“Eyes” that discover ultraviolet light ——Solar-blind photomultiplier tube

Photomultiplier tube (PMT) is a vacuum electronic device that converts weak light signals into electrical signals, possessing the high sensitivity and fast response. It can measure extremely weak radiation power at wavelength 115 nm-1700 nm. With the continuous advances of technology, PMT are widely used in optical analysis instruments, nuclear radiation measurement, medical instruments, biotechnology, petroleum logging, high-energy physical research and many other fields.
    Due to its solar blindness, solar-blind PMTs have been widely used in ultraviolet radiation detection, ultraviolet communication and atomic fluorescence analysis instruments. In recent years, people's demands on medicines, food and environmental protection are getting higher and higher. Therefore, the technical requirements of atomic fluorescence spectrometer are ever growing. As the vital detector of this instrument, the demand of solar-blind photomultiplier tubes is increasing day by day. Currently, the main manufacturer of solar-blind PMT in the world is Hamamatsu Photonics Co., Ltd. in Japan. In contrast, it is understood that there is only one company in China which can produce qualified products of solar-blind PMTs, but the output sensitivity and life of the solar-blind PMTs are not good enough. The solar-blind PMT needed in China market are mainly imported from abroad. Therefore, it is of great scientific value and practical significance to develop the solar-blind PMT with high output sensitivity, long lifeto satisfy application requirements.
    The R&D team of the electronic tube department of BHP Technology Co., Ltd. realized the huge market demand and broad development prospects of solar-blind PMT. A project on the solar-blind PMT (CR340) was initiated, aiming to develop  this type of solar-blind PMT. BHP R&D team explored different kinds of incident window materials and photocathode materials, and continuously optimized the synthetic process of the solar-blind PMT. Consequently, a high-performance solar solar-blind PMT (CR340) was successfully obtained. In order to further improve the performance of solar-blind PMT and other types of solar-blind PMT, our company continuously imports higher-end equipment and technology to complete the improvement of production process, and is determined to make photomultiplier tubes with better performance.
    The measurement results of the solar-blind PMT invented by BHP show that the PMT has good solar-blind characteristics. The response cut-off wavelength is 320 nm, the typical quantum efficiency is 30% at the peak value of 230 nm, the quantum efficiency is higher than 25% at 250 nm, the sensitivity of the anode output could reach 5×105 A/W (250 nm), the gain reach 1.3×107, the stability of the anode output is good. And the durability of high-current is over 1000 hours. This solar-blind PMT is supplied to numerous domestic manufacturers of analytical instruments (e.g. Beijing General Instruments Co., Ltd. and Beijing Haiguang Instruments Co., Ltd.) with good feedback. This product fills in the blank of the application of domestic solar-blind PMT in atomic fluorescence analysis instrument.
 


Spectral response curve of CR340

Research Group
The R&D team of the electronic tube department of BHP Technology Co., Ltd. is mainly engaged in the research of vacuum optoelectronic devices. The team members have deep knowledge in their professional academic fields. The R&D team members of the electronic tube department of BHP include Zhao Li (the head of department), Dang Xiangyu (the person in charge of R&D team), Cheng Xianqi (senior engineer, mainly responsible for equipment production and new product performance test), Xie Zhangyi (project leader), Liu Haihui (mechanical design engineer, mainly responsible for product structure design), Zhao Jie (material engineer, mainly responsible for product materials and process improvement). In recent years, the team has achieved many scientific research results and published many papers and patents.

The main research results of this team are shown below. 
1) The preparation and performance studies of Solar Blind Photomultiplier Tubes
2) A new type for testing plateau characteristic of scintillation detector 
3) A device for cutting magnetic shielding of photomultiplier tube 
4) A device for automatically measuring uniformity of Spherical photomultiplier
5) An equipment for testing life of Photomultiplier tube
6) A system for testing water pressure resistance of photomultiplier tube 
7) A compact coating device of Magnetron sputtering
8) An oven of double light source 

Article
Dang Xiangyu. Preparation and properties of solar-blind photomultiplier tube[J]. Opto-Electronic Engineering, 2019, 46(6): 180460
DOI:10.12086/oee.2019.180460