This is the third article in the series on the 6 MeV linear accelerator to be used for the injector of 1 BeV electron synchrotron, and describes the construction and early tests of the accelerator including the fabrication and the assembly of the components (accelerator guide, waveguide system, electron gun and vacuum system etc.) The accelerator guide has been carefully fabricated so as to match the designed structure reported in the preceding paper. An rf driven prebuncher has been provided in order to obtain a narrow energy spread and high trapping efficiency. The results obtained the preliminary tests were the energy spread of about 3 percent at 6.6 MeV, whereas the spread increased up to 5–6 percent without the prebuncher.

View full abstract

The reaction F¹⁹(p, γ)Ne²⁰ was studied for proton energies from 550 to 1500 keV. The 1322 keV resonance reported previously was not observed. The angular distributions of the gamma rays from Ne²⁰ compound states corresponding to the E_p=669 and 1425 keV resonances to the first excited state were found to the isotropic within 2% in both cases. The angular distribution of the gamma ray to the first excited state of Ne²⁰ at E_p=1090 keV was found to be W(θ)=(1±0.028)+(0.363±0.051)P₂(cosθ)−(0.019±0.069)P₄(cosθ). From this result the spin and parity of the 13.91 MeV state of Ne²⁰ was determined to be 2⁻.

View full abstract

The energy spectra of protons from the reactions H(d, p)pn with E_d=18 MeV and D(p, p)pn with E_p=9 MeV have been measured as a function of angle. After conversion to the c.m. system, the shapes of the spectra have been examined in connection with pair interaction between nucleons in the final state. The differential cross section of protons emitted by the reaction p+d→p+p+n has a minimum at about 120° similar to the cross section of p+d elastic scattering.

View full abstract

Protons accelerated the 105 cm cyclotron of Kyoto University were used to investigate the energy dependence of the angular distributions and the reaction mechanism of the inelastically scattered protons from the odd-even nuclei, B¹¹, F¹⁹, Al²⁷ and P³¹ at 6.0∼7.5 MeV using conventional electronic techniques. It was found that (a) the energy dependence of the angular distribution has close relation to the excitation energy of the compound system, namely above the excitation energy of about 13 MeV in the compound system, many patterns of the angular distributions including that of the light even-even nuclei were relatively energy-independent: (b) Total cross sections were considerably smaller than that of the neighbouring even-even nuclei and less energy-dependent: (c) In the case of F¹⁹ the shapes of the angular distributions suggested the existence of a direct interaction: (d) The relative yields from the various levels of Al²⁷ might have some relation to its nuclear structure in the Nilsson model.

View full abstract

Angular distributions of α particles resulting from O¹⁶(d, α₀)N¹⁴ (ground state), N¹⁴(d, α₀)C¹² (ground state), N¹⁴(d, α₁)C¹² (first excited state), C¹²(d, α₀)B¹⁰ (ground state) and C¹²(d, α₁)B¹⁰ (first excited state) reactions were studied, α particles from the O¹⁶(d, α₀)N¹⁴, C¹²(d, α₀)B¹⁰ and C¹²(d, α₁)B¹⁰ reactions exhibited forward peaks and backward peaks simultaneously, while α particles from N¹⁴(d, α₀)C¹² reaction showed forward peaks and oscillatory behavior.
α particles leaving N¹⁴ and C¹² nuclei in their T=1 state were also observed in the forward angle, and the isotopic spin conservation rule seemed to be violated.
The reaction mechanism is then discussed on the basis of the surface direct reaction, the compound nucleus formation and α particle clustering in the target nucleus. It is concluded that α clustering may play an important role in the (d, α) reaction.

View full abstract

Fifty-two nuclear interactions produced by the nuclei of cosmic radiation with charge Z=6, 7 and 8, and with energies around 4×10¹⁰ eV/nucleon were studied in nuclear emulsions. The ratio of the number of interactions with heavy nuclei (Ag and Br) to that with light nuclei (H, C, N and O) was found to be 1.03, which is in good agreement with the value calculated by assuming the geometrical cross sections of the colliding nuclei. The features of interactions in which the colliding volume of an incident nucleus was equal to that of an alpha-particle were similar to those of a free alpha-particle. The average number of heavily ionizing tracks, N_h, indicated the exponential increase as the impact parameter decreased. The distribution of the total charge of the fragments showed rather regular bumps at even charge. Almost all shower particles ejected with the smallest angles to the primary direction (shower axis) were the nucleons which came from primary nuclei. The angular distribution of mesonic shower particles was nearly isotropic in C. M. system at these energies.

View full abstract

The parasitic ferromagnetism found in the ammonium tutton salt of Mn and Co ions is discussed. By assuming the two sublattice model, we look for the lowest energy state of spin direction, where the exchange and dipole interactions are taken into account. It can be shown that the origin of parasitic ferromagnetism in MnNH₄-tutton salt is the crystalline field and in CoNH₄-tutton salt the anisotropic dipolar and exchange interactions. The estimate of the angle with which the spins incline to the K₁K₂-plane are found to be 21°42′ and 10°42′ for Mn- and Co–NH₄-tutton salts respectively, agreeing well with the experimental results. It appears theoretically that the spin direction for the lowest energy state lie within a plane which inclines to the K₁K₃-plane with angle −15°2′ and −9°53′ for Mn- and Co-tutton salts respectively. The Néel temperature and the susceptibilities are also calculated in rather good agreement with the measured values. It is noted that the directions corresponding to the maximum and minimum values of susceptibility within K₁K₂-plane deviate considerably from K₁- and K₂-axes.

View full abstract

A sharp maximum of permeabilities has been found in the narrow concentration range of about 12 percent aluminium in the slow cooled iron-aluminium alloys. It is found, however, that the permeabilities of this alloy are decreased and its coercive force is increased the reheat-treatment at temperatures between 400° and 650°C, followed slow cooling. For example, after reheating the alloy to 550°C μ_m was decreased from 23,500 to 4,800, μ₀ from 1,600 to 1,000 and H_c was increased from 0.09 to 0.37 Oe. Since such a reheating effect was not found in the other concentration of iron-aluminium alloys, it is concluded that the phenomenon is due to something characteristic of 12 percent aluminum-iron alloy, that is the growth of a small quantity of precipitation or the short range order, which would result in an increase of internal strain.

View full abstract

The change in magnetization in weak magnetic field of nickel quenched from high temperatures was measured means of a sensitive astatic magnetometer, and it was found that the magnetization increased nearly proportionally to the logarithm of the time elapsed after quenching. It is shown that the effect can be analyzed phenomenologically one of formal theories proposed on the magnetic after effect. On the other hand, the formation energy of the vacancies was estimated roughly to be 1.4 eV, which showed a good agreement with the results of other observations. It is, therefore, quite likely that the observed change in magnetization is entirely due to the annihilation of the frozen-in vacancies.

View full abstract

The absorption spectra of the fundamental ν₂ of the nitrite ions in NaNO₂ crystals were investigated over the temperature range between 25°C and 190°C with infrared radiation plane-polarized at various angles with respect to the crystallographic axes. Marked changes were observed around the transition point of 163°C. The contours of the absorption band tell us that the amplitude of the torsional oscillation of the nitrite ions around the a axis is fairly large as compared with the amplitude around the c axis. The amplitude around the a axis grows larger with increasing temperature, whereas that around the c axis remains very limited over the whole range of temperatures of experiments. The contours of the absorption band observed with polarized radiation parallel to the c axis show no trace of inversion doubling even in the high temperature phase. Hence the possibility of the tunneling of the N atoms through the potential hill was ruled out.

View full abstract

The influence of dislocations which were introduced into germanium crystal by plastic deformation on the current-voltage characteristics of the p-n junction was investigated experimentally using grown junction diode bars. It was revealed that the theory of carrier generation and recombination in a p-n junction was applicable to explain the junction characteristics. When the width of the transition layer in a p-n junction was as great as about 200 micron, the anomalous characteristics were observed after plastic deformation twisting. Some considerations were made about the p-n-p-n structure which was produced in the original p-n junction region plastic deformation.

View full abstract

The theoretical consideration of the magnetic anisotropy energies of magnetic compounds with a nickel arsenide type crystal structure was made. The anisotropy energy due to the magnetic dipolar interaction for an appropriate spin structure in this crystal structure, and the one originating from the spin orbit interaction and the interaction related to this were studied assuming the ionic constitution of transition metal elements, from the stand point of one ion approximation. Some experimental data are explained the present theoretical results.

View full abstract

In NaNO₂ crystals, prepared by both of the fusion method and the aqueous solution method, the D-E hysteresis loops were observed by the 50 c/s ac field and the dielectric constant along the ferroelectric b axis, ε_b, was measured by the 100 kc/s ac voltage. The pyroelectric current was measured by the usual galvanometer method. The values of the spontaneous polarization determined by two methods agreed well with each other. ε_b showed a distinct anomaly around the Curie temperature and obeyed the Curie-Weiss law below and above the Curie temperature. The ratio of two Curie constants was found to be 9.6:1. Some discussions, taking account of the crystal structure, were made.

View full abstract

A macroscopic theory of mixed conduction—partly electronic and partly ionic conduction—is developed with special reference to the conduction in silver sulfide group semiconductors. Current equations combined with continuity equation give an equation which can be reduced to a diffusion equation under simplifying assumptions. It can be integrated with ease under boundary conditions which are prescribed by the nature of electrodes employed.
General expressions for potential distributions are derived. Two kinds of potentials are distinguished. One is the potential as measured by the use of probes consisting of electronic conductor, and the other as measured by the use of probes consisting of ionic conductor such as silver iodide for silver sulfide. The former reveals the relative electrochemical potential of electrons and the latter that of ions.
Calculated time variations of potential distributions for formation and decay processes of stationary polarizations are compared with experiments for Ag_1.93Te at 161°C showing satisfactory agreements.

View full abstract

The resistivity of reduced rutile was measured from 80°K down to about 2°K. Activation energies derived from the slopes of resistivity curve are 0.01∼0.02 eV above about 20°K and 0.0005∼0.005 eV below about 20°K. It is proposed that the electronic conduction in this substance below about 20°K is due to the “defect level conduction”. Conduction mechanisms at higher temperatures are also discussed.

View full abstract

Multiple elastic scattering of electrons by crystals is considered based on the Dirac’s wave equation with the perturbation method. The result shows that besides the usual relativistic correction for wave-length, a new correction factor appears in the intensity formula of reflection, corresponding to the mass correction of electron. The new correction factor plays an important role in the dynamical theory of electron diffraction, and, for instance, it brings about an essential modification in the nonrelativistic result concerning the dependence of the reflection intensity on wave-length. It follows that the dynamical effect does not vanish at the limit λ→0.

View full abstract

The extrapolation was performed by the approximation in the series of Legendre polynomials and the error in the radial distribution function caused by a failure of the extrapolation was discussed. As the result, the method is inferred to be successfully applied to the experimental data so that the extrapolation can be obtained straightforwardly without any assumption of the structure in advance. Furthermore, the criterion for judging the uniqueness and correctness of the extrapolation is proved to be the absence of the ripple beyond non-zero range in the radial distribution curve.

View full abstract

Weakly bent LiF crystals are successively annealed at various temperatures from 400°C to 800°C and the polygonization process is observed. Slip lines disappear at about 450°C and appear again at about 500°C. At higher temperatures than 500°C, edge dislocations move to form polygon walls. The complete polygon walls are produced at 660°C, and coarsening of polygon domains occurs above this temperature. The coarsening proceeds through either of two processes: coalescence of two branches of the Y-shaped polygon walls and absorption of a polygon wall by another parallel polygon wall. The L-shaped polygon domains are formed when two glide systems, perpendicular to each other, are acting, which are predominant on either side of the neutral plane, respectively.

View full abstract

Intensity of electron diffraction Debye-Scherrer rings of evaporated films of aluminum, nickel, gold and sodium fluoride was measured for electrons in a range of wavelength λ from 0.1 to 0.025 Å (accelerating voltage from 15 to 200 kV).
Logarithm of observed intensity varies linearly with λ² for not too large λ in accordance with the dynamical theory of two-wave approximation. The value extrapolated to λ=0 coincides with the kinematical value within experimental errors 5∼15%. The gradient of the linear relation, too coincides with the value calculated from the theory. No complication was found which requires explicitly the many-wave theory. The deviation from the linearity for large λ was reasonably explained as a result of absorption.

View full abstract

Fluctuations of the electric field in a plasma are treated on the basis of the fluctuation-dissipation theorem. The treatment is applied to the relaxation between ion and electron temperatures. The interaction between ion and electron which causes the relaxation is reduced to the interaction between the ion and the fluctuating electric field caused by the surrounding electrons. The short range encounters between electrons are neglected but the long range encounters are included through the dielectric permeability which is obtained use of the fluctuation-dissipation theorem. The rate of relaxation agrees with the result obtained Kihara et al. who considered that the ion interacts with the individual electrons.

View full abstract

Effects of external magnetic field on the amplitude and frequency of ammonia maser oscillator employing the J=3, K=2 line were measured and compared with theory. The variation of the traveling-wave effect by the external field is calculated and theoretical curves of the frequency shift as a function of the external field are given. Definitions of line center by magnetic perturbation method are discussed. It is concluded that the resettability with an accuracy of a few parts in 10¹¹ can be obtained, when the variation of maser frequency of about 0.5 cps. caused by a magnetic perturbation of 2 to 3 oersteds can be detected and corrected.

View full abstract

Observed increase of the frequency of an ammonia maser with magnetic field on the J=3, K=2 line which was determined by a magnetic perturbation method is explained by assuming a small difference between magnetic coupling constants of upper and lower inversion states. Theoretical analysis developed by neglecting the magnetic moment of nitrogen nucleus is given. The magnetic coupling constant in the upper inversion state is found to be smaller by 0.5±0.2 percent. This seems to be a reasonable magnitude, when the dependences of interatomic distances and of the rotational magnetic moment on the inversion state are considered.

View full abstract

The ionization efficiency curves for Na⁺, Na⁺⁺, K⁺, K⁺⁺, Mg⁺ and Mg⁺⁺ are studied with essentially monoenergetic electrons.
It is proved that Na⁺, K⁺ and Mg⁺ follow the linear law up to 1.5 eV, 0.8 eV and 2 eV above the thresholds, respectively, and that Na⁺⁺ and K⁺⁺ follow the square law up to about 20 eV and 15 eV above the thresholds, respectively. These results agree with the theoretical prediction that n-fold multiple ionization would be proportional to a n-th power of excess electron energy.
Two remarkable humps are found in the I. E. curve for Mg⁺, which are attributed to autoionization processes, These processes occur at 2.3±0.1 eV and 5.0±0.2 eV above the ionizotion potential, the first one may correspond to the excited states of Mg atom, ¹F° and ³D°, but any excited states to be correlated to the second one is not known.
Contrary to expectation, the I. E. curve for Mg⁺⁺ is not a square curve of excess energy but has a complex shape. In order to explain the shape, possibility of autoionization due to excitation of inner shell electron is suggested.

View full abstract

Recovery behaviors of lattice expansion and optical absorption of neutron-irradiated LiF crystals have been measured as a function of annealing temperature. Remarkable correspondence between the two properties leads an interpretation of steps or humps and reduction in recovery curves of lattice constant respectively by formation of colloidal centers which are probably coagulations of vacancies and recombination of vacancies and interstitials.
Optical microscopic observations reveal the fact that the square cavities, considered to be coagulations of vacancies remaining after displacement of atoms by neutron irradiation, preferentially formed on dislocation lines, along which F₂ gas escapes from the crystals.
It is suggested that the colloidal centers are formed by clustering of point defects and some of them, which probably consist of vacancies, grow to square cavities during heat treatment.

View full abstract

The flow of viscous fluid in a two-dimensional rectangular cavity has been studied. It is assumed that the cavity is bounded by three rigid plane walls, on which the fluid velocity is zero, and by a flat plate moving in its own plane. For the ratio of the lengths of sides of rectangular cross section, three cases have been chosen: 2:1, 1:1, 1:2. The Reynolds number of the flow is varied as 0, 1, 2, 4, 8, 16, 32, 64, 128. For these cases, the Navier-Stokes equations have been numerically integrated with the aid of high-speed electronic digital computers. Stream-lines, equi-vorticity lines, and isobaric lines for some typical cases are shown in figures. Velocity distributions along the centre line and pressure distributions over the both side walls are also shown.

View full abstract

Unsteady three-dimensional boundary-layer equations can be reduced to two-dimensional type, if one component of the velocity and the pressure gradient in that direction are negligible throughout the boundary layer. Conditions for the existence of similar solutions for such quasi-two-dimensional boundary layer are obtained. In particular it is found that the velocity at the outer edge of the boundary layer must be proportional to Y₁exp (at⁄Y), Y₁(bt+Y)^a⁄b or (x+Y₁)⁄(bt+Y), where a and b are constants, Y and Y₁ are arbitrary functions of y. Here x, y, z are geodesic normal plane coordinates (the x-axis being the geodesic of the body surface z=0). New similar solutions are found, and velocity distributions for various cases are calculated. All the known similar solutions, being two-dimensional, are only special cases of our results. Axisymmetric similar solutions are also among our results.

View full abstract

Two-dimensional flow of a viscous incompressible fluid past a rotationally-oscillating circular cylinder is investigated on the basis of Oseen’s equations of motion. The cylinder is assumed to oscillate about its axis periodically. It is found that the solution is composed of a steady part and a periodic part, the latter of which is due to the periodic motion of the cylinder. The forces acting on the cylinder are calculated by two different methods; in one method the law momentum conservation is applied to the flow region surrounded by a large surface, while in the viscous stresses on the surface of the cylinder are integrated. The results by these two methods do not agree with each other, however, and there appears to exist something like Garstang’s paradox. The flow field is calculated numerically at several instants of time in one period, and the flow patterns are shown graphically.

View full abstract

p. 706   The value of 2.436 in Eq. (9) should be changed to 1.684.
Eq. (10) is incorrect (Private communication, D. M. Van Patter, May 25, 1961).
Such errors might not be so remarkable that the final result should be changed.

View full abstract