Results of three-year systematic measurement of nuclear fall-out

A survey is given of the results of measuring the radioactivity of rain-out from 1. 11. 1956 to 1. 2. 1960 and of fall-out from 1. 11. 1958 to 1. 2. 1960.The temporary cessation of nuclear weapon tests from 1. 11. 1958 became apparent in the second half-year after the cessation (from 1. 5 to 31. 10. 1959) by a decrease in the cumulative activity to 45% of the value for the first half-year (from 1. 11. 1958 to 30. 4. 1959). At the end of 1959 another decrease was apparent.It was shown on the basis of long-term investigation into the activity that the samples of fall-out with greater activity contain relatively very little admixture from earlier nuclear tests so that in the period of a few weeks to months the sets of fission products may be regarded as practically isolated. The exponentn in the relationA=at ^–n is most frequently 1.2 for the period of the first four mounths and for older samples is most oftenn=1.5. The energy of the beta and gamma rays from fall-out was estimated on the basis of absorption measurements. It was shown that the quality of the beta radiation varies with the age of the samples.A brief survey is given of the results of determining the Sr 90 content in fall-out and milk, and of the methods of physical evidence of Sr 90 used.

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1. 11. 1956 1. 2. 1960 1. 11. 1958 1. 2. 1960. 1. 11. 1958 , ( 1. 5. 31. 10. 1959) 45% ( 1. 11. 1958 30. 4. 1959). 1959 . . , , . n A=at ^–n 4 1,2; n=1,5. - - . , - . Sr⁹⁰ . Sr⁹⁰.

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The author thanks Prof. F. Bhounek, member of the Czechoslovak Academy of Sciences, for valuable advice during this work.     

ИССЛЕДОВАНИЕ ЭРОЗИЙ НОГО ДЕЙСТВИЯ ИМПУЛЬ СНЯХ ЭЛЕКТРИЧЕСКИХ РАЗРЯ ДОВ С СЛАБЫМ ТОКОМ

50–100 , 1–2 1–10 . - . - . , , - . -.     

The elastic coupling between longitudinal and transversal vibrations оf isotropic rods II. Rods of circular cross-section

The new approximative method for calculating the frequencies of longitudinal vibrations of isotropic homogeneous rods described in part I. is used for rods of circular crosssection. Similarly to the rods of rectangular cross-section there does not exist any dead zone of frequencies.

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II.

, I. (. . 366), . , , .

     

On the photo-electroluminescence of ZnS-Cu

The influence of weak ultra-violet irradiation on the brightness waves of electroluminescence is investigated for two types of ZnS-Cuphosphors. The observed effects (increase in brightness in the primary peak and its phase shift, the disappearance of the secondary peak) are explained on the basis of present-day conceptions on electroluminescence.

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ZnS-Cu

ZnS-Cu. ( , ) .

     

ЛОКАЛЬНЫЕ КОЛЕБАНлЯ ДВУХАТОМНОЙ ЛлНЕЙНО Й ЦЕПОЧКл С ДЕФЕКТАМл

. n : , . npou u , n . n n npocm .     

КОРРЕКЦИОННЫЕ ФАКТО РЫ ПРИ АБСОЛЮТНОЙ ДОЗ ИМЕТРИИ ПЛОСКИХ ИСТОЧНИКОВβ-ИЗЛУЧЕНИЯ С ПОМОЩЬЮ СЧЕТЧИКА ГЕЙГЕРА-МЮЛ ЛЕРА

n n, n , .     

ГАЛЬВАНОМАГНИТНЫЙ Э ФФЕКТ В ОБЛАСТИ ТЕМПЕРАТУРЫ КЮРИ

. - II- . .     

Two-barrier detector

The paper describes the principle of a detector with two opposite surface barriers and the experimental verification of its functioning. The detector permits double the effective depth to be attained on the material with a given bias voltage. The principle of opposite barriers also permits a reduction in the system of dE/dx andE detectors to one detector.

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. . dE/dx E .

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The authors thank A. Irra for carefully preparing the plates, K. Putz and J. imková for very effective help in measuring on the cyclotron and the members of of the cyclotron staff for their cooperation.     

тЕМпЕРАтУРНАь жАВИс ИМОсть ЁФФЕктА ДЕМБЕ РА НА AgCl

AgCl . –190C +20C. –60C . T–130°C, . .

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The temperature dependence of the Dember effect on AgCl

The condenser method was used to study the temperature dependence of the Dember effect on monocrystalline plates of AgCl when illuminating with ultra-violet light. The dependence was studied from –190C up to room temperature. At approximately –60C a change in the effect from negative to positive was found. At temperatures around –130C there was a maximum the magnitude of which changed when the measurement was repeated. A possible interpretation of the experiments is put forward.

     

The change in primary extinction during decomposition of a super saturated solid solution 1. System Al-Ag

On the basis of the correlation of diffraction data (intensity and width) of a precipitate with the intensity of reflection of a matrix solid solution it is shown that the change in primary extinction during the decomposition of a solid solution of Agin Alis caused by the precipitation of the phase Ag₂Aland not by the production of lattice defects (zones, stacking faults).

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I. Al-Ag

( ) , Ag Al Ag₂Al, ( , ).

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Reported in part at the VIth Scientific Technical Conference on the Application of X-rays held in Leningrad in 1958.

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The author thanks M. Mikovský for preparing the single crystals of the alloy Al-Ag having a high primary extinction and J. Laek and Prof. J. Bedná for carefully checking their homogeneity and chemical composition.     

Mikrophy'sikalische Vorgänge,die die Entstehung der Schnellen Schichtungswellen in der Neonglimmentladung bedingen

Zusammenfassung Im nachstehenden Artikel werden mikrophysikalische Vorgänge behandelt, die das Auftreten schneller Schichtungswellen in Neonglimmentladungen veranlassen können. Es werden sowohl die qualitativen Abhängigkeiten, als auch die ziffernmäigen Werte der Parameter der Schichtungswellen mit den charakteristischen Gröenwerten der in diesem Entladungstypus vor sich gehenden Vorgänge verglichen. Auf Grund der vorgenommenen Vergleiche kann gesagt werden, da die Relaxationszeiten der schnellen Wellen durch die Diffusionslebensdauer der atomaren, bzw. molekularen Ionen gegeben sind.

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,

, . , . , , .

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Zum Schlu danken wir F. Kroupa und V. Krejí für die aufmerksame Lesung der Arbeit und wertvolle Hinweise.     

Static and Vibrational Properties of Transition Metals

A model pseudopotential depending on an effective core radius but otherwise parameter free is proposed to study the equation of state by incorporating the s-d hybridization effects. Very recently proposed screening function due to Sarkar et al has been used to obtain the screened form factor. The equations of state for Cu, Ta, Mo, W and Pt have been studied up to the pressure of 1000 GPa. The vibrational properties such as phonon dispersion curves (in q and r space), phonon density of states, mode Grüneisen parameters, maximum frequency _max, mean frequency , ^21/2 = (/ ^-1)^1/2 and fundamental frequency ² and static properties such as dynamical elastic constants of rhodium and iridium are also calculated. The theoretical results are compared with experimental findings wherever possible. A good agreement between theoretical investigations and experimental findings has confirmed our formulation.     

Double cascade transitions of gamma rays from radiative capture on Co59

Pairs of gamma quanta, giving a sum equal to the binding energy of the last neutron in a Co⁶⁰ isotope, were studied during radiation capture on a Co⁵⁹ nucleus. The energies of the gamma quanta giving such cascades were determined and an attempt was made to determine the relative intensities of the different cascades.

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- Co⁵⁹

Co⁵⁹ -, Co⁶⁰. -, , .

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In conclusion the authors thank J. Vávra for cooperation in the measurements.     

тРЕхлУЧЕВыЕ ВжАИМОД ЕИстВИь π−-МЕжОНОВ с ИМпУльсОМ 4 GeV/c В пРОпАНОВОИ пУжыРь кОВОИ кАМЕРЕ

Altogether 1648 cases of three-prong interaction of ^–-mesons with a 4 GeV/c impulse were found on 90 000 pictures from a propane bubble chamber 55 × 28 × 14 cm³ in size; all three secondary particles were pions, two having a negative and one a positive charge. Analysis of these cases showed that at an impulse of 4 GeV/c of primary ^–-mesons the process of the coherent production of pions was not observed. On the other hand, this analysis led to an interesting result: (19 ± 9) % of the total number of (⁺, ^–) pairs in A interactions is due to the decay of the meson ^{0 +} + ^–. A value of = (764 ± 36) MeV was obtained for the mass of mesons and = (166 ± 55) MeV fort he width of its resonance curve. Investigation of the distribution of masses in the case in question gave no answer due to the insufficiently determined course of the background curve.

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On leave from:Institute of Physics, Czechosl. Acad. Sci., Lumumbova 1, Praha 8, Czechoslovakia.

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Joint Institute of Nuclear Research, Dubna, USSR.

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Institute of Physics, Czechosl. Acad. Sci., Lumumbova 1, Praha 8, Czechoslovakia.

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Faculty of Mathematics and Physics, Charles University, Brehová 7, Praha 1, Czechoslovakia.

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. , . , . , . . , , . . . .     

Polarization of photo-luminescence of ZnS: Cu monocrystals

Different models of luminescence centres are discussed on the basis of measurements of the composition of ZnS monocrystal photo-luminescence in different polarizations and temperature dependence of the degree of polarization. Those of the models submitted by Birman, which assume the polarization to be due to the different force of the oscillators for transitions withEc andEc, or models assuming luminescence polarization to be due to the orientation of the luminescence centres, agree with the results of experiments, i.e. the temperature independence of the degree of polarization and the conformable spectral composition of both polarizations. It is also shown that measurements made up to now of the degree of polarization must be taken as orientational as a consequence of the depolarizing influence of the diffused rays of luminescence on its value.

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ZnS: Cu

ZnS , . , . . , , , E E, , . , , - .

     

Влияние эмиссионных свойств анода на характеристики сч етчиков гейгера-мюлл ера

.

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The influence of the emission properties of an anode on the characteristics of GM counters

The hitherto unknown mechanism of the production of false pulses is investigated and its influence on the characteristics of counters is discussed.

     

К теории коэрцитивно й силы и кривой намагничивания

. , , . .     

The movement of single 90° domain walls of BaTiO3 in an alternating electric field

Single crystals of BaTiO₃, containing one 90° domain wall, were used to study the origin and character of the movement of such a wall in an alternating electric field having a frequency of 50 c/s. The experimental results are discussed from the phenomenological point of view.

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90- BaTiO₃

iO₃, 90- , 50 Hz. .

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The authors would like to thank A. Glanc for preparing the crystals for measurement, V. Dvoák, J. Kaczér and V. Janovec for fruitful discussions.     

π0 → γγ in the Spinor Strong Interaction Theory

An expression for the decay rate (⁰ ) has been derived in the frameworkof the spinor strong interaction theory, a first-principles strong interaction theoryproposed some years ago as an alternative to low-energy QCD. The startingpoint is the SO(3) gauge-invariant action for two quark mesons which has beensuccessful in accounting for confinement, ^{+ +} , e⁺, and ⁰ e⁺, nonexistenceof the Higgs boson, and other low-energy mesonic phenomena. The quasi-four-quarkmeson equations developed for the decay of a vector meson into twopseudoscalar mesons V PP has been taken over here to apply to P(⁰) VV(^{+ –}) (plus ⁺ and ^– which annihilate each other). This mechanismin principle agrees with that of the assumption of vector meson dominance inthe literature. It, together with the effect of form factors, arises naturally in theformalism and need not be assumed. Equations for the perturbed vector mesonwave functions cannot be simply solved and an assumption has been made toobtain an estimate of their magnitude. Together with a constant associated withthe strong coupling obtained earlier from V() PP(K⁺K^–), the estimated decayrate is 19.2 eV, in order-of-magnitude agreement with data (7.74 eV).     

Bemerkung über die Reziprozität beim Durchgang des Lichtes Durch Leitfähige Schichten

Zusammenfassung Im vorliegenden Artikel wird die Durchlässigkeit eines beliebigen Systems homogener oder inhomogener Schichten mit beliebiger Leitfähigkeit bei senkrechtem Einfall einer elektromagnetischen Welle untersucht. Es wird bewiesen, da\ das Verhältnis der Durch-lässigkeiten beim Auftreffen der Welle von der einen und von der anderen Seite lediglich von den Leitfähigkeiten der Medien auf beiden Seiten des Systems abhängt. Falls die Leitfähigkeiten beider Medien gleich sind, sind auch die Durchlässigkeiten in beiden Richtungen gleich.

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. , . , .