The following report describes a current beam modulation designed to replace the standard regulator and to achieve an ion beam free from amplitude modulation.

From abstract: "Benzene shows weak absorption bands in the 3 aliphatic C-Z region of the spectrum. The peaks of these bands are at 3.439, 3.459, 3.504, and 3.545."

Report describing processes to prepare metallic calcium of a very high purity. Report details promising methods for electrolyte purification. Methods of chemical analysis for nitrogen are also improved upon and spectrochemical methods and standards established for twelve other specified elements.

The following report is a quarterly report done by the Physics Division of the University of California's Radiation Laboratory, covering the period of February 1, 1948 to May 1, 1948. This report discusses general physics research and the development and operation of the accelerator.

In an effort to gain information on the nature of the photon-meson and photon-nucleon interaction, a study of the artificial production of mesons by photons has been made at the Berkeley synchrotron. The major effort of this research was concentrated on a measurement of the energy and angular distribution of u+-mesons produced when the photons strike a target of liquid hydrogen. Detection of the mesons is accomplished electronically by the technique of delayed coincidence.

From abstract: "The purpose of this investigation was to establish basic rates of formation of chemical films deposited on aluminum surfaces from water flowing over such surfaces. It was desired to obtain specific information, within certain ranges, as to the influence of temperature, water velocity, and type of aluminum on the rate of film formation."

This report discusses preliminary results acquired from investigations made on the ultrasonic properties of uranium, such as sonic vibrations in the megacycle frequency range.

The angular distribution of charged x mesons produced by 300 <x> 30 Mev neutrons on C12 and Be9 have been studied. An analysis of the kinematics for meson production in a nucleon-nucleon collision indicates a fairly well defined center-of-mass system.

Plus-minus ratios for pion production by 340-Mev proton bombardment were measured at 13 Mev, 18 Mev, and 42 Mev with the use of the spiral orbit spectrometer.

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 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.

The hydrogen contents of several types of fabricated uranium have been determined by a vacuum method and expressed in terms of ccH2/ccU. The data indicate that alpha-rolled metal contains about 0.25 ccH2(STP)/ccU whereas beta heat-treated uranium yielded values between 0.30 and 0.37 cc per cc. Restricted efforts were made to determine where in the heat treatment the 5 to 10 cc of hydrogen per slug were taken up. It appears that no one operation is wholly responsible for this additional gas, although reactions between beta heat treated surfaces containing microscopic defects, and nitric acid may possibly play a large role. In general it may be said that slug produced by powder metallurgical techniques contain less hydrogen than pieces produced by rolling and heat treatment.

The design and construction of a 1,000,000 fps rotating mirror frame camera is described. Twenty five consecutive pictures 20 mm in diameter can be obtained on a strip of 35 mm film. A resolution of at least 20 lines/mm is obtained on a moderately fast film like Linagraph Shellburst. Accurate synchronization of the event to be photographed is required. The camera has been most useful in the investigation of explosive and related phenomena.

This paper describes the method developed and the results obtained in an extensive program of measurement of the masses of charged pions. Measurements were made of the total ranges in nuclear track emulsion and the momenta (obtained from the curving of the particle trajectory in the magnetic field of the 184-inch cyclotron) of pions and protons of nearly the same velocity.

From introduction: "This article constitutes the third of a series of three papers on the "direct" measurements of the meson masses by the "Hp vs. Range" mass ratio method...The study here reported is a logical extension of the pion-proton mass ratio technique."

"Work has continued on high temperature methods for processing irradiated uranium fuel. Additional results have been obtained with fused halide treatment, solid scavengers and direct Pu distillation. With fussed fluorides about 95 per cent of the Pu was removed from a uranium sample, while treatment of uranium with HC1 gas removed almost all the Pu and many fission products. treatment of molten uranium with uranium oxide removed a substantial fraction of the fission products without removing Pu. Uranium carbide treatment results were similar to the oxide but not as effective. A small scale distillation of Pu from uranium showed that Raoult's law is obeyed."

"Continued progress has been made with the high temperature decontamination processes for irradiated uranium fuel. The fused salt treatment of molten uranium has been extended to UCl3. Plutonium and rare earths were extracted into the UCl3 phase. Direct plutonium distillation from molten irradiated uranium has been scaled up to the hundred gram scale. Solid scavenging experiments using uranium oxide, uranium carbide, and uranium nitride in contact with molten uranium have indicated fission product removal. A scaled-up investigation of the separation and recover of uranium from an SIR type ceramic fuel using the volatile fluoride process has indicated the feasibility of this separation method. The effect of irradiation on the decomposition of BrF3 has been further studies in experiments using the NAA statitron.'

"Scale-up work on high temperature fuel recovery processes has progressed to the point where the (high temperature) vacuum furnace for several operations to the hot cells has been completed and tested under operating conditions. Small scale experiments on high temperature methods for processing molten irradiated uranium fuel have been made with spent X-10 fuel slug pieces. The results of direct Pu evaporation, treatment with fused fluorides and oxide scavenging were every similar to those found with tracer experiments."

The liquid metal level instrument will operate at tank temperatures up to 1000 F. Overall system accuracy depends on operating conditions, as described in the report. Test accuracies from 2 to 8% have been obtained from full to empty tank. The primary detector unit successfully passed navy HI shock test.

Abstract: "A theoretical criterion is given for the conditions under which the ions from an ion source may be decelerated by a decelerating grid, following the accelerating grid which extracts ions from the emitter, without causing a reduction in the current supplied by the source."

"Yields of N¹⁷ relative to that produced in LiF have been measured in the 190-Mev deflected deuteron and the 380-Mev alpha beams of the 184-inch synchrocyclotron. The measurements have been performed in all the light elements from 0 through V, with the exception of Sc and the noble gases. In addition, yields were measured in the separated isotopes of Mg...Comparisons are made with other types of yield studies performed with neutrons and protons, and the areas of agreement are noted."

Metallographic examination of an irradiated powder metal uranium slug from PT-313-105-4M⁽¹⁾ was undertaken primarily as an evaluation of recently remotized metallographic equipment. It was, also, proposed to compare the grain size with values obtained ultrasonically on the same slug. It was further proposed to make a comparison, so far as limited data permitted, of post-irradiated powder metal uranium grain size with that to be expected from normal uranium similarly irradiated.

Thorium is determined in uranium alloys by means of a fluoride separation followed by a complexometric titration. A nitric of hydrochloric acid solution of the alloy is neutralized to a pH of 2.0 to 3.0 and the thorium precipitated as thorium fluoride by the addition of hydrofluoric acid and ammonium fluoride using lanthanum as a carrier.

Abstract: "Formulas are derived for the trajectory of a charged particle in a magnetic field which is a linear function of time. Graphs of certain functions are presented, by means of which a trajectory with given initial position and velocity may be plotted."