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The spectra of electrons scattered inelastically from 4 He have been measured at incident energies from 150 MeV to 400 MeV for scattering angles from 38° to 90°. Through the use of a liquid 4 He target, a high momentum resolution (≈0.25%) was obtained, and the 20 MeV 0 + state of the α-particle was observed for the first time in electron scattering. The excitation energy and the total width of this state were determined and are in good agreement with the results from other experimental methods. It was found that the total disintegration cross section appears be smaller than 2(σ p +σ n ) by more than an order of magnitude at the lowest q 2 (≈ 0.33 fm −2 ). In earlier work the assumption of a total cross section of 2(σ p +σ n ) was found to be quite accurate for higher q 2 . As a new result, the partial radiative width for the 0 + state is determined to be Γ rad = 1.1±0.3 meV.

The greater accuracy of multidetector systems used in conjunction with magnetic spectrometers in high resolution electron scattering experiments has raised the problem of determining accurately the relative efficiencies of the individual detectors. A calibration technique utilizing an unknown spectrum of high energy scattered electrons is presented. Application to present equipment at Stanford University is discussed.

New information is reported on differences between the charge distributions of Ca40 and of Ca44, obtained by means of elastic scattering of 250 MeV electrons. Attention is focused, experimentally and theoretically, on the difference in scattering between the two isotopes.

Using a target material consisting of methane enriched to 58% in 13 C, we have studied elastic electron scattering of 250 MeV energy incident electrons at a variety of angles. The absolute target density was determined by electron scattering from the nuclei of hydrogen contained in the methane, and by comparing the measured cross sections with known proton cross sections. The contribution to the elastic scattering due to the 12 C in the target material has been subtracted by a calculation which uses previously measured 12 C cross sections. The data are analysed using a harmonic oscillator model. The ratio of the rms radius of the charge distribution for 13 C to that of 12 C is found to be 0.96±0.01.

Previous measurements of the transition probabilities for low-energy excitations in 12 C, using high-energy electron scattering techniques, required considerable extrapolation of the data to obtain the desired results. The present paper reports the results of new data obtained at lower values of momentum transferred to the nucleus. Transition widths for the three lowest-energy excited states in 12 C are determined using the new data. The results of the experiment allow a much greater confidence in the method employed in this study for determining transition widths.

We have searched for virtual excited states of 3 He by inelastic electron scattering at E = 200 MeV and θ = 60°. No evidence for narrow states excited with cross section greater than 3 × 10 −33 cm 2 /sr has been found for excitation energies up to 17 MeV.

The purpose of the paper is to present a summary of recent developments in high energy electron physics at Stanford. The material is divided into the following topics: nucleon form factors; deuteron form factors; (coincidence studies of elastic scattering, inelastic continuum studies); nuclear physics; (Ca40, Ca44 Investigations, study of the inelastic continuum in He3, magnetic octupole moments in light nuclei); shower studies at 900 MeV.