Status of the MICE SciFi Simulation

1
Status of the MICE SciFi Simulation

• Edward McKigney
• Imperial College London

2
Outline

• General Status
• Description of current reconstruction scheme
• Additional modifications required
• Review Panel Questions and Responses
• Current Results
• Multiplexing
• Inefficiency from dead fibers not completed
• Cross Talk for MICE SciFi
• A brief summary of MuScat Tracking
• A brief summary of D0 Tracking
• Conclusions

3
Track Parameters
y
?0
(x0,y0)
r
?
B
x
z
4
Space Point Reconstruction

1. For each tracker station, all fibers above the
   2.0 PE threshold are selected for processing
2. Doublet Clusters of adjacent fibers are formed
3. Space points are formed from the intersection of
   doublet clusters
4. Space points with at least one doublet cluster in
   each view are passed to the pattern recognition

Space Points
Accepted Space Points
5
Seed Helix and Road Definition

1. Sets of space points from three stations are used
   to define a helix, and if the momentum found is
   compatible with the beam, a search of the other
   stations is performed
2. Any points with a ?2 below the threshold (100)
   are passed to the track fit

6
Energy Loss Correction in the fit

• For a given set of track parameters, the track is
  propagated from the origin to the first plane,
  and the intersection of the track and plane is
  calculated, for comparison with the measured
  values
• Mean energy loss through the detector plane is
  calculated
• A new set of track parameters is calculated,
  based on the energy loss
• The process is repeated

7
Helix Fit

1. A helix fit is performed using one space point
   from at least four stations
2. The track with the best track probability is kept

8
Additional Modifications to Tracking

• Reconstruction of tracks with three triplet hits
  and two doublet hits

9
Questions from Review Panel

• Fibre tracker
• It seems essential to perform a full simulation
  of a tracker with five planes, including nominal
  inefficiency and assessment of the redundancy by
  simulation of the loss of readout dead fibres.
  The impact of noise and misalignment should also
  be assessed. What is the status of this
  simulation?
• Because of the cost saving by multiplexing, it is
  important to repeat the simulation in a
  realistically multiplexed arrangement.
• Will the main alignment be derived from straight
  through muons?
• Some documented information on the performance of
  the fibre tracker in the MUSCAT experiment would
  be useful.

10
Response

• The following functionality has been implemented
  and tested
• Simulation of a five station tracker
• Reconstruction of tracks in five station tracker
  with 4/5 and 5/5 stations hit, including energy
  loss correction
• Multiplexing of fibers per VLPC, up to 7
• VLPC noise
• Implemented, testing in progress
• Dead VLPCs and/or fibers
• Misalignment of stations (displacements
  implemented, no rotations yet)

11
Alignment Scheme

• Alignment comes in four parts
• Good mechanical alignment and repeatability
  engineered in from the beginning
• Survey for initial alignment
• Cosmics for final alignment (E gt 1 GeV)
• Cross check using straight through muons
• Final test is measurement of residuals from five
  point tracks

12
Performance Study List

• Comparison case
• No MUX, Dead Channels (beam and cosmics)
• Nominal MUX, Dead Channels(beam and cosmics)
• RF Background series (beam, nominal tracker)
• MUX series (beam, nominal tracker, RF Bkg)
• Dead Channel series (beam, nominal tracker, RF
  Bkg)
• Alignment series (cosmics, nominal tracker)
• Two parameter series as appropriate

Alex Tapper(IC), Julia Sedgbeer(IC), Akram Kahn
(Edinburgh)
All nominal except parameter varied for the
series
13
Resolution for Transverse Momentum (pt)
Distributions from the Berkeley meeting
14
Multiplexed pt Resolution
Thanks to Dave Colling at IC for generating
these samples on the Grid
multiplexing 7 fibers together reduces pt
resolution by a factor of about 1.5 compared
to the value presented at Berkeley
15
Cross Talk for MICE SciFi

• Use 3HF scintillator at high concentration (5000
  ppm)
• 3HF as primary fluor gives 95 of light and no
  cross-talk
• Cross Talk in optical system zero by engineering
  design
• No open paths for light to get from one fiber to
  another

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Summary of MuScat Tracking

• MuScat is now set up at TRIUMF, and the detector
  has been calibrated
• Full reconstruction, run control, data acqusition
  and data quality monitoring is in place and has
  been tested
• Data taking starts in the middle of April and
  continues into may
• Results are expected for NuFact03

17
MuScat Calibration
All channels have been calibrated using
photo-tube noise events in a self triggering
configuration
Calibrated Single PE Peak
18
Cosmic Ray Angular Distributions
19
MuScat Cosmic Ray Events
An Air Shower?
A Muon?
20
Summary of D0 Tracking

• Tracking Performance
• Doublet layer hit efficiency is 98-99
• Position resolution is 96 microns (preliminary)
• Dead Channels
• lt200 out of 77,000 compromised fibers (0.25)
• 190 out 77,000 compromised VLPCs (0.25)
• Noise
• Intrinsic VLPC noise ltlt X-ray background (see
  next slide)

21
VLPC Performance
(A. Bross)

• VLPC (Visible Light Photon Counter) Cryogenic
  APD _at_ 9K
• VLPC HISTE VI
• High QE 80
• Low noise lt5X104 Hz (_at_1.0 pe)
• High Rate capability
• gt40 MHz
• High production yield
• 70
• (vs. 27 projected)

22
Conclusions

• Most of the functionality to answer the Review
  Committees questions has been implemented
• Submitting jobs to the Grid is now possible, and
  the process is being automated
• SciFi performance studies are underway