1. The very forward region Tel-Aviv meeting summary
September, Tel-Aviv, ISRAEL
FCAL
FCAL
Collaboration
High precision design
Ronen Ingbir
ECFA2005

2. FCAL Collaboration FCAL Goals : design and construction of
Luminosity detector
Beam monitor
Photons calorimeter
Goals : design and construction of
University of Colorado
AGH University, Cracow
Institute of Nuclear Physics, Cracow
Jagellonian University, Cracow
DESY
Joint Institute Nuclear Research Dubna
Institute HEP Protvino
National Center of Particle & HEP Minsk
Prague Acad. of Science
Tel Aviv University
Cooperation with: SLAC Iowa State University Wayne State University
FCAL
Collaboration
High precision design 2
ECFA2005

3. PhotoCal FCAL Beam diagnostics from beamstrahlung photons
Collaboration
High precision design 3
ECFA2005

4. PhotoCal - BS photon analysis
Etot= TeV
Gas calorimeter IP
>100m
Good energy resolution (10-15%)
21 radiation length : two absorber thickness (1.5, 3.0 mm) of Pb.
High intrinsic radiation hardness
tails!
GPIG simulation + neural network
Photon selection: |angle x| > 0.2 mrad |angle y| > 0.1 mrad
FCAL
Collaboration
High precision design 4
ECFA2005

5. Vertical beam waist variation
vert. waist shift > 0
vert. waist shift < 0
FCAL
Collaboration
High precision design 5
ECFA2005

6. BeamCal FCAL Detection of electrons/photons at low angle
Shielding the inner detector
Beam diagnostics from beamstrahlung electrons/positron pairs.
FCAL
Collaboration
High precision design 6
ECFA2005

7. Beam diagnostics : BS Pairs
Observables (examples):
total energy
first radial moment
left/right, up/down,
forward/backward asymmetries
Solve by matrix inversion
(Moore-Penrose Inverse)
Beam Parameters
Observables
1st order Taylor-Exp.
Observables
Δ BeamPar
Taylor
Matrix
nom
= *
Being tested also for the 20mrad case
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Collaboration
High precision design 7
ECFA2005

8. Particle identification in the BeamCal
The Physics:
SUSY particles production  ~ 102 fb-1
Signature:
+ - + missing energy
The Background:
two photons event  ~ 106 fb-1
Signature:
+ - + missing energy
(if electrons are not tagged)
Excellent electron identification is needed down to as small angle as possible
FCAL
Collaboration
High precision design 8
ECFA2005

9. Electron detection in the BeamCal
4 mm
10 mm
Nrings 20
Ncells
1660
Nchannels
49800
Nrings 8
Ncells
264
Nchannels
7 920
Low BG ( ~ 0°)
High BG ( ~ 90°)
5mm
8mm
10mm
Inefficiency to identify
Lost particles for R < 55 mm
electrons 200 GeV
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Collaboration
High precision design 9
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10. Distribution of BeamStrahlung pairs
Headon
2 mrad
FCAL
Collaboration
High precision design 10
ECFA2005

11. 20mrad crossing angle and DID field
20 mrad, DID
20 mrad, DID – extended Rmax
FCAL
Collaboration
High precision design 11
ECFA2005

12. Anti DID FCAL 20 mrad, DID 20 mrad, anti DID Collaboration ECFA2005 12
High precision design 12
ECFA2005

13. Sampling diamond-tungsten calorimeter
Diamond sensors
Diamond samples (CVD):
- Freiburg (FAP)
- GPI (Moscow)
- Element6 (De Beers)
Sampling diamond-tungsten calorimeter
Electric features:
1.Leakage current.
2.Mip & electric field and dose
Some sensors show microcracks (and leakage)
The CCDs are between 0 and 150 mm
Some are stable under irradiation, other not.
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Collaboration
High precision design 13
ECFA2005

14. Diamond sensors – test results-1
Element 6 – E6_4p
Freiburg, FAP7 l
CCD performance of
One FAP7 sample is
poor, but a signal can still
be extracted.
Element 6 sample was remetallized and shows good performance.
Stable under irradiation
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Collaboration
High precision design 14
ECFA2005

15. Diamond sensors – test results-2
Linearity over large dynamic rage
CERN PS Hadron beam – 3,5 GeV. fast extraction ~ / ~10ns (Wide range intensities)
Freiburg, FAP22
Element 6
Particle flux [mip/(cm2*10ns)]
Particle flux [mip/(cm2*10ns)]
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Collaboration
High precision design 15
ECFA2005

16. LumiCal
Precise measurement of the luminosity by using Bhabha events
Extend coverage of the ILC detector
FCAL
Collaboration
High precision design 16
ECFA2005

17. Polarised Bhabha
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Collaboration
High precision design 17
ECFA2005

18. Fast Detector Simulation
Motivation :
High statistics is required to notice precision of :
There is an analytic calculation (and approximation) :
Luminosity precision determination :
BHWIDE generated properties + smearing to simulate detector
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Collaboration
High precision design 18
ECFA2005

19. Data and MC
In 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 ?
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Collaboration
High precision design 19
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20. Bhabha selection cuts L R FCAL In Eout-Ein P= Eout+Ein Out 3 cylinders
Collaboration
High precision design 20
ECFA2005

21. Present Understanding (pad option)
Based on optimizing theta measurement
10 cylinders (θ)
60 cylinders (θ) 14
Cylinders
(mrad)
11 layers (z)
15 layers (z)
4 layers (z)
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Collaboration
High precision design 21
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22. Strip design FCAL Every other ring: 64 cylinders 120 sectors 30 rings
Collaboration
High precision design 22
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23. Performance of present configurations
Strip Performance
Pad Performance
Parameter
8:16%
25%
Energy resolution
3.3 * rad
3.5 * rad
resolution
10-3 rad
10-2 rad
~2.9* rad
~ 1.5 * rad
3720 (with bonding sectors)
13,320 (without bonding)
25,200
Electronics channels
With this performance the
goal can be reached.
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Collaboration
High precision design 23
ECFA2005

24. FCAL Two photon events Collaboration ECFA2005
Energy [GeV]
LUMICAL
BEAMCAL
Polar angle [deg.]
Independent generator studies (WHIZARD, Vermasseren) have shown that physics background from the four-lepton processes is present in the Luminosity Calorimeter with an average rate of 10-3 tracks per bunch crossing for head-on collisions. Further studies for crossing angles is under way.
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Collaboration
High precision design 24
ECFA2005

25. FCAL Collaboration ECFA2005
Lumical is positioned on detector axis
Lumical is centered around the outgoing beam
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Collaboration
High precision design 25
ECFA2005

26. X- angle background FCAL Beamstrahlung pair background Collaboration
250 GeV
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Collaboration
High precision design 26
ECFA2005

27. FCAL Systematic effects: radial beam offset and LumiCal tilt y y dr x
Similar behaviour for 20 mrad and 2 mrad when LumiCal is centered around the outgoing beam.
up to three orders of magnitude change when LumiCal is centered around the 'detector axis'. x y x y dr
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Collaboration
High precision design 27
ECFA2005

28. Electronics FCAL Collaboration ECFA2005
Readout electronics: facing the challenges:
- 5 bunch trains per second (5 Hz)
bunches within one train
- One bunch every 300ns, 150ns possible
- Each bunch to be registered
- High dynamic range (better 1:10k)
- More than 10k channels, depending on design
- Fast, low power, radiation hardness to be considered
Next Steps:
- Investigation of preamp principles
- Feasibility studies of digitization
Investigation of known systems
Pads for wire bonding should be at least 60 µm x 60 µm
Width of traces can be small as 1 µm, but the impedance will be high
Grounded lines between signal traces will reduce the crosstalk
FCAL
Collaboration
High precision design 28
ECFA2005

29. Effective wafer size – more detector tiles
Mechanical design and production constrains
Segmented silicon sensors interspersed into the tungsten half disks
Two half barrels to allow for mounting on closed beam pipe
The blue bolts support the heavy part of the detector, tungsten half disks
The red bolts carry only the sensors
Holes for precision survey the sensors position
Guardring reduces the active sensor surface by ~1 mm on each side of a tile
Effective wafer size – more detector tiles
FCAL
Collaboration
High precision design 29
ECFA2005

30. FCAL Detector Position XYZ displacement mesurement with two beams
BW camera DX1-1394a from Kappa company 640 x 480 with Sony ICX424AL sensor 7.4 μm x 7.4 μm unit cell size
Laser module LDM635/1LT from Roithner Lasertechnik
ThorLabs ½” travel translation stage MT3 with micrometers (smallest div. 10 μm)
Neutral density filters ND2
Two laser beams (one not perpendicular to the sensor) allow us
to measure XYZ translation in one sensor
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Collaboration
High precision design 30
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31. Summary
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Collaboration
High precision design 31
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32. Head-on design FCAL LumiCal BeamCal Collaboration ECFA2005
Overlap region
LumiCal
rmin=8 cm
rmax=28 cm
BeamCal
rmin=1.5 cm
rmax=10 cm
Beam hole
FCAL
Collaboration
High precision design 32
ECFA2005

33. (Reasonable Statistics)
X- angle design (step 1)
LumiCal
rmin=13 cm
rmax=28 cm
(Reasonable Statistics)
BeamCal
rmin=2 cm
rmax=16 cm
Beam hole
FCAL
Collaboration
High precision design 33
ECFA2005

34. X- angle design (step-2)
Detectors are centered around the outgoing beam
BeamCal
+ 30o blind area
(incoming beam)
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Collaboration
High precision design 34
ECFA2005

35. More detailed information can be found at the collaboration web page :
FCAL
Collaboration
High precision design
Thank you !
You are invited to the more focused talks given by our collaboration in this meeting
More detailed information can be found at the collaboration web page :
FCAL
Collaboration
High precision design 35
ECFA2005