Investigations of the electrical response of diffused p-n junctions in silicon to charged particles were made on detectors obtained from two sources.

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

The development of high-energy charged particle accelerators such as the Bevatron and of improved nuclear-event detection devices such as the Berkeley 72-in. hydrogen bubble chamber has greatly increased the need for high-speed data reduction of nuclear events. Full exploitation of the potential of the 72-in. bubble chamber demands a very high-speed analysis system. This paper describes an approach to such a system.

To date limited agreement has been obtained between theory and experiment for 4f to 4f transitions for Tm (IV) (4f12). It is clear from the considerations that have appeared so far in the literature that intermediate coupling is important in the case of Tm (IV). Solutions of the intermediate field equations yield [formula], and [formula]. Experimental agreement to [formula] was obtained.

Our aerosol program employing monkeys has been initiated. A plutonium oxilate solution was introduced into the trachea. Preliminary results of the fecal and urinary determinations appear here.

Based on the assumption that the noise contribution of a semiconductor detector is due solely to the bulk properties of the semiconductor, equations are presented which indicate the theoretical limits of noise in detector-amplifier combinations. These equations show that an optimum amplifier time constant and detector bias voltage exist for which condition the minimum noise is independent of the semiconductor resistivity. The optimum performance of a detector-amplifier system is shown to depend only upon detector area, input capacity (less detector capacity), semiconductor minority carrier lifetime, and the transconductance of the amplifier input tube. A new detector structure including a guard-ring electrode as an integral part of the detector structure is described which largely eliminates noise due to surface leakage. Experimental results for detector leakage and energy resolution are presented which agree well with theory.

If a piston with constant velocity moves into a shock tube containing material at rest and at uniform density, the result is well known and trivial. The shock propagates with uniform speed, the state and speed of the material behind the shock is constant. One can ask if similar flows exist for cylindrical of spherical symmetry. Quickly one rules out the possibility of a solution which retains all the properties of this trivial solution. One asks if there are any solutions such that the material behind the shock is not accelerated. Indeed, there are. In the following, it is shown that for a y-law gas, there is a family of densities such that if a piston moves into the material with uniform velocity, the material behind the shock is not accelerated. Further, these are the only densities with this property. In the case of planar symmetry, the trivial case mentioned above is a member of the family, as is to be expected.

The root locus method of the treatment of stability problems in the field of servomechanisms is briefly summarized. A simple mechanical instrument of the analogue type (a summing device) containing no gear mechanisms, and designed to do most of the numerical work of the root locus method, is also described.

Statistical methods were employed to measure relative values of electron loading and spark-over voltage for a large number of unoutgassed electrode materials. Test voltages up to 110 KV were employed in vacuum of the order of 10<sup>-7 mm Hg. All metals showed a square root dependence between spark-over voltage and spacing.

In the Plowshare Program many calculations of the effects of underground explosions are made. Usually these are done on high-speed digital computers. The effects are calculated for ranges up to hundreds of meters from the explosion; at these ranges pressures become less than one kilobar. In order to make these calculations, information about the properties of the materials involved is required. Benedick [13] has developed a low-pressure, plane-wave lens using nitroguanidine. It was decided to use a similar lens in the Plowshare Program. A number of lenses were built using Benedick's technique. This report is of a study of simultaneity and pressure uniformity of these lenses, with some attempts at development of a reflection pressure vs particle velocity curve for them.

A fraction of the energy released by the underground detonation of nuclear explosives is locally deposited as residual thermal energy. An accurate prediction of this usable fraction of the energy released is necessary to evaluate the feasibility of several of the proposed projects in the Plowshare Program. This paper will present a summary of the available data on residual thermal energy from nuclear detonations in three different geological media: tuff, halite, and granodiorite.

Recent studies on the separation of cobalt and nickel and on the behavior of iron in hydrochloric acid on Dowex-1 resin in relation to the selective adsorption of chloride complexes of these elements have suggested the use of resin for the separation of iron and cobalt.

Let F be the flux of radiation going from a sample of radius R2 to a counter of radius B1 then the emitted intensity of radiation per unit solid angle. Then the flux between two elements of area do1 and do2 will be given by [equation] since [equation] and [equation]. Calculations and equations follow.

Even in its present primitive stage the molecular beam method promises to open up many opportunities for detailed studies of reactive collisions. The early results described here have revealed several features inaccessible to the traditional methods of kinetics. We hope this program of beam studies will ultimately provide the basis for constructing a theory of the molecular mechanics of reactions. By borrowing what are now everyday techniques in nuclear physics (modulation of the beams; mass analysis and counting of detected ions) it appears possible to gain from four to six orders of magnitude.

A method is presented for measuring the average energy of the neutrons from a source. The attenuation of the neutrons by polyethylene is measured by the use of a long counter in good geometry. The attenuation length is a sensitive function of the neutron energy. The average neutron energies from several (o, n) sources have been measured and agree well with values obtained by other techniques.

A calculation method has been developed in order to correlate continuous-flow extraction results in mixer-settlers with rate data for batch experiments. This correlation utilizes dynamic extraction coefficients (E's) that are calculated from the rate data and the equilibrium extraction coefficients. The dynamic coefficients may then be used in stage-by-stage calculations, or their average values used in equations derived herein from the overall performance of center-fed columns.

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.

Individual Samarkand wildtype D. melanogaster males were permitted to choose between either two white-eyed or two red-eyed females or between a red-eyed and a white-eyed female. Observations of the flies were made over a period of about two hours and premating periods, intermating periods and the durations of copulations were recorded.

Certain aspects of mating behavior in two different types of Drosophila melanogaster females (Basc and Bv) and wildtype males (Samarkand) have been investigated and compared.

Certain isotopes in the region of the heaviest elements have been produced by cyclotron and pile bombardment techniques, and their nuclear decay properties have been investigated. The orbital electron capture decay of At210, At211, Np234, Np235, Pu234, Pu237, and Am242m has been studied and decay schemes have been proposed. In addition, the alpha spectra of Po211, At210, and At211 have been observed.

The increasing exponential function e-at [a > 0] characterizes such natural events as gas discharges, neutron multiplication, and the transistor avalanche phenomenon. This report describes an instrument for measuring the rate of rise, a, of an increasing electrical exponential signal.

This report was prepared at the request of the Subcommittee on Radiochemistry of the Committee on Nuclear Science of the National Research Council as a contribution to a proposed master file on the radiochemistry of all the elements. All known material on the radiochemistry of thorium is included in this report.

This revised version contains material published in the two years since the original report was issued in January 1960. The report covers the history of the discovery of fission, fission theory, and the probability of fission. It discusses the distribution of mass in fission, the distribution of nuclear charge in fission, kinetic energy of fission fragments, and the role of neutrons and gamma rays in fission.

The absolute differential cross sections for elastic scattering of 31-Mev He3 ions on Be, Al, Cu, Sn(nat), Sn120, and Bi have been measured in the angular range of approximately 10 to 120 deg in the center-of-mass system. Thin self-supporting foil targets were chosen to span the parameter A 1/3, where A is the target mass number. The first excited states of the isotopes of the above elements had sufficient energy separation from the ground state to enable elastic scattering to be resolved from inelastic scattering. The detection system, consisting of Cal(Tl) scintillation crystals, was capable of 3%pulse-height resolution and 1 degree angular resolution. Characteristically, the light-element angular distributions show strong diffraction effects. The differential cross section divided by the Rutherford cross section decreases exponentially at large angles for the heavy elements, and the differential cross sections break away from Rutherford behavior at angles which increase almost linearly with increase of atomic number of the target nucleus. A comparison of the results for natural tin, and tin enriched to 85% in Sn120, indicated that within the experimental uncertainties over the measured angular interval, there were no pronounced isotopic effects. The data are presented both in tabular and graphical form to allow …