1986 Vol. 10, No. 3
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The electromagnetic cascade processes in the atmosphere is simulated three-dimensionally. The number, the mean energy spectrum and the transverse behaviour of secondary particles of electromagnetic cascades produced at different heights (within 1.5c.u) are analysed.
Albedo neutron personnel dosimeter has been more and more widely used due to its small volume and easy in measurement. Great attention should be paid to the calibration technique which finally determines the error of the measurement. In fact, thereusually exists certain difference between the energy spectrum of the radioactive source for calibration and that of the radiation field to be measured. In order to improve the accuracy of the measurement, the problem of the in-field calibration technique should be solved. In this paper, the method of the in-field calibration and the use of so-called Bonner cylinder for the in-field calibration of accelerator are deseribed.
An improved version of the grand unification composite model propose earlier is suggested. Under the hypothesis of partly broken global chiral symmetry, we give the four family of Fermions at low energies to realize unification of four family of Fermions. Neutrino may acquire naturally the Dirac mass. Proton lifetime and weak neutral current at low energy are consistent with experimental results.
In this paper, We present a view point that the reduction of bounded nucleon radius naturally explains the EMC effect. Some discussion is given at the end of the paper concerning the prevalent explanations about the EMC effect.
In this note new co-boundary operators are defined in the product form. The associative composition law of spatial translation group field is discussed using these new operators. The quantization condition of monopoles in SU(2) and SU(3) gauge theories follows easily from the new formalism.
Based on lattice QCD, we use the linear variational method to calculate the hadron spectrum and wave functions, our results are in reasonable agreement with experiment in the region of medium coupling constant.
In the lattice gauge theory, by using cumulant expansion, we calculate the average plaquette for U1 and SU2 group up to the third order approximation in 4 and 5 dimensions analytically. Our results are consistent with MC data. We also discuss the application of cumulant expansion techneque in lattice theory.
Right-handed Currents in 0νββ decay with lepton-number nonconservation is discussed by using two nucleons mechanism and the effective operator approach of nuclear matrix elements in this paper. The relation between the mixing parameter η of right-handed currents and the Majorana neutrino mass mν is calculated from the experimental decay lifetime of 0νββ decay in 40Ca. Our results show that i) mν≤(18~23)eV, if |η|=0;ii) |η|≤(1.6~2)×10－5, if mν=0
In this paper, the design investigation and magnetic field measurement of a 10 period hybrid undulator are given.
By using ΔE-E telescope and the time of flight detector, the energy spectra of products between 6Li and 16O were measured for the reaction 12C+27Al, at 61.8MeV. The contour plots of differential cross section in c.m. system and the angular distributions of emitted fragments were obtained. The calculated values of fully relaxed energies in deep inelastic collistions agree with the experimental values. The mean interaction time of di-nuclear system was estimated as from 1×10－21s to 1.4×10－22s
The strength functions of the isoscalar giant resonance monopole resonance and giant quardropole resonance in 40Ca are calculated by coupling the 1p-1h states to 2p-2h states. The results can explain the recent experimental data.
Microscopic optical potential calculations in the Hartree-Fock (HF) approximation with Extended Skyrme forces are investigated. The HF equation is derived from the variation principle and the potential formula of spherical nuclei is obtained by two different ways. Then the calculations for symmetric nuclei 16O, 40Ca and asymmetric nucleus 90Zr with eight sets of Skyrme force parameters are presented. Our results show that the potential from and variating tendency with incident energy are reasonable and there apparently appears a "wine-bottle-bottom" shape in the intermediate energy region. Furthermore, our calculations reflect shell effects clearly.
Traceless operators of sd bosons are introduced and used to construct the SU6SO6SO5SO3 wave functions of sd bosons according to the method of T.S.Yang
According to the physical picture of dinucleus molecule and considering the particle-hole interaction between two nuclei, the exchange of valence nucleons and nuclear potential between two nuclei were studied.
During the bombardment of 14.8MeV neutron on natural wolfram samples a γ-ray with energy 291.7keV and halflife 5.17±0.03 sec is observed. From the experimental facts it is assumed that in addition to the two well known transition branches from the decay of 5.2 sec isomer in 138W there exists another 11/2+11/2→5/2－3/2 isomeric (E3) transition. The hindrance factor of this new transition is calculated. It is well cosistent with the general empirical rule of k－ forbidden isomeric transition.
The nuclecus 31Si17 is studied by the composite particle representation theory and compared with the shell model calculations. It is shown that the entire energy spectrum agrees with the shell model results very well, and the wave function is equivalent to the shell model wavefunction exactly. Therefore it strongly supports the composite particle representation theory.
Excited states of 128Ba are investigated via the 120Sn(12C, 4nγ) 128Ba reaction by means of in-beam gamma spectroscopy Λ 12+ state other than the previously reported one is observed according to the properties of the 935.0keV γ-ray. It does not belong to the ground state band. Two new interband transitions, 224.8keV and 632.7keV, are observed and assigned to sidefeeding between the negative-parity band and ground state band.
The antisymmetrization effects in nuclear scattering are studied with GCM. The coulomb interaction is included and the energy dependence is discussed.
The low magnetic field distribution of an iron-core double-focusing low-energy β spectrometer is measured with a second harmonic magnetic flux gate magnetometer, the relative measuring precision is better than ±0.05%. The field strength of the spectrometer is about 10G. This spectrometer is used to measure the β spectrum from tritium β decay for estimating the rest mass of electron antineutrion.
It is proposed in this paper that the effect of the core of closed shells to IBM spectrum can be taken into account through the renormalization of the moment of inertia. Thus, the corrected IBM spectra can significantly improve the fitting of the experimental data at high spin states.
The angular momentum theory in the schwinger boson representation is developed to derive a new normal product expression for the commutator [eiaJx,eiβJy] by means of the integral technique within normal product, and the effect on the coherent state caused by two rotations which are in different seqences. Some new normal product expressions for exponential operators, such as eσJ-eλJ+ etc, are also derived and their applications in atomic coherent states are presented.
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