig:pid_sim}), the banding on the
|
With the aid from MC study (\cref{fig:pid_sim}), the banding on the
|
||||||
$\Delta$E-E plots can be identified as follows:
|
$\Delta$E-E plots can be identified as follows:
|
||||||
\begin{itemize}
|
\begin{itemize}
|
||||||
\item the densest spot at the lower left conner belonged to electron hits;
|
\item the densest spot at the lower left conner belonged to electron hits;
|
||||||
@@ -804,13 +799,13 @@ $\Delta$E-E plots can be identified as follows:
|
|||||||
\end{figure}
|
\end{figure}
|
||||||
|
|
||||||
It is observed that the banding is more clearly visible in a log-log scale
|
It is observed that the banding is more clearly visible in a log-log scale
|
||||||
plots like in Figure~\ref{fig:si16p_dedx_cut_explain}, this suggests
|
plots like in \cref{fig:si16p_dedx_cut_explain}, this suggests
|
||||||
a geometrical cut on the logarithmic scale would be able to discriminate
|
a geometrical cut on the logarithmic scale would be able to discriminate
|
||||||
protons from other particles. The protons and deuterons bands are nearly
|
protons from other particles. The protons and deuterons bands are nearly
|
||||||
parallel to the $\ln(\Delta \textrm{E [keV]}) + \ln(\textrm{E [keV]})$ line,
|
parallel to the $\ln(\Delta \textrm{E [keV]}) + \ln(\textrm{E [keV]})$ line,
|
||||||
but have a slightly altered slope because $\ln(\textrm{E})$ is always greater
|
but have a slightly altered slope because $\ln(\textrm{E})$ is always greater
|
||||||
than $\ln(\Delta\textrm{E})$. The two parallel lines on
|
than $\ln(\Delta\textrm{E})$. The two parallel lines on
|
||||||
Figure~\ref{fig:si16p_dedx_cut_explain} suggest a check of
|
\cref{fig:si16p_dedx_cut_explain} suggest a check of
|
||||||
$\ln(\textrm{E}) + 0.85\times\ln(\Delta \textrm{E})$ could tell
|
$\ln(\textrm{E}) + 0.85\times\ln(\Delta \textrm{E})$ could tell
|
||||||
protons from other particles.
|
protons from other particles.
|
||||||
|
|
||||||
@@ -829,11 +824,11 @@ $\ln(\textrm{E}) < 9$, which corresponds to $\textrm{E} < 8$~MeV.
|
|||||||
|
|
||||||
The cut of $\ln(\textrm{E}) < 9$ is applied first, then
|
The cut of $\ln(\textrm{E}) < 9$ is applied first, then
|
||||||
$\ln(\textrm{E})+ 0.85\times\ln(\Delta \textrm{E}) $ is plotted as
|
$\ln(\textrm{E})+ 0.85\times\ln(\Delta \textrm{E}) $ is plotted as
|
||||||
Figure~\ref{fig:si16p_loge+logde}. The protons make a clear peak in the region
|
\cref{fig:si16p_loge+logde}. The protons make a clear peak in the region
|
||||||
between 14 and 14.8, the next peak at 15 corresponds to deuteron.
|
between 14 and 14.8, the next peak at 15 corresponds to deuteron.
|
||||||
Imposing the
|
Imposing the
|
||||||
$14<\ln(\textrm{E})+ 0.85\times\ln(\Delta \textrm{E})<14.8$ cut,
|
$14<\ln(\textrm{E})+ 0.85\times\ln(\Delta \textrm{E})<14.8$ cut,
|
||||||
the remaining proton band is shown on Figure~\ref{fig:si16p_proton_after_ecut}.
|
the remaining proton band is shown on \cref{fig:si16p_proton_after_ecut}.
|
||||||
|
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
@@ -854,7 +849,7 @@ the remaining proton band is shown on Figure~\ref{fig:si16p_proton_after_ecut}.
|
|||||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
\subsection{Number of muon captures}
|
\subsection{Number of muon captures}
|
||||||
\label{sub:number_stopped_muons}
|
\label{sub:number_stopped_muons}
|
||||||
The X-ray spectrum from this silicon target on Figure~\ref{fig:si16_xray} is
|
The X-ray spectrum from this silicon target on \cref{fig:si16_xray} is
|
||||||
significantly noisier than the previous data set of SiR2, suffers from both
|
significantly noisier than the previous data set of SiR2, suffers from both
|
||||||
lower statistics and a more relaxed muon definition. The peak of $(2p-1s)$
|
lower statistics and a more relaxed muon definition. The peak of $(2p-1s)$
|
||||||
X-ray at 400.177~keV can still be recognised but on a very high background. The
|
X-ray at 400.177~keV can still be recognised but on a very high background. The
|
||||||
@@ -881,7 +876,7 @@ reducing the background level under the 400.177 keV peak by about one third.
|
|||||||
Using the same procedure on the region from 396 to 402 keV (without
|
Using the same procedure on the region from 396 to 402 keV (without
|
||||||
self-absorption correction since this is a thin target), the number of
|
self-absorption correction since this is a thin target), the number of
|
||||||
X-rays recorded and the number of captures are shown in
|
X-rays recorded and the number of captures are shown in
|
||||||
Table~\ref{tab:si16p_ncapture_cal}.
|
\cref{tab:si16p_ncapture_cal}.
|
||||||
\begin{table}[htb]
|
\begin{table}[htb]
|
||||||
\begin{center}
|
\begin{center}
|
||||||
\begin{tabular}{l l c c c}
|
\begin{tabular}{l l c c c}
|
||||||
@@ -920,8 +915,8 @@ Table~\ref{tab:si16p_ncapture_cal}.
|
|||||||
To check the origin of the protons recorded, lifetime measurements were made by
|
To check the origin of the protons recorded, lifetime measurements were made by
|
||||||
cutting on time difference between a hit on one thick silicon and the muon
|
cutting on time difference between a hit on one thick silicon and the muon
|
||||||
hit. Applying the time cut in 0.5~\si{\micro\second}\ time steps on the proton
|
hit. Applying the time cut in 0.5~\si{\micro\second}\ time steps on the proton
|
||||||
events in Figure~\ref{fig:si16p_proton_after_ecut}, the number of surviving
|
events in \cref{fig:si16p_proton_after_ecut}, the number of surviving
|
||||||
protons on each arm are plotted on Figure~\ref{fig:si16p_proton_lifetime}. The
|
protons on each arm are plotted on \cref{fig:si16p_proton_lifetime}. The
|
||||||
curves show decay constants of $762.9 \pm 13.7$~\si{\nano\second}\ and $754.6 \pm
|
curves show decay constants of $762.9 \pm 13.7$~\si{\nano\second}\ and $754.6 \pm
|
||||||
11.9$,
|
11.9$,
|
||||||
which are consistent with the each other, and with mean life time of muons in
|
which are consistent with the each other, and with mean life time of muons in
|
||||||
@@ -939,7 +934,7 @@ The fits are consistent with lifetime of muons in silicon in from after 500~ns,
|
|||||||
before that, the time constants are shorter ($655.9\pm 9.9$ and $731.1\pm8.9$)
|
before that, the time constants are shorter ($655.9\pm 9.9$ and $731.1\pm8.9$)
|
||||||
indicates the contamination from muon captured on material with higher $Z$.
|
indicates the contamination from muon captured on material with higher $Z$.
|
||||||
Therefore a timing cut from 500~ns is used to select good silicon events, the
|
Therefore a timing cut from 500~ns is used to select good silicon events, the
|
||||||
remaining protons are shown in Figure~\ref{fig:si16p_proton_ecut_500nstcut}.
|
remaining protons are shown in \cref{fig:si16p_proton_ecut_500nstcut}.
|
||||||
The spectra have a low energy cut off at 2.5~MeV because protons with energy
|
The spectra have a low energy cut off at 2.5~MeV because protons with energy
|
||||||
lower than that could not pass through the thin silicon to make the cuts as the
|
lower than that could not pass through the thin silicon to make the cuts as the
|
||||||
range of 2.5~MeV protons in silicon is about 68~\si{\micro\meter}.
|
range of 2.5~MeV protons in silicon is about 68~\si{\micro\meter}.
|
||||||
@@ -954,7 +949,7 @@ range of 2.5~MeV protons in silicon is about 68~\si{\micro\meter}.
|
|||||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
\subsection{Proton emission rate from the silicon target}
|
\subsection{Proton emission rate from the silicon target}
|
||||||
\label{sub:proton_emission_rate_from_the_silicon_target}
|
\label{sub:proton_emission_rate_from_the_silicon_target}
|
||||||
The number of protons in Figure~\ref{fig:si16p_proton_ecut_500nstcut} is
|
The number of protons in \cref{fig:si16p_proton_ecut_500nstcut} is
|
||||||
counted from 500~ns after the muon event, where the survival rate is
|
counted from 500~ns after the muon event, where the survival rate is
|
||||||
$e^{-500/758} = 0.517$.
|
$e^{-500/758} = 0.517$.
|
||||||
|
|
||||||
@@ -974,7 +969,7 @@ The emission rate per muon capture is:
|
|||||||
&= \dfrac{2.625 \times 10^5}{6.256\times10^6} \nonumber\\
|
&= \dfrac{2.625 \times 10^5}{6.256\times10^6} \nonumber\\
|
||||||
&= 4.20\times10^{-2}\nonumber
|
&= 4.20\times10^{-2}\nonumber
|
||||||
\end{align}
|
\end{align}
|
||||||
The proton spectra on the Figure~\ref{fig:si16p_proton_ecut_500nstcut} and the
|
The proton spectra on the \cref{fig:si16p_proton_ecut_500nstcut} and the
|
||||||
emission rate are only effective ones, since the energy of protons are modified
|
emission rate are only effective ones, since the energy of protons are modified
|
||||||
by energy loss in the target, and low energy protons could not escape the
|
by energy loss in the target, and low energy protons could not escape the
|
||||||
target. Therefore further corrections are needed for both rate and spectrum of
|
target. Therefore further corrections are needed for both rate and spectrum of
|
||||||
@@ -989,11 +984,11 @@ The uncertainty of the emission rate could come from several sources:
|
|||||||
background under the X-ray peak (5.5\%) and the efficiency calibration
|
background under the X-ray peak (5.5\%) and the efficiency calibration
|
||||||
\item number of protons: efficiency of the cuts in energy, impacts of the
|
\item number of protons: efficiency of the cuts in energy, impacts of the
|
||||||
timing resolution on timing cut. The energy cuts' contribution should be
|
timing resolution on timing cut. The energy cuts' contribution should be
|
||||||
small since it can be seen from Figure~\ref{fig:si16p_loge+logde}, the peak
|
small since it can be seen from \cref{fig:si16p_loge+logde}, the peak
|
||||||
of protons is strong and well separated from others. The uncertainty in
|
of protons is strong and well separated from others. The uncertainty in
|
||||||
timing contribution is significant because all the timing done in this
|
timing contribution is significant because all the timing done in this
|
||||||
analysis was on the peak of the slow signals. As it is clear from the
|
analysis was on the peak of the slow signals. As it is clear from the
|
||||||
Figure~\ref{fig:tme_sir_prompt_rational}, the timing resolution of the
|
\cref{fig:tme_sir_prompt_rational}, the timing resolution of the
|
||||||
silicon detector could not be better than 100~ns. Putting $\pm100$~ns into
|
silicon detector could not be better than 100~ns. Putting $\pm100$~ns into
|
||||||
the timing cut could change the survival rate of proton by about
|
the timing cut could change the survival rate of proton by about
|
||||||
$1-e^{-100/758} \simeq 13\%$. Also, the low statistics contributes a few
|
$1-e^{-100/758} \simeq 13\%$. Also, the low statistics contributes a few
|
||||||
@@ -1024,7 +1019,7 @@ By using only the lower limit on
|
|||||||
$\ln(\textrm{E}) + 0.85\times\ln(\Delta \textrm{E})$, the heavy charged
|
$\ln(\textrm{E}) + 0.85\times\ln(\Delta \textrm{E})$, the heavy charged
|
||||||
particles can be selected. These particles also show a lifetime that is
|
particles can be selected. These particles also show a lifetime that is
|
||||||
consistent with that of muons in silicon
|
consistent with that of muons in silicon
|
||||||
(Figure~\ref{fig:si16p_allparticle_lifetime}).
|
(\cref{fig:si16p_allparticle_lifetime}).
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.85\textwidth]{figs/si16p_allparticle_lifetime}
|
\includegraphics[width=0.85\textwidth]{figs/si16p_allparticle_lifetime}
|
||||||
@@ -1041,7 +1036,7 @@ The ratio between the number of protons and other particles at 500~ns is $(1927
|
|||||||
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
%\subsection{Rate and spectrum correction}
|
%\subsection{Rate and spectrum correction}
|
||||||
%\label{sub:proton_spectrum_deconvolution}
|
%\label{sub:proton_spectrum_deconvolution}
|
||||||
%The proton spectra on the Figure~\ref{fig:si16p_proton_ecut_500nstcut} and the
|
%The proton spectra on the \cref{fig:si16p_proton_ecut_500nstcut} and the
|
||||||
%emission rate are only effective ones, since the energy of protons are modified
|
%emission rate are only effective ones, since the energy of protons are modified
|
||||||
%by energy loss in the target, and low energy protons could not escape the
|
%by energy loss in the target, and low energy protons could not escape the
|
||||||
%target. Therefore corrections are needed for both rate and spectrum of protons.
|
%target. Therefore corrections are needed for both rate and spectrum of protons.
|
||||||
@@ -1054,7 +1049,7 @@ The ratio between the number of protons and other particles at 500~ns is $(1927
|
|||||||
%The initial spatial distribution of protons is inferred from the muon beam
|
%The initial spatial distribution of protons is inferred from the muon beam
|
||||||
%momentum using Monte Carlo simulation, and available measured data in momentum
|
%momentum using Monte Carlo simulation, and available measured data in momentum
|
||||||
%scanning runs. The response function for this thin silicon target is shown in
|
%scanning runs. The response function for this thin silicon target is shown in
|
||||||
%Figure~\ref{fig:si16p_toyMC}.
|
%\cref{fig:si16p_toyMC}.
|
||||||
%\begin{figure}[htb]
|
%\begin{figure}[htb]
|
||||||
%\centering
|
%\centering
|
||||||
%\includegraphics[width=0.85\textwidth]{figs/si16p_toyMC}
|
%\includegraphics[width=0.85\textwidth]{figs/si16p_toyMC}
|
||||||
@@ -1069,7 +1064,7 @@ The ratio between the number of protons and other particles at 500~ns is $(1927
|
|||||||
%The Bayesian method is chosen because it tends to be fast, typical number of
|
%The Bayesian method is chosen because it tends to be fast, typical number of
|
||||||
%iterations is from 4--8.
|
%iterations is from 4--8.
|
||||||
|
|
||||||
%Figure~\ref{fig:si16p_unfold_train} presented results of two tests unfolding with
|
%\cref{fig:si16p_unfold_train} presented results of two tests unfolding with
|
||||||
%two distributions of initial energy, a Gaussian distribution and
|
%two distributions of initial energy, a Gaussian distribution and
|
||||||
%a parameterized function in~\eqref{eqn:EH_pdf}. The numbers of protons obtained
|
%a parameterized function in~\eqref{eqn:EH_pdf}. The numbers of protons obtained
|
||||||
%from the tests show agreement with the generated numbers.
|
%from the tests show agreement with the generated numbers.
|
||||||
@@ -1084,8 +1079,8 @@ The ratio between the number of protons and other particles at 500~ns is $(1927
|
|||||||
%\end{figure}
|
%\end{figure}
|
||||||
|
|
||||||
%Finally, the unfolding is applied on the spectra in
|
%Finally, the unfolding is applied on the spectra in
|
||||||
%Figure~\ref{si16p_proton_spec}, the results are shown in
|
%\cref{si16p_proton_spec}, the results are shown in
|
||||||
%Figure~\ref{si16p_unfold_meas}.
|
%\cref{si16p_unfold_meas}.
|
||||||
%\begin{figure}[htb]
|
%\begin{figure}[htb]
|
||||||
%\centering
|
%\centering
|
||||||
%\includegraphics[width=0.85\textwidth]{figs/si16p_unfold_meas}
|
%\includegraphics[width=0.85\textwidth]{figs/si16p_unfold_meas}
|
||||||
@@ -1127,7 +1122,7 @@ passive silicon runs were applied.
|
|||||||
\subsection{The number of stopped muons}
|
\subsection{The number of stopped muons}
|
||||||
\label{sub:the_number_of_stopped_muons}
|
\label{sub:the_number_of_stopped_muons}
|
||||||
The X-ray spectrum on the germanium detector is shown on
|
The X-ray spectrum on the germanium detector is shown on
|
||||||
Figure~\ref{fig:al100_ge_spec}.
|
\cref{fig:al100_ge_spec}.
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=0.85\textwidth]{figs/al100_ge_spec}
|
\includegraphics[width=0.85\textwidth]{figs/al100_ge_spec}
|
||||||
@@ -1153,7 +1148,7 @@ target are:
|
|||||||
\label{sub:particle_identification}
|
\label{sub:particle_identification}
|
||||||
Using the same charged particle selection
|
Using the same charged particle selection
|
||||||
procedure and the cuts on $\ln(\textrm{E})$ and $\ln(\Delta\textrm{E})$, the
|
procedure and the cuts on $\ln(\textrm{E})$ and $\ln(\Delta\textrm{E})$, the
|
||||||
proton energy spectrum is shown in Figure~\ref{fig:al100_proton_spec}.
|
proton energy spectrum is shown in \cref{fig:al100_proton_spec}.
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
\includegraphics[width=1\textwidth]{figs/al100_selection}
|
\includegraphics[width=1\textwidth]{figs/al100_selection}
|
||||||
@@ -1163,13 +1158,13 @@ proton energy spectrum is shown in Figure~\ref{fig:al100_proton_spec}.
|
|||||||
\end{figure}
|
\end{figure}
|
||||||
|
|
||||||
The lifetime of these protons are shown in
|
The lifetime of these protons are shown in
|
||||||
Figure~\ref{fig:al100_proton_lifetime}, the fitted decay constant on the right
|
\cref{fig:al100_proton_lifetime}, the fitted decay constant on the right
|
||||||
arm is consistent with the reference value of $864 \pm 2$~\si{\nano\second}~\cite{}.
|
arm is consistent with the reference value of $864 \pm 2$~\si{\nano\second}~\cite{}.
|
||||||
But the left arm gives $918 \pm 16.1$~\si{\nano\second}, significantly larger than
|
But the left arm gives $918 \pm 16.1$~\si{\nano\second}, significantly larger than
|
||||||
the reference value.
|
the reference value.
|
||||||
%The longer lifetime suggested some contributions from
|
%The longer lifetime suggested some contributions from
|
||||||
%other lighter materials, one possible source is from muons captured on the back
|
%other lighter materials, one possible source is from muons captured on the back
|
||||||
%side of the collimator (Figure~\ref{fig:alcap_setup_detailed}).
|
%side of the collimator (\cref{fig:alcap_setup_detailed}).
|
||||||
%For this reason, the emission rate calculated from the left arm will be taken as upper
|
%For this reason, the emission rate calculated from the left arm will be taken as upper
|
||||||
%limit only.
|
%limit only.
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
@@ -1185,7 +1180,7 @@ and the decay constant on the SiL1-1 alone was nearly about 1000~\si{\micro\seco
|
|||||||
The reason for this behaviour is not known yet. For this emission rate
|
The reason for this behaviour is not known yet. For this emission rate
|
||||||
calculation, this channel is discarded and the rate on the left arm is scaled
|
calculation, this channel is discarded and the rate on the left arm is scaled
|
||||||
with a factor of 4/3. The proton spectrum from the aluminium target is plotted
|
with a factor of 4/3. The proton spectrum from the aluminium target is plotted
|
||||||
on Figure~\ref{fig:al100_proton_spec_wosil11}.
|
on \cref{fig:al100_proton_spec_wosil11}.
|
||||||
|
|
||||||
\begin{figure}[htb]
|
\begin{figure}[htb]
|
||||||
\centering
|
\centering
|
||||||
|
|||||||
@@ -52,11 +52,11 @@ bookmarks
|
|||||||
\RequirePackage{verbatim}
|
\RequirePackage{verbatim}
|
||||||
\RequirePackage{lipsum}
|
\RequirePackage{lipsum}
|
||||||
\RequirePackage{datatool}
|
\RequirePackage{datatool}
|
||||||
\RequirePackage[capitalise]{cleveref}
|
|
||||||
\RequirePackage[final]{listings}
|
\RequirePackage[final]{listings}
|
||||||
\RequirePackage{xfrac}
|
\RequirePackage{xfrac}
|
||||||
%% Units
|
%% Units
|
||||||
\RequirePackage[]{siunitx}
|
\RequirePackage[]{siunitx}
|
||||||
|
\RequirePackage{hepnames}
|
||||||
%% Various fonts ...
|
%% Various fonts ...
|
||||||
%\RequirePackage[T1]{fontenc}
|
%\RequirePackage[T1]{fontenc}
|
||||||
%\RequirePackage{charter}
|
%\RequirePackage{charter}
|
||||||
@@ -76,6 +76,8 @@ bookmarks
|
|||||||
%\linespread{1.025} % Palatino leads a little more leading
|
%\linespread{1.025} % Palatino leads a little more leading
|
||||||
%\usepackage[small]{eulervm}
|
%\usepackage[small]{eulervm}
|
||||||
|
|
||||||
|
|
||||||
|
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
||||||
\RequirePackage{tabularx}
|
\RequirePackage{tabularx}
|
||||||
\RequirePackage{color}
|
\RequirePackage{color}
|
||||||
\RequirePackage{pifont}
|
\RequirePackage{pifont}
|
||||||
@@ -270,3 +272,6 @@ bookmarks
|
|||||||
\endgroup%
|
\endgroup%
|
||||||
}
|
}
|
||||||
\renewcommand{\maketitle}[1]{\titlepage{}}
|
\renewcommand{\maketitle}[1]{\titlepage{}}
|
||||||
|
|
||||||
|
%% Cleveref should be the last package to not be messed up by others
|
||||||
|
\RequirePackage[noabbrev]{cleveref}
|
||||||
|
|||||||
@@ -33,8 +33,8 @@ for the COMET experiment}
|
|||||||
%\input{chapters/chap2_mu_e_conv}
|
%\input{chapters/chap2_mu_e_conv}
|
||||||
%\input{chapters/chap3_comet}
|
%\input{chapters/chap3_comet}
|
||||||
%\input{chapters/chap4_alcap_phys}
|
%\input{chapters/chap4_alcap_phys}
|
||||||
%\input{chapters/chap5_alcap_setup}
|
\input{chapters/chap5_alcap_setup}
|
||||||
\input{chapters/chap6_analysis}
|
%\input{chapters/chap6_analysis}
|
||||||
%\input{chapters/chap7_results}
|
%\input{chapters/chap7_results}
|
||||||
|
|
||||||
\begin{backmatter}
|
\begin{backmatter}
|
||||||
|
|||||||
Reference in New Issue
Block a user