1984 Vol. 8, No. 2
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Abstract:
Calculation and simulation measurement have been done in two dimension fashion for the electric field of the pictorial drift chamber. The results obtained from calculation and measurement provide the basis for choosing the electric potential of the field wires in the chamber.
Calculation and simulation measurement have been done in two dimension fashion for the electric field of the pictorial drift chamber. The results obtained from calculation and measurement provide the basis for choosing the electric potential of the field wires in the chamber.
Abstract:
An analysis of the gamma-ray family (ΣEγ
1300TeV) obtained with Mt. Kambala emulsion chambers is made. The event is produced by one nuclear interaction occurred at lower altitude than 150 m above the chamber. Central region of the event is composed of 5 clusters. Characteristics of the event is discussed.
An analysis of the gamma-ray family (ΣEγ
1300TeV) obtained with Mt. Kambala emulsion chambers is made. The event is produced by one nuclear interaction occurred at lower altitude than 150 m above the chamber. Central region of the event is composed of 5 clusters. Characteristics of the event is discussed.
THE EXPERIMENTAL INVESTIGATION ON IMPROVING THE ENERGY RESOLUTION OF THE GAS SAMPLING SHOWER COUNTER
Abstract:
The charge spectra of the proportional, saturated proportional and SQS signals produced by the minimum ionizing β particles in the gas counter are presented. It is pointed out that using the SQS mode instead of the traditional proportional mode as the sampling means in gas sampling shower counter is a promising way to improve the energy resolution. The measured results of SQS dead time and dead space vary with different gas mixtures, but they are in the same order of magnitude and the typical values are ~10 μs for dead time and ~3 mm for dead space.
The charge spectra of the proportional, saturated proportional and SQS signals produced by the minimum ionizing β particles in the gas counter are presented. It is pointed out that using the SQS mode instead of the traditional proportional mode as the sampling means in gas sampling shower counter is a promising way to improve the energy resolution. The measured results of SQS dead time and dead space vary with different gas mixtures, but they are in the same order of magnitude and the typical values are ~10 μs for dead time and ~3 mm for dead space.
Abstract:
In this article some Feynman rules in the method of collective bag-quark current are given, and, by use of these rules, the zeroth-order transition matrix elements of various photon-hadron processes are obtained. Then the structure functions of nucleons and pions in the processes of deep-inelastic electron-positron annihilation are calculated. The time-like structure functions thus obtained have Bjorken scaling, satisfy Collan-Gross relation, vanish when x=q2/2p﹒q<1, and F1≡W1≥0, F2≡v/M W2≤0 when x≥1. All these characteristics are required by definition. Besides, a counting rule is obtained for the time-like structure functions, i.e., F1(x~1)∝(x－1)3N-2, which is quite symmetric with the one we obtained for the space-like structure functions.
In this article some Feynman rules in the method of collective bag-quark current are given, and, by use of these rules, the zeroth-order transition matrix elements of various photon-hadron processes are obtained. Then the structure functions of nucleons and pions in the processes of deep-inelastic electron-positron annihilation are calculated. The time-like structure functions thus obtained have Bjorken scaling, satisfy Collan-Gross relation, vanish when x=q2/2p﹒q<1, and F1≡W1≥0, F2≡v/M W2≤0 when x≥1. All these characteristics are required by definition. Besides, a counting rule is obtained for the time-like structure functions, i.e., F1(x~1)∝(x－1)3N-2, which is quite symmetric with the one we obtained for the space-like structure functions.
Abstract:
The influence of coset pure gauge fields of a non-abelian chiral group on confinement properties of a quark system is discussed in lattice gauge theories. By calculating the current-current propagator of the model G/H=SU(2)L×SU(2)R/SU(2), it is found that the pure gauge fields on coset space contribute only a perimeter law factor which has no influence on confinement properties of the system.
The influence of coset pure gauge fields of a non-abelian chiral group on confinement properties of a quark system is discussed in lattice gauge theories. By calculating the current-current propagator of the model G/H=SU(2)L×SU(2)R/SU(2), it is found that the pure gauge fields on coset space contribute only a perimeter law factor which has no influence on confinement properties of the system.
Abstract:
The light quark mass m(g) is renormalized by fixing the ρ meson mass. m(g) for g≥2 is obtained by strong coupling expansion. Variatonal calculation extends m(g) to g~1, which is already in the crossover region. The two methods agree in the strong coupling region. In the crossover gegion, m(g) drops quickly towards the weak coupling value.
The light quark mass m(g) is renormalized by fixing the ρ meson mass. m(g) for g≥2 is obtained by strong coupling expansion. Variatonal calculation extends m(g) to g~1, which is already in the crossover region. The two methods agree in the strong coupling region. In the crossover gegion, m(g) drops quickly towards the weak coupling value.
Abstract:
By means of the real time Green's functions, the elementary excitation spectra of Mohapatra-Senjanovic model at finite temperature are given. It is shown that the results given by first order normal pair and abnormal pair cut off approximation of the equations of motion is in good agreement with the results given by DJWB effective potential method under one loop approximation. The correlations between mass and temperature, condensational density and temperature of four elementary excitation spectra are also presented.
By means of the real time Green's functions, the elementary excitation spectra of Mohapatra-Senjanovic model at finite temperature are given. It is shown that the results given by first order normal pair and abnormal pair cut off approximation of the equations of motion is in good agreement with the results given by DJWB effective potential method under one loop approximation. The correlations between mass and temperature, condensational density and temperature of four elementary excitation spectra are also presented.
Abstract:
The adjustment of the mean axial electric field in the 10 MeV cavity of Beijing Proton Linac is described. The comparsion of the adjusting fesults with those of some foreign proton linacs is presented. It is demonstrated that adjusting result of the mean axial electric field is satisfactory in the beam transmissive experiment of the 10 MeV cavity.
The adjustment of the mean axial electric field in the 10 MeV cavity of Beijing Proton Linac is described. The comparsion of the adjusting fesults with those of some foreign proton linacs is presented. It is demonstrated that adjusting result of the mean axial electric field is satisfactory in the beam transmissive experiment of the 10 MeV cavity.
Abstract:
In this paper, the theory for the mutual transformations of strip ion beams and axisymmetrical ion beams is studied. The methods of the transformations by means of thin lenses and deflecting magnets are discussed.
In this paper, the theory for the mutual transformations of strip ion beams and axisymmetrical ion beams is studied. The methods of the transformations by means of thin lenses and deflecting magnets are discussed.
Abstract:
Angular distribution for (α,t), (α,d) and (α,p) reactions of α particle on nuclei 10,11B at 31.2 MeV incident energy have been measured by particle identification system. The shapes of the outgoing particle angular distribution show that the cross sections in backward angular region have different enhacement in 11B(α,t0)×12Cg﹒s, 11B(α,d0)13Cg﹒s, 10B(α,d0)12Cg﹒s, 10B(α,d1)12C1st, 11B(α,p0)14Cg﹒s. and the isotopic effect of the backward angle anomaly in the reac tions (α,t0) and (α,p0) is just opposed to that of (α, α) elastic scattering from nucleus B.
Finally, the reaction mechanism is discussed qualitatively in terms of the Dispersion Theory of direct nuclear reaction. The calculation of the singularity position of the (α,t), (α,d) and (α,p) reactions on nuclei 10,11B is performed using the Feynman Graphs. The initial conclusion is the following:
The principal mechanism is direct stripping in the for-ward angle region and heavy particle stripping in the backward angle region.
For the raction 11B(α,d0)13Cg﹒s. however, there is a multimechanism superposition in the backward angle region.
Angular distribution for (α,t), (α,d) and (α,p) reactions of α particle on nuclei 10,11B at 31.2 MeV incident energy have been measured by particle identification system. The shapes of the outgoing particle angular distribution show that the cross sections in backward angular region have different enhacement in 11B(α,t0)×12Cg﹒s, 11B(α,d0)13Cg﹒s, 10B(α,d0)12Cg﹒s, 10B(α,d1)12C1st, 11B(α,p0)14Cg﹒s. and the isotopic effect of the backward angle anomaly in the reac tions (α,t0) and (α,p0) is just opposed to that of (α, α) elastic scattering from nucleus B.
Finally, the reaction mechanism is discussed qualitatively in terms of the Dispersion Theory of direct nuclear reaction. The calculation of the singularity position of the (α,t), (α,d) and (α,p) reactions on nuclei 10,11B is performed using the Feynman Graphs. The initial conclusion is the following:
The principal mechanism is direct stripping in the for-ward angle region and heavy particle stripping in the backward angle region.
For the raction 11B(α,d0)13Cg﹒s. however, there is a multimechanism superposition in the backward angle region.
Abstract:
In order to preserve all the symmetry properties for the effective collective hamiltonian obtained with the generator coordinate method, it is necessary for the trial wave function to have proper transformation properties. The generator coordinates should then transform in the same way as the represented collective operators respectively. And the mass-centre motion should be independent with respect to the internal motion in conformity with the invariance of the nuclear hamiltonian with respect to space rotation and Galilean transformation.
In order to preserve all the symmetry properties for the effective collective hamiltonian obtained with the generator coordinate method, it is necessary for the trial wave function to have proper transformation properties. The generator coordinates should then transform in the same way as the represented collective operators respectively. And the mass-centre motion should be independent with respect to the internal motion in conformity with the invariance of the nuclear hamiltonian with respect to space rotation and Galilean transformation.
Abstract:
The Hartree-Fock method is used to calculate the binding energy of Λ hypernuclei 5ΛHe and 9ΛBe and the binding energy of charmed Λ(Λc) nuclei 5ΛHe and 9ΛBe. By setting the ratio of the binding energy of Λ in 5ΛHe and 9ΛBe to be equal to the ratio of the binding energy of Λc in 5ΛHe and 9ΛBe, the Λc-N interaction is determined to be equal to 4/5 of the Λ-N interaction. With the interaction thus obtained the binding energ of 1p-shell Λ hypernuclei and 1p-shell Λc nuclei are calculated.
The Hartree-Fock method is used to calculate the binding energy of Λ hypernuclei 5ΛHe and 9ΛBe and the binding energy of charmed Λ(Λc) nuclei 5ΛHe and 9ΛBe. By setting the ratio of the binding energy of Λ in 5ΛHe and 9ΛBe to be equal to the ratio of the binding energy of Λc in 5ΛHe and 9ΛBe, the Λc-N interaction is determined to be equal to 4/5 of the Λ-N interaction. With the interaction thus obtained the binding energ of 1p-shell Λ hypernuclei and 1p-shell Λc nuclei are calculated.
Abstract:
Starting from the Bohr Hamiltonian we investigate the spectrum of well-deformed nucleus of which the axial asymmetry is not too large. To diagonalize the Bohr Hamiltonian a suitable potential with certain singularity is assumed and the terms of (sin43γ) in the rotational energy operator expanded in powers of sin 3γ are omitted. The usually adopted adiabatic approximation is given up in present treatment. It is shown that the nuclear collective excitation spectrum manifests the vibrational-rotational band structure and can be described by a convenient closed formula. Within a vibrational-rotational band the moment of inertia and the deformation no longer remain constant and the energy spectrum deviates from the I(I+1) rule in varying degrees.
Starting from the Bohr Hamiltonian we investigate the spectrum of well-deformed nucleus of which the axial asymmetry is not too large. To diagonalize the Bohr Hamiltonian a suitable potential with certain singularity is assumed and the terms of (sin43γ) in the rotational energy operator expanded in powers of sin 3γ are omitted. The usually adopted adiabatic approximation is given up in present treatment. It is shown that the nuclear collective excitation spectrum manifests the vibrational-rotational band structure and can be described by a convenient closed formula. Within a vibrational-rotational band the moment of inertia and the deformation no longer remain constant and the energy spectrum deviates from the I(I+1) rule in varying degrees.
Abstract:
The phase shifts and differential cross sections of n+6Li elastic scattering are calculated and the d+α cluster structure in 6Li and the exchange effects in n+6Li scattering states are studied by the QRGM which is a RGM with omitting the antisymmetrization with the nucleons in α cluster. The results show that there exists a marked d+α cluster structure in 6Li. Therefore carefully choosing the cluster structure wave function of 6Li, expecially the relative motion wave function between d and α, is very important. The results obtained by the QRGM are in agreement with those obtained by the RGM.
The phase shifts and differential cross sections of n+6Li elastic scattering are calculated and the d+α cluster structure in 6Li and the exchange effects in n+6Li scattering states are studied by the QRGM which is a RGM with omitting the antisymmetrization with the nucleons in α cluster. The results show that there exists a marked d+α cluster structure in 6Li. Therefore carefully choosing the cluster structure wave function of 6Li, expecially the relative motion wave function between d and α, is very important. The results obtained by the QRGM are in agreement with those obtained by the RGM.
Abstract:
Both spin-0 meson and diguark contributions to the ratio R=σL/σT in deep inelastic scattering processes are discussed. The calculated results are quite reasonable in comparison with the experimental values of R.
Both spin-0 meson and diguark contributions to the ratio R=σL/σT in deep inelastic scattering processes are discussed. The calculated results are quite reasonable in comparison with the experimental values of R.
Abstract:
Isomeric cross-sections and their ratio were measured for the reaction 85Rb(n,2n) 84m.gRb induced by 14.7 MeV neutrons. The results of the cross-sections are compared with values in the literatures. The ratio is also compared with calculated value by using of the Vandenbosh-Huizenga's method. Value of the spin cut-off parameter σ of the nuclear level density is deduced for the measured ratio.
Isomeric cross-sections and their ratio were measured for the reaction 85Rb(n,2n) 84m.gRb induced by 14.7 MeV neutrons. The results of the cross-sections are compared with values in the literatures. The ratio is also compared with calculated value by using of the Vandenbosh-Huizenga's method. Value of the spin cut-off parameter σ of the nuclear level density is deduced for the measured ratio.
Abstract:
Beta-delayed proton precursors 33Ar and 49Fe have been produced by the reaction (12C, 3n) using 65 MeV carbon ion bombardments of 24Mg and 40Ca respectively. Their beta-delayed proton spectra have been observed. The major proton peaks are at 3.28±0.07 MeV and 1.98±0.04 MeV for 33Ar and 49Fe respectively. While the corresponding cross-sections obtained for 33Ar and 49Fe are 0.4±0.08 μb and 0.7±0.14 μb respectively. The half-life of 33Ar was determined to be 167+24 ms.
Beta-delayed proton precursors 33Ar and 49Fe have been produced by the reaction (12C, 3n) using 65 MeV carbon ion bombardments of 24Mg and 40Ca respectively. Their beta-delayed proton spectra have been observed. The major proton peaks are at 3.28±0.07 MeV and 1.98±0.04 MeV for 33Ar and 49Fe respectively. While the corresponding cross-sections obtained for 33Ar and 49Fe are 0.4±0.08 μb and 0.7±0.14 μb respectively. The half-life of 33Ar was determined to be 167+24 ms.
Abstract:
A mixing method of working gas Ar—CH4—CH2(OCH3)2 in SQS μ-counter model and a method of monitoring the concentration of CH4, CH2(OCH3)2 in working gas by chromatography are reported. Chromatographic column coated with 15% DNP and thermal conductivity detector are used in chromatography. Using gas sampling valve, sample of working gas in SQS μ-counter model is injected, then the chromatogram peak heights are measured, The concentration of CH4 and CH2(OCH3)2 are obtained by means of comparison with standard curves.
A mixing method of working gas Ar—CH4—CH2(OCH3)2 in SQS μ-counter model and a method of monitoring the concentration of CH4, CH2(OCH3)2 in working gas by chromatography are reported. Chromatographic column coated with 15% DNP and thermal conductivity detector are used in chromatography. Using gas sampling valve, sample of working gas in SQS μ-counter model is injected, then the chromatogram peak heights are measured, The concentration of CH4 and CH2(OCH3)2 are obtained by means of comparison with standard curves.
Abstract:
It is shown that in order to introduce the gauge invariant Wess-Zumino-Witten effective action a global anomalyfree condition should be satisfied by the gauged subgroup of SU(3)L×SU(3)R. The condition requires that the left handed and the right handed Chern-Simons 5-forms with respect to the gauge group be equal to each other and it turns out in the local sense to be the usual perturbative anomaly-free condition. It is also constructed a gauge invariant effective action under the anomaly-free condition by means of a systematic method rather than the trial and error Noether method. In the non-abelian case, the gauge invariant effective action presented here contains less terms than the one obtained by Witten. The case of pure gauge is discussed in the present note as well.
It is shown that in order to introduce the gauge invariant Wess-Zumino-Witten effective action a global anomalyfree condition should be satisfied by the gauged subgroup of SU(3)L×SU(3)R. The condition requires that the left handed and the right handed Chern-Simons 5-forms with respect to the gauge group be equal to each other and it turns out in the local sense to be the usual perturbative anomaly-free condition. It is also constructed a gauge invariant effective action under the anomaly-free condition by means of a systematic method rather than the trial and error Noether method. In the non-abelian case, the gauge invariant effective action presented here contains less terms than the one obtained by Witten. The case of pure gauge is discussed in the present note as well.
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