**Product Overview: 9817B Photomultiplier Tube** The 9817B photomultiplier tube is a sophisticated detection device designed to meet the demands of high-precision applications. With a 51 mm (2”) diameter end window, this photomultiplier is equipped with an S20 infra-red sensitive photocathode. Its 12 BeCu dynodes are crafted in a linear focused design, ensuring optimal performance in a variety of settings. The 9817B is particularly adept at capturing high-energy physics phenomena, making it an excellent choice for scientific research and film scanning applications. Its high pulsed linearity further enhances its suitability for these tasks. **Spectral and Sensitivity Characteristics**

The 9817B covers a broad spectral range from 290 nm to 870 nm, where the quantum efficiency exceeds 1% of its peak. This wide spectral response makes it versatile for detecting a range of light wavelengths. The active diameter of the photocathode is 46 mm, and at its peak, the quantum efficiency is rated at 21%. Luminous sensitivity ranges from 120 to 200 µA/lm, providing flexibility for varying light conditions. The anode sensitivity in divider B configuration is nominally set at 500 A/lm, with a maximum rated sensitivity of 2000 A/lm, ensuring robust performance across different operating environments. **Performance and Durability** The 9817B is engineered for reliability and precision. It operates with an overall voltage for nominal anode sensitivity between 2000V and 2400V, and up to 2300V for maximum rated sensitivity.

The gain at nominal anode sensitivity is approximately 2.5 x 10³. Even at a dark current of 20 ºC, it maintains a low dark count rate of 15000 s⁻¹, demonstrating its efficiency in low-light conditions. The tube is designed to withstand magnetic fields and temperature variations, with a temperature coefficient of ±0.5% per ºC. Its timing characteristics, including a single electron rise time of 2 ns and a full-width half-maximum (FWHM) of 3 ns, ensure precise timing measurements. **Construction and Maximum Ratings** Constructed with a borosilicate window and weighing 160 grams, the 9817B is both durable and lightweight. It is designed to operate within a maximum ambient pressure of 202 kPa.

The device is rated to handle cathode currents up to 1000 nA and anode currents up to 100 µA, with a maximum gain of 10⁶. The maximum voltage ratings include 2800V for V(k-a) and 500V for V(1d-k), providing robust electrical performance. These specifications make the 9817B an ideal choice for demanding applications requiring reliable and accurate photon detection.