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pad design present understanding
Tel Aviv University HEP Experimental Group
Ronen Ingbir
CollaborationHigh precision design Tel-Aviv Sep.051
High statistics MC, Fast simulationDesign optimization (GEANT) :
1. Granularity and reconstruction algorithm (Log. Weighting).
2. Electronics channels (Maximum peak shower design).
Present understanding design (head on ILC, Crossing angle).
Method of counting Bhabha events
Summary
CollaborationHigh precision design Tel-Aviv Sep.052
Outline
Fast Detector SimulationMotivation :
High statistics is required to notice precision of : 410L
L
There is an analytic calculation (and approximation) :
(Which is the precision goal of the ILC)
*2
L
L
Luminosity precision determination :
N1 : Reconstructed and generated in acceptance region.
N2 : Generated in acceptance region but reconstructed outside.
N3 : Generated outside acceptance region but reconstructed inside.
21
23
NN
NN
L
L
CollaborationHigh precision design 3 Tel-Aviv Sep.05
High Statistics Simulation
BHWIDE generated properties + smearing to simulate detector
min
*2
L
L
Changing the bias with a fixed resolution.
CollaborationHigh precision design 4 Tel-Aviv Sep.05
High Statistics Simulation
Changing the detector resolution with no bias
CollaborationHigh precision design 5 Tel-Aviv Sep.05
Data and MCIn real life we can include the detector performance (which is measured in test beam) into MC. The only question is: How well should we know the detector performance ?
CollaborationHigh precision design 6 Tel-Aviv Sep.05
Logarithmic Weighting
CollaborationHigh precision design 7 Tel-Aviv Sep.05
)]}ln()([,0max{T
ibeami E
EEconstW )]}ln()([,0max{
T
icelli E
EEconstW
Granularity in theta, GEANT results
Resolution Bias
CollaborationHigh precision design 8 Tel-Aviv Sep.05
Our basic detector is designed with
30 rings * 24 sectors * 15 cylinders = 10,800 channels
Do we use these channels in the most effective way?
Maximum Peak Shower Design
30 rings 15 cylinders
20 cylinders
10 cylinders
24 sectors * 15 rings * (10 cylinders + 20 cylinders) = 10,800 channels
4 rings 15 rings 11 rings
10 cylinders
CollaborationHigh precision design 9 Tel-Aviv Sep.05
Maximum peak shower design
Basic Design
Angular resolution improvement
without changing the number of
channels
Other properties remain the same
Polar Reconstruction
0.11e-3 rad0.13e-3 rad
CollaborationHigh precision design 10 Tel-Aviv Sep.05
Present Understanding (pad option)
15 layers
(z)
11 layers
(z)
4 layers
(z)
10 cylinders (θ)
60 cylinders (θ)
CollaborationHigh precision design
Based on optimizing theta measurement
14
Cylinders
)mrad(
11 Tel-Aviv Sep.05
X- angle background
CollaborationHigh precision design
Christian Grah, DESY-Zuethen
Beamstrahlung pair background
0.E+00
1.E+09
2.E+09
3.E+09
4.E+09
5.E+09
6.E+09
8 9 10 11 12 13 14 15 16
R min (cm)
Num
ber
of B
habh
a ev
ets
per
year
0
500
1000
1500
2000
2500
3000
3500
Bac
kgro
und
(GeV
)
Events per year
Background (GeV)
250 GeV
12 Tel-Aviv Sep.05
Method of counting events
CollaborationHigh precision design 13 Tel-Aviv Sep.05
Applying tight acceptance cut on one detector arm.
Count events which satisfy the back to back requirement using a band cut.
Maximum peak shower design and logarithmic weighting : working with a constant (Beam energy and cells size dependents) + applying differential weighting between the parts.
Applying a looser acceptance cut on the second detector arm.
Repeat method for the other side of the detector and compare results.
Tight cut
Out
In
)(rad
Eout-EinEout+EinP=
3 cylinders
2 cylinders
1 cylinders
CollaborationHigh precision design 14 Tel-Aviv Sep.05
Forward-Backward Balance RL
Simulation distribution
Distribution after acceptance and energy balance selection
Right side PH
Lef
t si
de
PH
Right PH - Left PH
CollaborationHigh precision design
deg5
rad310
15 Tel-Aviv Sep.05
Performance of present configuration
CollaborationHigh precision design
ParameterPad Performance
Energy resolution25%
resolution3.5 * 10-5 (rad)
resolution0.63 (deg)
~ 1.5 * 10-6 (rad)
Electronics channels
25,200
~19,000 (X-angle)
410/ LLWith this performance thegoal can be reached.
16 Tel-Aviv Sep.05
Next (and immediate) steps
CollaborationHigh precision design 17 Tel-Aviv Sep.05
Taking the present understanding design as a basis design for future simulation.
Understanding the criteria for identifying and selecting Bhabha event (maybe better detector resolutions are necessary).
Testing the crossing angle recommendation design in a crossing angle Bhabha scattering simulation which includes serpentine magnetic field.
