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The mean heat capacity of a sample of powdered beryllium carbide, a possible moderator material for a nuclear reactor, was determined as a function of temperature. A thin-walled stainless steel capsule containing the material was heated in an electric furnace and dropped into a water calorimeter. The following linear equation for mean heat capacity over the temperature range 50 f C-T f C as a function of temperature, T, was derived from the data by the method of least squares: C/sub p/ = 0.299 + 2.16 x 10/sup -4/ T f C el temperatures 0.005 cal gm/sup -1/( f C)/sup -1/. The numerical value of C/sub p/ expressed by this equation is also equal to the mean heat capacity in Btu lb/sup -1/( f F)/sup -1/. (auth)

Analytical methods are given for determining the composition and impurities of beryllium carbide. A summary of the experimental work leading to these procedures and supporting data are also presented. Analytical procedures for the determination of free and combined carbon, moisture, nitrogen, beryllium oxide, silica, iron, total beryllium, and beryllium metal are outlined. Diagrams of special apparatus used are included. (auth)

The mean heat capacity of a sample of powdered U/sub 3/O/sub 8/ was determined as a function of temperature from measurements of heat content. A thin-walled nickel capsule containing the material was heated in an electric furnace and dropped into a water calorimeter The Mean heat capacity values calculated from the experimental data were nearly constant over the temperature range, room temperture to 250-975 deg C (482-1790 deg F). The average value was 0.074 plus or minus 0.004 cal gm/sup -1EDE/C/sup -2/ (0.074 plus or minus 0.004 Btu lb/sup -1 deg F/du p -1/). From 975-1100 deg C (1790-2012 deg F) a small rise was observed. (auth)

N{sup 12} is shown to have a half life of 12.5 {+-} 1 milliseconds, and a positron upper limit of 16.6 {+-} 0.2 Mev. It is produced by the reaction C{sup 12}(p,n)N{sup 12}, and has a threshold proton energy of 20.0 Mev. This indicates that N{sup 12} is within about 200 Kev of being unstable against proton emission. The mass of N{sup 12} is 12.0228 {+-} 0.00015, and the beta transition is allowed.

A comparison of the decay constants of Be{sup 7} in beryllium oxide and in beryllium fluoride has given {lambda}{sub BeO}-{lambda}{sub BeF{sub 2}} = (+1.375 {+-} 0.053)10{sup -3}{lambda}{sub BeO} thus showing a definite effect of the chemical binding on the radioactive decay constant.

Isotopes of francium with 126 or fewer neutrons have been looked for in bombardments of Th{sup 232} with 350 Mev protons from the 184-inch cyclotron. Fr{sup 212} with an apparent half-life of 19.3 minutes for branching decay by alpha emission (44%) to At{sup 208} and by orbital electron capture (56%) to Em{sup 212} has been found. Em{sup 212} is shown to be a 23-minute alpha-emitter. At{sup 208} decays primarily (99.5%) by orbital electron capture to Po{sup 208}, but shows 0.5% alpha-branching. The francium and emanation isotopes have alpha half-lives completely out of line with the predictions based on the previously known isotopes of these elements. Their high alpha stability is believed to be due to a closed shell of 126 neutrons in analogy to the behavior of elements 83-85. The non-existence of long-lived francium in nature is discussed in the terms of this and other recent work on francium isotopes.

Among the spallation products obtained from the 350-Mev proton bombardment of Th{sup 232} they have identified two gaseous alpha-emitters which apparently do not decay into any presently known alpha-decay chains. The half-lives observed for the decay of the alpha-activities are 23 minutes and 2.1 hours. These half-lives may be principally determined by an unknown amount of orbital electron capture. At least one alpha-emitting daughter (about 4 hours half-life) has been observed to grow from a gaseous parent, but it has not been determined whether it arises from alpha-decay or electron-capture. Since these gaseous atoms emit alpha-particles it is assumed that they are isotopes of element 86 (emanation or radon) rather than a lighter rare gas. if they were heavy isotopes such as Em{sup 221} or Em{sup 223}, both unknown, they would decay into known alpha-decay series, the neptunium and actinium series, respectively, and so would grow known short lived alpha-emitters which would have been detected. It thus appears reasonable that they must be lighter than the known emanation isotopes.

Correlations of alpha-decay energies in terms of mass number and atomic number have been made for all of the alpha-emitting species now numbering over 100. For each element isotopes show increase in alpha-energy with decrease in mass number except in the region of 126 neutrons where there is an explainable reversal. This reversal has the effect of creating a region of relatively low alpha-energy and long half-life at low mass numbers for such elements as astatine, emanation, francium, and possibly higher elements as had been noted already for bismuth and polonium. Methods and examples of using alpha-decay data to define the energy surface in the heavy element region are discussed. The regularities in alpha-decay are used for predictions of nuclear properties including prediction of the beta-stable nuclides among the heavy elements. The half-life vs. energy correlations show that the even-even nuclides conform well with existing alpha-decay theory, but all nuclear types with odd nucleons show prohibited decay. The reason for this prohibition is not found in spin changes in the alpha-emission but in the assembly of the components of the alpha particle, and this theory is discussed further in terms of observations made on nuclides having two or more alpha-groups. …

The experiment outlined in this proposal has the possibility of giving an answer to the important question, 'Does the neutrino exist'? It is unfortunate that at the present time, there is no convincing experimental that neutrinos exist. Two recent articles review the status of various experiments which could give information about neutrinos. In general, these experiments give results in agreement with the predictions of beta decay theory. But actually, if even the most complete of the 'recoil type' experiments could be performed satisfactorily, all that could be concluded would be the following: the energy and momentum relationships in beta decay are consistent with the theory that the known energy deficit is carried away by a single particle. But to emphasize the fact that this would not constitute a proof of the real existence of that particle, the following quotations from the review articles should be noted. Crane says, 'All of the evidence about the neutrino is, as already pointed out, indirect in character since neutrinos have not yet been caught after leaving the nucleus. It can, of course, be argued on very general grounds that, if energy is not conserved between nucleus and electron, momentum should not be expected to …

The cyclotron is the only practical source of many carrier-free radioisotopes. The preparation and radiochemical isolation of a number of these activities, produced in the 60-inch cyclotron of Crocker Laboratory, will be presented in this paper and in subsequent papers of this series. In most cases the carrier-free radioisotopes were prepared for use in biological systems and the final preparations were in the form of isotonic saline solutions at a range of pH from 5 to 8. The present paper reports the radiochemical isolation of carrier-free Sn{sup 113} and In{sup 114} produced by bombarding cadmium with 38 Mev alpha-particles. At this energy, Sn{sup 113} and In{sup 114} are produced in a thick target by the nuclear reactions; Cd{sup 110}({alpha},n)Sn{sup 113}, Cd{sup 111}({alpha},2n)Sn{sup 113}, Cd{sup 112}({alpha},3n)Sn{sup 113}, Cd{sup 111}({alpha},p)In{sup 114}, Cd{sup 112}({alpha},pn) In{sup 114}. The shorter-lived tin and indium activities together with the possible radioisotopes of silver produced by (n,p) reactions, were allowed to decay out prior to the chemical separations.

Fireman(1) has reported the results of a rather difficult beta-particle coincidence counting experiment in which the decay of Sn{sup 124} by the simultaneous emission of two negative beta-particles, with a half-life between 0.4 x 10{sup 16} years and 0.9 x 10{sup 16} years, seems to have been observed. This note reports the results obtained from a different and somewhat simpler method of looking for the phenomenon of simultaneous emission of two beta-particles. These results are negative so far and show that this process is considerably less probable in the case chosen by us than in that reported by Fireman. The method consists of looking in uranium samples for 90-year Pu{sup 238} which would come from U{sup 238} by the double beta-particle mechanism since Np{sup 238} is heavier than U{sup 238}, which in turn is substantially heavier than Pu{sup 238}, in the isobaric triplet {sub 92}U{sup 238}-{sub 93}Np{sup 238}-{sub 94}Pu{sup 238}. This chemical method of investigation is particularly applicable to this isobaric triplet because there appears to be no other mechanisms to account for the Pu{sup 238} should it be found. The energetics of the situation are summarized in the following diagram, where the disintegration energies are derived from sources which …

Some time ago we started work in an attempt to observe alpha-particle decay in isotopes of atomic number less than 83. In the first experiments, thin targets of gold leaf were bombarded with 190-Mev deuterons in the 184-inch cyclotron. Two alpha-decay periods were observed in these targets; one of 0.7 minutes half-life and another of 4.3 minutes half-life. The alpha-particle energies were 5.7 and 5.2 Mev, respectively. Chemical separations proved that the 4.3-minute period is due to a gold isotope and suggested that the 0.7-minute period is due to a mercury isotope. The mass numbers of these new isotopes have not been determined. However, the results of excitation-functions in the production of the gold isotope by bombarding gold and platinum with protons suggest that its mass number lies in the range 185-188. The work on this isotope indicates that the alpha to electron capture branching ratio is of the order of magnitude of 10{sup -4}, and that positron activity accompanies the 4.3-minute alpha-period.

At the spring, 1949, meeting of the National Academy of Sciences(l) a preliminary account was given of some observations of mesons produced by the 335 Mev x-ray beam from the Berkeley synchrotron. The present paper is a progress report of this work; no claim is made for completeness, but sufficient new data are available to make publication at this time worth while, especially since some of the numerical results given in the earlier report require revision. The x-ray beam, produced by the impact of 335 Mev electrons on a 20 mil thick platinum target, has a width at half maximum of 0.0135 radian (about 1 inch at 6 feet from the target). In all but the earliest experiments the beam was further defined by a 1 inch hole in a lead block, then passed through a piece of carbon which served as the meson source. The x-ray intensity at one meter from the target was about 3500 r per hour (measured behind 1/8 inch of lead) under the best running conditions; the average was about half this. The actual exposures at the carbon meson source (6 feet from the target) ranged from 500 to 2000 r in the later runs. …

This report summarizes in somewhat more detail than the monthly H.I. Environs reports the extent and magnitude of the radioactive contamination detected in the environs of the Hanford Works. Radioactive contamination resulting from the operation of the Hanford Works as well as that found occurring in natural quantities is included. This belated report is being issued merely for the records to serve as a composite summary of measurements already reported in the monthly H.I. Environs reports and covers the quarterly period January, February, and March, 1949.

This progress report discusses the activities of the P Division for the month of September, 1949. The B and F piles operated at 275 megawatts (MW) and the D pile at 305 MW throughout the month except for cutages listed under Area Activities. A total of 60.22 tons of metal, at an average concentration of 396 megawatt days/ton (MWD/ton) was discharged from the piles during the month. The 105-H Building was accepted from the Construction Division on September 28 with certain exceptions noted under the Operating Experience section of this report. At month end P Division operating personnel are making preparations for activation of the H pile. On September 28 the operation of the 300 Area oxide burning process was reduced from a two shift to a one shift five day operation. This change in schedule was possible as a result of working off the backlog of uranium oxide. The shipment of 200 tons of canned slugs to Building 105-DR for storage was completed on September 9 and the shipment of 250 tons of canned slugs to Building 105-H for the initial loading charge was completed on September 26.

This report summarizes the radioactive contamination measured at the Hanford Works and vicinity for the quarter July, August, and September 1948. Topics discussed are: meteorology; airborne contamination and contamination of the Columbia River; vegetation; drinking water; and in Hanford Wastes.

The progress report discusses activities of the P Division for the month of July, 1949. The B and F piles operated at 275 megawatts and the D pile at 305 megawatts throughout the month except for outages listed under Area Activities. A total of 57.5 tons of metal, at an average concentration of 363 megawatt days/ton (MWD/ton) was discharged from the piles during the month. This included 41.9 tons of Class V (alpha-rolled, triple-dipped, completely transformed) metal at an average concentration of 397 MWD/ton which was discharged without difficulty. A portion of this material was inspected and appears to be satisfactory for exposures at this concentration.

This progress report discusses activities at P Division for the month of March, 1949. All piles operated at 275 megawatts throughout the month except for the outages listed under Area Activities in this report. The average time operating efficiency''was 91.4%. A total of 47 tons of metal was discharged from the piles during the month. During the month, 16.6 tons of alpha-rolled, triple-dipped metal were discharged without difficulty at a nominal concentration of 320 megawatts day (MWD) per ton. Inspection of selected tubes of this material indicated that exposures at this level are satisfactory. In view of these results the programs of stepwise increases in concentration will be continued, with the next test tonnages being discharged at a nominal concentration of 360 MWD per ton. The nominal monthly production rate of acceptable canned pieces was reduced from 90 tons to 60 tons on March 28. This curtailment of production was possible in view of the favorable inventory of slugs available for charging DR and H piles.

This progress report discusses activities for the P Division for the month of May 1949. The nominal operating level for both B and F Piles was 275 megawatts (MW) throughout the month except for outages listed under Area Activities. The D Pile operated at 275 MW until May 23 when the nominal level was raised to 290 MW in the first step of the program covered in Production Test No. 105-260-P to evaluate the feasibility of operating piles at higher power levels. A total of 44 tons of metal, at an average concentration of 285 megawatt days/ton (MWD/ton), was discharged from the piles during the month. Considerable difficulty was experienced during the month with stuck tubes containing Class IV (alpha-rolled, triple-dipped, randomly transformed) metal. A total of nine tubes with concentrations in the range of 320--370 MV/ton was encountered. As a result of these difficulties with the Class IV material, future discharges of this type metal will be limited to concentrations in the range 300--320 MWD. Approximately one ton of Class V (alpha-rolled, triple-dipped, completely transformed) metal was discharged at a concentration of 368 MV/ton for test purposes. Inspection of this material indicated that all the slugs were in satisfactory …

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The experimental data presented in HDC-1255 for the pressure drops through the various portions of a standard process tube assembly for isothermal flow are correlated in this report. Data include orifice sizes up to 0.310 inches. The equations have been adapted for the calculation of pressure drops or flow rates for clean tubes in pile operation. A systematic procedure is outlined for determining the pressure drops through each portion of the tube assembly. A method is presented for calculating the flow rate through a process tube from header pressure and panellit age readings.

This report describes the basic design, intermediate and final stacking procedures, and graphite behavior of nuclear reactors DR and H during construction. Included in the report are test records to substantiate basic design assumptions and data and the actual performance of the graphite during preliminary and final stacking.

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