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Cathodeon Hollow Cathode Lamp (Cobalt)

Jowlabar · Chemical Engineering

A glass cathode lamp consisting of a sealed glass tube with an orange and while label housed in a green plastic box with an orange foam liner. The tube is narrow at the top, wider at the bottom. At the base of the tube is a black plastic vacuum tube plug with two metallic electrical pins protruding from one end.

The tube is a “Co” (Cobalt) tube filled with neon gas. The tube has a labelled max current of 15 MA.

Accession Number: 2018.che.132

Alternative Name:

Primary Materials: Glass, Metal, Plastic


A label affixed to the tube has the following information: “Type: 3QNY/Co”, ” Serial No 48011″.

A piece of white tape affixed to the front of the green plastic case has the following information written in blue ink: “PMV = 345”, “08/30/93”.

A white label at the top of the green case identifies the distributor as Spectrex Limited or Montreal, Qc. and has “Co” written on it in pencil.

Dimensions (cm):

Plastic case is: Height = 7.5, Width = 8, Length = 21.5; Tubes is: Length 16.5, Max Diameter = 4.


A Hollow Cathode Lamp (HCL) is a standard light source that produces a spectrum of light representing one or more chemical elements.

HCLs are used in atomic analysis instruments such as the atomic absorption spectrometer. The sealed glass tube contains an inert gas such as argon or neon. An element of interest is housed in the hollow cathode within the glass envelope. Current applied across the anode and cathode ionizes the gas within the tube creating a plasma. This ionized gas is accelerated towards the cathode, which sputters atoms off the sample element at the cathode. These freed atoms are excited by collisions within the plasma. When these atoms decay to a lower energy state, they produce a characteristic spectrum of light that can be compared to that of a sample for the purpose of chemical analysis.


Excellent: There is no evident damage to the tube or its case.

Associated Instruments:


Cathodeon Ltd., Nuffield Road, Cambridge, UK.

Date of Manufacture: 20th century, post c. 1969.


This artifact was acquired by the UTSIC collection from the University of Toronto Department of Chemical Engineering and Applied Chemistry on June 15, 2018.

Additional Information and References:

Historical Notes:


  • Donated to UTSIC