A principle for bending crystals with a minimum of strain so that they will focus x-rays and gamma-rays accurately to a point is explained. Detailed calculations are made of the aberrations in the foci resulting from various applications of the principle. the application of the principle in making a point focusing monochromator for low angle x-ray diffraction studies is discussed, and theoretical and experimental determinations of the reflection coefficient of the crystal are compared. A few experiments in low angle diffraction from biological materials using the new monochromator are described, and the results are compared with those obtained using other instruments.

The status of research is reviewed in a study of pulmonary granulomatosis in beryllium workers. Equipment for use in dust exposure studies is described. Preliminary results are reported from studies on the tissue distribution and pathological effects of beryllium dust in rats; the physical chemistry of solutions of beryllium salts; the effects of beryllium on enzyme systems, and the effects of ascorbic acid on beryllium excretion.

A wet collection system for aerosols has been developed using fibrous media. Tests show the performance to be in accord with recently developed theory of collection by fibrous media. The effects of varying aerosol particle size, particle density, and gas velocity have indicated that inertial impaction is the primary collection mechanism. Three-year operating experience on several full scale plant installations shows reliable performance.

A method to determine the correction to Grüneisen's law corresponding to the effect of the electrons at high pressure. It is assumed that the lattice contribution to the pressure is small and that the equation of state of the solid can be approximated by results of the statistical Thomas-Fermi atom model for the electron pressure.

"ABS>Injection trajectories were calculated for different injection conditions for the Cambridge Electron Accelerator, considering also the effect of magnetic fringing fields. The general problem of matching the emittance of the linac to the acceptance of the synchrotron in the transversal phase space is considered, and it is shown that this can be done by a set of two quadrupole lenses. In order to eliminate rudial betatron oscillations due to energy deviations of the injected particles, a pulsed electric quadrupole lens in the synchrotron in combination with two deflectors between linac and synchrotron can be used to place particles of different energies on their specific equilibrium orbits. A layout of the whole injection system following the output of the linac is given."

A method is described for the production of single‐crystal films of copper at temperatures as low as −40°C. This method utilizes the epitaxy of copper on rock salt. A thin layer of copper is evaporated on a single crystal of salt at 350°C. Then a thick layer is evaporated at the low temperature. Films grown by this method have been examined using x‐ray and etching techniques. It was found that some of these films had single‐crystal regions of 1 mm diameter and larger. These crystallites had [100] directions within 1° to a normal to the film surface.

Detailed information on the radiations associated with several even-even isotopes has been obtained. In some instances enough information has been gathered to allow construction of skeleton energy level diagrams for the isotopes. Activities studied were obtained from pile irradiation of pure odd-even natural isotopes and included Dy160, W182, Sm152, Gd152 and Gd154. Details of the work done on and results obtained for these isotopes are reported in section 3. Some analytic and experimental studies were carried out on the application of tilting beta-ray spectrograph sources for improvement of resolution. The uses and limitation of this technique are discussed in section 2.

Methods of prebatching the electron beam by velocity-modulation techniques prior to injection into a linear accelerator are discussed. A particular method (i.e., bunching at the injection energy) is analyzed in detail for one- and tw0-cavidy bunching. The physical design f a single cavity prebuncher is given for a modulation voltage 10 percent of the injection voltage and a drift space of 40 cm.

The statistical theory of pressure broadening is developed for any interaction law in which the potential energy is inversely proportional to some power of the distance between the molecules, including cases in which the forces change sign. This note is intended to prove two propositions: A. When a spectral line is broadened by single impacts of perturbing molecules and the half-width of the line is delta infinity, the statistical theory of broadening is applicable provided delta infinity . R >> 1. In this criterion T is a time comparable to the interval in which the perturbed traverses a distance equal to the impact parameter. B. Far in the wings of a line the statistical theory is always applicable.