Hamamatsu Photonics K.K.’s Electron Tube Div. has introduced a photomultiplier tube with enhanced UV sensitivity. The R11540 is a 28-mm-diameter side-on device with a spectral response ranging from 185 to 760 nm. It produces 40% quantum efficiency at 350 nm and anode sensitivity of 11.3 x 105 A/W at 350 nm and 12 x 105 A/W at 420 nm. Its sensitivity and high gain of 1 x 107, typical, make it suitable for low-light detection of UV and visible light in fluorescence spectrometers. It also can be used as a fluorescence detector for high-performance liquid chromatography, as a sulfur dioxide monitor, as a fluorescence immunoassay detector for clinical use, and as a fluorescence, emission and atomic absorption spectrophotometer. The photocathode material is Bialkali, the window material is UV glass, and the wavelength of maximum response is 420 nm. Average anode current is 0.1 mA, and operating temperature is from —30 to 50 °C. The instrument has an 11-pin base and weighs 45 g.