1987 Vol. 11, No. 3
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The experimental method of calibrating chaoyang No.1 polycarbonate solid state nuclear track detector using heavy ions is reported. V vs REL response curves and empirical formulae for six etching conditions are also given.
The gamma rays emitted from three photon annihilation of positrons and electrons were selected with a triple coincidence method and the linear polarization of one of the three photons was investigated by using Compton scattering. Under two geometric conditions of three photons annihilation (α1=α2=α3=120° and α1=90°, α2=α3=135°), the ratio of the scattered photons which were parallel with the annihilation plane to those perpendicular with the annihilation plane were 1.82±0.06 and 1.53±0.08, thus the linear polarization of the photons to the annihilation plane were 0.56±0.04 and 0.40±0.09.
The two dimensional drift chamber was formed by gluing a delay-line in a MIT-Harvard type drift chamber. An average drift velocity about 3.34cm/μs was obtained when the chamber was operated at plateau region and filled with P-9 gas. Its average space resolution is 570μm. The output signal amplitude of the chamber being changed when alter the incident particle's (both β－ and X-ray) position was observed.
Tests on the read out of the second coordinate (along the anode wire) of the MIT-Harward-type drift chamber by using a Naples type flat solenoieal delay line were conducted. Spatial resolution of 2～5mm and linearity better than 1% were obtained along the delay line of 80cm in length with the gas mixture of P9 or Ar/CH4=70/30.
In this paper Indium active detector is suggested to measure the pulsed neutrons around Electron Lanic. It can be hopefully expected to have correcrt dose response of detector in the short pulsed neutron field, high resolution ability of the neutrons to γ-rays and of against electromagnetic disturbance.
This detector was used to measure the distribution of neutron flux and dose equivalent rate both inside and outside of the 300MeV Electron Linac shield. The results are compared with TLD measurement. At the end of this paper the Indium activation products by high energy photon reaction (γ, n) are estimated.
A gas sampling Em Shower counter of the lead-SQS tube sandwich type was constructed and tested. The Shower counter uses Aluminium tubes and anode readout. Energy resolution σ/E is 15.5% at Ee=1GeV. Range of the energy response linearity is 0—2GeV. This paper describes the beam test and the performance studied under various conditions.
The BES barrel shower counter prototype was tested with electron and pion beam in the momentum range from 0.2 to 2.0GeV/c at 12GeV PS test beam line of KEK, the preliminary results were reported. Four types of gas mixtures which were used in prototype have been tested: 40% Ar/60% Isobutane, 44.5% Ar/44.5%CH4/11% Methylel, 47%Ar/47%%CH4/6% Methylel, 49.3%Ar/49.3%CH4/1.4% Ethyl alcohol. The results show that using SQS tube as sampling means in BES shower is feasible way for BEPC region.
A new phenomenological potential model on interaction between quark and antiquark is proposed by the hint of QCD and experimental data. Spectroscopies, leptonic decay and electromagnetic transition widths of the heavy quarkonia, cc, bb and tt, are calculated using nonrelativistic SchrÖdinger equation with numerical method. The most results of the model are well consistent with experimental data.
A Scheme of quantum treatment for transition radiation is proposed. The Fresnel coefficients are adopted to describe the stationary states of electromagnetic fields near the interface between two mediums before a canonical field quantization procedure can be performed. Then an usual perturbation approach in field theory leads to the general expressions of radiation intensity in two different polarizations. The second order quantum corrections are ascribed to the existence of electron spin. Some concrete formulas for the cases of electron or monopole acrossing a metal surface are presented as well.
A systematic study of the evolution pattern of symmetries in the Pati's minimal superstring preon model is presented. It is thought that this pattern more preferable than the original one.
In this paper the quark self-energy with nolocal quark-pion interaction is calculated and the convergent self-energy is obtained. Based on the results it is found that the divergence is merely due to the assumption of pointlike pion made in the calculation.
In this paper,the magnetic field distribution of the modulating width multipole permanent magnets is analyzed. Only radially magnetized permanent magnet segments are used and the required magnetic field is formed by modulating the widths of the segments in this project. In 2-dimensional ideal case pure 2N-pole magnetic field can be formed. The spatial expressions of the scalar potential for the ideal and real 2-dimensional cases are given. And the methods for reducing the undesirable higher harmonics of the magnetic field in the real case are also discussed.
The 12 cumulative yields and 7 independent yields in the symmetric region were determined in the fission of 232Th induced by 14.7MeV neutrons with nuclear chemistry techniques. The independent yields of the present work, along with the independent yields obtained in our previous work, were used to calculate the empirical Zp values on the basis of a Gaussian charge distribution function with a σ of 0.56. A mean value of 0.49±0.25 for ΔZ(=Zp—ZUCD) is obtained from all Zp values in the asymmetric region. Abnormal ΔZ values in the symmetric region seem to suggest that the width of charge distribution for symmetric splits is larger than the value of 0.56. The results show strongly in favor of the Two-Mode-Fission-Hypothesis.
The choice and representation of degrees of freedom of collective motions are thoroughly discussed. Starting from the dynamical group of a shematic model, it is pointed out that the number of independent collective degrees of freedom is uniquely determined, although there exist different continuous variable or boson representations. If more collective degrees of freedom were involved, there must be accompanied conditions.
The partially violated U(3) limits of the U(6/12) model is presented. The theoretical predictions are compared with existing experimental data of energy spectra and B(E2). The theory tallies with experiment fairly good.
By using the Double Delta Interaction (DDI) and the Modified Surface Delta Interaction (MSDI) as the effective interaction respectively and by the mixed-configuration, the low-lying spectra of oxygen isotopes 17-22O in the (s-d) shell space are calculated. The results are favourable for DDI.
The condensation probability γβ is studied by assuming that γβ=γβ(A, E)[εβ/MeV]χ When χ=0.425, the best agreement between the calculated dσ/dε and the experimental data is obtained for 18 reactions. For the same composite systems, the extracted γβ(A, E) are nearly the same. When the mass of the composite system increases, the γβ(A, E) increases too. For the α-decay nucleus 210Po, γβ(A, E) is larger than the others considerably.
On the bases of s, d IBM, octupole states are taken into account and the two-quasiparticle excitation is treated as boson-like in the SU(3) limit. The energy spectra are obtained analytically and the nondegenerated 1+ and 3+ bands are also reproduced. The calculated spectra of eight nuclei, which possess with 1+ or 3+ bands in their energy spectra in the rotational rigion, agree with the experimental ones fairly good.
HIRFL magnetic field measuring system was built in October, 1983. There are 94 Hall probes on a detecting arm. The positioning device, which mainly consists of a detecting arm, a rotating ring and a fixed ring, is of a polar coordinate type. For 16KG magnetic field, the measuring repeatability of the system is better than ±5×10－5, the measuring accuracy is about ±1×10－4. The measuring rate is about 188 data per minute.
In this letter it is shown that even in mπ≠0 case the Goldberger-Treiman relation is still hold in the Skyrme model. The mean square radius of strong interaction of nucleon <r
The influence arising from overall energy conservation kinematics modification on the impulse approximation is discussed. It is found that this kinematics modification plays an important role in both deep inelastic lepton nucleon scattering and deep inelastic lepton nucleus scattering. This can give explanations of the Bjorken scaling violation and the EMC effect.
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