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Experimental studies of light emission phenomena in superconducting RF cavities, which we categorize under the general heading of cavity lights, are described. The cavity lights data, which were obtained using a small CCD video camera, were collected in a series of nine experimental runs ranging from ∼1/2 to ∼2 h in duration. The video data were recorded on a standard VHS tape. As the runs progressed, additional instrumentation was added. For the last three runs a LabVIEW-controlled data acquisition system was included. These runs furnish evidence for several, possibly related, light emission phenomena. The most intriguing of these is what appear to be small luminous objects ≤1.5 mm in size, freely moving about in the vacuum space, generally without wall contact, as verified by reflections of the tracks in the cavity walls. In addition, on a number of occasions, these objects were observed to bounce off of the cavity walls. The wall-bounce aspect of most of these events was clearly confirmed by pre-bounce and post-bounce reflections concurrent with the tracks. In one of the later runs, a mode of behavior was observed that was qualitatively different from anything observed in the earlier runs. Perhaps the most perplexing aspect of this new mode was the observation of as many as seven luminous objects arrayed in what might be described as a macromolecular formation, coherently moving about in the interior of the cavity for extended periods of time, evidently without any wall contact. It is suggested that these mobile luminous objects are without explanation within the realm of established physics. Some remarks about more exotic theoretical possibilities are made, and future plans are discussed.

We have measured the neutron structure function g$_{2}^{n}$ and the virtual photon-nucleon asymmetry A$_{2}^{n}$ over the kinematic range $0.014\leq x \leq 0.7$ and $1.0 \leq Q^{2} \leq 17.0$ by scattering 48.3 GeV longitudinally polarized electrons from polarized $^{3}$He. Results for A$_{2}^{n}$ are significantly smaller than the $\sqrt{R}$ positivity limit over most of the measured range and data for g$_2^{n}$ are generally consistent with the twist-2 Wandzura-Wilczek prediction. Using our measured g$_{2}^{n}$ we obtain results for the twist-3 reduced matrix element $d_{2}^{n}$, and the integral $\int$g$_{2}^{n}(x)dx$ in the range $0.014\leq x \leq 1.0$. Data from this experiment are combined with existing data for g$_{2}^{n}$ to obtain an average for $d_{2}^{n}$ and the integral $\int$g$_{2}^{n}(x)dx$.

Elastic electron scattering cross sections for $^{3}\mathrm{He}$ were measured relative to those of $^{12}\mathrm{C}$ in the range of momentum transfer squared between 0.032 and 0.34 ${\mathrm{fm}}^{\ensuremath{-}2}$. The $^{3}\mathrm{He}$ rms charge radius was determined from the data to be 1.89 \ifmmode\pm\else\textpm\fi{} 0.05 fm.

The continuum spectra of $^{3}\mathrm{He}$ have been measured up to excitation energies of 40 MeV by means of inelastic electron scattering. Incident electron beam energies between 60 and 120 MeV were used, corresponding to a momentum transfer range of 0.3 ${\mathrm{fm}}^{\ensuremath{-}1}$ to 1.1 ${\mathrm{fm}}^{\ensuremath{-}1}$. Scattered electrons were observed at two angles, 92.6\ifmmode^\circ\else\textdegree\fi{} and 127.7\ifmmode^\circ\else\textdegree\fi{}. The radiation corrected spectra and the form factors are presented, and compared with calculations based on a zero-range approximation. In this model, the sharp rise from the $p+d$ threshold previously reported may be identified as a $^{2}S\ensuremath{\rightarrow}^{2}S$ Coulomb monopole transition.

Electrons at five energies between 60 and 120 MeV were used to study the giant electric-dipole and -quadrupole resonances in /sup 20/Ne. Prominent electric-dipole peaks were found at 17.7, 19.1, 20.2, and 23 MeV in good agreement with photoreaction results. In addition our analysis reveals weaker fragmented electric-dipole strength in the region between 12.5 and 15 MeV. Prominent electric-quadrupole peaks were found at 13.0, 13.7, and 16.2 MeV, and a broad peak was found from 14.2 to 15.9 MeV. Two different analyses reveal a broad quadrupole excitation between 16 and 25 MeV. The dipole and quadrupole resonances deplete about 65% and 100% of the energy-weighted sum rule, respectively.

A relatively background-free gas target with replaceable foil windows is described.