Lecture
This lecture covers the principles and applications of photomultiplier tubes (PMTs), focusing on their structure and operation. It begins with an overview of vacuum tubes, explaining the roles of the photocathode, anode, and the vacuum environment in electron extraction. The instructor discusses the importance of high voltage in creating a current and the use of transimpedance for measuring output voltage. The lecture then introduces the concept of gain in PMTs, detailing how primary quantum efficiency and secondary emission ratios contribute to signal amplification. The process of electron acceleration through dynodes is explained, highlighting the generation of additional electrons and the resulting high output signal. The instructor provides examples of PMT gains and compares the efficiency of PMTs to standard photodiodes, emphasizing the significant amplification achievable with PMTs. The lecture concludes with practical data on responsivity and sensitivity, illustrating the advantages of PMTs in optical detection applications.