An experiment was designed utilizing a charge-exchange reaction to study the decay and interactions of the neutral K mesons produced. The experiment produced no events that could be interpreted as either the decay or interaction of neutral K mesons. The nature of the experiment and the possible explanations of this unexpected result are presented in this paper.

Techniques involving the use of high-intensity short-duration light pulses have been applied t o the study of the kinetics of photoconductivity in films of metal-free phthalocyanine. These experiments, in conjunction with measurements of steady-state photoconductivity, are consistent with the following scheme. The principal route for the formation of charge carriers is via the first excited singlet state, although the lowest triplet state can, t o some extent, contribute to charge - carrier production. The mobility of the carriers is low and is concentration-dependent, being lower at higher carrier concentration. The decay of the photocurrent is the result of a diffusion-limited bimolecular recombination, with a capture radius of approximately one molecular diameter. The experiments indicate that carriers produced thermally in the dark do not interact with light-produced carriers.

The addition of ortho-chloranil to the surface of films of metal-free phthalocyanine has been found (a) to increase the dark conductivity of such films by as much as 10{sup 7}, (b) to increase the steady-state photoconductivity by as much as 10{sup 5}, and (c) to result in the formation of unpaired electrons whose concentration decreases reversibly as a result of illumination. These systems exhibit a light-induced polarization, the phthalocyanine layer becoming more positive with respect t o the ortho-chloranil layer. Kinetic studies demonstrate that, upon illumination, a single process (time constant = 40 seconds) results in the increase in conductivity, the decrease in unpaired spins, and the increase in polarization. The results are consistent with the following scheme. An electron transfer from phthalocyanine to ortho-chloranil occurs in the dark at room temperature, producing holes in the phthalocyanine layer and ortho-chloranil negative ion radicals (high conductivity, ESR signal). Illumination results in the transfer of an electron from an excited phthalocyanine molecule to the ortho-chloranil negative ion, producing further phthalocyanine holes and ortho-chloranil double-negative ion (increase in conductivity, increase in polarization, decrease in ESR signal). By equating spin concentration with charge - carrier concentration (phthalocyanine holes) it is possible to calculate a …

Electron microscopy was used to supplement metallographic studies of bonds between Zircaloy-2 interfaces. Treated surfaces before bonding, and bonded sections made by a variety of techniques were examined. Electron micrographs of belt-abraded surfaces exhibited a consistent fine-scale roughness. Chemically pickled surfaces were nearly smooth regardless of prior treatment. Chemically pickled samples and a zirconium oxide-coated sample pressure bonded at 1500 F and 10,000 psi had pitting at bond lines that could have been due to voids or to contaminant at the interface which etchod out. The pitting was almost completely eliminated in one sample by pressing one hour at 500 F and 350,000 psi. This indicated that the bond-line pitting in these samples was due to voids at the interface. Zircaloy-2 samples pressure bonded after coating with carbon chromium, iron nickel, or tin etched in relief along the bond line, indicating the presence of contaminant at the interface. On the basis of the present investigation, it is proposed that grain growth across the interface in chemically pickled samples may have been inhibited by the presence of a thin contaminant film originally present on the Zircaloy surfaces. However, the poor grain-growth characteristics of chemically pickled samples may also be due in …

In another paper there was reported an attempt to observe the charge-exchange process in a counter-triggered multiplate cloud chamber at the Bevatron but the interpretation was ambiguous. Shortly after the close of that experiment the 30-in. propane bubble chamber at the Lawrence Radiation Laboratory was completed and able to be used for a combined engineering test and experiment. The existence of Reaction (1) has been confirmed in this experiment, and an approximate cross-section value for carbon is calculated.

The objective of the test detailed in this report is to irradiate self-supported fuel elements under conditions of severity comparable in these expected for future loadings of this geometry, to attempt to determine the resistance to corrosion of cooled cladding, the effect of supports on cladding corrosion and coolant flow patterns, and the relative resistance to ``hot-spot`` type attack and rupture of ``projection`` fuel elements and rib supported elements. This test will authorize irradiation of four columns of self-supported and four columns of rib-supported I and E, 1.47% enriched fuel elements until two ruptures are sustained in each group on type demonstrates a significant factor of improvement in rupture resistance over the other.

In the preliminary stages of getting up a time-of-flight system for measuring neutron spectra from proton reactions, a study of the time dependence of the beam in the 86Inch Cyclotron was made. This study revealed the expected bunching of the protons to produce a short burst of beam on each cycle of the 13.4 Mc/s accelerating voltage. In addition to the 13.4 Mc/s structure, however, there was a 360 c/sec modulation of the beam pulses and a complicated pattern built upon that.

The study revealed the bunching of protons to produce a short beam burst on each cycle of the l3.4 Mc/sec accelerating voltage. In addition to the l3.4 Mc/sec structure, there was a 360 cps beam pulse modulation. Oscilloscope patterns are given which show: (l) the envelope of the r-f accelerating voltage; (2) 60 cps line voltage with time scale; (3) beam intensity; and (4) beam intensity at faster oscilloscope sweep. Apparently the beam intensity is critically dependent on the accelerating voltage, but is not a monotonic function of that voltage. (B.O.G.)