For high fluence, good S/N ratio thanks to:Single strip leakage current Ileak 95nA at T -5C Interstrip capacitance 3pF

SVX4 chip

After Irradiation Leakage Current vs Bias Voltage environmental chamber T = - 25C

1.0E-05

1.0E-04

1.0E-03

1.0E-02

0 100 200 300 400 500 600 700 800 900 1000

Bias Voltage

Leak

age

Cur

rent

(A)

Sensor 60 T = - 25C

Sensor 60 expected @T= - 5 C

Sensor 60 T = 20C

After irradiation Interstrip Capacitance vs Bias Voltage

T=14C f=1MHz & AC signal = 5V

3.0E-12

3.5E-12

4.0E-12

4.5E-12

5.0E-12

5.5E-12

6.0E-12

6.5E-12

7.0E-12

0 100 200 300 400 500 600 700 800 900 1000

Bias Voltage (V)

Inte

rstr

ip c

ap

ac

ita

nc

e (

F)

sensor 63 U250

sensor 63 D120

sensor 60 U256

After IrradiationDepletion Voltage sensor 63 V = 130Vsensor 60 V = 128V

Before Irradiation sensor 63 Cint = 3.17 +/- 0.01 pF sensor 60 Cint = 3.46 +/- 0.17 pF

After Irradiation sensor 63 3.3 pFsensor 60 3.4 pF

10 modules fully assembled: hybrids work well

2 Electrical staves ALREADY build

The new SVXIIb will be installed in 2006

(6 months shutdown)

Silicon Sensors in High Luminosity environment

Silicon detectors are damaged by radiation primarily through displacement of Silicon or impurities from the lattice.

As a result the sensors are subjected to:

increase in leakage current and thus in shot noise, heat,..

substrate-type inversion which affect the depletion voltage

All 2300 sensors are <100> n-type single-sided high resistivity bulk silicon microstrip detectors:

operating at high voltages ( 350V), they are radiation hard

all SVXIIb detectors have intermediate strips yielding excellent resolution

More sensors are required to maintain the same tracking capability (SVXIIa had double-side sensors that decrease the number of detectors used) Silicon is actively cooled down (L0&L1-5C) to decrease the leakage current

Irradiation damage Study:Neutron Irradiation performed at UC Davis:

7*1013 1MeV eq-n cm-2

&

1.4*1014 1MeV eq-n cm-2

Prototype sensorsDetectors are manufactured by Hamamatsu Photonics: all un-irradiated prototyped sensors have been FULLY CHARACTERIZATED at Tsukuba, Purdue and UNM:

Svx4 chip

SVX4 is 0.25 m CMOS translation of SVX3D chip. Chips have been irradiated to 16Mrad with Co-60 facility and no change has been observed: enhanced radiation tolerance.

The data plot is from the 1st module where the bonding for each chips was different: not bonded to anything, bonded to pitch adapter,bonded to PA and one sensor, bonded to PA and 2 sensors. As the capacitance increases you can see that the noise level increases as expected: signal/noise 30% better than SVX3

128-channel device; 8-bit digitization on chip, deadtime less, dynamical pedestal substraction,low power

Stave design

The new silicon detector

Layer 0: 12 fold AxialLayer 1: 6 fold Axial-AxialLayer 2: 6 fold Axial-SAS(1.2)Layer 3: 12 fold SAS(1.2)-AxialLayer 4: 16 fold SAS(1.2)-AxialLayer 5: 20 fold Axial-Axial

LayoutThe new detector SVXIIB has 6 layers with 2 barrels in z, each 66cm long. As in RunIIa, the staves within a layer are arranged in a castellated patter. The RunIIa portcards have been removed from the tracking volume to minimize the mass

Improvements extension of the “contained b-jets” region

more uniform radial distribution

A stave, the RunIIA ladder, is a structural element with 6 axial sensors on one side and 6 axial or small angle stereo sensors on the other side. The two sides are separated by a few mm.

The key feature of the RunIIb design is the uniform stave design for 90% of the sensors

L1-L5: 180 staves can be produced with the same mechanical fixture (SVXIIa has 180 ladders, 5 sizes and 36 of each size)

L0 is similar to RunIIa L00: axial sensor at small radius, small strip pitch and with very low mass

Schematic of a stave:1 bus cable, 6 sensors, 3 hybrids, 4 chips on each hybrid (2 chip for beam pipe layer)

Improvements layout easy to mass produce

L0 will guarantee a good impact parameter resolution for unshared hits

L1 strengthens the pattern recognition near the beam pipe (redundancy of the axial layers ensures a good axial hit)

L5 strengthens the connection to the COT

Loss in z-resolution but better hits-tracks association

Impact parameter resolution in r- for all axial sensors

Impact parameter resolution in r-z for all stereo sensors

The average material for the RunIIa and RunIIb silicon detector designs is compared for normal incidence trajectories as a function of position along beam line

Less material than in RunIIa due to compact stave structure and progress in hybrid technology

The plots show the b-tagging efficiency vs b-jet (studies performed using RunIIa simulation) and the Higgs mass sensitivity as a function of b-tag efficiency ( is relative to 65%)

SENSORS

The new Silicon detector at RunIIb

Configuration

d (m) Asymptoti

c

d (m) Pt=2GeV

All layers 6 25

NO L1 7.5 27

NO L0 9 51

NO L0 or L1 15 79

Configuration

z (m) Asymptotic

z (m) Pt=2GeV

L2-L5 + 1 ISL

1.4 1.4

L2-L4 + 1 ISL

1.8 1.8

L2-L5 only 1.4 1.4

L2-L4 only 2.0 2.0

Parts SVXIIa SVXIIb

Hybrids 10 1

Sensors 5 2

Ladders 5 1

Layer

R (cm) Calcul. Dose RunIIb *1013

(1 MeV eq-n cm-

2 )0 2.1 13.61 3.5 5.72 5.9 2.33 9.1 1.14 11.9 0.75 14.7 0.5