The Bevatron requires an intense source of high energy protons. The machine should accept monoenergetic protons for a duration of approximately 500 microseconds once every 6 seconds. To satisfy the requirements of small loss due to scattering by the gas in the accelerating chamber, a 9.9-Mev linear accelerator has been built and operated.

An R.F. joint tester was designed to determine the relative heating and tendency toward arching at high RF current density (100 amps/linear inch) of a 12 inch diameter circular copper butt joint in vacuum with several types of inserts and at various amounts of axial loading, ranging from a very small contact pressure to one of 1400 pounds per linear inch of joint.

Describes the investigation of a particular method of extracting ions from an arc. Experimental results of a low extraction voltage ion source are given in some detail.

In another paper there was reported an attempt to observe the charge-exchange process in a counter-triggered multiplate cloud chamber at the Bevatron but the interpretation was ambiguous. Shortly after the close of that experiment the 30-in. propane bubble chamber at the Lawrence Radiation Laboratory was completed and able to be used for a combined engineering test and experiment. The existence of Reaction (1) has been confirmed in this experiment, and an approximate cross-section value for carbon is calculated.

An experiment was designed utilizing a charge-exchange reaction to study the decay and interactions of the neutral K mesons produced. The experiment produced no events that could be interpreted as either the decay or interaction of neutral K mesons. The nature of the experiment and the possible explanations of this unexpected result are presented in this paper.

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.

Analysis of the problem of accelerating ions in a Thomas cyclotron has been confined almost entirely to the integration of various equations of motion (for single particles) for which a complete field description is necessary. In contrast, the problem of principal interest to rf system engineers concerns the gross transfer of electrical energy from an rf generator into an accelerated beam.

Measurements were made on the full scale drift tube magnets to check values predicted from the model magnets measurements. These investigations were carried out by the magnetic measurements group.

We have preliminarily reported the interpretation of our experimental results that the intensity of the spectrum at the maximum energy was zero. But, as reported in the second paper UCRL-1261 we found that the results may also be fitted to a different spectrum with finite intensity at the maximum energy. Quite recently, however, the most probable value for the mass of the p-meson has been revised by two independent groups based on two different experiments.

The previous calculation of the energy spectrum of the high energy deuteron beam from the stripping of He3 (UCRL-2150) was thought to be in error, especially as regards the low energy tail, on the basis of some experiments with the neutron time-of-flight detector, which indicated a considerably narrower spectrum than that calculated in UCRL-2150. Since the value used for the attenuation cross section of deuterons in uranium is considerably lower than that presently considered correct a new calculation was made using this latter cross section. Since the equations used in this new calculation differ somewhat from those used in the previous report a brief derivation is given here.

A "particle" of charge Ze moves with velocity v, mass M, energy [formula], through a "substance" of atomic number Zo, density N atoms/cm3. We have to consider the process of slowing down, and the nature of the trail of ions produced. Very slow particles are of little interest, as their range is very short. If Z is large, or if the particle is an electron, there are complications which we postpone. Thus, our considerations will apply particularly to protons, deuterons, o< -particles, and mesons.

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.