[en] When measuring (n, χnγ) partial γ-ray cross section of heavy fissionable nuclei, the technique of coincidence measurement was applied to depress Compton platform and background of energy spectrum. Five energy points of ⁵⁶Fe(n, χnγ) cross sections were measured directly by two Clover detectors on 600 kV Cockcroff-Walton accelerator in CIAE, and then the offline data analysis at 1238.3 keV was performed by using the coincidence technique. The result is approximately the same as direct measurement result and the availability of the technique of coincidence measurement is proved. (authors)

[en] We have built the Array of HPGe detectors, electronics and acquisition system, which will be used to measure the γ/rays from (n, xn) reaction. Every detector were surrounded by BGO detector. We had improved the shielding of the experiment hall of high voltage multiplier. Nanosecond and microsecond pulse beam experiments had been carried out. By experiment on natFe target, we validated the whole detection system. In experiment of U target, We can observe the γ rays peaks of "2"3"8U(n, xn) reactions. The cross sections is consistent with others' result. (authors)

[en] The safety of spent fuel pools in nuclear power plants is a very important safety issue for nuclear power plants, and the performance of neutron absorbing materials is related to the safety of spent fuel pools. The hanging piece of the same kind of neutron absorbing material is placed in the spent fuel pool, and the reliability of the neutron absorbing material in the spent fuel pool can be evaluated by periodically checking the performance of the hanging piece. The development of our B₄C_-Al alloy coupon testing equipment is expected to play an important role in assessing the safety of spent fuel pools in nuclear power plants. The test equipment firstly establishes a standard curve by using the standard samples with known surface density of ¹⁰B, and then the surface density of the sample would be calculated according to the neutron transmittance, thereby reflecting the neutron absorption capacity of the spent fuel pool storage material, and providing a technical means for the safety inspection of reactor spent fuel pools. The equipment is the first boron aluminum alloy coupon testing equipment in China. The development of this equipment lays the experimental foundation for the future non-destructive inspection of domestic boron-containing neutron absorption materials. (authors)

[en] The background of high voltage multiplier hall is high, which effects our experiment. So it is critical to improve the shield of experiment hall. We measured and analyzed the background of experiment hall. By simulation, the article gives the scheme of improving wall and collimator. After adding paraffin beside the wall, we have done a simple validating experiment. The results on Iron target show that the improvement is very well. (authors)

[en] In the study of D(d, γ)⁴He radiative capture reactions research, which is very important for fusion and astrophysics, the efficiency calibration of the detector is necessary. Due to the restriction on energy of the standard gamma source, the efficiency calibration of high-energy gamma-rays can not be calibrated by a standard source. In this paper, the method combining the experimental measurements and calculations for the efficiency calibrations of high energy gamma rays is given in the experiment of 6.13 MeV gamma rays efficiency calibration using NaI detector, the efficiency curve of which is calculated by MCNP-4C and corrected experimentally. In this case, the detection efficiency of 23.8 MeV gamma ray is known. The method provides a reference to high energy gamma ray efficiency calibration. (authors)

[en] This paper developed a thermal-assisted single point incremental forming (SPIF) method for biodegradable composite sheets made from jute woven fabric and polylactic acid (PLA) resin. A forming device equipped with a thermal radiation plate was designed for the SPIF of the composite sheets on a three-axis CNC milling machine. A three-tier-plate method in which the composite sheet was sandwiched between an iron plate and an alumina plate was adopted to clamp the composite sheet. The proposed SPIF method was demonstrated on forming of a truncated pyramid part. The effects of clamping method, toolpath, step size and thickness on the formability of the composite were investigated. It was found that the three-tier-plate fixture method was crucial for the successful implementation of the SPIF of the composite. The toolpath had a significant effect on the forming depth. While the surface quality was mainly determined by the step size. The thickness of the composite sheet had a positive effect on is forming depth.

[en] Applications of wavelet analysis and neutral networks in the field of nuclear physics and engineering are reviewed. The principle of these two methods are introduced briefly, and then the applications of multi-resolution analysis technique in the smoothing of γ-ray spectroscopy, and in nuclear power plant monitoring are discussed in detail. Applications of the continuous wavelet analysis method in γ-ray spectroscopy analysis, in particle identification, and in nuclear reactor safety monitoring are also talked over. In addition, the applications of neutral networks in above fields are introduced. Finally, the trends of the future development for these two methods are prospected. (authors)

[en] In the experiment of measuring (n, xnγ) reaction cross section with prompt γ ray method, the experiment background has a significant influence on the result and is the key factor. In order to achieve the goal of reducing a certain amount of the experiment background, the improvement scheme of shield and collimator was given through Monte Carlo method and the shielding scheme was finally selected: add 30 cm(C₂H₄)n + 9 cm Pb on the original shield, 54 cm heavy concrete on the original shield wall and then 2 cm thick lead(Pb) on the shield and shield wall. The collimation effect and energy uniformity of symmetrical double cone collimation hole are the best among cylindrical, conical, and symmetrical double cone. After the completion of the transformation of shield, the relative intensities of the transmitted neutron and γ rays from the 70 cm in right radial of the transformed collimation hole were measured with ϕ5.08 cm × 5.08 cm type liquid scintillator detector(BC501). After deducting the natural background of no beam current, the neutron background of the beam current is reduced by 7.75 times and the γ background is reduced by 38.5 times, which meets the requirement. (authors)

[en] Background: The fission ionization chamber is constituted by ²³⁵U and ²³⁸U materials as monitor in China Spallation Neutron Source (CSNS) reverse angle. Purpose: This paper mainly introduces the whole system time precision influence on the energy resolution and the actual measurement corrections. Method: The flux energy spectrum is measured accurately using n-TOF method. Results: The time resolution which is caused by energy resolution is proportional to 3/2 power energy, and the correction is induced less than 0.1% due to differences of the standard cross section energy. Conclusion: The experimental results show that the design of the ionization chamber can meet the requirements of CSNS neutron flux measurements. (authors)

[en] The D(d, γ)⁴He fusion reaction at low energy was studied in this paper. Due to the small yields, the high energy and the strong background of γ-ray, a big NaI-plastic scintillator anti-Compton spectrometer was employed to increase the detect efficiency and reduce the impact of the cosmic rays, and the method of the time-of-flight (TOF) was used to discriminate neutron and gamma to reduce the background of neutron and cosmic rays. The thick and thin deuterium-loaded titanium target experiments were performed at E_d = 300 keV. The background was subtracted by our fitting method. The cross section is 2.47 × 10^-37m² for the thick target and 4.36 × 10^-37m² for the thin target. (authors)