NuMI Secondary Beam Monitors S. Kopp University of Texas at Austin I. Detector Description II. Chamber Performance III. In-beam Observations IV. My rant: is it a flux monitoring or measuring tool? November 10, 2003Robert Zwaska NBI Particles / cm 2 / spill Neutron fluences are ~ 10 that of charged particles at Hadron Monitor & Alcove 0 locations Hadron Monitor insensitive to horn focusing Muon Monitor distributions flat Alcove 1 Alcove 2 Alcove Muons / cm 2 / spill Radius (cm) Particle Fluences Function of the Hadron Monitor As target monitor (1 st fin broken) Monte Carlo As alignment tool: Data! LE Beam Alcove 1 Alcove 2 Function of the Muon Monitors HE Beam Alcove 1 Alcove 2 Monte Carlo! Concerns High Rad Levels Response to high particle fluences Inaccessibility Chambers inaccessible during beam operations Hadron monitor activated to 58 R/hr after 1yr, impossible to repair (requires remote handling procedure to replace) Requirements for Monitors Muon Monitors (Low Energy Beam) Muon Monitors (High Energy Beam)Hadron monitor ElementAlcove 1Alcove 2Alcove 3Alcove 1Alcove 2Alcove 3 Distance from target (m) Charged Particle Flux (10 7 /cm 2 /spill) Radiation Level (10 6 rad/yr.) 2000 Parent Particle Threshold (Gev)