1. F.Forti, INFN and University, Pisa Paris, May 9 2007
The Detector
Things to add
Btau nu
Beta’ Ks
LFV
F.Forti, INFN and University, Pisa
Paris, May

2. F.Forti - SuperB Project
Outline
Detector requirements and considerations
The SuperB Baseline Detector
SVT
DCH
PID
EMC
IFR
Trigger/DAQ
Computing
Budget and Schedule
May 9, 2007
F.Forti - SuperB Project

3. Experimental considerations
Babar and Belle designs have proven to be very effective for B-Factory physics
Follow the same ideas for SuperB detector
Try to reuse same components as much as possible
Shifted physics emphasis
Rare decays
t physics
Decays involving n’s.
Additional emphasis on:
Angular coverage
Improve n reconstruction
Resolution&efficiency
Tracking & vertexing
Energy resolution
Particle ID
Muon ID
Often more relevant for background rejection than for signal reconstruction
May 9, 2007
F.Forti - SuperB Project

4. F.Forti - SuperB Project
SuperB Detector
Main issues
Machine backgrounds
Higher than and different from PEP-II/KEKB
Beam energy asymmetry
Smaller: 7+4 GeV  bg=0.28
Strong interaction with machine design
Of course, as in Babar and Belle
Impact on
Detector segmentation
Radius of beam pipe and first sensitive layer
Radiation hardness
Aging
Several components are not reusable because of aging, even if the design would be ~OK.
May 9, 2007
F.Forti - SuperB Project

5. Detector Layout – Reuse parts of Babar (or Belle)
BASELINE
OPTION
May 9, 2007
F.Forti - SuperB Project

6. SuperB Layout with dimensions
May 9, 2007
F.Forti - SuperB Project

7. F.Forti - SuperB Project
Backgrounds
More details in Gianni’s talk
Dominated by QED cross section
Low currents / high luminosity
Beam-gas are not a problem
SR fan can be shielded
May 9, 2007
F.Forti - SuperB Project

8. F.Forti - SuperB Project
Pair production
Huge cross section (7.3 mbarn)
Produced particles have low energy and loop in the magnetic field
Most particles are outside the detector acceptance
May 9, 2007
F.Forti - SuperB Project

9. We have an IR design coping with main BKG source
Radiative BhaBha
Need serious amount of shielding to prevent the produced shower from reaching the detector.
May 9, 2007
F.Forti - SuperB Project

10. F.Forti - SuperB Project
Backgrounds
SuperB beam currents (2A) are similar to PEP-II/KEKB
Background is not too much larger than what with have today
Except for SVT Layer0
Detailed simulations ongoing, especially for radiative Bhabhas and Touschek backgrounds
Need to design a robust detector with the enough segmentation and radiation hardness to withstand surprises (x5 safety margin)
IR design is critical
Shielding
More studies needed
May 9, 2007
F.Forti - SuperB Project

11. Beam Pipe Radius and Detector
Small beam pipe radius possible because of small beam size
Studied impact of boost on vertex separation (Bpp)
Rest of tracking is Babar
Beam pipe needs to be cooled.Study is in progress to keep total thickness low in the order of % of rad
7+4GeV
Boost bg=.28
Instead of 0.56
Separation significance
Proper time difference resolution
May 9, 2007
F.Forti - SuperB Project

12. F.Forti - SuperB Project
Beam pipe
1.0 cm inner radius
Be inner wall
≈ 4um inside Au coating
8 water cooled channels (0.3mm thick)
Power ≈ 1kW
Peek outer wall
Outer radius ≈ 1.2cm
Thermal simulation shows max T ≈ 55°C
Issues
Connection to rest of b.p.
Be corrosion
Outer wall may be required to be thermally conductive to cool pixels
May 9, 2007
F.Forti - SuperB Project

13. F.Forti - SuperB Project
SVT
40 cm
30 cm
20 cm
Layer0
Baseline: use an SVT similar to the Babar one, complemented by one or two inner layers.
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
inner radius: 1.0cm,
layer0 radius: 1.2cm,
thickness: 0.5% X0
May 9, 2007
F.Forti - SuperB Project

14. F.Forti - SuperB Project
SVT Layer 0
7.7 cm
Depends critically on background level
Striplet solution (baseline)
Basically already available technology but more sensitive to background. OK for 1MHz/cm2
Some margin to improve background sensitivity
Monolithic Active Pixel Solution solution (option)
R&D is still ongoing but giving a big safety margin in terms of performance and occupancy
Cooling and mechanical issues need to be addressed
See talks in the afternoon
1.35 cm U V
May 9, 2007
F.Forti - SuperB Project

15. Striplets detector concept
May 9, 2007
F.Forti - SuperB Project

16. F.Forti - SuperB Project
DCH
Basic technology adequate.
Cannot reuse BaBar DCH because of aging
Faster gas and smaller cell would be beneficial
Baseline:
Same gas, same cell shape
Some gas improvement possible (order 20%)
Reducing cell dimension deteriorates resolution
Carbon fiber endplates instead of Al to reduce thickness
Backgrounds simulated, dominated by radiative Bhabhas
Depend critically on shielding
About 7% occupancy with current solution, could be reduced to 1.5%
Options/Issues to be studied:
Miniaturization and relocation of readout electronics
Critical for backward calorimetric coverage
Conical, Carbon fiber endplate
Further optimization of cell size/gas
May 9, 2007
F.Forti - SuperB Project

17. F.Forti - SuperB Project
DCH Gas and Cell Size
May 9, 2007
F.Forti - SuperB Project

18. F.Forti - SuperB Project
Particle ID
Barrel PID essential for hadron PID above ~0.7GeV.
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
Readout options motivated by reduction of background generated in SOB
SOB: Faster PMTs using the standoff box and water coupling
Smaller SOB: Pixilated MaPMTs and fused silica coupling
No SOB: Focusing readout with pixilated MaPMTs
May 9, 2007
F.Forti - SuperB Project

19. Forward/Backward PID option
Extending PID coverage to the forward and backward considered
Possibly useful, physics case needs to be established quantitatively
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
May 9, 2007
F.Forti - SuperB Project

20. F.Forti - SuperB Project
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
Background simulation indicates the need for a careful shielding design
dominated by radiative Bhabha’s
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 assessed
DIRC bars are necessarily in the middle
DCH electronics relocation is critical for the perfomance
May 9, 2007
F.Forti - SuperB Project

21. F.Forti - SuperB Project
EMC Backgrounds
Integrated over f
120 crystals in the barrel, 100 in the forward
Limit for CsI(Tl) at about 1MeV/us/crystal
More detailed studies and optimization are needed
May 9, 2007
F.Forti - SuperB Project

22. F.Forti - SuperB Project
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
Mechanically easier to assemble
Leaves PID option open
CsI option still open
in case of cost/availability issues
May 9, 2007
F.Forti - SuperB Project

23. F.Forti - SuperB Project
Crystal properties
May 9, 2007
F.Forti - SuperB Project

24. F.Forti - SuperB Project
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 ?
Baseline:
Fill gaps in Babar IFR with more iron
Leave 7-8 detection layers
Need to verify structural issues
Scintillator bars à la MINOS
Cost effectiveness of steel reuse needs to be fully assessed
May 9, 2007
F.Forti - SuperB Project

25. F.Forti - SuperB Project
IFR Backgrounds
Rates in the range of a few x 100Hz/cm2
May 9, 2007
F.Forti - SuperB Project

26. Electronics and Trigger/DAQ
L1 Trigger rate of KHz
Unless a hardware Bhabha rejector is developed
Up from 5KHz current Babar rate
Some electronics could be reusable
Especially front-end cards, maybe 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
Costed using recent experiments experience (LHC)
May 9, 2007
F.Forti - SuperB Project

27. F.Forti - SuperB Project
Computing
Computing model extrapolated from Babar
Scales with luminosity
Requires distributed computing on the grid
May 9, 2007
F.Forti - SuperB Project

28. F.Forti - SuperB Project
Cost estimate
A full cost estimate of the SuperB project has been done
Based on Babar/PEP-II actual costs
Escalated from 1995 to 2007
Bottom-up for almost all elements
Separate new components from reused elements
Replacement value of reused components = how much would it cost today to rebuild those components (extrapolated from Babar/PEP-II costs)
New costs: everything that’s needed today, including refurbishing
Transport is not included, but disassembly and reassembly is.
Keep separate categories:
EDIA: engineering, design, inspection and administration (man-months)
Labour: technicians (man-months)
Materials and Services: Euros.
All details available in the CDR
We have not tried to fully optimize the cost yet. Some reduction might be possible
May 9, 2007
F.Forti - SuperB Project

29. F.Forti - SuperB Project
Detector cost
Note: options in italics are not summed. We chose to sum the options we
considered most likely/necessary.
May 9, 2007
F.Forti - SuperB Project

30. F.Forti - SuperB Project
Computing costs
Computing depends critically on the time scale
Moore’s law
Evaluated in two scenarios:
startup in 2011 or 2012
Not included in basic detector budget
LHC model:
distributed computing resources
provided by many partners
The on-site computing center is included in the estimates
should probably called out as a separate entity
May 9, 2007
F.Forti - SuperB Project

31. F.Forti - SuperB Project
Schedule
Overall schedule dominated by:
Site construction
PEP-II/Babar disassembly, transport, and reassembly
We consider possible to reach the commissioning phase after 5 years from T0.
May 9, 2007
F.Forti - SuperB Project

32. The Università di Roma Tor Vergata Site
Area available
Strong interest of University and INFN
Tunnel at about -12m
Synergy with approved FEL (SPARX)
Engineering group created
Issues: water, power
750m
May 9, 2007
F.Forti - SuperB Project

33. F.Forti - SuperB Project
Summary and outlook
A SuperB detector based on Babar has been developed
It could be based on Belle as well
Technology is available
Some areas require focused R&D to be finalized (see David’s talk)
Final technology choices will need to be made
Main goals for the workshop
Understand the needed R&D effort
Create some structure to move forward
Longer term
Arrive to a Technical Design Report in 1-2 years
May 9, 2007
F.Forti - SuperB Project

34. BACKUP

35. Accelerator and site costs
Note: site cost estimate not as detailed as other estimates.
May 9, 2007
F.Forti - SuperB Project