Transcript Development of Tracking Systems for Low Energy Muons and

Status of the MICE SciFi Simulation
Edward McKigney
Imperial College London
• General Status
Outline
– 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
Track Parameters
y
(x0,y0)
0
r

B
z
x
 z
x  r sin(z  0 )  x0
y  r cos(z  0 )  y0
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
Seed Helix and Road Definition
5. 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
6. Any points with a 2
below the threshold
(100) are passed to the
track fit
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
Helix Fit
7. A helix fit is performed using one space point
from at least four stations
8. The track with the best track probability is kept
2
2
 xi  x( zi )   yi  y ( zi )   ti  t ( zi ) 
  
  

   
x
y
t

i 
  
  i 
2
2
Additional Modifications to
Tracking
• Reconstruction of tracks with three triplet
hits and two doublet hits
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.
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)
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 > 1 GeV)
– Cross check using straight through muons
• Final test is measurement of residuals from
five point tracks
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
Resolution for Transverse
Momentum (pt)
Distributions
from the
Berkeley
meeting
Multiplexed pt Resolution
multiplexing
7 fibers
together
reduces
pt resolution
by a factor
of about 1.5
compared
to the value
presented
at Berkeley
Thanks
to Dave
Colling
at IC for
generating
these
samples
on the
Grid
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
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
MuScat Calibration
All channels have
been calibrated
using photo-tube
noise events in
a self triggering
configuration
Calibrated Single PE Peak
Cosmic Ray Angular
Distributions
MuScat Cosmic Ray Events
An Air Shower?
A Muon?
Summary of D0 Tracking
• Tracking Performance
– Doublet layer hit efficiency is 98-99%
– Position resolution is 96 microns (preliminary)
• Dead Channels
– <200 out of 77,000 compromised fibers
(~0.25%)
– ~190 out 77,000 compromised VLPCs
(~0.25%)
• Noise
– Intrinsic VLPC noise << X-ray background
(see next slide)
VLPC Performance
(A. Bross)
VLPC (Visible Light Photon Counter) –
Cryogenic APD @ 9K
VLPC HISTE VI
– High QE 80%
– Low noise <5X104 Hz (@1.0 pe)
– High Rate capability
>40 MHz
– High production yield
70%
(vs. 27% projected)
Conclusions
• Most of the functionality to answer the
Review Committee’s questions has been
implemented
• Submitting jobs to the Grid is now possible,
and the process is being automated
• SciFi performance studies are underway