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Investigate energy loss of charged particles through ionization in gas mixtures and study drift properties like velocity and diffusion. Discover differences in electron production and performance with varied gas compositions. Evaluate implications for safety and efficiency in ALICE TPC.
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TPG Drift Studies Edda Gschwendtner
Concentrate on Helium based gas mixtures • Energy loss of charged particles through ionisation in gas • clusters/cm, electrons/cluster • Drift properties of electrons • Drift velocity, transversal diffusion, longitudinal diffusion HEED Magboltz Edda Gschwendtner
He/CH4 mixtures: Clusters/cm cluster/cm Ekin = mc2 ( -1) mc2 () ~ 105 MeV ( -1) ~ 2 cluster/cm electrons/cluster for 200MeV/c muons electrons/cluster for 200MeV/c muons gamma-1 gamma-1 Edda Gschwendtner
He/CO2 mixtures: Clusters/cm cluster/cm Ekin = mc2 ( -1) electrons/cluster for 200MeV/c muons mc2 () ~ 105 MeV ( -1) ~ 2 cluster/cm electrons/cluster for 200MeV/c muons gamma-1 gamma-1 Edda Gschwendtner
Helium, E=520V/cm Drift Properties 0 Edda Gschwendtner
He/CH4 mixtures, E=520V/cm Drift Properties I Edda Gschwendtner
Drift Properties II He/CO2 mixtures, E=520V/cm Edda Gschwendtner
Summary • He/CH4 mixtures: with more CH4 • More electrons/cm produced • Less diffusion • Faster drift velocity • take maximum CH4 value still compatible with safety? • He/CO2 mixtures: with more CO2 • More electrons/cm produced • Less diffustion • But slower drift velocity • Sufficiently enough gain with little CO2? In ALICE TPC: Neon based gas look at that… Edda Gschwendtner