Локалъная чувствите лъностъ фотокатодов фотоумножителей

. . .

---

The local sensitivity of photo-multiplier photo-cathodes

The influence of the non-uniform distribution of the sensitivity of a photo-multiplier photo-cathode on the spectrum shape of the output pulses from a scintillation detector is studied. Methods of scanning the local sensitivity and determining its distribution function are described. The theory was compared qualitatively with measurement on a slow-neutron detector from a mixture of zinc sulphate and boric acid.

     

Change in primary extinction during decomposition of supersaturated solid solution II. Al-Cu 4% alloy-formation of G.P. zones

The change in integrated intensity of the (200) reflections of a solid solution during the formation of G.P. zones was measured and compared with the change in the character of the diffuse streaks corresponding to them. It was found that the. formation of G.P. zones does not lead to a decrease in primary extinction despite the great changes in the distribution of the copper atoms. It was shown that the formation of a precipitate accompanied by the formation of crystallographically incoherent boundaries greatly decreases the primary extinction.

---

. II. 1-u 4%: [. . ]

(200) . . , . , . . , . , , , .

     

ОДНОНУКЛОННАЯ МОДЕЛ Ь ЯДРА. ЧАСТЬ I

. . , - , - , - .     

The physical nature of the production of moving striations in a d-c discharge plasma

The physical nature of the stratification of the d-c discharge plasma is found and physically interpreted. The interpretation is based on the mathematical expression of the production of periodic structure in plasma after an aperiodic disturbance, derived from an extremely simplified system of equations. Only three basic phenomena occurring in the plasma of each d-c discharge are included: a) the dependence of the rate of ionization on the electron temperature and hence on the electric field, b) the production of space charges due to the different rates of diffusion of the electrons and ions, c) the creation of additional electric fields due to the creation of space charges. The interactions of these phenomena gives rise to a chain, expanded in time and space, which leads to the production of moving striations. In agreement with experiment this structure is developed only on the side towards the anode from the place where the equilibrium state is disturbed.

---

. (9, 10) (4, ), . , , : ) , , ; ) , ; ) , . , , — — . , .

---

---

In conclusion the authors thank J. Fousek, J. Kaczér and M. Novák for carefully reading this paper and for valuable remarks, and J. Holub for carrying out the numerical and graphical work.     

Equilibrium state of toroidal electron beam

The paper deals with the collective behaviour of electrons which rotate in a magnetic field used in a betatron. It is shown experimentally that there exists strong interaction between the electrons, which leads to the rapid formation of the equilibrium state with characteristic distribution of the charge density in the cross-section of the toroidal beam. The corresponding relaxation time is of the order of 1 sec. A statistical theory of the equilibrium beam is elaborated. Its main result is that the effective radius of the beam is a function of two parameters, one of which is proportional to the thermal energy of the electrons and the other to the perveance of the beam. The charge contained in a toroidal beam of given effective cross-section is equal to the product of the charge the beam would contain at zero temperature and a coefficient, which is a function of the temperature of the beam. Its value is unity at zero temperature and rapidly decreases with increasing temperature. The cause of cooling of the beam is shown.

---

, . , , . 1S. . , , — I/(E₀/q)^3/2 (I — , ₀ — q ). , , , , , . . .

---

---

Now Institute of Vacuum Electronics, Czechosl. Acad. Sci., Prague.

---

In conclusion the author thanks J. Luká and L. Hyttych for invaluable help in the experiments, A. Rajský for constructing the electronic apparatus and J. Sokol for preparing the miniature probe.     

The influence of compression on the absorption of AgBr single crystals

The influence of compression on the edge of self absorption of AgBr single crystals was studied. The measurements were performed at a temperature of –180°C. The shift of the edge of self absorption was studied both in the field of elastic and plastic deformations. The shift of the absorption edge towards the UV end of the spectrum was determined in the field of elastic deformations and towards the i.r. end in the field of plastic deformations. After the ending of the deformation and after unloading the crystal the return of the absorption edge towards the original position was observed.

---

AgBr

AgBr. –180°C. , . , — . .

---

---

The author thanks Prof. Dr. L. Zachoval and K. K. Vacek C. Sc. for their interest in this work and for many comments given during the work.     

The quantum efficiency of the internal photo-electric effect in indium antimonide

A method is described for measuring the relative quantum efficiency of the internal photo-electric effect in semi-conductors by simultaneously measuring the photo-magnetoelectric and photo-conductive effect. The results of measurements on indium antimonide are given. The quantum efficiency begins to increase if the energy of the photon exceeds 0·47 eVat room temperature. The quantum efficiency as a function of the energy of the photon is analysed on the basis of the conception of impact ionization and it is shown that a study of the structure of this curve can supply information on the, band structure of a semi-conductor in the region of high energies of electrons and holes.

---

. . , 0,47 eV . , .

---

---

The authors thank M. Závtová and M. Vantuchová for efficient help with the measurements, K. mirous and V. Vrchovská for preparing the material, E. Antoník for critical remarks and M. Matyá and A. Müller for determining the constants of the material.     

ИЗМЕРЕНИЕ ЦИКРУЛЯРН ОЙ ПОЛЯРИЗАЦИИ γ-КВАН ТОВ, ИСПУСКАЕМЫХ ЯДРАМИ П ОСЛЕ ЗАХВАТА ПОЛЯРИЗ ОВАННЫХ ТЕПЛОВЫХ НЕЙТРОНОВ

---

Measurement of the circular polarization of gamma-quanta emitted from the nuclei after the capture of polarized thermal neutrons

---

, .

---

, -.     

A note on the Watanabe theory of weak interactions

It is shown that according to the Watanabe theory of weak interactions a resonant scattering of electrons by protons must take place. The resonant energy depends on the massm _B of the intermediate boson. Form _B=2300m _e this energy is about 213 MeV in the centre of the mass system (c. m. s.). The energy width at resonance is 1·4 MeV.

---

, . , , . _{m B}=2300_{m B} , 213 MeV -. 1,4 MeV.

---

---

The author would like to thank Professor V. Votruba for suggesting this note and for valuable advice and help during the work.     

Влияние сильного выс окочастотного поля на расслоение положи тельного столба постоянного тлеющег о разряда

. . , .

---

The influence of a strong high-frequency field on the stratification of the positive column of a D-C glow discharge

An experimental study is made of the damping of moving striations in a d-c glow discharge by a strong high-frequency field. The results of measurement are in agreement with existing conceptions on the production and mechanism of propagation of moving striations. Apart from the process of damping the paper also describes the standing stratification of the positive column of a d-c discharge as a result of a superposed high-frequency discharge.

---

---

.     

СЕРНИСТЫЙ ТЕЛЛУР — ПО ЛУПРОВОДИОЕ СОЕДИНЕ НИЕ

, , , , .     

The temperature vibrations of urea molecules

The structural and dynamic parameters of urea at 112°K and 295°K were determined by the least squares method. The characteristic temperature of the torsional optical vibrations of a molecule about a C-O bond was determined and is in good agreement with the value determined by Raman scattering. The fractional X-coordinate of the nitrogen atom corrected for torsional vibrations was determined and it was found that the magnitude of the projection of the C-N bond in the given temperature range changes only within the limits of observational errors. A new method, called temperature difference synthesis, is described and it is shown that it is suitable for rapid qualitative determination of the thermal anisotropy of the vibrations of atoms in a crystal lattice.

---

112°K 295°K. C-O , , . X- , C-N . , , , .

     

Die Temperaturabhängigkeit des Brechungsindex von Silizium

Zusammenfassung Es wird die Abhängigkeit des Brechungsindexn von Silizium von der TemperaturT im Wellenlängenbereich 1,1–5,5 und im Temperaturbereich 109–750°K angeführt. Die Abhängigkeitn=f(T) ist unlinear, für tiefe Temperaturen (T170°K) giltnT ². Theoretisch kann die beobachtete Abhängigkeit nicht unstreitig interpretiert werden, da eine explicite quantenmechanische Beziehung für den Brechungsindex der homeopolaren Kristalle nicht existiert. Es kann jedoch die Lorentzsche klassische Beziehung für Isolatoren angewandt werden. Für diese kann dn/dT numerisch ausgedrückt werden. Die berechneten Werte stimmen befriedigend mit den experimentalen überein. Unsere Ergebnisse sind in guter Übereinstimmung mit der Antoníkschen Theorie der Temperaturabhängigkeit des Brechungsindex der homeopolaren Kristalle.

---

T =1,1–5,5 109– 750°. n=f(T) , (T170°) nT ². , . , . dn/dT . . .

---

---

Abschließend danke ich Dr. Z. Trousil von dem Inst. f. techn. Physik der Tschechosl. A. d. W., Prag für die gewährung von Silizium, dem Kollegen Irra für polieren des Prismas, Dr. Tauc von demselben Institut dafür, daß er mir einige Messungen in seinem Laboratorium ermöglichte und der Kollegin ilhavá für ihre Hilfe bei den Messungen.     

The distribution of ions and their valencies in manganese ferrites I. MnFe2O4+γ ferrites

A model for the distribution of cations in the spinel lattice of manganese ferrites MnFe₂O₄₊ was elaborated on the basis of the experimental studies of the basic magnetic quantities, electrical conductivity and magnetic relaxation of the given ferrites, taking into consideration their crystallographic properties. The conclusions following from this model are in good agreement with the experimental results obtained by us and by other authors both for stoichiometric manganese ferrite and for a ferrite where 0.

---

I. MnFe₂O₄₊

, MnFe₂O₄₊ . , , , , , 0.

     

КРУГОВОЙ УСКОРИТЕЛЬ ЭЛЕКТРОНОВ С КОЛЬЦЕВ ЫМ волноводом

, 4 cm , E _8,1,1. 10 GHz. .

---

Circular electron accelerator with toroidal wave-guide

A small electron model of a synchrotron with weak focusing and betatron injection was constructed and tested. In it the electrons are accelerated on a radius of 4 cm by a partial traveling wave in a rectangular toroidal resonator, excited in aE _8,1,1 mode. The source of the h-f power is a tunable impulse magnetron in the 10 GHz band. The possibility of synchronous acceleration of relativistic particles in a smooth toroidal wave-guide in the presence of a strong radial component of the h-f field was thereby confirmed experimentally.

     

A possible test of quantum electrodynamics by means of polarization effects in electron-nucleon scattering

The differential cross-section is given for the electromagnetic scattering of polarized relativistic electrons on polarized nucleons. The finite size of each particle is taken into account by means of two form-factors. The effect of the possible non-punctiform structure of the electron on the polarization effects in scattering is discussed. It is shown that the internal structure of the anomalous magnetic moment of the electron would show itself in the cross-section by terms depending on the transversal polarization of the incident electrons.

---

. . . , , .

---

---

Summary of results of a diploma-thesis for the degree of graduate physicist.

---

In conclusion the author wishes to express his sincere gratitude to prof. V. Votruba and J. Kvasnica for suggesting this problem, for helpful discussions and valuable advice.     

Three variations in the intensity of cosmic radiation in the first half of 1958

The time courses are given of three variations in the intensity of cosmic radiation, which occurred in the first half of 1958. The measuring apparatus is described and the energies of the particles recorded a reestimated. The paper is the partial result of systematic measurements of the intensity of cosmic radiation carried out in Czechoslovakia in the International Geophysical Year.

---

1958

, 1958 . . , .

---

---

The authors heartily thank the Institute of Geomagnetism in Krasnaja Pachra, near Moscow, and especially its director, Prof. M. B. Pukov, and Dr Ju. M. Kopylov for the neutron counters.The authors wish to thank Prof. V. Petrílka, corresponding member of the Czechoslovak Academy of Sciences, and Prof. L. Jurkiewicz, from the Academy of Mining and Heavy Industry in Cracow for help in the work and Academician J. Novák, who made possible the numerical evaluation of the data in the Mathematical Institute of the Czechoslovak Academy of Sciences. Especial thanks go to F. Pilát and B. Slavík for their great help in setting up the apparatus and to all colleagues who took part in the measurements.     

Paramagnetic resonance of Fe3+ ion in CdWO4 monocrystal

The paramagnetic spectrum of the Fe³⁺ ion in a CdWO₄ monocrystal was measured on a frequency of 9600 kMHz at 290°K. The spin-Hamiltonian of the Fe³⁺ ion was determined and had the form of (1). The constants derived for the spin-Hamiltonian areE/D=0·144±0·002,D=23·8 kMHz.

---

Fe³⁺ CdWO₄

Fe³⁺ CdWO₄ 9600 kMHz 290°K. - Fe³⁺ (1), E/D 0,144±0,002 D 23,8 kMHz.

---

---

In conclusion, the authors thank . Bárta and V. Kment from the Society for Chemical and Metallurgical Production in Ústí n/L for producing and supplying the monocrystals and for much valuable advice.     

Влияние давления на а бсорбцию галогенидо в серебра. Часть II

AgBr, Agcl AgI — 160°C. AgBr AgCl . AgI .