Transcript Sci-Fi Tracker Performance • Software Status – RF background simulation – Beam simulation – Reconstruction – Data sample • • • • Expected performance Performance Emittance calculation Summary M.

Sci-Fi Tracker Performance
• Software Status
– RF background
simulation
– Beam simulation
– Reconstruction
– Data sample
•
•
•
•
Expected performance
Performance
Emittance calculation
Summary
M. Ellis - MICE Collaboration Meeting - Wednesday 27th October 2004
1
RF Background Simulation
• As described by Rikard at VC of 22/9/04
• Software used from tag mice-0-9-10
• Background generated in 100 jobs of 100
events each on CSF farm at RAL.
• Total time to produce 10k events on CSF
was over 4 days!
• Output files merged into one file that is then
used as input for each of the 10k event
samples.
2
TURTLE Beam
• Added as G4MICE option
• In CVS as tag mice-0-9-11
• 720,000 events produced using the
“June04” configuration were provided by
Kevin Tilley
• Sample broken up into 72 sets of 10,000
events each for submission as jobs on
CSF farm at RAL
3
Reconstruction
• TDC aspect of Digitisation is now more realistic
(exact details of discriminators still to be
perfected).
• Duplets (space point made from 2 views in a
station) are now reconstructed and used in the
pattern recognition.
• Individual clusters are used as separate
measurements in the Kalman track fit.
• Still need to add the use of a field map
(particularly with the more detailed simulation now
in use) – currently assuming a fixed field!
4
Data Sample
• Four sets of events processed:
– Various sets of 20k events to study effects of multiple
scattering, non-uniform field, etc...
– 720k events with all physics processes, but no RF
background
– 720k events with all physics processes and overlaid
RF background events
– 7k events with 100x nominal RF background
• All performance plots are from the sample with
nominal RF and all physics processes.
• A summary table at the end will show differences
between performance with and without RF
background
5
Expected Performance
• Expected momentum
resolution based on
“back of the envelope”
calculations.
• Determine effect that
multiple scattering will
have on resolution.
• Predict resolution as a
function of PT and PZ
6
No Multiple Scattering - PT
sR
R
PT = Q B · R
sPT / PT = sR / R
sPT = Q B R sR / R
sPT = 1.202 x sR
sR = 0.427 * 3.5 / √12
sR = 0.431 mm
 sPT = 0.52 MeV/c
7
PT Resolution
• From the previous slide, it
is clear that the PT
resolution should be flat as
a function of PT: sPT = Q B
sR
• So long as the track does
not have an excessively
high PZ (resulting in the
projection in XY being a
small fraction of a circle),
the PT resolution should
also be flat in PZ
8
No Multiple Scattering - PZ
f
a
z
tan(a) = df / dz
PZ = PT / tan(a)
9
PZ Resolution
• PZ = PT / tan(a)
• The resolution in f depends on the
radius of curvature:
stan(a) = k / PT
• Therefore the uncertainty on PZ
depends on the uncertainty in PT (which
is fixed) and that in tan(a) in quadrature
• For cases of High PT, or Low PZ, the
resolution in PT will dominate over the
resolution in tan(a):
sPZ = PZ x sPT / PT
• High PT (100 MeV/c):
sPZ = 0.52 / 100 x 225 = 1.15 MeV/c
• Low PZ (150 MeV/c):
sPZ = 0.52 / 50 x 150 = 1.56 MeV/c
sPZ2 = (k1 / PT)2 + k22
sPZ2 = k12 + (k2 + k3 PZ)2
10
With Multiple Scattering
Dz = 1.9 mm
X0 = 42 cm → x/X0 = 0.45%
Qms = √2 x 13.6 MeV / bcp x 0.053
Not to scale!
Qms
100 < p < 350 MeV/c
68.76 < bcp < 335.1 MeV
V X W
3.1 < Qms < 14.9 mrad
11
Point Resolution with MCS
• 3.1 < Qms < 14.9 mrad
• Station is 1.9 mm thick
• Mean total momentum is 240 MeV/c,
giving a typical Qms = 5 mrad.
• MCS produces additional error on the
point resolution of between 6 and 30 mm.
• MCS has no appreciable effect on the
resolution of measuring an individual point
12
Multiple Scattering - PT
Typical distance
between planes
= 175 mm
Error on position
= 175 * 5 mrad
= 0.875 mm
Resolution in R
becomes 0.97 mm
sPT = 1.202 x sR
sPT = 1.16 MeV/c
13
Multiple Scattering - PZ
• For case of high PT and high P, expect sPZ to
depend just on new sPT:
sPZ = PZ x sPT / PT
= 160 x 1.16 / 100
= 1.86 MeV/c
• In general, the effects of multiple scattering will
increase as P drops, so expect resolution to
approach no multiple scattering level at high P
and PT, and get worse as the momentum
drops.
14
Performance
• Position resolution
– X, Y
• Momentum pulls
– PX, PY and PZ
• Momentum resolution
– PT, PZ
– sPT versus PT, sPT vs PZ
– sPZ versus PT, sPZ vs PZ
• “Primes” resolution
– X’, Y’, T’
• Efficiency and Purity
15
X Position Resolution
RMS = 48.49 mm
RMS = 0.391 mm
16
Y Position Resolution
RMS = 57.05 mm
RMS = 0.392 mm
17
PX PY and PZ Pulls
18
PT Resolution
RMS = 28.65 MeV/c
RMS = 1.75 MeV/c
19
PZ Resolution
RMS = 25.65 MeV/c
RMS = 2.41 MeV/c
20
Resolution vs PT
21
Resolution vs PZ
22
X’ Resolution
RMS = 182.1 mrad
RMS = 8.00 mrad
23
Y’ Resolution
RMS = 172.3 mrad
RMS = 7.91 mrad
24
T’ Resolution
RMS = 5.48 x 10-2
RMS = 5.06 x 10-3
25
Efficiency vs PT
26
Efficiency vs PZ
27
Efficiency vs PT / PZ
28
Purity vs PT
29
Purity vs PZ
30
Purity vs PT / PZ
31
Emittance Calculation
• Analysis code developed by Chris:
– Trace and phase space
– Monte Carlo truth, reconstructed parameters, virtual
planes, ICOOL output files...
– Can calculate 2D, 4D, 6D emittance, apply cuts, reweighting, etc...
– Performance checked against ecalc9f
• For each 10,000 event run, calculate one value
of emittance from Monte Carlo truth information
and one from reconstructed track information.
• Determine resolution and bias in 4D (XY)
emittance (TOF unavailable, hence no 6D
emittance).
32
Emittance Resolution
33
Performance Summary:
RMS of
True
RMS
resolution
(no RF)
RMS
resolution
(with RF)
RMS
resolution
(100x RF)
% RMS/RMS
(no RF)
% RMS/RMS
(with RF)
% RMS/RMS
(100x RF)
X (mm)
48.49
0.390
0.391
0.384
0.80
0.81
0.79
Y (mm)
57.05
0.391
0.392
0.389
0.69
0.69
0.68
PT
(MeV/c)
28.65
1.75
1.75
1.69
6.11
6.11
5.90
PZ
(MeV/c)
25.65
2.41
2.41
2.43
9.40
9.40
9.47
X’ (mrad)
182.1
8.02
8.00
8.08
4.40
4.39
4.44
Y’ (mrad)
172.3
7.90
7.91
7.58
4.59
4.59
4.40
t’
(x10-3)
5.48
0.506
0.506
0.519
9.23
9.23
9.47
Efficiency in %
Efficiency out %
Purity in %
Purity out %
e4D bias %
e4D resolution %
No RF
99.99(85)
99.81(17)
99.15(12)
99.17(66)
-0.121
0.060
With RF
99.99(85)
99.83(43)
99.13(14)
99.17(57)
-0.138
0.062
100x RF
100.(00)
99.(73)
95.(28)
96.(47)
N/A
N/A