Concept design of the target/horn system for the BNL neutrino oscillation experiment

The design concept for the integration of the target and the focusing horn system for the proposed BNL neutrino oscillation experiment is described in this paper. Also presented are issues associated with the functionality and thermo-mechanical response of the selected target intercepting the 28 GeV protons of the 1 MW upgraded AGS beam, the loading and mechanical response of the focusing horn subjected to high currents and energy deposited due to beam/target interaction, the integration of the two systems, and the heat removal schemes. The proposed target intercepts the 8.9×10¹³, 28 GeV protons with a 2.5 Hz cycle time over a spot that encloses the 3σ of the beam. In the baseline design the inner conductor of the aluminum horn encloses the target while allowing for an annular space for forced cooling. Approximately 250 kA pulse of current of 20 μs duration will flow through the horn at 2.5 Hz repetition rate inducing high compressive forces, vibration and heat. The paper addresses these issues of horn mechanical response, heat removal scenario, and useful life estimation including radiation damage.