| 摘要 |
1,190,394. Discharge lamps. PERKINELMER CORP. 12 June, 1967 [24 June, 1966], No. 27064/67. Heading H1D. In a hollow cathode lamp for atomic absorption spectroscopy, a metal for investigation forms a thin coating 30 on the interior surface of a hollow cathode 10 which has inturned ends 22 to prevent the coating material, melted during the operation of the lamp, running out of the cathode. The cup material is chosen to ensure that no alloy is formed with the coating metal having a melting point lower than that of the coating metal, e.g. titanium is used for a coating of tin or indium, or niobium for a coating of gallium. The cup is provided with a cylindrical aperture 16 for the receipt of a lamp stem assembly. A tin coating in the cup is formed by introducing tin shot into the cup, flushing, baking out, and sealing the lamp after the introduction of a few torr of neon, and running the lamp at a sufficiently high current to melt the tin, whereafter the lamp is tilted and rolled about its axis to cause the tin to wet and coat the interior of the cup. A gallium or indium coating may be formed by introducing the molten material into the cup, or by heating the cup, and centrifuging prior to assembly of the lamp. |
