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EXO Progress Update. Laurentian University Jacques Farine. EXO Gas Option Simulation. First step: containment efficiencies Pressure and mass dependence Cylinder, take H=2R to minimize S/V Filled with 136 Xe Cu walls 0 decay, Q = 2457.8 keV
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EXO Progress Update Laurentian University Jacques Farine
EXO Gas Option Simulation First step: containment efficiencies • Pressure and mass dependence • Cylinder, take H=2R to minimize S/V • Filled with 136Xe • Cu walls • 0 decay, Q = 2457.8 keV • Differentiate e–//both crossing fid. vol.
Uncertainties obtained from 20 independent simulations. + Points include detailed low energy processes, scintillation and E=1kV/cm ( .. 30x CPU cycles).
2 / 0 differential c at edges • Simulations for 1T at 5 atm, equator • 10,000 evts ea. • Contam. of 2 in 0 increases towards the edge • > Optimize fiduc. volume and/or vary fraction of contamination
0 events (1 T, square=1m) 1 atm 20 atm > Investigate single/ discrimination
Next steps • Add chemical composition / drift / attenuation / absorption / attachment // light+charge readout • Add backgrounds as source of singles • Write code to detect Bragg peaks • For single/double separation, determine: • Contamination / sacrifice • Effect of Bremsstrahlung • Light collection options > E resolution
Material screening - radon emanation tests • Continued program at SNOLAB • Sensitivity 10 220Rn/day, 20 222Rn/day • Measure EXO-200 plumbing • No substantial source • Clean !
Characterize counters for Ar/Xe • Allow for: • Absolute emanation measurements • Diffusion studies in • Absolute cross-calibration between gases N2 = Ar; Xe 23% lower
Radon Trap Development 1) ESC on EXO-200 • Augmented with: • CO2 trap • Rn source • Water vapour trap • Radon trap Mark I (LN2) • Heat exchanger • Recirculation pump • Study Rn removal efficiency: • In misc. gases Air/N2/Ar > Xe • Rn trap Mark I
Radon trap tests at ES-III (Stanford) • Mark I trap: 2” of SS wool at LN2, multiple passes • efficiency too low (60% in 160 mbar N2) - sets scope
Radon Trap Development 2) At SNOLAB • 222Rn and 210Rn sources development • Radon extractor board as trap testbed • Refrigerator purchased • Cold head integration underway • Xenon purchased • Xe plumbing assembly initiated (w/ RCV vessels) • ESC integration underway
Gas at p,T L Diffusion of Rn in Xe Reduction factor along dead legs • Known, irreducible source term • Want max. ingress rate at distance L • For 220/222Rn in N2/Ar/Xe Theory - KTG in binary, dilute mixture, calculate D12 • 1D diffusion model with decay Experimental check • Diffusion length for 222Rn at 1 atm: d = 2m in Ar; 1.2m in Xe