The principal types of particle accelerators are described briefly according to operation and history. Known operating particle accelerators are listed with their pertinent dimensions.

This report summarizes the original construction and recent modifications of the electron-electron coincidence spectrometer BRS-IV located in Building 70 of the Lawrence Radiation Laboratory. In addition to new information on the modified spectrometer, this report also contains a large amount of material taken from two previous UCRL reports.

Ever since the existence of a bound state of Hydrogen was discovered, it has been uncertain whether any other bound states existed. In addition to its importance in astrophysics this question has also come up in discussions of the scattering of electrons from hydrogen. To settle this problem it is necessary to calculate lower bounds for the eigenvalues of the Schrodinger equation. A simple calculation has been carried out for the problem of the negative hydrogen ion.

An exact treatment of the structure of tracks in nuclear research emulsion recently was attempted with some success. Many of the proofs also appear to be generally valid for bubble tracks in Wilson chambers. This is a summary of the results that are applicable to tracks of charged particles in bubble chambers.

A preliminary investigation of four types of multiplier phototubes under conditions simulating their use in scintillation and Cerenkov nuclear detectors is described. The investigation involves time-spread and rise-time measurements at different reference points on the outpost pulses, as well as observations of some special characteristics of these tubes.

The problem of the reduction of an arbitrary truth function to the minimal union of basic cells is discussed. The solution to this problem has applications to pattern recognition and logical circuit design. An algorithm is presented that solves the problem and generates the class of minimal unions. It partitions an arbitrary truth function into a well-defined set of subfunctions (components) in such a way that the partition is invariant under all transformations that preserve the topology of the original truth function.

The theoretical half lives for alpha emissions have been calculated for nearly all of the complex alpha spectra. The spin independent equations of Preston were used for the calculations. The nuclear radius for the even-even nuclei was determined with the assumption that the alpha transition to the ground state is unhindered. For odd mass nuclides the average of the nuclear radii of the adjacent even-even nuclides was used. For odd-odd nuclides the average of the nuclear radii of the adjacent odd mass nuclides of the same atomic number was used.

This paper reports an extension of previous experimental work with Alfven waves. We consider hydromagnetic waves propagating in a cylindrical plasma in a uniform axial magnetic field. The copper tube is filled with highly ionized plasma by an electrically driven switch-on ionizing wave. After the tube is filled with plasma, a hydromagnetic wave is induced by a radial current flow from the small molybdenum electrode to the copper tube. The force produced by this radial current together with the static axial magnetic field displaces the plasma in the azimuthal direction, and a transverse wave is propagated in the axial direction, along magnetic field lines. The transient magnetic field associated with the wave is also in the azimuthal direction.

Volatile hydrides may be prepared from ether solutions by the reaction of the appropriate chlorides with lithium hydroaluminate. In this general method, it is necessary to work with strictly anhydrous reagents and solvents because of the great reactivity of lithium hydroaluminate toward water. The procedures described here are believed to be much more convenient because the reducing agent employed is potassium hydroborate, which is relatively insensitive toward water. Since only aqueous solutions are involved, there are no solvent-purification steps and there is no dissolution or contamination of stopcock grease, etc.

It is possible to generate a relatively uniform, highly ionized plasma by passing a powerful discharge between electrodes so arranged that the current is forced to flow across an initial strong magnetic field. The magnetic induction due to the discharge causes a bending of the original field. If the discharge is operated with a low-impedance current source, the electric breakdown starts in a limited region near the current-input connections (minimum-inductance path) and propagates as a well-defined front in the manner of a hydromagnetic shock wave. In this paper we analyze the phenomenon as a one-dimensional single-fluid hydromagnetic problem, neglecting dissipation behind the wave.

In a previous publication we reported measurements of the momentum spectra of He<sup>3 and H<sup>3 nuclei produced in collisions of 740-MeV protons with deuterium. The He<sup>3 spectrum exhibited an anomaly in the form of a peak in the region corresponding to double pion production. For reactions resulting in a He<sup>3 the two pions (or particle) can be isotopic spin states 0 or 1; if a H<sup>3 nucleus results only 1 = 1 is allowed. We have since repeated the experiment with a new arrangement which enabled us to measure both the He<sup.3 and H<sup>3 spectra with improved resolution and accuracy.

The problem of the natural convection of an electrically and thermally conducting fluid within a long, narrow, vertical toroidal channel centered in a large block of an electrically and thermally conducting solid is analyzed. A uniform horizontal magnetic field is applied to the fluid, and the bottom of the solid block is maintained at a higher fixed temperature than the top. The laminar steady-state single-cell convective motion of the fluid is considered and an approximate solution is found for the heat transfer rate between the bottom and top surfaces of the block in the limiting cases of small and large Hartmann number. A numerical example is given for liquid sodium in which the application of a magnetic field of a few hundred gauss is shown to significantly reduce the rate of heat transfer.

An electron can suffer a very large acceleration in passing through the Coulomb field of a nucleus, and in this interaction the radiant energy (photons) lost by the electrons is called bremsstrahlung (also, bremsstrahlung sometimes designates the interaction itself). If an electron whose total energy [formula] traverses matter of atomic number Z, the electron loses energy chiefly by bremsstrahlung. This case is considered here.

The sodium-ammonia solution system permits investigation of an array of compositions spanning the transition from non-metallic to metallic bonding. Reflection spectra in the range 1-20 [ ] were measured for solutions of mole ratio 5.5 to 168 [ ] per Na. The dilute solutions show peaks characteristic of the vibrations of ammonia and a strong peak near 1.5 [ ] which is assigned to the solvated [ ] species. Concentrated solutions show high reflectivity over broad wavelength ranges. The results for nearly saturated solutions are fitted reasonably by the free electron model, but in the range of mole ratio 10-15 a complex array of energy absorption processes of finite frequencies are required to fit the spectra.

Females heterozygous for a wildtype X chromosome from a Samarkand stock and an chromosome of the composition [formula] were tested for the frequency of X-chromosomal non-disjunction and segregation of the X's when Y chromosomes of different types were present in the females. The Y chromosomes used were 1) a normal unmarked Y, 2) [formula], 3) [formula] and 4) [formula] (a chromosome which arose in one of our experiments and has not yet been analyzed). Since this was only a preliminary test no attempt was made to isogenize the stocks. Larger scale experiments are planned in which these and other Y's will be used and the genetic background will be strictly controlled.

Use of that portion of the characteristic curve of photographic film in which transmission is linear with log exposure eliminates the distributional error and thus makes possible the assessment of total mass of an inhomogeneously distributed cell consistent without scanning or measuring the cell's projected area. Measurement consists of obtaining the difference in output of a photocell receiving the total light transmitted by a photomicrograph of the cell, and a photomicrograph of the microscope field illumination against which the cell was photographed. A method of making such measurements is given, and its basis is described.

The effect of temperature on the yield strength of the polycrystalline hexagonal Ag-Al intermetallic phase was investigated over the temperature range 77 to 775 K. It was found that the curve for yield stress vs temperature for both polycrystalline Ag-33 at .% Al specimens that were heavily cold worked prior to deformation and those that were recrystallized prior to deformation was parallel to that for prismatic slip in single crystals.

This report was written from the notes used by Dr. York in delivering his three lectures on considerations pertinent to the problem of utilizing controlled thermonuclear reactions for the production of power. The first lecture discussed fundamental properties of the DD and DT reactions and the reacting substances. The second lecture described the stellarator, a proposed machine for the controlled production of power from the above reactions. The third lecture described the pinch effect and considered its possible application to the thermonuclear power problem.

Physics Division quarterly report - general physics research projects and accelerator operation and development.

Summary of research progress meetings of October 2 and October 9, 1952: High speed high vacuum ion pump, High energy ion irradiation, Space charge accelerator for protons, Availability of the [ ] meson beam at the cyclatron, Effect of chemical structure on stopping powers for high energy protons.

The final r.f. characteristics of A-12 are shown. The mechanical features are available in UCRL-1859. If A-12 were to be changed to 24.2 mm rather than 12.1 mm, keeping the same length and the same constant average coil gradient of 0.375 MV/ft., the characteristics of such an A-24 can be obtained from the attached curves.

Reports on the biological studies of radiation effects, the metabolic properties of various materials, health physics and chemistry.

The intuitive concept that a sector shaped centrifuge cell is free from convection is criticized. Not only is a form of convection present for a single sedimenting species, but a more insidious type occurs in a mixture having an appreciable Johnston-Ogston effect. Rather than striving for convection-free sedimentation, the proposal is to utilize if possible an apparently harmless type of convection occurring in a very thin annulus in order to avoid the convection extending between boundaries in a mixture. The requirement that the concentrations be independent of time meets this condition and yields a hyperbolic cell, which is approximated by a sector cell placed in the rotor backwards. Simultaneously, area measurements and calculations involving the Johnston-Ogston anomaly are simplified because of the time independence.

Quarterly progress reports on various projects in the Chemistry Division.