1997 Vol. 21, No. 6
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This paper describes the structure and performance of the phoswich telescope made of lmm thick scintillator NE102A and 40mm thick CsI(T1).The front area of CsI(T1) is 24mm×24mm and back area is 37mm×37mm.The p,d and t of isotope and all fragments have been separated clearly using QDC method.
Supposed that all of cosmic ray particles of energy below 3×1018eV are mainly originated and accelerated in an individual explosion of the galactic supernovae(SNs).By using an isotropic diffusion propagation model,non-steady state density of the iron nucleus is investigated.Considering the effect of extra-galactic cosmic rays and the variety of the galactic cosmic ray nuclei,the statistic model of galactic cosmic rays with a reasonable distribution of the SNs in space and time can account for the spectrum of cosmic ray in the energy range of 1012—1020eV quitewell.
Micro-gas chambers (MGC) have been produced with a gain of ～500 and the enegy resolution (FWHM) of ～14% for 55Fe 5.9keV X-ray at anode voiltage of 380V.
A new set of fpc is introduced to build the orthogonal set of basis for the states with many S and D pairs in the microscopic theory of low-lying collective motion.
Starting from the configuration-space generating functional for gauge theory obtained by using the Faddeev-Popov method,the conservation laws at the quantum level for the gauge-invariant system are derived.Appling to non-Abel Chern-Simons(CS)theory,the quantum BRS conserved charge and quantuml conserved angular momentum for the non-Abelian CS fields coupled to Fermion field are deduced.The property of fractional spin in CS theory is discussed.
One-dimensional projection of two-dimensional self-affine phase space for two typical self-affine fractals is studied,and one-dimensional projection α model is obtained.About this model,starting from characterstic function,we study its correlation densities and the wavelet correption moment.The wavelet basis functions of split number Λ=2,3,4 are found out.It turns out that the various wavelet-coefficents decouple when the second order wavelet correlation moments are considered.This is a general conclusion and model independent.
Multifragmentation is studied in correlation with energetic protons.A cold multifragmentation pattern is proposed based on the numerical simulation of the stochastic Boltzmann-Langevin model for describing the intermediate heavy ion collisions,i.e.,a sizable fraction of the available energy is released from the system by fast non-equilibrium proton emission,in which the explosion is caused to happen by a violent,but cold expansion of the system.Some typical examples simulated for 40Ca+40Ca central collisions at 90MeV/u are presented.A possible experimental signature which could be detected with the help of a 4π detector system is suggested.
The gross structure appeared in the total fusion cross section for 16O+12C system is studied by using the LCNO theory and the folding model of the paritydependent potential.The experimental data of the fusion cross section,elastic scattering excitation functions and angular distributions for this system are well explained.
The underlying Hamiltonian involved with the rotating two-center shell model is multi-parameter dependent and belongs to the Gaussian unitry ensemble(GUE).It is found that the spacing distribution and two curvature distributions(with respect to the separation and the cranked frequency,respectively)of the levels individually approach to those of GUE in the different regions of separation and cranked frequency.They,however,share a common parameter region.It is suggested that the chaotic motion of the single-particle in a heavy nucleus is possibly realized in the condition of superdeformation and high spin.
The approximate angular momentum projected Hartree-Fock(PDHF)method is used to some odd-A nuclei in the fp shell:47Ti,47V,47Cr,49Cr.Their energy spectra are calculated and compared with the experimental data.The results are fairly satisfactory.In addition,the characteristics of those spectra are analyzed with the particle-rotor model.It is found that those spectra possess the properties of the no alignment limit Spectra.
Considering that the original Q2-rescaling model has some shortcomings in explaining the experimental data,we propose animproved Q2-rescaling model in which,in order to compensate for the loss of nuclear momentum,we employ different Q2-rescaling parameters for momentum distributions of valence quark,sea quark and glouns.By using improved Q2-rescaling model,We can well explain the experimental data of the EMC effect in the whole x region,the nuclear Drell-Yan Process and J/ψ photoproduction process.
In this Paper,We study the antiproton-nucleus charge exchange reaction in the mirror nuclei.Under the distorted wave impulse approximation,using the exact partial wave calculation,the differential cross sections to every final states of 13N(p,n)13C and 15O(p,n)15N at antiproton energies of 179.7MeV and46.8MeV are analysed.The differences between the isospin analog transition and the non-analog transition are also discussed.
The necessity and feasibility of beam polarizaion on Beijing Electron-Positron Collider (BEPC)and the principes and methods of measurements for beam polarization are briefly introduced in this paper.The design of a Compton polarimeter used for measurements of beam polarization of BEPC beam by using a synchrotron radiation pipe-line and the experiments under way are presented.
Relative ionizations(Bragg curves)of 30MeV/u and 25MeV/u 40Ar ion beams supplied by HIRFL through degraders of Mylar films with different thicknesses were measured respectively.The experimental results were compared with calculations by TRIM88 code.It is found that the experimental results are in good agreement with the calculated ones when the 40Ar ions penetrate a smaller distance from target surface.Furthermore,a heavy ion radiotherapy planning for shallow-seated and small tumor is put forward according to the calculated relationship between intermediate energy heavy ion penetration depth in water and relative ionization.
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