Upgrade magnets and power supplies Large Area RICH detector @ JLab/CLAS12 Measure polarized ep, ed Deep-Inelastic-Scattering at high luminosity (~ 1035 cm-2 s-1) Hadron structure in 3D !!!!! Hall B Central Detector Forward Detector Beam current 90 mA Beam polarization 85 % CHL-2 CEBAF 12 GeV upgrade in 2013 Upgrade magnets and power supplies Basic Requirements Hadron ID from 3 to 8 GeV/c Pion rejection > 100 Additional system requirements of the PID detectors: non invasive: small and uniform material budget Minimize photon detector surface (minimize cost) operate in large background environment (GeV/c) K/ ratio ~ 0.1-0.15 M. Contalbrigo, E. Cisbani, P .Rossi RICH 2010, 6-7 May, Cassis 1 1

Mean pk separation (5-8 GeV) Preliminary design of the large area RICH B ~ 40 G Projective geometry: 6 radial sectors ~ 1 m gap B ~ 500 G RHIC TOROID RHIC Mean pk separation (5-8 GeV) Mean p.e. number (5-8 GeV) Radiator: Aerogel  3 cm thickness  1.03 refraction index K-p separation > 4s at 8 GeV with smaller than 1 cm detector pixel Optmized geometry Photon detector options with light concentrator (a` la COMPASS)  MAPMT’s  SiPM with narrow time window to suppress background M. Contalbrigo, E. Cisbani, P .Rossi RICH 2010, 6-7 May, Cassis 2