Triple your sensitivity with large GaAs photocathode end-window PMT's from Varian. Varian's new generation of photomultiplier tubes with semitransparent lll-V Gallium Arsenide (GaAs) photocathodes are priced like oldstyle glass PMT's having small, opaque GaAs photocathodes, but that's where the comparison ends. With a luminous sensitivity of at least 50C^A/lumen over an 18 mm diameter semitransparent photocathode, Varian ceramic-metal body, end-window PMT's can triple the sensitivity of certain analytical instruments equipped with conventional photodetectors. The large photocathode permits light collection over a wider angle than any existing GaAs PMT sensitive to photons between 550 and 900 nm. Highly sophisticated electron optics, solid first dynode, and - 7 8 ° C coolability add the ultimate signal-to-noise performance to the semiconductor photocathode. Varian's end-on tubes; normally supplied with inte-
grated voltage divider, fiber glass housing, and flying leads; can be fitted with pins and sockets for easy installation into new or existing systems. Priced from approximately $1,500, the VPM-192M requires no further costly preparation such as light shielding or voltage divider fabrication. Simply make three solder connections, apply voltage, and begin measurements at any temperature between +30°C and - 7 8 ° C , within 90 days after placing your order. Triple your results from analytical instruments, astronomy, fiber optic diagnostics, laser detection, photon counting, radiometry and Raman spectrophotometry by contacting Varian, LSE Division, 601 California Avenue, Palo Alto, California, 94304. Telephone (415) 493-4000 extension 3608/3094. Or call any of the more than 30 Varian Electron Device Group offices throughout the world. Ask about the new generation VPM-192M.
varian
WAVELENGTH (nm)
CIRCLE 224 O N READER SERVICE CARD
ANALYTICAL CHEMISTRY, VOL. 4 9 , NO. 3, MARCH 1977 ·
293 A
