Transcript Impact parameter resolutions for ILC detector

Impact parameter resolution
study for ILC detector
Tomoaki Fujikawa (Tohoku university)
ACFA Workshop in Taipei
Nov. 11 2004
Outline
Study the pair e+e- background hit rate for vertex detector
with various B fields. (tool:CAIN,Jupiter)
Optimize the vertex detector radii for each B field.
Obtain the impact parameter resolutions with optimized radii.
(tool:TRACKERR)
Pair background hit rate study
Simulation tools
CAIN (for e+e- pair background (dominant) generation)

Monte-Carlo program for the beam-beam interaction.
(by Yokoya-san)
Included interactions are…
 Breit - Wheeler  +   e + + e  Bethe- Heitler
 + ` `  e + + e -
 Landau- Lifshitz ` ` + ` `  e + + e (` ` meansvirtualphoton)
・Jupiter (for pair background hit rate
estimation)
JLC Uniform Particle Interaction and Tracking EmulatoR.
GEANT4 based full simulator for ILC (under
construction…)
Beam parameters (input parameters for CAIN)
Beam parameters are similar to those in the TESLA TDR.
E CM  500GeV, Ne  2.01010 (/bunch),n b  2820(/train)
x  10( m),  y  0.03( m)
 x  553(nm ), y  5(nm),  z  0.3(m m)
L  3.4 1034 (/ cm2  s)
crossing angle = 7mrad.
Detector configuration (for the Jupiter)
Detector is constructed with the Beam pipe, Vertex
detector (Ladder construction), Intermediate tracker,
Mask, etc. and base geometry is “Old” one. (Namely,
designed for “Warm” machine.)
The configuration of the vertex detector
 theregion which has | cos | 0.9 are coverd
 T hickness 300m
 thedistancebetween each layeris 1.2cm(4 - layers)
 thedistancebetween beam pipe and innermostlayeris 0.4cm
These conditions are applied to estimate pair background hit
rate as first layer radius is varied.
Pair background hit rate for the vertex detector
1.hit point uniformity (for 1st. layer)
B = 3tesla, R1 = 1.2cm.
| cos |  0.9
Z vs. phi
Z
Hit distribution is uniformwithin| cos | 0.9 region.
We can use the average hit rate to estimate the occupancy.
2. Number of fired pixels per track hit (for 1st. layer)
(sensorpixelsize  25m  25m,
thicknessof thesensitiveregion  30m)
Number of fired pixels per 1
track passage is about 3.7.
(independent of radius and B
field)
Number of fired pixel per track hit
3. Determination of first layer radius

20 readouts per train

3.7 fired pixels per track hit

Pixel occupancy(%) = hit rate (/bunch/cm2)  0.326
Set the first layer radius such that its pixel
occupancy = 0.5%

First layer hit rate vs. first layer radius
3 tesla
4 tesla
fit function: f ( x)  p0  exp(- p1( x - p2)) / x + p3
0.5 % occupancy occurs at
R1  1.920 0.034cm (3 tesla)
R1  1.694 0.028cm (4 tesla)
R1  1.554 0.029cm (5 tesla)
5 tesla
Impact parameter resolutions
Use TRACKERR program (also momentum resolution).
Assume pions.
TRACKERR:
FORTRAN program to calculate tracking error matrix with
using cylindrically symmetric system.
Energy loss, energy loss fluctuation and multiple scattering
effects are included. Track fitting uses Kalman filter.
Detector configurations for TRACKERR
3 tesla
Beam pipe
(Be)
VTX
detector
(Si pixel)
IT (Si strip)
TPC
(Ar : CO 2 : CH 4
 93 : 2 : 5)
4 tesla
5 tesla
R bp  R VTX1 - 0.4 (cm), thickness(dBP)  500,250μm
distancebetween each layer  1.2cm(4layers),
σ  2m, thickness(dVT X)  300,100,50m
R VTX1  1.92cm
1.69cm
1.55cm
R IT1  R VTX4 + 3cm,distancebetween each layer  7cm (5layers),
σ rφ  10m, thickness 300m
σrφ  150m, Padsize : (x,y)  (2mm,6mm),R inner  45cm
R outer  200cm
160cm
130cm
Impact parameter resolutions of the r-phi plane
ex : dBP  250m, dVT X  50m case
Impact parameter resolutions are mostly the
same for each magnetic field case. (true for
other configurations with different
thickness for BP and VTX detector.)
(in t hebellow table,A and B are fit paramet ers
for t herelat ion  A 2 + (B/P )2 /sin 3 .
P(GeV/c) vs.IP resolution(m)
A  5m and B  10m are required.)
Impactparameterresolutions (m) at polarangle  90
B = 3tesla
B = 4tesla
B = 5tesla
P = 1.0GeV/c
8.84
7.79
7.16
P = 10GeV/c
2.47
2.34
2.27
P = 100GeV/c
1.39
1.43
1.48
A(micron)
1.44
1.49
1.53
B(micron)
11.12
9.56
8.66
Other configuration results are as follows (at polar angle = 90 deg.):
Impactparameterresolutions (m) at polarangle  90
dBP (micron)
dVTX(micron)
500
300
100
250
50
B (tesla) P = 1.0GeV/c P = 10GeV/c
3
16.22
3.33
4
14.24
3.08
5
13.03
2.94
3
10.57
2.69
4
9.32
2.52
5
8.56
2.44
3
8.84
2.47
4
7.79
2.34
5
7.16
2.27
P = 100GeV/c A(micron) B(micron)
1.44
1.33
22.31
1.47
1.38
19.38
1.52
1.37
18.45
1.40
1.42
13.69
1.44
1.47
11.83
1.49
1.49
10.96
1.39
1.44
11.12
1.43
1.49
9.56
1.48
1.53
8.66
For P = 1GeV/c 3tesla is worse than 4(5) tesla by 12.0(19.2) %.
For P = 10GeV/c 3tesla is worse than 4(5) tesla by 6.4(8.8) %.
For P  ~ 30GeV/c, B  3teslacase is better than
B  4, 5teslacases. But thedifferences are quite small.
Momentum resolutions
ex : dBP  250m and dVT X  50m case
Momentum resolution is better
for high B at low P, and better
for low B at high P.
P(GeV/c) vs.momentumresolution P / P
Momentumresolutions ( P / P) at polarangle  90
B = 3tesla
B = 4tesla
B = 5tesla
P = 1.0GeV/c P = 10GeV/c P = 100GeV/c
1.50E-03
1.38E-03
3.82E-03
1.40E-03
1.50E-03
4.29E-03
1.35E-03
1.75E-03
5.10E-03
Other configuration results are as follows (at polar angle = 90 deg.):
Momentumresolutions ( P / P) at polarangle  90
dBP (micron)
dVTX(micron)
500
300
100
250
50
B (tesla)
3
4
5
3
4
5
3
4
5
P = 1.0GeV/c
1.50E-03
1.42E-03
1.37E-03
1.51E-03
1.41E-03
1.36E-03
1.50E-03
1.40E-03
1.35E-03
P = 10GeV/c
1.38E-03
1.51E-03
1.78E-03
1.38E-03
1.50E-03
1.76E-03
1.38E-03
1.50E-03
1.75E-03
P = 100GeV/c
3.83E-03
4.31E-03
5.12E-03
3.82E-03
4.30E-03
5.10E-03
3.82E-03
4.29E-03
5.10E-03
Momentum resolution is better for high B at low P, and better for low B
at high P.
Comparison with other detector configurations
1. TESLA detector:
B  4tesla
BP : R bp  1.4cm, thickness 500m
VT X(Si pixel): R VTX  1.5cm,2.6cm,3.7cm,4.8cm,6.0cm(5 - layers),
thickness  300m
IT (Sistrip): R IT  16cm,30cm(2 - layers),thickness 300m
T P C: inner radius  32cm, outer radius  170cm
( , P ad size et c.are same as above detectors)
Comparison between TESLA and 3 tesla case
Impactparameterresolutions (m) with polarangle  90
TESLA
GLD
P = 1.0GeV/c P = 10GeV/c P = 100GeV/c A(micron) B(micron)
13.22
2.86
1.47
1.60
15.95
16.22
3.33
1.44
1.33
22.31
(dBP  500m, dVT X  300m)
Comparison between TESLA and 3 tesla case
Momentumresolutions ( P / P) with polarangle  90
TESLA
GLD
P = 1.0GeV/c P = 10GeV/c P = 100GeV/c
1.36E-03
1.21E-03
4.16E-03
1.50E-03
1.38E-03
3.83E-03
(dBP  500m, dVT X  300m)
2.New VTX detector configuration (proposed by Sugimoto-san):
R VTX  2.0cm,2.2cm,3.0cm,3.2cm,4.8cm,5.0cm(6 - layers(3 layerdoublets)),
thickness  50m
(conditions for theIT etc.are same as abovedetector)
Polystyrene foam
VTX
detector
Layer
Comparison between double and single layer (3
tesla)
Impactparameterresolutions (m) with polarangle  90
double layer
single layer
P = 1.0GeV/c P = 10GeV/c P = 100GeV/c A(micron) B(micron)
11.18
2.40
1.18
1.29
12.78
8.84
2.47
1.39
1.44
11.12
(dBP  250 m, dVT X  50 m)
Comparison between double and single layer (3
tesla)
momentumresolutions ( P / P) with polarangle  90
double layer
single layer
P = 1.0GeV/c P = 10GeV/c P = 100GeV/c
1.50E-03
1.38E-03
3.80E-03
1.50E-03
1.38E-03
3.82E-03
(dBP  250 m, dVT X  50 m)
Other configuration results:
Impactparameterresolutions (m) with polarangle  90
double layer
single layer
B (tesla)
3
4
5
3
4
5
P = 1.0GeV/c
11.18
11.15
11.14
8.84
7.79
7.16
P = 10GeV/c
2.40
2.40
2.42
2.47
2.34
2.27
P = 100GeV/c
1.18
1.25
1.34
1.39
1.43
1.48
A(micron)
1.29
1.34
1.38
1.44
1.49
1.53
B(micron)
12.78
12.86
12.85
11.12
9.56
8.66
momentumresolutions ( P / P) with polarangle  90
double layer
single layer
B (tesla)
3
4
5
3
4
5
P = 1.0GeV/c
1.50E-03
1.41E-03
1.36E-03
1.50E-03
1.40E-03
1.35E-03
P = 10GeV/c
1.38E-03
1.50E-03
1.75E-03
1.38E-03
1.50E-03
1.75E-03
P = 100GeV/c
3.80E-03
4.27E-03
5.08E-03
3.82E-03
4.29E-03
5.10E-03
(dBP  250 m, dVT X  50 m)
Momentum resolutions are mostly the same as single layer case,
but impact parameter resolutions are different. (single layer case
does not have support design yet.)
Summary and Plan
Summary
Impact parameter resolution and momentum resolution
are mostly the same in each B field case. (More detailed
study (namely, b- and c-taging efficiency study) is needed
to estimate the best B field.)

Thickness of the detector components are quite
important to obtain the good impact parameter resolution.

Plan
Estimate the impact parameter resolutions (and
more) by using a full simulator. (To do so,
development of the simulator is necessary…)