Speaker
Description
High-intensity proton beams are routinely used to generate secondary beams of particles such as neutrinos and muons.. High-current (∼100 µA), medium-energy (1 - 10 GeV), continuous-wave electron beams with a delivered large integrated charge (∼1000 C/y) can be also used to generate secondary beams. After interaction with a thin target in fixed-target experiments at the Thomas Jefferson National Accelerator Facility (Jefferson Lab), the electron beam is deposited on a block of material (beam "dump") where electrons produce showers, degrading the initial energy down to values at which ionization and excitation of atoms dominates. If the primary beam’s initial energy is higher than the pion production threshold, hadronic interaction and electromagnetic processes contribute to the production of a sizable number of secondary particles that may re-interact or escape from the dump material. The beam dump is usually surrounded by heavy shielding (e.g., a thick concrete vault) to minimize the escaping radiation. Nevertheless, a significant flux of neutrons, muons, and neutrinos propagate through the shielding, making intense secondary beams that may provide an opportunistic extension of investigations performed with the primary electromagnetic probe. Monte Carlo simulations for secondary beams produced from an 11 GeV electron beam at JLab experimental Hall A have been published that predict a secondary neutrino beam with a typical decay-at-rest energy spectrum providing up to ∼7×10⁻⁵ ν/EOT when integrated over a 1 m² detector located 10 m above the beam dump. Considering a delivered charge of 10²² EOT per year, the annual neutrino flux would be in the range of 1018 ν. Possibilities and plans for this potential new facility will be discussed.