DESIGN OF A 180 DEGREE ELECTRON SCATTERING FACILITY,
Abstract
The study of elastic electron scattering from nuclei, at angles near 180 degrees, permits an examination of nuclear magnetic multipole distributions as well as the testing of certain aspects of quantum electrodynamics. Apparatus has, therefore, been designed to enable such experiments to be performed at the Stanford Mark III linear accelerator. The special problems connected with 180 degrees elastic scattering are discussed. In general, it is necessary to subtract from the data, contributions from ordinary charge (Coulomb) scattering. This background is mainly due to electrons which scatter at angles other than 180 degrees and yet enter the detector because of multiple scattering in the target, finite beam spread and finite solid angle. 180 degrees scattering is achieved by passivng the incident beam through a magnetic field before it strikes the target. Backward scattered electrons then pass through the field a second time, bending away from the incident beam, and enter a spectrometer. The momentum range restrictions of the magnet optics and the optimization of the solid angle are discussed. A novel method is presented of varying the scattering angle around 180 degrees without causing significant phase space restrictions. Practical details of the apparatus are discussed and an outline of the data reduction methods used in such experiments is presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1965
- Accession Number
- AD0468908
Entities
People
- R. E. Rand
Organizations
- Stanford University