The **9954B** is a robust 51mm (2”) diameter end window photomultiplier tube, designed to deliver exceptional performance in a variety of applications. At its core, it features an enhanced green-sensitive bialkali photocathode, which ensures high sensitivity and efficient photon detection. The device is equipped with 12 BeCu dynodes, crafted in a linear-focused design, providing excellent linearity and timing characteristics. This makes the 9954B an ideal choice for applications requiring precise and reliable photon detection.

One of the standout attributes of the 9954B is its spectral range, which spans from 290 nm to 680 nm. This range ensures that the photomultiplier is effective across a wide spectrum of light, making it versatile for different scientific and industrial uses. The borosilicate window with a refractive index of 1.49 further enhances its optical performance. Additionally, the tube's quantum efficiency peaks at 28%, with a luminous sensitivity of 110 µA/lm, ensuring that even low-light conditions are handled with high accuracy.

The 9954B is engineered for durability and reliability, with an active diameter of 46 mm and a nominal anode sensitivity of 500 A/lm, extendable to a maximum rated sensitivity of 2000 A/lm. Its robust construction is reflected in its ability to operate effectively within a voltage range of 1800 V to 2300 V for nominal operations and up to 2100 V for maximum rated sensitivity. The photomultiplier's dark current is impressively low, ranging from 2 nA to 20 nA at nominal sensitivity, ensuring minimal noise and high signal integrity. With a weight of just 150 g, the 9954B is a compact yet powerful solution for high-energy physics studies and other demanding applications.