the detector f.forti, infn and university, pisa pisa, 5 maggio 2007

The Detector

F.Forti, INFN and University, Pisa

Pisa, 5 maggio 2007

F.Forti - SuperB Project 2May 5, 2007

Outline

Detector requirements and considerations The SuperB Baseline Detector

SVTDCHPIDEMC IFRTrigger/DAQComputing

Budget and Schedule


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 physics Decays involving ’s.

Additional emphasis on: Angular coverage

Improve reconstruction Resolution&efficiency

Tracking & vertexing Energy resolution Particle ID Muon ID Often more relevant for

background rejection than for signal reconstruction


SuperB Detector Main issues

Machine backgrounds Higher than and different from PEP-II/KEKB

Beam energy asymmetry Smaller: 7+4 GeV =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.


Detector Layout – Reuse parts of Babar (or Belle)BASELINE

OPTION


SuperB Layout with dimensions


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


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


Need serious amount of shielding to prevent the produced shower from reaching the detector.

0.5 11.52

2.533.5

4

4.5 5

5.56 6.5

QD0 QD0

QD0H

QD0HB00LB00H

QF1 QF1

QF1QF1

B0L

B0H

B0H

B0L

SuperB Interaction Region

0

10

20

-10

-200 1 2 3-1-2-3m

cm

M.SullivanNov. 13, 2006SB_IT_ILC_G3_300

2 1.51

0.5

2.53

3.5

QD0 QD0

QD0H

QD0HB00LB00H

QF1 QF1

QF1QF1

B0L

B0H

B0H

B0L

SuperB Interaction Region

0

10

20

-10

-200 1 2 3-1-2-3m

cm

M.SullivanNov. 13, 2006SB_IT_ILC_G3_300

We have an IR design coping with main BKG source

Radiative BhaBha


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


Beam Pipe Radius and Detector

Separationsignificance Proper time

differenceresolution

7+4GeV

Boost =.28

Instead of 0.56

Small beam pipe radius possible because of small beam size Studied impact of boost on vertex separation

(B) 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


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


SVT

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

40 cm30 cm

20 cm

Layer0


SVT Layer 0

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

V

U1.35 cm

7.7 cm


Striplets detector concept


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


DCH Gas and Cell Size


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


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


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. Physics impact needs to be quantitatively assessed DIRC bars are necessarily in the middle DCH electronics relocation is critical for the perfomance


EMC Backgrounds Integrated over 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


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


Crystal properties


IFR and steel BaBar configuration has too

little iron for ID > 6.5 I required; 4-5

available in barrel Fine segmentation overdid

KL efficiency optimization Focus on 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 detectionlayers

Need to verify structural issues

Scintillator bars à la MINOS Cost effectiveness of steel reuse needs to be fully

assessed


IFR Backgrounds

Rates in the range of a few x 100Hz/cm2


Electronics and Trigger/DAQ L1 Trigger rate of 100-150KHz

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)


Computing Computing model

extrapolated from Babar Scales with luminosity

Requires distributed computing on the grid


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: 2007 Euros.

All details available in the CDR We have not tried to fully optimize the cost yet. Some reduction

might be possible


Detector costEDIA Labor M\&S Rep.Val.

WBS Item mm mm kEuro kEuro

1 SuperB detector 3391 1873 40747 464711.0 Interaction region 10 4 210 0

1.1 Tracker (SVT + L0 MAPS) 248 348 5615 01.1.1 SVT 142 317 4380 01.1.2 L0 Striplet option 23 33 324 01.1.3 L0 MAPS option 106 32 1235 01.2 DCH 113 104 2862 0

1.3 PID (DIRC Pixilated PMTs + TOF) 110 222 7953 67281.3.1 DIRC barrel - Pixilated PMTs 78 152 4527 67281.3.1 DIRC barrel - Focusing DIRC 92 179 6959 67281.3.2 Forward TOF 32 70 3426 0

1.4 EMC 136 222 10095 301201.4.1 Barrel EMC 20 5 171 301201.4.2 Forward EMC 73 152 6828 01.4.3 Backward EMC 42 65 3096 01.5 IFR (scintillator) 56 54 1268 01.6 Magnet 87 47 1545 96231.7 Electronics 286 213 5565 01.8 Online computing 1272 34 1624 01.9 Installation and integration 353 624 3830 01.A Project Management 720 0 180 0

Note: options in italics are not summed. We chose to sum the options weconsidered most likely/necessary.


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


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.


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


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

BACKUP


Accelerator and site costs

NumberEDIA Labor M\&S Rep.Val.

WBS Item Unitsmm mm kEuro kEuro

1 Accelerator 5429 3497 191166 1263301.1 Project management 2112 96 1800 0

1.2 Magnet and support system 666 1199 28965 25380

1.3 Vacuum system 620 520 27600 14200

1.4 RF system 272 304 22300 60000

1.5 Interaction region 370 478 10950 0

1.6 Controls, Diagnostics, Feedback 963 648 12951 8750

1.7 Injection and transport systems 426 252 86600 18000

NumberEDIA Labor M\&S Rep.Val.

WBS Item Unitsmm mm kEuro kEuro

2.0 Site 1424 1660 105700 02.1 Site Utilities 820 1040 31700 0

2.2 Tunnel and Support Buildings 604 620 74000 0

Note: site cost estimate not as detailed as other estimates.

the detector f.forti, infn and university, pisa pisa, 5 maggio 2007

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