The key technologies and devices of neutron detectors have been domesticated

According to the Institute of High Energy Physics of the Chinese Academy of Sciences, recently, the China Spallation Neutron Source (CSNS) detector team used the self-developed magnetron sputtering large-area boron plating special device (Figure 1) to successfully prepare a high-performance large-area boron carbide film sample that meets the needs of neutron detectors (Figure 2), with a single area of 1500mm×500mm, a film thickness of 1 micron, and a thickness uniformity of better than ±1.32% in the full size range, which is currently the largest area of boron carbide film used for neutron detection in the world.

Figure 1. Self-developed magnetron sputtering large-area boron plating special device

With the second phase of CSNS project about to start, the proposed neutron spectrometer has an urgent demand for a new neutron detector with large area, high efficiency and sensitive position. How to prepare high-performance neutron converted boron carbide film is the most core technology, and only a few developed countries such as the United States and Europe have mastered this technology.

In 2016, with the support of the State Key Laboratory of Nuclear Detection and Nuclear Electronics, the CSNS detector team cooperated with Professor Zhu Jingtao of Tongji University to develop a magnetron sputtering large-area boron plating special device with a coating thickness range of 0.01~5 microns, and support single- and double-sided coatings, RF and DC coatings. In June 2021, the device passed the acceptance of the key laboratory and was put into use.

Figure 2.  High-performance large-area boron carbide film samples

After years of technical research and process trial production, the team has overcome the key technologies that have a great impact on the coating quality, such as sputtering target production, transition layer selection, substrate surface treatment, etc., and used the device to prepare a variety of specifications of boron carbide film, and successfully applied to the ceramic GEM neutron detector on multiple neutron spectrometers of CSNS, realizing the localization of key technologies and devices of neutron detectors, and providing strong technical support for the next development of a larger area of high-performance new neutron detectors.

This project was funded and supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, and the State Key Laboratory of Nuclear Detection and Nuclear Electronics.