NEW 14-STAGE MULTIPLIER PHOTOTUBE RCA-6810
...for investigations involving unusually low-level light sources!
RCA-6810—the most sensitive phototube in the RCA line—is a head-on type multiplier phototube designed for scintillation counters, spectrophotometers, and other applications involving low-level light sources. Featuring fast response, high current shown 2/5 actual gain, relative freedom size. from after-pulses, and small spread in electron- fore, has high sensitivity transit time, the 6810 is to blue-rich light. particularly useful for fast coincidence scintillaDesign Features of RCAtion counting. Because 6810 · semitransparent the 6810 is capable of de- cathode on inner surface livering pulse currents of tube face · face has flat having magnitudes up to surface · 14 electrostat0.5 ampere without ap- ically focused multiplypreciable deviation from ing (dynode) stages • folinearity, the need for an cusing electrode with exassociated wide-band ternal connection for amplifier is eliminated in shaping the field which many applications. directs photoelecfrons from the cathode onto The spectral response the first dynode · accelerof the 6810 covers the range from about 3000 to ating electrode with external connection for 6500 angstroms. Maximinimizing space-charge mum response occurs at effects · multiplies feeble approximately 4400 angstroms. The 6810, there- photoelectric currents
approximately 66,000,000 times when operated with 2300 volts supply potential · short timeresolution capability in the order of 1 or 2 millimicroseconds. Designers and manufacturers of radiation detection a n d s p e c t r o photometry apparatus, and schools, institutions, and laboratories making use of such equipment can obtain complete technical data on RCA6810 and other RCA Phototubes by writing to RCA, Commercial Engineering, Sect. B-80-XJ, Harrison, N. J.
LABORATORY TUBES ®
Radio Corporation of America Tube Division Harrison, N. J .
For further information, circle number 20 A on Readers' Service Card, page 91 A
20 A
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ANALYTICAL CHEMISTRY
nature. In addition, the best detector for infrared radiation was the high sensitivity thermocouple which originally was extremely slow in response, delicate, and difficult to build. The first infrared instruments were subject to drift due to variation in ambient temperature, were nonrecording, and were so unstable and difficult to use that only a specialist operating under controlled conditions could obtain data of value. Infrared Contains Many Bands. A typical infrared spectrum contains from 20 to over 100 major bands. Therefore, the chemist had extreme difficulty in locating the band of interest with a nonrecording instrument. Only a recording infrared spectrometer was at all useful for analysis. This led to far more complexity in equipment and required much higher skill on the part of the operator and interpreter of results than with the ultraviolet instrument. The sampling problem was much more severe than in ultraviolet analysis, because most solvents absorb in the infrared. However, infrared analysis was so specific (approximately 10 times as many organic compounds have characteristic spectra in the infrared as in the ultraviolet) that infrared laboratories were established to which the organic chemist brought his samples for analysis. The trend in infrared development since that time has been toward greater and greater versatility, as desired by the infrared spectroscopist. Low-Cost Instruments Appear. The new low-cost infrared spectrophotometers are aimed at putting infrared finally in the hands of the organic chemist. The prime purpose in developing the instruments was to make them so simple and rugged that organic chemists without special training in instrumentation could use them easily and profitably. Since the infrared spectrum provides so much valuable information about a specific compound, these instruments will represent a tremendous economy in time and an increased efficiency to the organic chemist. He has long been familiar with the value of infrared, through scientific literature or through contact with his company's infrared laboratory. Now he will be able to use this powerful analytical tool on his own laboratory bench for analytical problems when and as often as needed. These instruments are of equal importance to the smaller companies which have not been able to afford the expensive infrared spectrophotometers previously available. Another group which can benefit from the new instruments are universities, whose budgets have often precluded the acquisition of
