Changlin Lan

Cross-section measurement for the reactions producing short-lived nuclei induced by neutrons around 14 MeV

The cross-sections of 180W(n,2n)179mW, 186W(n,2n)185mW, 165Ho(n,2n)164mHo, 64Ni(n,alpha)61Fe, 165Ho(n,alpha)162Tb and 51V(n,p)51Ti reactions induced by neutrons around 14 MeV were measured using activation technique and calculated by a previously developed formula in this work. The neutron flux was determined using the monitor reactions 93Nb(n,2n)92mNb and 27Al(n,alpha)24Na, the neutron energies were measured with the method of cross-section ratios for 90Zr(n,2n)89Zr to 93Nb(n,2n)92mNb reactions. The results of this work are compared with data published previously.

Measurement of fission cross-section for the 232Th(n,f )141Ba reaction induced by neutrons around 14 MeV

In order to investigate the fission process in more detail, and to compare with the measurement of cumulative fission yields, the fission cross section of the (232)Th(n,x)(89)Rb reaction induced by 14 MeV neutron was measured using the activation technique. In our measurement the neutron flux was determined using the monitor (27)Al(n,α)(24)Na reaction, and the neutron energies were measured by the method of cross-section ratios of (90)Zr(n,2n)(89)Zr to (93)Nb(n,2n)(92m)Nb reactions. The cross sections were deduced as 14.0±0.9 mb at E(n)=14.7±0.3 MeV and 13.2±1.0 mb at E(n)=14.1±0.3 MeV.

Measurements of the cross section for the 182W(n,p)182(m+g)Ta and 184(n,p)184Ta reactions in the 14 MeV energy range using the activation technique

The cross section for the (182)W(n,p)(182(m+g))Ta and (184)W(n,p)(184)Ta reactions has been measured in the neutron energy range of 13.5-14.7MeV using the activation technique and a coaxial HPGe γ-ray detector. In our experiment, the fast neutrons were produced by the T(d,n)(4)He reaction at the ZF-300-II Intense Neutron Generator at Lanzhou University. Natural wolfram foils of 99.9% purity were used as target materials. The neutron flux was determined using the monitor reaction (93)Nb(n,2n)(92m)Nb and the neutron energies were determined using the method of cross-section ratio measurements employing the (90)Zr(n,2n)(89)Zr to (93)Nb(n,2n)(92m)Nb reactions. The results of this work are compared with experimental data found in the literature and the estimates obtained from a published empirical formula based on the statistical model with Q-value dependence and odd-even effects taken into consideration.

Study of an unfolding algorithm for D-T neutron energy spectra measurement using a recoil proton method

A proton recoil method for measuring D-T neutron energy spectra using polyethylene film and a Si(Au) surface barrier detector is presented. An iteration algorithm for unfolding the recoil proton energy spectrum to the neutron energy spectrum is investigated. The response matrices R of the polyethylene film at angles of 0 degrees and 45 degrees were obtained by simulating the recoil proton energy spectra from mono-energetic neutrons using the MCNPX code. With an assumed D-T neutron spectrum, the recoil proton spectra from the polyethylene film at angles of 0 degrees and 45 degrees were also simulated using the MCNPX code. Based on the response matrices R and the simulated recoil proton spectra at 0 degrees and 45 degrees, the respective unfolded neutron spectra were obtained using the iteration algorithm, and compared with the assumed neutron spectrum. The results show that the iteration algorithm method can be applied to unfold the recoil proton energy spectrum to the neutron energy spectrum for D-T neutron energy spectra measurement using the recoil proton method.

Determination of neutron capture cross sections of ~(232)Th at 14.1 MeV and 14.8 MeV using the neutron activation method

The Th-232(n, gamma)Th-233 neutron capture reaction cross sections were measured at average neutron energies of 14.1 MeV and 14.8 MeV using the activation method. The neutron flux was determined using the monitor reaction (27) Al(n,alpha)Na-24. The induced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. The experimentally determined cross sections were compared with the data in the literature, and the evaluated data of ENDF/B-VII.1, JENDL-4.0u+, and CENDL-3.1. The excitation functions of the Th-232(n,gamma)Th-233 reaction were also calculated theoretically using the TALYS1.6 computer code.

Activation cross-section measurement of a sort of nuclide produced with a target including two isotopes

Based on a formula used to calculate the activation cross-section sum of two reactions producing a sort of nuclide with a target including two isotopes, the related problems in some references have been analyzed and discussed. It is pointed out that the calculation methods of the cross-section sum of two reactions producing the same radioactive nuclide for two isotopes in some references are improper and usually it is impossible to obtain the correct cross-section sum of two reactions producing the same radioactive nuclide for two isotopes in the case of using natural samples. At the same time, the related concepts are clarified and the correct processing method and representation are given. The comparison with the experimental results show that the theoretical analysis results are right.

Particle identification using CsI(Tl) crystal with three different methods

Three pulse-shape-discrimination (PSD) methods are applied to study the particle identification (PID) by using CsI(Tl) crystal, especially for identifying light charged particles. The zero-cross time method, fast and total component method and signal rise time method are used. The experiment, data analysis and results are compared. Good PID for p, α and γ can be achieved with a CsI(Tl)-photomultiplier assembly.