File:Notes on Standard Wave lengths spectographs, and spectrum tubes (1922) (14783577862).jpg

Identifier: notesonstandardw18185megg (find matches)
Title: Notes on Standard Wave lengths spectographs, and spectrum tubes
Year: 1922 (1920s)
Authors: Meggers, W.F., Burns, K.
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Publisher: National Bureau of Standards
Contributing Library: NIST Research Library
Digitizing Sponsor: NIST Research Library

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ds us to believe that the spectrafrom a grating in parallel light are effectively from 5 to 10 times asintense as when mounted according to Rowland. IV. THE PREPARATION OF SPECTRUM TUBES The spectroscopy section of this Bureau has for many yearsbeen making and testing glass tubes containing various gases andfurnishing these to scientific institutions which require them forstandard sources of monochromatic light to be used in opticaltesting and research. Tubes containing hydrogen, oxygen, nitro-gen, helium, neon, and argon have been produced in considerablenumbers, but the demand is always greater than the supply, andit is therefore thought advisable to give a few notes on our simplemethods, so that institutions possessing a fairly good vacuumpump and a glass blower can prepare their own tubes. Detailed instructions for the filling of Pliicker tubes for theproduction of luminescence in gases were given in 1912 by Baly, M Baly, Spectroscopy, Longmans, Green & Co., pp. 421-438; 1912.
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bu!IT~\ Spectroscopic Notes 197 but certain features of the process have been simplified or requiremodification to accord with recent experience or with local labora-tory facilities. The number of Pliicker tube designs is very large,and a certain variety of special forms are essential for specialpurposes, but for all ordinary investigations and tests the simpleform described in Bureau of Standards Bulletin, 4, page 511(1907), has been found to be quite satisfactory. The electrodes are aluminum disks of 25 mm diameter and 1mm thickness, contained in spherical glass bulbs of 35 mmdiameter, which are connected by a stem with 1 to 2 mm bore and10 cm length. This form of electrode permits relatively largecurrents with a minimum of heating and evaporation and deposi-tion. Convenient apparatus for filling such tubes with a lowpressure of pure gas is illustrated in Fig. 6. Its principal featureis a good vacuum pump operating with oil. Pumps operatingwith mercury are not recommended, since the

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