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Pye Unicam Hollow Cathode Lamp (Nickel)

Jowlabar · Chemical Engineering

A glass cathode lamp consisting of a sealed glass tube with a blue and while label housed in a grey plastic case. The tube is narrow at the top, wider at the bottom. At the base of the tube is a translucent plastic vacuum tube plug with two metallic electrical pins protruding from one end.

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

Accession Number: 2018.che.131

Alternative Name:

Primary Materials: Glass, Metal, Plastic.


A damaged label affixed to the tube has the following information –the part number, serial number, and date have likely been truncated because part of the label is missing: “Wavelength 232.0”, “Part No 61128”, “Serial No 4085”, Date “Ew00500”.

“Ni” is written on the top surface of the grey case in pencil.

Dimensions (cm):

Plastic case is: Height = 8.5, Width = 8, Length = 21.5; Tubes is: Length 17, 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.


Good: The tube label is damaged; both edges of the label are missing. The plastic case was lined with a plastic foam that was disintegrating into powder. This was removed and the object was dusted. Thin Ethafoam sheet was placed inside the case to cushion the tube.

Associated Instruments:

Manufacturer: Pye Unicam Ltd., Cambridge, England.

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