D.Kawama HES Simulation Log Nov ’06 Part2 1.VP Flux につい て 2.HES Acceptance 3.HES Tracking

D.Kawama About VP Flux (e,e’K + ) reaction The definition of VP Flux (Γ) (e,e’K + ) diff. Cross Section Ω, ω : Angle and Momentum of e’ VP absorption Cross Section 要するにどれだけの数の vp を生成したか、という量 T.DEForest, Jr and J.D.Walecka, ”Electron Scattering and Nuclear Structure”, Advances In Physics 15 (1966) 1. Γ Formula Reference:

D.Kawama VP Flux and its integration Total VP Yield → Integration of Γ(Ω,ω) represent the Acceptance of Spectrometer Independent on the target and beam intensity (Integrated) VP Flux (unit : [NoVP/NoE]) NoVP : Number of Virtual Photon NoE : Number of Electron N total → depend on the target and beam intensity VP Rate [NoVP/sec]

D.Kawama VP E Assumption : 100mg/cm 2 12 C target, 20uA beam, σ γ =100 [nb/sr] HKS Solid Angle = [rad], Kaon Decay Rate = 0.3 VP Flux [NoVP/NoE] VP Rate [NoVP/sec/sr ] 12 Λ B g.s Ratio [g.s./hr] Rough Estimation ～ 0.20×10 -4 ～ 1.2 ～ 19 Geant3 Simulation 0.35× Measured Value ? Conditions on Rough Estimation : -120<x’<120[mrad], 70<y’<90[mrad], p=300[MeV], dp=±30% inconsistent

D.Kawama VP E (HES) Assumption : 100mg/cm 2 12 C target, 20uA beam, σ γ =100 [nb/sr] HKS Solid Angle = [rad], Kaon Decay Rate = 0.3 VP Flux [NoVP/NoE] VP Rate [NoVP/sec/sr ] 12 Λ B g.s Ratio [g.s./hr] Geant4 Simulation 1.1×

D.Kawama HES の Acceptance その 1 メインの領域で大体 8msr は確保できていると思われる Tilt : 7.3deg, Central Mom: 967MeV

D.Kawama HES の Acceptance その 2

D.Kawama HES Tracking for Detector Size [cm] Distance from D Magnet [cm] magenta: abs(δ)<5%, blue: 5%<abs(δ)<10% green: 10%<abs(δ)<15%, red: 15%<abs(δ) *Plot is not only for mid plane, but for all available y value

D.Kawama収束の様子 p=0.967[GeV/c ] 1.15p p 0.85p

D.Kawama Splitter Pole の効果 赤： SPL Pole にぶつからなかった粒子。数にして 5% くらい減っている。