Reversible photoinduced electron paramagnetic resonance (EPR) signals and photoconductivity were observed when a solution of tetracyancethylene (TCNE) in tetrahydrofuran (THF) was irradiated in the charge-transfer band of the complex formed between these two compounds. The eleven-line hyperfine structure of the EPR spectrum which was obtained demonstrated the presence of TCNE negative ion radical. The concentration of this radical was found to be directly proportional to the square root of the light intensity. Second order decay kinetics were followed when the light was shut off. Both the EPR signal and the photoconductivity rose initially as the square of the time. The latter portions of the growth curves could be fit to the latter portions of a hyperbolic tangential growth curve. From these data a reaction mechanism was proposed. The rate law dn/dt + kn{sup 2} = {alpha}L(1-e{sup -{beta}t}) = 0, where n = the concentration of radicals, t = the time, k, {alpha}, and {beta} are rate constants, and L = the light intensity, described both the photo-induced EPR and the photoconductivity within the limits of experimental accuracy.

In its usual form activated complex theory assumes a quasi-equilibrium between reactants and activated complex, a separable reaction coordinate, a Cartesian reaction coordinate, and an absence of interaction of rotation with internal motion in the complex. In the present paper a rate expression is derived without introducing the Cartesian assumption. The expression bears a formal resemblance to the usual one and reduces to it when the added assumptions of the latter are introduced. The new equation for the transmission coefficient contains internal centrifugal terms. The derivation employs an extension of the Stackel-Robertson formalism for separation of variables in mechanics. The fourth assumption can also be weakened and a rotational interaction included in the formalism. In applications of the rate equation use is made of the recent findings that in the immediate vicinity of a saddle-point or a minimum a potential energy surface can be imitated in some major topographical respects by a surface permitting separation of variables. The separated wave equation for the reaction coordinate is then curvilinear because of the usual curvature of the path of steepest ascent to the saddle-point. Calculations of transmission coefficients and rates can be made and compared with those obtainable from the usual one-dimensional …

In its usual classical form activated complex theory assumes a particular expression for the kinetic energy of the reacting system one associated with a rectilinear motion along the reaction coordinate. The derivation of the rate expression given in the present paper is based on the general kinetic energy expression.

None

The variational method is applied to the monoenergetic time dependent transport equation to obtain a simple relation for the asymptotic decay constant in small pulsed assemblies. The results indicate that flat trial functions may be a reasonable representation of the flux distributions in the thin slab limit. This approach is superior to many of the usual transport approximations. (auth)

Monte Carlo (MC) calculations were made that show that an observed reactivity increase due to fuel rod bowing in the Sodium Reactor Experiment can be accounted for by the accompanying change in the thermal flux distribution. The questionable reliability of calculations with a simplified fuel element model that indicated the same relation prompted the MC calculations. Comparison with experimental results and results calculated by other means established the reliability of the MC calculations. (D.C.W.)

A process for the production of seamless tungsten tubing is described. The process consists of the extrusion of sintered powder sleeves at elevated temperatures to sizes close to the final dimension. The tubing is finished by warm drawing. A size range of 0.100-in, diameter to 1 1/2-in. diameter has been fabricated. A preliminary evaluation of properties of the extruded tubes is given. (auth)

Economic and operational ground rules and their effects on fuel management are summarized, and examples showing the approach to typical fuel management problems are presented. The problems associated with in-core fuel management are also discussed, and the merits of various fuel cycling methods are evaluated. (D.C.W.)

None

A method of operation developed for maintaining a minimum power peaking factor throughout the operating cycle of a power reactor is described. The basic operating principle for peaking factor minimization is presented, and its use in the design phase to compare and set design parameters and in the operational phase to establish control rod patterns is outlined. The method will (hopefully) increase the power density in the Big Rock Point Reactor. (D.C.W.)

A digital computer program FLARE was developed for calculating the core reactivity and power distributions in the Big Rock Point Reactor. The calculations are restricted to a relatively coarse mesh, but good agreement was obtained in comparisons with operating data from the Kahl reactor. (D.L.C.)

It was thought that if a multi-detector device could be developed, the scanning time would be greatly shortened, with such consequent advantages as being able to work with lower dose of radiation, to obtain serial determinations, and to work with shorter-lived isotopes.

None

The effect of finite resistance in the vacuum-tank walls on the longitudinal stability of an intense beam of particles in an accelerator is investigated theoretically. We show that even if the particle frequency is an increasing function of particle energy, the wall resistance can render the beam unstable against longitudinal bunching. In the absence of frequency spread in the unperturbed beam, the instability occurs with a growth rate that is proportional to (N/{sigma}){sup 1/2}, where N is the number of particles in the beam and {sigma} is the conductivity of the surface material. By means of the Vlasov equation a criterion for beam stability is obtained. In the limit of highly conducting walls the criterion involves the frequency spread in the unperturbed beam, the number of particles N, the beam energy, geometrical properties of the accelerator, but not the conductivity {sigma}. A numerical example presented indicates that certain observations of beam behavior in the MURA 40-Mev-electron accelerator may be related to the phenomenon we investigated.

None

The nuclear age, which has been with us slightly more than 20 years, has brought with it an unusual awareness of a relatively new toxic agent--ionizing radiation. In fact, a new science, health physics, was created to give special attention to this problem. As a consequence and in spite of the unparalleled hazards associated with ionizing radiation, this new nuclear industry is growing rapidly into a benevolent giant bringing a better way of life while at the Same time maintaining radiation damage at an insignificant level. Although i n the past few decades we have learned much more about the hazards associated with ionizing radiation than those associated with some of the common industrial hazards and although maximum permissible exposure levels for the radionuclides have been established with greater reliability and confidence than have the levels for many chemical agents with which man has been familiar for many centuries, there still remains a considerable uncertainty in many of the basic assumptions and in the parameters used in the calculation of maximum permissible body burden and maximum permissible concentration of the various radionuclides in food, water and air. There is need to determine the uptake, distribution and elimination of a variety …

None

About 70,000 pictures of 2.45-GeV/c K{sup -}-p interactions have been obtained in the present 72-inch hydrogen bubble-chamber experiment. Approximately 24,000 events of all topologies except 1-, 2-, and 3-prong events have been measured, and 50% have been remeasured. They report here on a study of the production of known resonances in the reactions: (1) K{sup -} + p {yields} {Lambda} + {pi}{sup +} + {pi}{sup -}; (2) K{sup -} + p {yields} {Lambda} + {pi}{sup +} + {pi}{sup 0} + {pi}{sup -}. The cross section for production and number of events in reactions (1) and (2) are given in Table I.

We have successfully conducted a series of experiments involving scattering of high energy pions and protons from a target containing polarized protons. Results of some of these experiments were reported at this conference, and in the literature. Proton polarizations as high as 65% have been measured; the average polarization during sustained data-taking has been typically 45%.

None

Using the Berkeley polarized-proton target, we have measured the polarization parameter P({theta}) for proton-proton (p-p) scattering. The measurements were obtained at beam kinetic energies of 0.330, 0.680, and 0.740 GeV at the 184-in. synchrocyclotron and 1.70, 2.85, 3.50, 4.00, 5.05, and 6.15 GeV at the Bevatron. The angular regions measured were from 20 to 100 degrees center of mass; the square of the four-momentum transfer ranged from 0.1 to 0.8 (GeV/c){sup 2}.

None

None

None