1. Summary of SuperB detector working group
Giovanni Calderini
LPNHE, Paris
LAL seminar, 25 April 2007

2. G.Calderini - Detector Summary
Detector layout
Strategy for baseline detector
Reuse as much as reasonable from BaBar
Satisfying performance
Maybe not full cost-benefit optimization
Strategy for options
Improve performance of some system, but affecting some other
...or...
Need R&D
Needed if backgrounds turn out to be higher
Apr 25, 2007
G.Calderini - Detector Summary

3. Machine detector interface
Baseline interaction region defined
300 mrad line separating detector from accelerator, backward and forward
No support tube
although magnet support still needs to be fleshed out
1 cm inner radius of the beam pipe
Still some leeway to make adjustments
Energy asymmetry
4x7 ok if we can use a 1cm beam pipe and get enough vertex resolution. Any changes have big impact on the machine.
Apr 25, 2007
G.Calderini - Detector Summary

4. G.Calderini - Detector Summary
Apr 25, 2007
G.Calderini - Detector Summary

5. G.Calderini - Detector Summary
Vertexing and Tracking at high luminosity
The beam-pipe and first-layer radius
The beam-pipe radius and the distance of the first tracker
layer from the beam are very important. Small radius is possible
due to the small beam size!
Study on (Bpp) vertex separation as a function of radius and boost
Proper time difference resolution
4 + 7
Apr 25, 2007
G.Calderini - Detector Summary

6. G.Calderini - Detector Summary
Beam pipe
1.0 cm inner radius
Be inner wall (300um)
≈ 4um inside Au coating
8 water cooled channels (0.3mm thick)
Power ≈ 1kW
Peek outer wall (500um)
Outer radius ≈ 1.2cm
Thermal simulation shows max T ≈ 55°C
Issues
Connection to rest of b.p.
Be corrosion (7um Ni)
Outer wall may be required to be thermally conductive to cool pixels
Apr 25, 2007
G.Calderini - Detector Summary

7. G.Calderini - Detector Summary
The break-through in the machine design is
making our life a bit easier.
Still important sources of background:
Luminosity sources
- beam-beam
- radiative Bhabha
Linear with currents
- lost particles and s.r.
Other sources of background
Touschek background
Thermal outgassing due to HOM losses; Not an issue with these currents
Injection background
Apr 25, 2007
G.Calderini - Detector Summary

8. G.Calderini - Detector Summary
Pair production
30MHz/cm2
Pt accept. @ 1.5 T , 1.2 cm
~Angular acceptance
1.2
1.5
R(cm)
Produced particles have low energy and they loop
Expected average rate O(15MHz/cm2) at R=1.2cm, decreasing to 5MHz at R=1.5cm (Guinea Pig)
Apr 25, 2007
G.Calderini - Detector Summary

9. G.Calderini - Detector Summary
Radiative Bhabhas
Need serious amount of shielding to prevent the produced shower from reaching the detector.
Apr 25, 2007
G.Calderini - Detector Summary

10. G.Calderini - Detector Summary
Radiative BhaBhas
At small radii, with the present simulation, it is negligible wrt to pairs. Rate O(100KHz) at 1.2cm
Present also at higher radii, (as in BaBar) due to backscattering from downstream machine elements (must be cured with suitable shielding)
Touschek, thermal outgassing and injection backgrounds are
expected to be negligible with respect to the above sources
Apr 25, 2007
G.Calderini - Detector Summary

11. G.Calderini - Detector Summary
40 cm
30 cm
20 cm
Layer0
Tracker
Baseline: use an SVT similar to the Babar one, complemented by one inner layer.
Question on whether it would possible/economical to add a layer between SVT and DCH, or move L5 to larger radius
Cannot reuse because of radiation damage
Beam pipe radius is paramount
Apr 25, 2007
G.Calderini - Detector Summary

12. Tracker layout Physics studies shows that we
Be Beam pipe
Physics studies shows that we
have the following constraints:
R beampipe ~ cm
Beampipe ~ 0.5% X0
Layer_0 radius ~ cm
Layer Radius cm cm cm cm
to 12.7 cm
to 14.6 cm
ADDED
15 cm
(Arched wedge wafers not shown)
BaBar SVT
Apr 25, 2007
G.Calderini - Detector Summary

13. G.Calderini - Detector Summary
Possible solutions for layer-0
Striplet (= short strips) solution
Basically already available technology but more sensitive to background. According to background simulations, it will work for a radius of 1.5cm or more
Monolithic Active Pixel solution
giving a big safety margin in terms of performance and occupancy. We could decrease the radius down to maybe 1.2 cm; R&D still ongoing
Also a radiation damage issue:
in terms of radiation damage, 1 MHz/cm2 of electrons
correspond to a dose of about O(250Krad/year)
Apr 25, 2007
G.Calderini - Detector Summary

14. G.Calderini - Detector Summary
A Layer-0 module
Readout Right
Readout Left z
HDI
Si detector
1st fanout, 2nd fanout
Layer-0 average thickness 0.46% X0
Silicon detector 200 um
Support structure ~ 100 um eq. Si
~1.5 fanout layers/module/side ~ 65 um Si eq. (can be improved by using the ALICE microcables)
Apr 25, 2007
G.Calderini - Detector Summary

15. G.Calderini - Detector Summary
F. Bosi
Apr 25, 2007
G.Calderini - Detector Summary

16. G.Calderini - Detector Summary
DCH
Basic technology adequate.
Cannot reuse BaBar DCH because of aging
Baseline:
Same He-C4H10, same cell shape
Carbon fiber endplates instead of Al to reduce thickness
 Need to do complete background estimate
Possible Options/Issues
Miniaturization and relocation of readout electronics
Critical for backward calorimetric coverage
Conical endplate
Further optimization of cell size/gas
Apr 25, 2007
G.Calderini - Detector Summary

17. G.Calderini - Detector Summary
Particle ID
Barrel DIRC baseline
Quartz bars are OK and can be reused
Almost irreplaceable
PMTs are aging and need to be replaced
Keep mechanical support
Barrel Options
Faster PMTs
Focusing readout
Different radiator
Extra tracking device outside DIRC
Apr 25, 2007
G.Calderini - Detector Summary

18. Forward/Backward PID option
Extending PID coverage to the forward and backward considered
Serious interference with other systems
Material in front of the EMC
Needs space
cause displacement of front face of EMC
require miniaturization and displacement of DCH electronics
TOF seems the only viable option
Technologies
Aerogel-based focusing RICH
Working device
Requires significant space (>25 cm)
Time of flight
Need about 10ps resolution to be competitive with focusing RICH
15-20ps OK. 10ps seems to be achievable, although not easy
Apr 25, 2007
G.Calderini - Detector Summary

19. G.Calderini - Detector Summary
EMC
Barrel CsI(Tl) crystals
Still OK and can be reused (the most expensive detector in BaBar)
Baseline is to transport barrel as one device
Various other transportation options
Forward Endcap EMC
BaBar crystal are damaged by radiation and need to be replaced
Occupancy at low angle makes CsI(Tl) too slow
No doubt we need a forward calorimeter
Backward EMC option
Because of material in front will have a degraded performance
Maybe just a VETO device for rare channels such as Btn.
Physics impact needs to be quantitatively further assessed
DIRC bars are necessarily in the middle
DCH electronics relocation is critical for the perfomance
Apr 25, 2007
G.Calderini - Detector Summary

20. G.Calderini - Detector Summary
Forward EMC crystals
Both pure CsI and LSO could be used in the forward EMC
LSO more expensive, but more light, more compact, and more radiation hard
Now LSO is available industrially
Cost difference still significant, but not overwhelming.
Use LSO as baseline
Gives better performance
Leaves PID option open
CsI option still open
in case of cost/availability issues
Backward calorimeter
Keep as an option
Backward endcap
Barrel extension
Could be less performant
Benchmark physics gain
Apr 25, 2007
G.Calderini - Detector Summary

21. G.Calderini - Detector Summary
IFR and steel
BaBar configuration has too little iron for m ID
> 6.5 lI required; 4-5 available in barrel
Fine segmentation overdid KL efficiency optimization
Focus on m ID : fewer layers and more iron
 Is it possible to use the IFR in KL veto mode ?
Present configuration
Baseline:
Fill gaps in Babar IFR with more iron
Leave 7-8 detection layers
Need to verify structural issues
Extruded scintillators
are a safe option
Avalanche RPC if evidence of lower rate
Apr 25, 2007
G.Calderini - Detector Summary

22. G.Calderini - Detector Summary
IFR and steel options
Cost-effectiveness of steel reuse needs to be fully assessed. Options
Fill some gaps (baseline)
Make a new belt and add material on the outside
Completely new steel (less dimensional constraints than in BaBar)
IFR technology options
Background simulation needed to estimate rate in EC at small angle
Scintillator is a safe possibility
Avalanche mode RPC (LHC-style) might be good
if background simulations will indicate a lower
expected rate
Apr 25, 2007
G.Calderini - Detector Summary

23. Trigger/DAQ/Electronics
Detailed evaluation in progress
Should prepare for a trigger rate of KHz
Unless a hardware L1 Bhabha rejector is developed
Some electronics could be reusable
Some front-end cards, power supplies
The bulk of the electronics is obsolete and unmaintainable
Should be remade with state-of-the-art technology
Clearly a major cost driver
Costing using recent experiments experience (LHC)
Apr 25, 2007
G.Calderini - Detector Summary

24. G.Calderini - Detector Summary
Detector Layout
BASELINE
OPTION
Apr 25, 2007
G.Calderini - Detector Summary

25. G.Calderini - Detector Summary
Costing
Costing basis
In some cases BaBar costing used, with proper escalation, as basis.
In many cases more recent experience available from other experiments
Special attention
Electronics – large cost driver
Integration and engineering
Baseline / options costing
The baseline detector may not be viable if backgrounds are high.
Full-option detector may be luxurious
Apr 25, 2007
G.Calderini - Detector Summary

26. Costing (for details see: http//www.pi.infn.it/SuperB )
Item EDIA Labor M&S Replacem.
(mm) (mm) kEuro ’07 kEuro ’07
Tracker
DCH
PID
EMC
IFR
Magnet
Electronics
Online comp
Install
Proj. engin
Total: about EDIA (mm) Labor (mm) + 40 MEuro
Apr 25, 2007
G.Calderini - Detector Summary

27. G.Calderini - Detector Summary
Conclusions
Baseline detector: BaBar +
Extra SVT layer0
LSO Forward calorimeter
More iron and fewer layers in IFR
Higher trigger rate
Present-technology electronics
Several options are possibly viable and need a cost benefit analysis:
Super pixel SVT layer0
Miniaturized DCH readout electronics
Better/smaller DIRC readout
Backward calorimeter
Forward and/or backward PID
Even more iron in the IFR or new steel
CDR now released; being submitted to Funding Agencies
Apr 25, 2007
G.Calderini - Detector Summary