29 January 2007 Fast photomultiplier tube gating system for underwater laser detector
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Proceedings Volume 6279, 27th International Congress on High-Speed Photography and Photonics; 627948 (2007) https://doi.org/10.1117/12.725375
Event: 27th International congress on High-Speed Photography and Photonics, 2006, Xi'an, China
Abstract
Laser will attenuate during its propagation in water and also be backward scattered by water when it is used to detect bubbles in the ocean. Meanwhile backward scattering intensity of the bubbles is feeble, its dynamic range reaches to the order of 6, which saturates PMT and its post-treatment circuit. Timely gating system is used to solve the problem. The system contains pulsed laser and gating PMT receiver. The wavelength of the laser is 532nm, with pulse width of several nanometers. Its operational delay is matched with the time period between laser traveling forward and back after scattered by the target. By doing this, the light scattered by other object is eliminated, dynamic range of the signal reduces, and consequently SNR increases. In order to avoid Signal Induced Noise(SIN), we choose PMT R1333 having no HA coating. TTL logical level, which is used as gating signal, controls the first dynode voltage of PMT to implement gating. Gating speed is about 100ns, of which the width is tunable. By carefully designing the electronic system, SNR is eliminated to a level as low as possible, and the output signal of PMT is fast integrated in order to reduce the influences of signal induced by opening the gate.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Xuanhua Lei, Xuanhua Lei, Kecheng Yang, Kecheng Yang, Jionghui Rao, Jionghui Rao, Xiaohui Zhang, Xiaohui Zhang, Min Xia, Min Xia, Yi Zheng, Yi Zheng, Wei Li, Wei Li, } "Fast photomultiplier tube gating system for underwater laser detector", Proc. SPIE 6279, 27th International Congress on High-Speed Photography and Photonics, 627948 (29 January 2007); doi: 10.1117/12.725375; https://doi.org/10.1117/12.725375
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