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Description: | REPAIRED BY CUTHBERT ANDREWS 6064 (acid etched on the glass envelope). LMP 202 D8 (spurious departmental catalogue number in black biro on a white gummed label,removed). DES THOMSON,Joseph,John,Sir. 1897 [Cavedish Laboratories, Trinity College, Cambridge] [England] MANU Unsigned. circa 1905 DES after PERRIN,Jean,Bapatiste,Professor. 1895 University of Paris, Paris. France This is Thompson's improved form of the Perrin type cathode ray tube. The tube is a cold cathode soft vacuum type. Electrons pass from the anode through two earthed focussing diaphragms, in the form of aluminium sheaths, into an open ended aluminium cylinder. This was connected to an electrometer. The second of the two diaphragms is in the form of a sheath surrounding the receiving cylinder. The charge registered at the electrometer is negative. Perrin's original tube had the electrodes placed axially along the tube. Thompson's "improvement" was to offset the electrodes so that a powerful magnetic field was required to deflect the electrons sufficiently to strike the the receiving cylinder. There also appears to be some form of fluorescent material surrounding the opening in the cathode, which is much wider than that of the receiving cylinder. This fluorescent material presumably was to aid positioning of the beam. | License: | http://www.hmag.gla.ac.uk/spirit/rights/ | Publisher: | Hunterian Museum and Art Gallery, University of Glasgow | Rights holder: | Hunterian Museum and Art Gallery, University of Glasgow | Subjects: | SCIENTIFIC COLLECTION : | Source: | Hunterian Museum | Creator: | Hunterian Museum and Art Gallery, University of Glasgow | Identifier: | http://www.huntsearch.gla.ac.uk/cgi-bin/... | Language: | en-GB | Go to resource |
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