Status report on the Asian Solid State Tracking R&D

March 31, 2003

M. Iwasaki University of Tokyo

1. Si -strip central tracker: Univ. of Tokyo2. Si -strip intermediate Tracker: Kyungpook National Univ., Ewha Univ., Yonsei Univ., Korea Univ. Today, I introduce these two groups activities

There are two groups working on SI tracker in Asian LC Group

1)Si -strip central tracker R&D by Tokyo Group

Univ. of Tokyo Group: M. Iwasaki, H. Aihara

GEANT4 Full simulation study on the SI tracker 1. Basic detector parameter studies 2. Photon BG estimation

U. Tokyo Group works on the Full detector simulation of the SI central tracker

In Linear Collider environment, Central Tracker must be robust SI tracker is one of the good candidate for LC

In our simulation, we use GEANT4 Full detector simulation + tracker hit position smearing Assuming NLC-SD detector parameters (SDMar01): 5 double-sided Si -strip layers R = 20cm - 125 cm B = 5.0 Tesla Track finding … cheater (gathering hits from the same particle) Track fitting … Using Kalman Filter (implemented by T.Abe)

Silicon Central Tracker

Tracker Hit Occupancy

10-3 10-2 at inner most

e+e- tt 6 Jets, s=500 GeV, noISR, no beamstrahlung

(strip pitch size * length)

- - - #hit1 in central & #VXD hit=5- - - #hit2 in central & #VXD hit=5

- - - #hit3 in central

- - - #hit=5 in central

|cos|<0.8

Vertex Detector linking is important to reconstruct low-P tracks

Track Reconstruction Efficiency (Central tracker + VXD)

Momentum resolutionGenerate single particle at |cos| = 0

Photon BG from IR region (from beamstrahlung)

We use theBG data made by T. Maruyama

We input this data go through GEANT4 detector simulation

SDMar01 Tracker region:

180 photons / bunch

180*190 = ~34000 /event

Ave. Energy = 1.0 MeV

(Peak at 0.511MeV positron annihilation)

Energy distribution for BG photon from IR

*On average,

~2000 /event make hits

in a SI tracker

*Ave. Energy of the photons

which make hits in a tracker

= 0.7 MeV

*Assuming 50m*20cm strip :

one makes 1.04 hits in average

BG photon detector simulation using GEANT4 (input ~34000 /event)

(Note: Hits which are seen between layers are from End-cap )

Tracker Hit OccupancySignal: e+e- tt 6 Jets, s=500 GeV, noISR, no beamstrahlung

Due to the BG, occupancy increases by an order of magnitude .. But still 1% level at inner most (for 50m*20cm)

GEANT4 Beam Delivery System simulation study at Tokyo K. Tanabe (JLC Road Map report design)

Currently we have outputs (ROOT) Using this BDS simulation, we’re going to do more detail detector BG studies

2) Si -strip intermediate tracker R&D

H. Park (KNU), I.H. Park (Ewha U.), H.J. Kim (Yonsei U.), J.S.Kang, HC Ha (Korea U.)

1. Simulation 2. Design and Fabrication 3. Measurements 4. Applications in LC

• Require good σrΦ and σz

• Reasonable (moderate) cost

Type σrΦ σz

MSGC 40μm 40μm Fast Signal

SSD 20 μm 40 μm

Straw Chamber 50 μm 1mm

Fiber Tracker 50 μm 1mm Fast Signal

Inner DC 80 μm 1mm

Intermediate Tracker

• 5 layers at r=9 to 37 cm• angular coverage: |cosΘ|<0.9• spatial resolution: σ = 40μm• thickness of a layer: 0.6% radiation length

Application in LC: Intermediate Tracker

CDC, 50 wires

IT, 5 layers

VTX, 4 layers

Beam pipe

e+ e-

Support Tube

Momentum Resolution

• Full detector simulation• 1 GeV single muon: • reconstruction including energy loss and multiple scattering

Momentum Resolution

Effect of Spatial resolution is dominant

Multiple scattering, dominant

- as function of spatial resolution for different energies of the incident particle

Design/Simulation/Fabrication of Si PIN diode

Clean wafer

Oxidation

Cover with photoresist

Expose through mask

Develop

Etch, Stip

N+Diffusion

P+ Implantation

Anneal

Metallization

P+ 0.6um

N+1.0um

Current

High Energy Particle

(1,1,1) 5 k N-type

N-sub

Metal

P+

Metal

P+

Oxide

100m

VfFloating

N-sub

Metal

P+

Metal

P+

Oxide

50m

VfFloating

Design and Fabrication

• wafer (500/625/380 m)

- n-type high resistivity

- (111) orientation

- single side polished

- A pad size : 1.5 x 1.4 cm2

30um10um

Leakage current : 70nA/1cm2 at 250V

Leakage Current Measurement

68nA

176nA

Assembly: Ladder

S/N Ratio Measurement

Dark box

Pb Pb

Photodiode sensor

Beta (90Sr) source

Heavy Ion Beam with A/Z=2, E=30GeV

Silicon Sensor vs dE/dx Correlation

Design of Si Strip

700um 700um

200 200 200100

20000um

200

250

SiO2 0.4um

For metal contact (n+) 0.4um

Aluminum 0.3um

50um

100um

n-type wafer 300um

Al

Design of Si Strip

Summary

1) Si -strip central tracker Using GEANT4, full simulation studies have been done

* Several basic parameters are studied … Vertex Detector Linking is important to reconstruct low-momentum tracks under the high magnetic field

* Estimated the photon BG from IR-region … We are also working for the IR/beam-delivery system simulation using GEANT4 at Tokyo useful for the detail BG study in Si tracker

* Track-fitting.. Use Kalman filter * Track-finding.. Not yet Need to be implemented

2) Si -strip intermediate tracker

* Korean group is accumulating knowHow of SI detector

* Korean group fabricated SI detector and test results showed that it is as good as others

* Submitted R&D proposal for SSD in LC

* Apply/extend to silicon detector (Intermediate tracker, Calorimetry) in LC

* Need study momentum resolution vs # of layers, thickness, ……