The purpose of this Note is to point out the advantages of the sideband technique over the derivative method in wideline NMR spectroscopy. In the sideband technique the absorption spectrum is recorded directly and the modulation amplitude is no longer a determining factor in the resolution.

Use of that portion of the characteristic curve of photographic film in which transmission is linear with log exposure eliminates the distributional error and thus makes possible the assessment of total mass of an inhomogeneously distributed cell consistent without scanning or measuring the cell's projected area. Measurement consists of obtaining the difference in output of a photocell receiving the total light transmitted by a photomicrograph of the cell, and a photomicrograph of the microscope field illumination against which the cell was photographed. A method of making such measurements is given, and its basis is described.

The power of nuclear track research emulsion as a fast neutron dosimeter is examined in the exposure of a human phantom to PuBe neutrons. Semiautomatic track scanning and high-speed data analysis obviate the major disadvantages of this dosimeter, and allow the following basic information to be obtained without a serious cost in time: the rulative proton recoil energy spectrum, the absolute differential proton track den sity spectrum, and the average proton recoil energy at various locations in the phantom. From this are calculated the total absorbed local tissue doze due is proton recoils, the local thermal neutron intensity, and that portion of the tissue doze due to thermal [formula] tracks.

The spin of neodymium-141 was measured by the method of atomic beams and found to be 3/2. A lower limit placed on the hyperfine separation of the states with total angular momentum [formula] by second-order perturbation theory shows [formula]. A prerequisite for the determination of the nuclear spin from hyperfine-structure measurements is the knowledge of the electronic structure. The ground-state configuration of neodymium is known and the value is used throughout this work.

In previous letters we have reported a Av resonance, called Y*1, observed through the study of the interaction of 1.15-Bev/c K* mesons in hydrogen in the Lawrence Radiation Laboratory 15-in. bubble chamber. We now wish to report the results of the study of the three reactions [formula](1), [formula](2) and [formula](3).

Recently a T=1 resonance in the [Alpha w] system called [Y*1] has been observed with a mass of 1385 Mev. Two types of resonances have been predicted that might relate this observation to other elementary-particle interactions: (1) P 3/2 resonances in the Alpha w and Sigma w systems predicted by global symmetry corresponding to the (3/2, 3/2) resonance of the wN system, (2) a spin-1/2 Y-w resonance resulting from a bound state in the KN system. The position and width of the observed [Y*1] resonance agree with both theories but since the spin and parity have not yet been determined, it is impossible at present to distinguish between the two theoretical interpretations.

The sodium-ammonia solution system permits investigation of an array of compositions spanning the transition from non-metallic to metallic bonding. Reflection spectra in the range 1-20 [ ] were measured for solutions of mole ratio 5.5 to 168 [ ] per Na. The dilute solutions show peaks characteristic of the vibrations of ammonia and a strong peak near 1.5 [ ] which is assigned to the solvated [ ] species. Concentrated solutions show high reflectivity over broad wavelength ranges. The results for nearly saturated solutions are fitted reasonably by the free electron model, but in the range of mole ratio 10-15 a complex array of energy absorption processes of finite frequencies are required to fit the spectra.

Specimens suitable for transmission electron microscopy have been prepared from bulk polycrystalline molybdenum after tensile deformation and recovery. The resulting dislocation substructures are described. Some tentative conclusions concerning the mechanism of plastic deformation in molybdenum are discussed.

In a previous publication we reported measurements of the momentum spectra of He<sup>3 and H<sup>3 nuclei produced in collisions of 740-MeV protons with deuterium. The He<sup>3 spectrum exhibited an anomaly in the form of a peak in the region corresponding to double pion production. For reactions resulting in a He<sup>3 the two pions (or particle) can be isotopic spin states 0 or 1; if a H<sup>3 nucleus results only 1 = 1 is allowed. We have since repeated the experiment with a new arrangement which enabled us to measure both the He<sup.3 and H<sup>3 spectra with improved resolution and accuracy.

The second and third law methods of thermodynamics are used to obtain the enthalpies of vaporization of the halides of Be, Mg, Ca, Sr, Ba, Zn, Cd, Hg, Sn, Pb, Ti, V, Cr, Mn, Fe, Co, Ni and Cu. Molecular and free energy data necessary for such calculations are presented. The structure of bonding in these molecules is briefly discussed.

It is shown that under very simple and general assumptions the existence of an antiunitary reflection transformation and the charge gauge group implies the existence of an antiparticle corresponding to a given charged particle. Similar consequences follow on replacing the charge gauge group by the baryon gauge group. No assumptions as to specific wave equations, or indeed the existence of local fields, are made.

The problem of the natural convection of an electrically and thermally conducting fluid within a long, narrow, vertical toroidal channel centered in a large block of an electrically and thermally conducting solid is analyzed. A uniform horizontal magnetic field is applied to the fluid, and the bottom of the solid block is maintained at a higher fixed temperature than the top. The laminar steady-state single-cell convective motion of the fluid is considered and an approximate solution is found for the heat transfer rate between the bottom and top surfaces of the block in the limiting cases of small and large Hartmann number. A numerical example is given for liquid sodium in which the application of a magnetic field of a few hundred gauss is shown to significantly reduce the rate of heat transfer.

A need for a small vertical cylinder-type furnace arises frequently in the Chemistry Department at the Lawrence Radiation Laboratory (LRL). Adequate heat is the major requirement; close control or calibration is not usually necessary. A heating unit of this type can either be used for quickly concentrating solutions in centrifuge cones or, by the addition of a refractory pedestal--can be made into a crucible furnace for size 0 and 00 crucibles. Because much of the chemistry done at LRL is with radioisotopes, disposal of contaminated equipment is an important consideration. In general, furnaces are difficult to decontaminate, hence there was a need for a disposable type. Because nothing meeting the requirements seemed to be commercially available, the Health Chemistry Department made up a simple furnace that has proved useful.

Antiproton-production and nucleon-interaction cross sections were investigated for antiprotons in the energy range 0.5 to 1.0 Bev. The antiprotons were distinguished from other particles produced at the Bevatron by a system of scintillation- and velocity-selecting Cerenkov counters. The excitation function and momentum distribution were recorded for antiproton production in carbon and compared with statistical model expectations.

This system presents a method for making remote sealed-bag passouts from a multicurie-level chemistry processing enclosure. In addition, the polyethylene bags are changed remotely without exposing contaminated surfaces while always maintaining a low leak-rate seal. Our system employs an interchange box (the Passout Box) attached to the chemistry enclosure. Integrated with the box is a hydraulically operated jack that raises and lowers the bags, and a welder-cutter for sealing them. A single master-slave manipulator teamed with the above units handles all operations.

Two types of apparatus are described for measuring the absorption spectra of metal-ammonia solutions with the Gary Model 14 Spectrophotometer. One apparatus was used for dilute solutions at -70'; the other was used for more concentrated solutions and had provision for holding the solutions at any temperature between their boiling points and -70'.

Based on the assumption that the noise contribution of a semiconductor detector is due solely to the bulk properties of the semiconductor, equations are presented which indicate the theoretical limits of noise in detector-amplifier combinations. These equations show that an optimum amplifier time constant and detector bias voltage exist for which condition the minimum noise is independent of the semiconductor resistivity. The optimum performance of a detector-amplifier system is shown to depend only upon detector area, input capacity (less detector capacity), semiconductor minority carrier lifetime, and the transconductance of the amplifier input tube. A new detector structure including a guard-ring electrode as an integral part of the detector structure is described which largely eliminates noise due to surface leakage. Experimental results for detector leakage and energy resolution are presented which agree well with theory.

Even in its present primitive stage the molecular beam method promises to open up many opportunities for detailed studies of reactive collisions. The early results described here have revealed several features inaccessible to the traditional methods of kinetics. We hope this program of beam studies will ultimately provide the basis for constructing a theory of the molecular mechanics of reactions. By borrowing what are now everyday techniques in nuclear physics (modulation of the beams; mass analysis and counting of detected ions) it appears possible to gain from four to six orders of magnitude.

The absolute differential cross sections for elastic scattering of 31-Mev He3 ions on Be, Al, Cu, Sn(nat), Sn120, and Bi have been measured in the angular range of approximately 10 to 120 deg in the center-of-mass system. Thin self-supporting foil targets were chosen to span the parameter A 1/3, where A is the target mass number. The first excited states of the isotopes of the above elements had sufficient energy separation from the ground state to enable elastic scattering to be resolved from inelastic scattering. The detection system, consisting of Cal(Tl) scintillation crystals, was capable of 3%pulse-height resolution and 1 degree angular resolution. Characteristically, the light-element angular distributions show strong diffraction effects. The differential cross section divided by the Rutherford cross section decreases exponentially at large angles for the heavy elements, and the differential cross sections break away from Rutherford behavior at angles which increase almost linearly with increase of atomic number of the target nucleus. A comparison of the results for natural tin, and tin enriched to 85% in Sn120, indicated that within the experimental uncertainties over the measured angular interval, there were no pronounced isotopic effects. The data are presented both in tabular and graphical form to allow …

A system for scintillations from nuclear events has been developed and is presently in use at the Lawrence Radiation Laboratory. This paper primarily describes the pulsed light source used to simulate nuclear events; it also describes the necessary nanosecond pulse techniques to measure the light source parameters and to operate large numbers of lamps. Considerations concerning distribution networks are shown. Use of the light source as a spark gap trigger is also discussed.

Volatile hydrides may be prepared from ether solutions by the reaction of the appropriate chlorides with lithium hydroaluminate. In this general method, it is necessary to work with strictly anhydrous reagents and solvents because of the great reactivity of lithium hydroaluminate toward water. The procedures described here are believed to be much more convenient because the reducing agent employed is potassium hydroborate, which is relatively insensitive toward water. Since only aqueous solutions are involved, there are no solvent-purification steps and there is no dissolution or contamination of stopcock grease, etc.

An electron can suffer a very large acceleration in passing through the Coulomb field of a nucleus, and in this interaction the radiant energy (photons) lost by the electrons is called bremsstrahlung (also, bremsstrahlung sometimes designates the interaction itself). If an electron whose total energy [formula] traverses matter of atomic number Z, the electron loses energy chiefly by bremsstrahlung. This case is considered here.

Recent experience in instrumentation of several nuclear-physics experiments has demonstrated the feasibility of automating the data-acquisition phases of the experiment. Electronic circuits are employed wherever the rate of data flow would be slowed by the use of human operations. Information is selected, temporarily stored, and then recorded in a form suitable for immediate entry into a computer. Experimenters thus freed from the tedious aspects of data collection can devote their time to studying the results of the experiments. Potentially useful nuclear events are first selected by the fast-logic part of the instrumentation. Circuits performing simple logical functions are packaged in modular form for easy grouping into particular coincidence, gating, and mixing configurations. Circuits with slower response times are used for temporary storage and recording operations. Automatic test routines are used to initially align the equipment as well as provide continuous calibration during the experiments. Some of the high-speed circuits are described as well as the methods used to incorporate them into a large counting system.

The method of dispersion relations has in recent years found a wide application for the study of elementary particle reactions. Most of the work, however, deals with reactions of the type [formula], while the theory of those with more than two particles in the final state is still in a very preliminary stage. One reason for this is that even with only three particles in the final state the theory is already much more complicated. Nevertheless, a further development of the theory seemed to us very desirable. The theory at present is being developed on various levels simultaneously. Generally speaking, the aim of this paper is to put the theory in a form as closely as possible analogous to Mandelstam's formulation of the theory of reactions of type [formula]. In the later sections we specialize on reactions [formula], but as much as possible the formulation is in more general terms.