Simulation of a Ring Imaging Cerenkov detector to identify relativistic heavy ions. Manuel Fernández-Ordóñez Universidad de Santiago Compostela
R 3 B Project
Detector requirements - Ionization chamber (MUSIC): z/z Position detectors: x 200 m - Velocity measurements: / In order to separate two neighbouring heavy nuclei it is necesary: (A/q) / (A/q) 1/350 ToF techniques present severe constraints to achieve a velocity resolution for large angular ranges. RICH advantages: High velocity resolution. Large angular aceptance. RICH disadvantages: Beam intensity loss due to nuclear interactions. Loss in identification resolution due to atomic interactions. RICH
Cerenkov radiation characteristics NatureMaterialnT th GasHe > 110 GeV/u Aerogel1.004> 9 GeV/u Aerogel GeV/u LiquidC 6 F MeV/u SolidMgF MeV/u SolidSiO MeV/u Frank-Tamm relation:
Velocity determination from the Cerenkov ring radii 8 mm thickness C 6 F 14 radiator. 96 Ru at 1 GeV/u R RR
Simulated performances of different radiators -The radiators have different ranges. -The required velocity resolution is achieved for ions above Z=15. (2mm) (4 mm) (2mm) 600 MeV/u 700 MeV/u for C 6 F 14
Key experiments: Fission 238 U + Pb (600 A MeV) Atomic interactions for 96 Ru
Conclusions -RICH detectors are better suited than ToF techniques to achieve high accuracy velocity measurements for large angular ranges. However they induce additional uncertainty sources: atomic and nuclear interactions Simulation. - Detailed simulations have been made: geometry, particle tracking, interactions of heavy-ions with matter, Cerenkov radiation, photon absortion, quantum efficiency and granularity of the photon detector. - Comprehensive analysis of the performances of different radiators: radiator thickness and radiator nature have been also made.