The out-of-plane electron scattering program at the MIT-bates accelerator

摘要

A project to develop a system of four portable, moderate resolution, magnetic spectrometers has been underway at the MIT-Bases Linear Accelerator Center. These new spectrometers and associated sophisticated mechanical supporting structures will be used for (e~-,e'p) electron-proton coincidence electron-scattering measurements in out-of-plane configurations. Such out-of-plane configurations allow access to small components of the nuclear response, which arise from interference between the longitudinal and transverse components of the nuclear currents. The intitial set of experiments include studies of the D-state admixture in the nucleon-#DELTA# transition using a liquid-hydrogen target, and studies of meson-exchange and isobar-configuration effects utilizing a liquid-deuterium target. Proof-of-principle experiments have been performed using a prototype spectrometer and support system. Three of the final spectrometers have been completed and commissioned in the summer of 1996, and will now be followed by the first set of experiments on the proton and the deuteron. The status of the project, including an overview of the equipment, will be presented.