This report addresses the control servo power requirements.

The availability of separated isotopes of Mg makes it easy to determine the half life of Al{sup 26}, a member of the Wigner series which has long been suspected to have a half life of approximately 7 seconds, but which has not been confirmed because of the masking 7 second activity of Al{sup 26}. Mg{sup 24}, Mg{sup 25} and Mg{sup 26} (in the form of MgO) have been bombarded with protons from the Berkeley Linear Accelerator, with the following results: (1) Mg{sup 24} yields an activity of approximately 23 seconds half life, presumably due to Na{sup 21} from the reaction Mg{sup 24}(p,a)Na{sup 21}; (2) the Mg{sup 25} yields an activity of approximately 8 seconds half life, which they assign to the reaction Mg{sup 25}(p,n)Al{sup 25}; and (3) The Mg{sup 26} yields an activity of approximately 6 seconds half life, assigned to Al{sup 26} according to a similar reaction. It seems probable therefore that the 7 seconds half life normally given for Al{sup 26} is a mixture of these two activities.

This paper describes a high voltage pulse generator developed to deflect the beam of the 184-inch cyclotron at Berkeley, California. The apparatus develops a deflecting potential of 200 kilovolts that rises from 10% to 90% of peak value in 0.1 microseconds. The unit employs two similar 100 kilovolt water cooled pulse transformers connected symmetrically about ground to the electric deflector bars. Water-cooled General Electric pulse capacitors are discharged through the two turn primary windings of the pulse transformers by triggering a battery of 16 paralleled Kuthe 5022 hydrogen thyratrons. Output voltages are developed across the 17 turn secondary winding of the pulse transformer. The transformer is mounted in an oil filled lucite case that provides both insulation and compact design.

Routine inspections of selected Van Stone flanges have been made at all three piles since start-up. In September, 1947, these inspections indicated that corrosion effects were becoming dangerously severe. Some of the flanges appeared to be corroied and pitted to a depth of two-thirds of the original flange thickness. To determine the extent and severity of the corrosion, residual flange thickness measurements were made on the flanges of about 64 scattered tubes. Included were front and rear flanges of tubes from all four orifice zones. Results of the survey indicated the immediate need for an extensive repair program to preclude the possibility of failure of some of the flanges.

In order to evaluate the feasibility of segmental discharge equipment, it was necessary to determine the time required for segmental discharge during the current operating procedures. This memorandum details this time study.

For a number of investigations, including fundamental studies of radiation effects on living tissues and therapeutic utilization of radioisotopes, it is valuable to have methods for the selective localization of radioisotopes in certain tissues. Finely dispersed anhydrous chromic phosphate has been found useful by Jones, Wrobel, and Lyons in selectively irradiating the liver and spleen with p{sup 32} beta particles. The present studies, reported in this and the following communication, are concerned with methods for controlled selective localization of colloids (incorporating radioisotopes) in the liver, spleen, or bone marrow, and with an analysis of some of the factors involved in the phenomenon of localization.

Several workers have shown that certain colloidally dispered materials are removed from the blood stream by the liver and spleen. Jones, Wrobel, and Lyons have utilized suspensions of anhydrous chromic phosphate for the selective irradiation of the liver and spleen with p{sup 32} beta particles. Gersh demonstrated that colloidal calcium phosphate is taken up by the liver and spleen. He stressed the failure of bone marrow phagocytes to take up this colloid in rats and dogs (though he referred to possible uptake in the marrow of rabbits under special conditions), and commented on the relative 'refractoriness' in general of the bono marrow as compared with liver and spleen with respect to the uptake of colloidal dyes from the blood stream. Some histological data indicate that 'Thorotrast' (a colloidal thorium dioxide preparation) is deposited in the bone marrow as well as in the liver and spleen, but no quantitative data as to the relative distribution are available. In the preceding communication the methods for the preparation of colloids incorporating radioisotopes of yttrium, columbium, and zirconium were given. The present studies are concerned with the localization of such colloids primarily in the bone marrow or primarily in the spleen and liver, with …

The reaction C{sup 12} (p,pn)C{sup 11} which has been studied by McMillan, Chubb and Miller for energies up to 100 Mev is an example of a reaction whose high energy behavior cannot be explained by a compound nucleus process. The purpose of the study was to investigate this reaction at the high resolution possible with the Berkeley linear accelerator near the excitation threshold. The excitation curve was obtained by stacking specially molded polystyrene (composition C{sub n}H{sub n}) foils of high uniformity and bombarding them in the proton beam. The resultant activity was then counted on a Geiger counter in standard geometry. The resultant curve is shown in Figure 1. An immediately evident feature is the sharp threshold of the reaction. The second derivative curve, illustrated in Figure 2, of the excitation shows an RMS width of 270 kV, the theoretical straggling width due to the foils of 170 kv, and the remaining width in accordance with the energy spread of approximately {+-} 100 kv half width of the linear accelerator. The data therefore are compatible with a sharp threshold for this reaction. This curve, incidentally, furnishes independent evidence as to the energy homogeneity of the linear accelerator beam.

None

The fission distribution of fission of thorium with alpha particle of average energy 37.5 Mev has been measured by the chemical method. The distribution found shows that the characteristic dip in the fission yield mass spectrum has been raised to within a factor of two of the peaks compared to a factor of 600 in slow neutron fission of U{sup 235}. The raise in the deip has caused a corresponding lowering in fission yield of these elements at the peaks. The cross section for fission of thorium with 37.5 Mev alphas was found to be about 0.6 barn, and the threshold for fission was found to be 23 to 24 Mev.

This trip was to provide an answer to these questions: Are Hanford meteorological instrumentation, methods, and records adequate? Do they conform to generally recognized practice? Are they effectively utilized? What is the percentage frequency of wind classified according to conditions normal, least favorable and most favorable for dilution? What is the habitability of the Wahluke Slope north and northeast of the Columbia River, considering stack gases, various stack heights, any pertinent meteorological features? What is the habitability if the only contaminating sources are the piles? In preparation for and in the event of a major catastrophe with attendant relief and evacuation operations, which additional observation should be taken: What weather data should be assembled from the general vicinity of Hanford: What sampling program should take place immediately after the event. To these may be added a question raised by Dr. Parker in connection with the high level of contamination at the ground in the vicinity of the separations. areas.

The production of U{sup 232} by the sum of {alpha},4n and {alpha},p 3n reactions on thorium has been studied. The cross section at an average energy of 37.5 Mev was 0.013 barns and the threshold for the reaction was about 30 Mev.

This report discusses progress on the following topics: (1) some new isotopes in the rare earth region; (2) remarks on a new alpha series; (3) solid counters; (4) naphthalene crystals have been replaced with anthracite in one of the experimental counters and some excellent results are obtained; and (5) biological experiments with the deuteron bean of the 184-inch cyclotron.

Fifty-four spectral lines of curium are listed together with estimated intensities. A brief description of the manner of taking the spectra and of measuring the lines is given. Three separate samples of curium, in all seven micrograms, were submitted for spectrochemical analysis. The samples in acidic solution (HCl) were evaporated on copper electrodes and analyzed as outlined for the copper spark method. An Applied Research Laboratories spark source was used. The spectra were taken on a Baird Associates spectrograph of the modified Eagle type which has a dispersion of 5.6 A/mm in the first order. Spectrum Analysis photographic plates were used and were processed according to the manufacturer's recommendations. The plates were placed in the projection comparator (also an Applied Research Laboratories Unit) and the lines measured using the scale associated with the projection screen. The copper lines of the spectra were used as a wavelength standard. In all 54 lines which we feel can be attributed to curium were found. These, together with an estimated intensity based on an arbitrary 1 to 10 scale, are listed in Table 1. Due to the high alpha-activity of curium special care had to be exercised in handling the samples. In this case …

This report provides a summary of the Health and Safety Conference held April 1948 at Chicago, Illinois. Representatives of Argonne National Laboratory, Rochester University, University of California Radiation Laboratory, Los Alamos Scientific Laboratory, New York Memorial Hospital, as well as a Canadian group and an United Kingdom group. Many topics were discussed some of which were plutonium in urine, toxicity of beryllium, and relative toxicity of radioelements.

None

This report documents the meteorological concerns for Hanford Atomic Production Operations (HAPO). There was a concern that the radionuclides that were being released in the atmosphere. The author suggests a hypothesis to keep the radionuclides from migrating in the atmosphere. This hypothesis describes the washout of radionuclides and the leaching into the soil as a method to contain the radionuclides at the production facility. The hypothesis takes into account wind velocity, stable and unstable atmospheric conditions, convection, boundary layer problems, diffusion at greater distances away from the source of pollutant, altitude, and a possible solution.

The authors have observed traks which they believe to be due to mesons in photographic plates placed near a ta5rget bombarded by 380 Mev alpha particles. The plates used were Ilford Nuclear Research Plates, type C.2. the identification of the particles responsible for the tracks was first made on the basis of the appearance of the tracks; they show the same type of scattering and variation of grain density with residual range found in cosmic ray meson tracks and about two-thirds of them produce observable stars at the end of their range. For a 10-minute exposure in the cyclotron, about 50 meson tracks are found along the 3-inch edge of a photographic plate. Carbon, beryllium, copper, and uranium have been used so far as target materials, and all are found to give mesons. When a carbon target was bombarded with 300 Mev alpha particles, mesons were found but with reduced yield.

This summary of the research progress meeting on April 1, 1948 discusses the following topics: (1) Meson fission counter; (2) Delayed neutron periods; and (3) Products of bombardment of copper with high energy deuterons and helium ions.