2
\label{Sect:Definitions}
4
\subsection{Labelling of upstream and downstream trackers}
5
\label{SubSect:TkrLabel}
7
The labels for two trackers are:
9
{\rm Upstream~tracker} & \rightarrow & {\rm Tracker \# 1} \nonumber \\
10
{\rm Downstream~tracker} & \rightarrow & {\rm Tracker \# 2} \nonumber
13
\subsection{Station numbering}
14
\label{SubSect:StnNumbering}
16
The TRD \cite{TRD} defines the station ``labelling'' of the
17
stations in relation to the focus-coil module that is immediately
18
downstream of tracker 1 or, equivalently, immediately upstream of
20
The station closest to the focus-coil module in question is labelled
22
The label then increases such that station 5 is the station
23
closest to the optical patch panel.
24
The scheme is summarised in table \ref{Tab:StnNum} and figure
28
Station numbering scheme.
29
The ``label'' of the stations that make up a MICE tracker runs
31
The location of the station in relation to the patch panel and the
32
absorber is reported in the column labelled ``Location''.
35
\begin{tabular}{|l|r|}
37
{\bf Location} & {\bf Label} \\
39
Closest to absorber (furthest from patch panel) & 1 \\
43
Furthest from absorber (closest to patch panel) & 5 \\
49
\includegraphics[width=0.7\textwidth]%
50
{02-Definitions/Figures/StnNum.eps}
53
Schematic diagram of the MICE tracker.
54
The five stations are shown supported by the carbon-fibre space
55
frame, with fibres omitted for clarity.
56
The station numbering scheme is indicated together with the
57
direction in which the clear-fibre light-guides leave the tracking
63
\subsection{Doublet layer}
64
\label{SubSect:DblLyr}
66
Each station consists of three ``doublet layers'' of 350\,$\mu$m
67
scintillating fibres glued onto a carbon-fibre station body.
68
The doublet layers are arranged such that the fibres in one layer run
69
at an angle of 120$^\circ$ to the fibres in each of the other layers as
70
shown in figure \ref{Fig:DblLyr}a.
71
The arrangement of the fibres within a doublet layer is shown in figure
73
The configuration of the seven fibres ganged for readout via a
74
single clear-fibre light-guide is also indicated.
75
The construction of the doublet layer is described in
76
\cite{TrackerPaper} along with the specification of the various
77
materials of which it is composed.
80
\includegraphics[width=0.95\textwidth]
81
{02-Definitions/Figures/doublet-layer.eps}
84
(a) Arrangement of the doublet layers in the scintillating-fibre
86
The outer circle shows the solenoid bore while the inner circle
87
shows the limit of the active area of the tracker.
88
The grey, blue, and green regions indicate the direction that the
89
individual 350\,$\mu$m fibres run (moving outward from the centre) in
90
the $u$, $v$, and $w$ planes respectively.
91
(b) Detail of the arrangement of the scintillating fibres in a
93
The fibre spacing and the fibre pitch are indicated on the
94
right-hand end of the figure in \,$\mu$m.
95
The pattern of seven fibres ganged for readout in a single
96
clear-fibre light-guide is shown in red.
97
The sheet of Mylar glued to the doublet layer is indicated.
102
\subsubsection{Doublet-layer numbering}
103
\label{SubSubSect:DblNmbrng}
105
The order in which the doublet layers were glued onto the station body
106
is shown in figure \ref{Fig:DblLyrOrder}.
107
The $u$ layer was glued to the station body first.
108
The doublet layer was glued such that the ``fibre side'' of the
109
doublet layer was glued to the station body; i.e. the mylar sheet
110
faces away from the station body.
111
The $w$ layer was then glued onto the outer surface of the $u$ layer.
112
The fibre side of the $w$ layer was glued to the mylar sheet of the
113
$u$ layer such that the mylar sheet of the ``w'' layer also faces away
114
from the station body.
115
Finally, the $v$ layer was glued onto the assembly.
116
The gluing arrangement was the same as for the $u$ and $w$ layers,
117
i.e. the mylar sheet of the $v$ layer also faces away from the station
119
The numbering of the layers, which follows the order in which
120
the layers were glued onto the station body, is summarised in table
121
\ref{Tab:DblLyrOrder}.
124
\includegraphics[width=0.55\linewidth]
125
{02-Definitions/Figures/doublet-layer-order.eps}
128
The order in which the doublet layers were glued onto the station
130
The station body is indicated by the solid black lines.
131
The $u$ layer (shown as the grey line) was glued to the station
133
The $w$ (indicated by the green line) was then glued onto the
134
outer surface of the $u$ layer.
135
The outer doublet layer, the $v$ layer (shown as the blue line)
136
was then glued onto the assembly.
137
The station reference surface and the direction of increasing $z$
138
are shown as the thin black lines.
140
\label{Fig:DblLyrOrder}
144
Doublet-layer numbering scheme.
145
The doublet-layer ``number'' runs from 0 to 2.
146
The correspondance between the doublet layer number and the
147
view is reported in the column labelled ``Doublet-layer number''.
149
\label{Tab:DblLyrOrder}
150
\begin{tabular}{|l|r|}
152
{\bf View} & {\bf Double-layer number} \\
161
\subsection{Fibre-channel numbering}
162
\label{SubSect:FbrNmbrng}
164
The numbering of the groups of seven fibres ganged for readout is
165
shown in figure \ref{Fig:FbrChnlNmbrng}.
166
With the mylar surface facing up, and with the tails leading out to
167
the station connectors taken to be at the bottom of the figure, the
168
fibre-channel increases from left to right.
169
The coordinate measured by the doublet layer ($u$, $v$ or $w$) is
170
taken to increase in the same direction as the channel number.
171
The origin of the measured coordinate is taken to be at the position
172
of the central fibre.
175
\includegraphics[width=0.75\linewidth]
176
{02-Definitions/Figures/fibre-channel-numbering.eps}
179
The order in which fibre channels (groups of seven fibres) are
181
The senstive surface of the doublet layer is indicated by the
183
The direction in which the fibres run is indicated by the vertical
185
The station optical connectors are taken to be at the bottom of
186
the figure as indicated.
187
With the mylar sheet taken to be facing up, fibre-channel number 1
188
is to the left of the central fibre.
189
The fibre-channel number increases from left to right.
190
The ``zero'' of the coordinate ($u$, $v$ or $w$ increases)
191
measured by the doublet layer is taken to be the position of the
193
The direction in which the coordinate measured by the double
194
layer increases is indicated by the red arrow.
196
\label{Fig:FbrChnlNmbrng}