Event Start Time Determination Ma Xiang 2005.9.21

Contents The Inf. from MDC, TOF & Trigger system Why need to Cal. Event Start Time? Principle of ESTime Calculation. ESTime Cal. by TOF ESTime Cal. by MDC Status of ESTime & some results Next to do

The Inf. from MDC, TOF & Trigger system ＊ REF ＊ (499.8M 2ns) TOF1(hit) 10ns TOF2(hit) 27ns TOF-Tmean 流水线时钟 (24ns 41.65) MDC-TRK 6.2μs0.2 L1 TOF1-TDC TOF2-TDC MDC-TDC

TDC measured by TOF TOF C D B A Charged particle TOF scintillator PMT C D B t A－>B : 粒子的飞行时间 t B－>C : 信号传输时间 t C－>D : PMT信号延迟 t elc : 电子学信号延迟  A TDC = t A->B ＋ t B->C＋ t C->D＋ t elc

TDC measured by MDC TDC= t A->B ＋ t B->C＋ t C->D＋ t elc Sense wire C D B Field wire MDC Drift cell t A－>B : 粒子的飞行时间 t B－>C : 电离电子的漂移时间 t C－>D : 信号传输时间  A t elc : 电子学信号延迟 TDC= t A->B ＋ t B->C＋ t C->D＋ t elc

Why need to Cal. Event Start Time(1)? 不同粒子种类、不同能量引起的事例起点的不确定性 Charged particle scintillator PMT e- : 3.0ns(1.5GeV) ~ 3.4ns(0.2GeV) p : 3.6ns(1.5GeV) ~ 16ns(0.22GeV) muon : 3.08ns(1.5GeV) ~ 3.9ns(0.2GeV) pion : 3.09ns(1.5GeV) ~ 4.1ns(0.2GeV) 不同种类、不同能量的粒子飞行时间的差别： 1 -- 13 ns

Why need to Cal. Event Start Time(2)? 触发周期引起的事例起点的不确定性:  50 ns RF 499.8MHz 2ns 束团 间隔 8ns 流水线时钟 RF/12=41.65MHz 24ns 束团和流水线时钟前沿的间隔: 0,8,16ns

Principle of the ESTime Calculation(1) 1. Event type: Beam collision & Cosmic 2. Fast Tracking & Particle ID 1) MDC Fast Tracking 2) EMC tracking 3) dE/dx 4) Particle ID 3. ESTime Calculation method * by TOF Information ( barrel & endcap) * by MDC fast tracking Information * by MDC Information itself

Principle of the ESTime Calculation(2) MDC Fast Reconstruction dE/dx EMC Reconstruction Particle ID Have TOF information TOF MDC No Yes MDC Fast Rec. information Calculate TOF time with Fast tracking Inf. No Yes No Recalculate MDC time w/o by MDC Inf. use TOF mean time Calculate MDC time with Fast tracking Inf. success Yes

UML Class Diagram

ESTime Calculation by TOF Z=0 ZTOF Charged particle TOF scintillator D C PMT B 根据MDC快速重建结果计算 常数 根据Ztof计算 A Test = TDCM － tev

ESTime Calculation by MDC Sense wire C D B Field wire Drift cell 根据MDC快速重建结果计算 常数 A (t0) Test = TDCM － tev

ESTime Calculation Flow MDC Tracking Tracking Particle ID Calculate Event-Time MDC-Track Calculate Event-Time Track-Fit dE/dx-Rec Trac-Ext

现状 Status & Results Programming MDC fast tracking EMC tracking dE/dx particle ID ESTime calculation TOF Information ( barrel & endcap ) MDC fast tracking Information MDC Information ( by Zhang Ling) Results 1) test results : event start time 2) single track 3) multi-tracks

result e-,1GeV,10000 MC Testset to”0” Test Measured : 1.Forward : Mean time: 0.09ns σ: 0.50ns 2.Backward : 0.042ns σ: 0.47ns

result p ,1.5GeV,1000 1.Forward : Mean time: 0.42ns σ: 0.52ns MC data Testset to”0” Test measured: 1.Forward : Mean time: 0.42ns σ: 0.52ns 2.Backward :

“Lund” 6000 Test Measured 1.Forward : Mean time: 0.12ns σ: 0.77ns MC data, Test set to”0” Test Measured 1.Forward : Mean time: 0.12ns σ: 0.77ns 2.Backward : 0.084ns σ: 0.75ns

“Lund” 6000 MC data, Test set to “2”, “10”, “18” Test Measured: Forward : Mean time: 2.122 (0.78) 10.11 (0.79) 18.11 (0.78) 2.Backward : 2.077 (0.74) 10.10 (0.80) 18.08 (0.71)

Gamma ppbar ,2000 Test Measured: 1.Forward : Mean time: 1.329ns MC data Testset to”0”, Mpsi Test Measured: 1.Forward : Mean time: 1.329ns σ: 0.82ns 2.Backward : 1.299ns σ: 0.85ns

Next to do Endcap TOF need to consider dE/dx & EMC tracking have not included Calculating event start time by MDC fast track (No TOF information) result need to check MDC tracking (without MDC fast tracking) calculate event start time (by Zhangling) Cosmic

Thank you ！

Belle 时间分辨 Bhabha: TOF：0.4ns MDC：1.3ns

事例起始时间图 流水线时钟 束团 TOF Test Tev TDCM