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 …

In an early continuation of the investigation of the radioactive isotopes of element number 43 (technetium) Segre and Seaborg produced by the deuteron and neutron bombardment of molybdenum the isotope Tc{sup 99}, which they observed to decay by means of an isomeric transition with a half-life of 6.6 hours to a lower isomeric state with a half-life greater than 40 years. The upper isomeric state of this isotope was observed by Segre and C. S. Wu to be produced in the fission of uranium and more recently R. P. Schumann and also D. C. Lincoln and W. H Sullivan working on the Plutonium Project of the Manhattan District have independently observed the beta-particles of half-life about 10 years due to the lower isomeric state. Later work by E. E. Motta and G. E. Boyd sets a more accurate value of 9.4 x 10{sup 5} years for this half-life. Since this isotope is formed in rather large amounts, namely, a fission yield of 6.2%, in the slow neutron induced fission of uranium it is now possible to isolate technetium in weighable amounts and in rather substantial quantities. For example, a uranium pile operating at a power level of 10{sup 5} kw …

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This report contains a review of this work conducted by the Electrodeposition Group for the last six months. Pictures and a discussion of the method used to convert production solutions to postum to hydrofluoride acid solutions of postum are given. Attempts to plate postum in an inert atmosphere by remote control have been made. As yet no successful runs have been completed. Standardization of normal calomel electrodes by comparison to silver-silver chloride electrodes and to hydrogen electrodes is described.

The two-electrode vacuum tube, or diode, consists of an electron-emitting cathode surrounded by a positive anode (plate). A plot of plate current (i{sub b}) vs plate voltage (e{sub b}) is shown. At low anode voltages, the anode current is limited by the repelling effect that the negative electrons already in the space have on the electrons just being emitted (space-charge effect). When a full space charge is present, the plate current depends upon the plate voltage according to Childs law: i{sub b} {approx} e{sub b}{sup 3/2}. Increasing the plate voltage eventually results in an electron flow equal to total cathode emission, after which further increases in anode voltage will produce practically no additional current (voltage saturation). However, for high field stresses, additional electrons are pulled out of the cathode (field emission), increasing the current even further.

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.

The Argonne National Laboratory model of the Vibrating Reed Electrometer was installed in the laboratory of Group 3 to detect the point at which electrodeposition of a radioactive element begins. As now set up, the Vibrating Reed Electrometer has a direct reading sensitivity of 10{sup {minus}12} amperes and this can be increased to 10{sup {minus}17} amperes by using it as a rate of charge instrument. During the past month the ionization chamber was designed and constructed and the complete system was set up for operation. One four-input gamma mixer was completed. Inputs for the GM tubes are on the back of the chassis with mixer output on the front panel, convenient to the Instrument Development Laboratory Model 162 GM input. The performance, on test, was equal to that of the prototype (EL-208). Two thyratron heater controls, EL-238 and EL-241 were completed and are being tested by the Assay Group. Three Scaler-Multipliers, scale of 16,384, are under construction. Two Instrument Development Laboratory methane-flow scalers were modified as outlined in the Electronics Progress Report, MLM-153, dated July 1--31, 1948. A portable power supply tester is being developed which will embody a simplified switching arrangement. Some trouble has been encountered in getting a …

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

Operation of the 100F pile is reported on. Ongoing construction is described; detailing population and occupancy. Visitors and the Schenectady report are discussed. A copy of the June 4 letter from Carleton Shugg to Carrol L. Wilson pertaining to flooding of the Columbia and Yakima rivers is included.

The excitation curve for the reaction C{sup 12}(n,2n)C{sup 11} has been calculated for energies up to 100 Mev. The calculations were done as described in the preceding letter for the similar reaction of C{sup 12} under proton bombardment. The results of the calculations for 50% charge exchange are shown in Figure 1. The calculated cross section for the reaction at 90 Mev is: .011 barns for 100% charge exchange and .013 barns for 50% charge exchange. The experimental value is 0.025 {+-} .004 barns. The ratio of the cross section of the reaction C{sup 12}(pnpn)C{sup 11} to the cross section of the above reaction at 90 Mev is 5.8 for 100% charge exchange and 3.8 for 50% charge exchange. The experimental ratio is 2.7 at 90 Mev. This difference in cross sections between the two reactions is established by two factors. Firstly, there is the part played by charge exchange in the C{sup 12}(pnpn)C{sup 11} reaction which leads to excited N{sup 12} with the subsequent boiling off of a proton, while a similar exchange process cannot take place for the C{sup 12}(n2n)C{sup 11} reaction. Secondly, there is the difference between the contributions of the knock out process as a result …

Chupp and McMillan have recently measured the excitation curve for the reaction C{sup 12}(pnpn)C{sup 11} at high energies. Using the model of the nucleus described by Serber, the excitation curve of the above reaction has been calculated for energies up to 100 Mev. The excitation of the nucleus is determined on the basis that the incident proton makes individual collisions with the nucleons, the transferred energy exciting the nucleus. n-p collisions are taken to be three times more probable than n-n or p-p collisions. Charge exchange is assumed. The calculations were made for both 50% and 100% charge exchange. The decay of the excited nucleus is treated by the usual evaporation mode.

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Included in this semi-monthly report written in 1943 are progress with neutron beams, neutron absorption in enriched materials, equipment operation and maintenance reports of the cyclotron neutron source facility, and instrumentation maintenance activities of individuals in the cyclotron group. (GHT)

In an attempt to detect a possible influence of the atomic electrons on the radioactive decay constant of Be{sup 7} they have measured {lambda}{sub Be}-{lambda}{sub BeO} and found (-3.0 {+-} 1.8) 10{sup -4} {lambda}{sub Be}. They describe also a method to measure mean lives of radioactive substances in a time short compared with the mean life.

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