The Secondary-emission Electron Multiplier Tube Used on a Mass Spectrometer and its Amplification of Ion Currents

Journal Article · Mon Jan 01 04:00:00 EST 1962 · Bulletin of the Chemical Society of Japan

DOI:https://doi.org/10.1246/bcsj.35.1257· OSTI ID:4761332

Sugiura, Toshio

For the purpose of measuring very small ion currents by the mass spectrometer, a secondary electron multiplier, using the dynodes of copper- beryllium, was constructed and installed. The amplification by the electron multiplier of various supplied voitages to the conversion dynode was measured for inert gas ions, and the amplification factor and ita variation with the supplied voltage to the conversion dynode was compared with both the activated and the electropolished dynode. For the electron multiplier using the electropolished dynodes, the amplification was roughly inversely proportional to the square root of the ion mass, while for the activated dynode this was not the case. The average yield of the secondary electrons impacted by electrons on the copper-- beryllium dynodes was determined, using the values of gamma ₁ which had been estimated by extrapolation of the data obtained in a previous study. The increase of the amplification factors of the electron multiplier due to the dynode activation was explained on the basis of an increase in gamma ₁ and delta due to dynode activation, an increase to be attributed to the formation of beryllium oxide layers. In this study, an amplification factor of a 10⁵ order for inert gas ions was obtained with the electron multiplier constructed with dynodes made from activated copper--beryllium. By using this electron multiplier, ion currents of 10 ^-19 amperes are easily detectable with a mass spectrometer using a conventional d-c amplifier.

• Research Organization: Osaka Univ.
• Sponsoring Organization: USDOE
• NSA Number: NSA-17-003278
• OSTI ID: 4761332
• Journal Information: Bulletin of the Chemical Society of Japan, Journal Name: Bulletin of the Chemical Society of Japan Journal Issue: 8 Vol. 35; ISSN 0009-2673
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
AMPLIFIERS
BERYLLIUM
COPPER
CURRENTS
DYNODES
ELECTRIC METERS
ELECTRIC POTENTIAL
ELECTRODES
ELECTRON BEAMS
ELECTRON TUBES
ION BEAMS
MASS
MASS SPECTROMETERS
MULTIPLICATION FACTORS
PHOTOMULTIPLIERS