FP-CCD GLD VERTEX GROUP Presenting by Tadashi Nagamine Tohoku University ILC VTX Ringberg Castle, May 2006

Outline FPCCD Vertex Detector Structure Simulation tools Geometry for Simulation study Impact Parameter resolution Track finding Background rejection by Cluster Shape Lorentz angle and diffusion measuremet R&D

FPCCD Large area device fabrication is established -> reduce dead area between sensors Fully depleted -> reduce smearing Very small pixel size is established -> good hit position resolution (~ 2  m) -> reduce occupancy No charge transfer during a bunch train -> Avoid EMI Very thin (a few 10  m) -> reduce Multiple scattering High back ground hit rate accumulated -> need background rejection and good tracking method

Structure of GLD Vertex Detector 3 doublets structure (6 Layers) Silicon thickness : 50  m (0.53x10 -3 X 0 ) Depletion layer thickness : 15  m Pixel size : 5  m x 5  m By Y. Sugimoto

R-  view By Y. Sugimoto

Ladder Structure 2 FPCCD on both side of Support Structure RVC will be used for main support structure.

FPCCD Support Material Very Low Density: 0.05 g/cm x10 -3 X 0 for 2 mm thickness

Software for Simulation SimTools-1-01 with geant4.7.0 p01 (For Impact Parameter Study) SimTools-1-02 with geant4.8.0 p01 (For Cluster Shape Study) Track fitting: Kalman filter based. (Fitting with semeared true hits, since No Track Finder yet!) Geometry data file: glddec05_2m.dat Pair Background generation: Cain v2.3 (data had been prepared by T. Fujikawa and N. Tani) SimTools ref:

GLD Tracking Devices for Simulation Study Magnetic Field : 3T 200 sample TPC 150  m position resolution 4 layer SIT ~10  m position resolution 3 Doublets VTX

FPCCD Vertex Detector Geometry for Simulation Study Cylindrical shape used for each layer No support material Layer thickness : 80  m 3 configurations are studied Layer 1 : R=17, 20, 24mm Layer 2 : R=32mm Layer 3 : R=58mm Hit position resolution: 2  m Beam Pipe : Beryllium t=500  m, R=15mm L1 L2 L3

Impact Parameter Resolution Impact Parameter Resolution(R-phi plane) v.s. Momentum  - at cos(  )=0.05

Track Finder It is under development in SimTools! Its performance (efficiency) depends on hit probability in track finding window. Estimate track finding window(area) from impact parameter resolution Area depends on polar angle of track as 1/sin 4 

Track-hit distance Solid line: track without layer 1 hit Red cross: true hit Black cross: extrapolated hit point D : gap between Layers R: true hit and extrapolated hit point distance

Distance between hit point and track extrapolated point on Layer 1 (10GeV/c  - ) D : 17mm cos  : 0.05 R98 : minimum R which 98% of tracks have hit closer than it.

R98 between hit point and track extrapolated point on Layer 1 D: 17mm cos  : 0.05

Cluster Shapes for Low P T and High P T tracks Pair Background (e + e - ) : Lower P T (blue line) Most particles in Interaction : Higher P T (green line) IP CCD

Energy Deposit by muon tracks Distribution of energy deposit by 1GeV/c  - (cluster) Isolated Delta-ray only cluster excluded Geant4 parameter: Range Cut = 0.3  m, Max Step Size = 1  m

Energy Deposit of Pair background Distribution of energy deposit by pair background (cluster) Delta-ray only cluster included Geant4 parameter: Range Cut = 0.3  m, Max Step Size = 1  m

Cluster Width Distributions 1GeV/c  - Left: D , Right: Dz

Cluster Width Distributions Pair background Left: D , Right: Dz

Distributions of Cluster Width v.s. Z 1GeV/c  - Left: D , Right: Dz

Distributions of Cluster width v.s. Z Pair background Left:  , Right: Dz

Hit Efficiency for Pair Background Layer 1 Left: all hits (black) and accepted (red) Right: efficiency

Hit Efficiency for Muon Track 1GeV/c  - Left: all hits (black) and accepted (red) Right: efficiency

Short Summary of Simulation Pair background can be reduced by using cluster shape by factor of 1/10 ~ 1/20 for z > 1/2 Layer length Need to development track finder work well for z<1/2 utilizing narrow gap of doublet structure. Need physics study to check effects of low momentum tracks.

Lorentz Angle and Diffusion measurements By Y. Sugimoto

Setup By Y. Sugimoto B=1T

Reference Test Front Illumination test Pixel size : 25x25  m No Magnetic Field Laser is well focused as small as 2~3  m

R&D needed 1 st priority –Development of FPCCD (funded) –Study of wafer thinning and the support structure 2 nd priority –Development of front-end readout ASIC (Partially funded) –Minimization of power consumption –Data compression and back-end electronics –Cooling system –Development of thin beam pipe Simulation –Track finding –Physics performance