Direct detection of momentum flux in atomic and molecular beams

J. G. Choi, J. S. Hayden, M. T. O'Connor, G. J. Diebold

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

We describe the use of a microphone for detection of atomic and molecular beams in a high-vacuum environment. Two experiments were carried out to demonstrate this detection method. Pulsed beams of argon were detected using a conventional electret microphone where the output of the microphone was displayed directly on an oscilloscope or processed with a boxcar averager to remove the transient oscillations of the microphone diaphragm. Amplitude modulated, continuous beams of atomic argon were also detected using a lock-in amplifier. The microphone possesses a response to the pressure or momentum flux in the beam that appears to be unique among beam detectors. We use the classical equipartition theorem to calculate the magnitude of the random fluctuations in the output voltage of the microphone that is used to give an expression for the minimum detectable momentum flux in the beam. For a typical microphone we find this to be 3×10-8 Pa, (in a 1-Hz bandwidth), which corresponds to a minimum number density of 1×106 cm-3 for an effusive argon beam at 300 K.

Original languageEnglish
Pages (from-to)6016-6020
Number of pages5
JournalJournal of Applied Physics
Volume52
Issue number10
DOIs
Publication statusPublished - 1981 Dec 1

Fingerprint

atomic beams
microphones
molecular beams
momentum
argon
transient oscillations
equipartition theorem
electrets
output
oscilloscopes
diaphragms
high vacuum
amplifiers
bandwidth
detectors
electric potential

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Choi, J. G. ; Hayden, J. S. ; O'Connor, M. T. ; Diebold, G. J. / Direct detection of momentum flux in atomic and molecular beams. In: Journal of Applied Physics. 1981 ; Vol. 52, No. 10. pp. 6016-6020.
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Direct detection of momentum flux in atomic and molecular beams. / Choi, J. G.; Hayden, J. S.; O'Connor, M. T.; Diebold, G. J.

In: Journal of Applied Physics, Vol. 52, No. 10, 01.12.1981, p. 6016-6020.

Research output: Contribution to journalArticle

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