This semiannual report includes references in future items in the Brookhaven National Labratory program as well as an account of progress in the post six months.

This is a progress report from Brookhaven National Laboratory for the period July 1 through December 31, 1949.

The constant temperature bath is in operation. A ballistic type instability was detected in the calorimeter circuits and corrected by grounding the bath. Calorimeters 37, 39, 40, and 43 have been installed are now being run. Calorimeter 40 was found to be unstable, and is to be disassembled and examined for the trouble. Calorimeter 46 was finished and placed in operation. Construction details are discussed. Six Logac samples were run in Calorimeter 38. Tests of this calorimeter are in Table 1. Comparison of Calorimeter 38 in a water bath and in an ice bath is shown in Table 2. Good results were obtained for such a drastic change in environment. Calorimeter 38 was turned over to Calorimetric Assay marking the end of the tests of this particular microcalorimeter. Calorimeter 44 was completed and installed in the ice bath. Table 4 shows the results of tests. The zero bridge potential is small and is very stable compared to Calorimeter 38. The comparison of the values with those from Calorimetric Assay is summarized in Table 3. The characteristics of Calorimeter 44 are shown in Table 5. Construction details are given for the platinum-manganin bridge-type thermometer. An instrument was needed that could be …

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The interaction between neutron and proton in the triplet state has been investigated. The central and tensor potentials have been assumed to be of the ''meson'' type but of possibly different ranges. The variational-iterational method has been utilized to determine V{sub o}, the strength of the central potential, and {gamma}V{sub o}, the strength of the tensor potential. A wide variation in the values of both central and tensor ranges were included. Calculations of this type have proved difficult in the past principally because of the sensitivity of the results to the quadrupole moment Q of the deuteron for which accurate wave functions are necessary. It would be desirable to have a more accurate value of Q deduced from experiment. The percent D state in the deuteron and the effective triplet range have also been computed. The results are applied to the discussion of the magnetic moment of the deuteron, the photoelectric disintegration of the deuteron, and neutron-proton scattering. It is concluded that experimental information on neutron-proton interaction at their present accuracy does not determine the range of the tensor forces except within rather broad limits. A decrease in the uncertainty in the triplet range by an order of magnitude would …

The following items of equipment have been completed: Two Scaler Multipliers, EO-18 and EO-338, undergoing test and adjustment. One Thyratron Heater Control for Scioto Laboratory. One Pilot model switch box for Group 16 hoods at Scioto Laboratory. One Pilot model patch box used as auxiliary to the present switch boxes. Installation of electronic equipment and sorting and cataloguing of stock at Scioto Laboratory has been started. The Y Section induction heaters have been installed electrically. With the present setup in the WD Building, it has been necessary to recycle all the solution which passes through the pH chamber on the clariflocculators. Sufficient tests have been run on the Berkeley Decimal scaler to indicate that, by using a pre-emplifier, it will be a satisfactory replacement for the scaler multiplier. Reworking of B-wall tubes has been held up pending the delivery of neon gas. Further investigations have been made on the frequency compensated constant voltage Sola transformers. Three automatic potential controllers have been modified in accordance with investigations of Group 10. The program of preventative maintenance on automatic potential controllers has resulted in a marked reduction of service calls and down-time for the operating group.

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This report details events of importance reported by the Hanford Operations Office for the week ending March 30, 1949.

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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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Labcratory data which indicate that the recovery of Pu and U and decontamination from fission products are feasible in a solvent extraction process using tributyl phosphate are given. The procedure consists of extracting Pu(IV) and U with 15% TBP--85% Varsol using 5.0 N HNO/sub 3/ as a salting agent. (J.R.D.)

The purpose of this report is to review the characteristics of particulate contamination which set it apart from the other phases of the radiation control program and make it necessary to apply to it different concepts, analytical procedures, and control measures. The program is treated as one in the appraisal and control of dusts and fumes. The fact that the material is radioactive introduces certain new details, but this does not make the problem basically different from others in the field of industrial dust control.

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