Transcript Sci Fi Tracker Simulations Reminder of Goals and a new definition  No multiple scattering or “ganging”  No ganging  7 times ganging 

Sci Fi Tracker Simulations
Reminder of Goals and a new definition
 No multiple scattering or “ganging”
 No ganging
 7 times ganging
 Nominal configuration
 100 times nominal background
 Conclusions

Malcolm Ellis - Imperial College
London
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Goals and Definition



Demonstrate that the Sci Fi tracker can efficiently
and accurately reconstruct track parameters
required for an emittance measurement in the
presence of RF background under a realistic set of
assumptions for detector performance
Definition – we do not multiplex, the fibres are
just read out in bundles of 7, so I will refer to
“ganging”, if I ever say the word “multiplex”, or
you see “mux” it is really ganging.
Code used to produce these plots was committed
to the MICE CVS repository on Tuesday
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No Multiple Scattering
• Point resolution
determined exclusively
by d/12
•Ganging times 7
makes resolution 7
times worse
•This is the
configuration that had
been (accidentally)
presented at previous
meetings.
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No Ganging


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Multiple scattering is
now on in all future
plots
Point resolution is
dominated by effect
of m/s with no
ganging
Momentum resolution
is still good enough
for a cooling
measurement
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7 Fibre Ganging


Position and
momentum
resolution have
degraded slightly,
but no longer by
factor of 7
Use of “projector”
in Kalman package
will allow
improvement in
resolution per
plane
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Nominal Configuration
Dead Channels (0.25%) based on D0
experience
 Official background source equivalent to
estimate of rate based on Lab G tests.
 All relevant physics processes simulated
 7 times Ganging
 Full simulation, digitisation, pattern
recognition and track fitting/extrapolation

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Nominal Position Resolution
• X Resolution:
626 microns
•Y Resolution:
503 microns
• Difference between
X and Y is due to
orientation of fibres
in simulation (one set
of fibres lies parallel
to X axis, other two at
60 degrees either side
of the Y axis)
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Nominal PT and PL Resolution
•PT resolution:
1.3 MeV/c
3.3%
•PL resolution:
4.2 MeV/c
2.1%
• Both numbers will be
improved when a
complete description
of energy loss is added
to the track fit and the
fibres are included as
individual
measurements
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Emittance Measurement
In addition to X and Y resolutions, already
presented, we also need the quantities, X’,
Y’ and t’
 X’ = Px/Pz
 Y’ = Py/Pz
 T’ = E/Pz

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X’ Y’ and T’ Resolutions
•X’:
7 mrad
(4.5%)
•Y’:
6 mrad
(3.9%)
•T’:
0.0056
(0.5%)
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Pattern Recognition Efficiency
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Number of space points
in fitted track (or zero if
no track fitted)
Most of the time 5
space points are made
and fitted in track
With no dead channels
or background:
99.9 ± 0.1 %
Overall tracking
efficiency in nominal
situation:
99.0 ± 0.5 %
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100 Times Nominal Background

Based on a small statistics run, with 100
times the nominal background rate, the
various resolutions do not differ
significantly from those presented for the
nominal case.
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Conclusions

In the nominal configuration, with realistic
assumptions for all relevant properties and
processes, the SciFi tracker, consisting of 5
stations is able to reconstruct position,
momentum and other relevant quantities
with sufficient resolution (better than 5%) to
determine the emittance to the required
accuracy.
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