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.

Draft of an article about Dr. May Owen. The article discusses her background, career, accomplishments, and major contributions to medicine.

The interaction Hamiltonian for the Coulomb exchange effect between conduction electrons and magnetic-shell electrons in rare-earth metals was derived from first principles. The approximations under which the interaction can be represented by the product of electron and ion spin vectors are exhibited. (auth)

The electrical resistivities of polycrystalline samples of La, Pr, Nd, and Sm are reported in the temperature range 1.3 to 300 deg K. La exhibits a superconducting transition at 5.8 deg K. The curve for Pr has slope changes at 61 and 95 deg K. The Nd curve shows small jumps at 5 and 20 deg K. Sm shows slope changes at 14 and 106 deg K. (auth)

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A study was made to determine whether secondary iso tope effects also occur in molecular structure. Electron diffraction studies were carried out on ethane and deuteroethane. In C/sub 2/H/sub 6/ the mean C-C and C-H bond lengths found agreed very closely with values determined for other paraffin hydrocarbons, and the C--H bond showed a normal primary isotope effect (~ 0.005 A) similar to that found in methane when H is replaced by O. The output of the leastsquares analysis suggested that the mean C-- C bond length in C/sub 2/D/sub 6/ is shorter than in C/sub 2/H/sub 6/ and by about 0.004 A. Th e decrease seemed to be real for the apparent uncertainty was not much greater than 0.001 A. (M.C.G.)

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Magnetic moment measurements are made on holmium single crystals (hcp) from 1.3 to 300 deg K in magnetic fields from 250 to 18,000 Oe, with the field applied along the c axis, the a axis, and a (1010) direction. The STA1010! direction is the direction of easy magnetization with an extrapolated effective moment per atom at saturation of 10.34 Bohr magnetons. Basal plane measurements show antiferromagnetism below the Neel temperature of 132 deg K with basal plane anisotropy occurring below 80 deg K. Below the Neel point, an anomalous type of transition to ferromagnetic behavior upon application of sufficient field is observed. Magnetization curves for the c axis are linear down to 60 deg K, while measurements below 20 deg K show an initial magnetization of approximately 1.7 Bohr magnetons followed by nearly linear magnetization curves. Electrical resistivity measurements are made from 4.2 to 300 deg K. For the a axis, the resistivity changes slope slightly at 20 deg K. A larger change in slope occurs at the Neel temperature of 132 deg K. For the c axis, the resistivity changes slope slightly at 20 deg K, reaches a peak at 120 deg K, goes through a minimum at 132 …

A noncanonical transformation of the boson creation and annihilation operators is performed in order to obtain a Hamiltonian which can be treated by the standard methods of field-theoretic perturbation theory. The standard results of Belyaev (with a slight modification) are rederived by this technique. (auth)

The bremsstrahlung emitted by an electron scattered in a Coulomb field was first calculated by Bethe and Heitler. The total cross section for production of photons with wave number between k and k + dk by a nonrelativistic electron of kinetic energy {epsilon} is d{sigma}/dk dk = 16/3 Z{sup 2}r{sub 0}{sup 2} (e{sup 2}/hc) (mc{sup 2}/{epsilon})log ({radical} {epsilon}/hck + {radical} {epsilon}/hck -1) dk/k, where Ze is the charge of the (heavy) ion, and r{sub 0} is the classical electron radius. Bremsstrahlung in a plasma has been computed by a number of authors in the approximation of replacing the Coulomb field by a cut-off Coulomb or static Debye potential. It is the purpose of this communication to call attention to another important effect of the medium upon the rate of emission of bremsstrahlung. This may be described as a modification of the relation of the photon's energy to its wave number, due to the index of refraction of the medium. Equivalently, we note that one must include in the calculation of bremsstrahlung in a medium the photon-medium interactions which result in the 'clothing' of a 'bare' photon. The replacement of a particle by a quasiparticle has long been known to be …

Cr{sup++} in solution produces a paramagnetic shift in the NMR absorption of 0{sup17} in C1O{sub4}{sup-}, as well as the expected paramagnetic shift for 0{sup17} in H{sub2}O. As the concentration of C1O{sub4}{sup-} increases, the shift in the H{sub2}O{sup17} absorption is diminished, and eventually changes sign. The effects are ascribed to preferential replacement by C1O{sub4}{sup-} of water molecules from the axial positions in the first coordination sphere about Gr{sup++}.

An information storage and retrieval system (PIC) was developed, utilizing the IBM 7090 computer, for handling data pertaining to the effects of neutron irradiation on metals. The input includes a reference identification, an appropriate abstract or extract summarizing the article, code identification parameters analogous to those used by the ASM-SLA Literature Classification System, and special codes identifying relevant irradiation and testing parameters. The output contains the same data plus printing out the meaning of all special codes. Presently, the information storage consists of more than two hundred references representing several thousand lines of information. The system is both general and definitive, permitting the selection of a single piece of information or of many references dealing with a general field. It is possible to select material on the basis of one or more of the following factors: material, general or specific; type of literature; general or specific property such as mechanical tests or tensile tests; conditions of irradiation including type and level of flux, integrated flux, irradiation temperature, and reactor environment; test conditions such as temperature and environment; and general variables that might be controlling such as strain rate, specimen geometry, grain size, and fabrication history. It is felt that this …

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A procedure is described for the activation determination of V in powdered milk using 3.77-min V/sup 52/. The quantity of V in the sample is obtained by comparing the V/sup 52/ radioactivity found in the test sample with the V/sup 52/ radioactivity in a V comparator sample that is treated in the same manner as the test sample. The procedure can also be used for the determination of V in a variety of materials. (P.C.H.)

An investigation was conducted on the impossible use of beta radiation to promote chemical reactions at high temperatures and pressures. The advantages of beta sources over other radiation sources are enumerated. A radiation processing apparatus is described which allows operations to 10,000 psi and 500 deg C and uses 90 C of Sr/sup 90/-Y/sup 90/. The dosimetry of the source was accomplished with an iodineheptane system, and the mean dose rate within the chemical reactor was determined to be 0.98 x 10/sup 6/ rad/hr. The radiation utilization efficiency in the dosimetry measurements was determined to be 34.7%. Results of runs on hydrogenation of coal extract indicate that radiation does not increase the extent of hydrogenation, but that radiation reduces the content of hetero atoms N and S in the 100 x 400 deg C boiling oil products. The use of beta radiation in the hydrorefining of oils is suggested. (D.L.C.)

From meeting on new developments in reactor physics and shieiding calculations; Lake Kiamesha, New York, USA (12 Sep The temperature coefficient of the HTOR is composed of a strong negative Doppler coefficient and a positive moderator coefficient, the net effect being about -10 x 10/sup -5// deg C at operating temperature. the positive moderator coefficient is a result of the absence of significant density coefficients and the nuclear characteristics of U- 233. In addition, selected iission products, principally Xe-135, contribute positive components to the temperature coefficient. Current estimates of the value of the temperature coefficient in the HTGR are presented along with recent experimental data pertinent to the subject. (11 references) (auth)

From joint power generation conference; New Orleans, Louasiana, USA (16 Sep 1973). The High Temperature Gas Cooled Reactor (HTGR) fuel recycle operation is described. The description includes the HTGR spent fuel shipping system and the proposed method of reprocessing the spent fuel to recover the bred /sup 233/U and /sup 235/U. The process for refabricating the recovered fuel into recycle fuel is also discussed. (auth)

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Included are descriptions of welding methods and joint design, welding equipment, and qualification tests. (DG)

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