PMT bare tube with wide spectrum and high gain is a side window type photomultiplier tube designed specifically for low light precision detection. Using quartz glass windows and multi alkali photocathodes, the spectral response covers 165-900 nm (deep ultraviolet to near-infrared), and a 9-stage ring doubling structure achieves high gain of 10 ⁶ -10 ⁷ and nanosecond fast response. It is widely used in environmental monitoring, semiconductor detection, fluorescence analysis, chemiluminescence detection, and photon counting, and supports customized sensitivity, gain, and structure according to drawings.