# JC and Marina 12/18/00 Pixel Detector Simulation with Magnetic Field  Effects with magnetic Field o Deflection o Effective mobility o Non-constant Hall.

## Presentation on theme: "JC and Marina 12/18/00 Pixel Detector Simulation with Magnetic Field  Effects with magnetic Field o Deflection o Effective mobility o Non-constant Hall."— Presentation transcript:

JC and Marina 12/18/00 Pixel Detector Simulation with Magnetic Field  Effects with magnetic Field o Deflection o Effective mobility o Non-constant Hall mobility  Comparison with magnet run

Jianchun (JC) WangSyracuse University2 Magnetic Field

Jianchun (JC) WangSyracuse University3 Deflection in Magnetic Field n+n+ n p+p+ -V 0 V  e e e e e e e e e e e e e B y  Effect of magnetic field  Effect of incident angle

Jianchun (JC) WangSyracuse University4 Deflection in Magnetic Field Assumption:  H = constant  eff =  The charge distributions are the same with B or 

Jianchun (JC) WangSyracuse University5 Effective Mobility Very small effect: B field  Cloud drifts slower  Larger Spread

Jianchun (JC) WangSyracuse University6 E-dependent Mobility Larger E  Smaller  Hall   Smaller deflection P + side larger E N+ Side Smaller E

Jianchun (JC) WangSyracuse University7 Effect of Magnetic Field With non-constant  Hall (E), and  eff The charge distributions are slightly different

Jianchun (JC) WangSyracuse University8 Conclusion We Don’t expect the magnetic field will reduce the ratio between two-pixel clusters and one-pixel clusters

Jianchun (JC) WangSyracuse University9 Magnet Run  Track at 1.3  angle ( ~ 0.242 Tesla )  Measurement: R min = 0.193  Simulation ( Q th = 2.5Ke ): R min = 0.250 What is wrong ?

Jianchun (JC) WangSyracuse University10 Magnet Run  Track at 1.32  ( 23 mrad ) ( ~ 0.245 Tesla )  Measurement: R min = 0.193  Simulation ( Q th = 4.0Ke ): R min = 0.197 Just to Play around But there is no other evidence that threshold was wrong

Jianchun (JC) WangSyracuse University11 Magnetic Field  Measured with Gauss meter: 45A  0.585 Tesla  Assume overall scale of the magnetic field uncertain  Use MC simulation to fit  0.517 Tesla (error?)  Error of Hall factor (  Hall /  =1.15) can make up the difference

Jianchun (JC) WangSyracuse University12 Summary  MC simulation accurate both for drift and B field simulation  Magnet Run data is not fully understood yet

Jianchun (JC) WangSyracuse University13 Lorentz Angle Lorentz angle is not a constant along z, shown are overall effects Larger bias voltage  Larger E field  Smaller mobility  Smaller Lorentz angle

Jianchun (JC) WangSyracuse University14 Lorentz Angle Comparison Magnetic field: 1.4 Tesla U depletion is calculated with effective thickness of the sensor

Jianchun (JC) WangSyracuse University15 Diffusion Constant Reduce T eff from 390K to 300K  Reduce fraction of doublet by 1.4% Einstein equation: D = k T  / q

Jianchun (JC) WangSyracuse University16 Angular Fit with  Distribution FPIX0-Pstop Normal Incidence Data  MC: 0.5  interval, interpolation between points  Normal incident data:  = (1.77  0.09) 

Jianchun (JC) WangSyracuse University17 Angular Fit with  Distribution   10° Data5° Data15° Data20° Data FPIX0-Pstop

Jianchun (JC) WangSyracuse University18 Detector Inclination Angle  In Minuit fit, the beam is assumed to normal incident on the first SSD, the overall rotation of the detector can not be fitted  In  fit, interpolation between MC points (0.5° interval) is used  The error from the fit is about 0.1°, which should be smaller than error from MC model

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