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Phonon Spectrum Analyzer

IP.com Disclosure Number: IPCOM000045357D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Rajeevakumar, TV: AUTHOR

Abstract

Phonons injected at one end of a superconductor are selectively attenuated under certain conditions related to their energy levels and the conditions of the superconductor, and thus an array of several super conductors with an array of differing related energy gaps may provide a wide-range phonon spectrum analyzer.

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Phonon Spectrum Analyzer

Phonons injected at one end of a superconductor are selectively attenuated under certain conditions related to their energy levels and the conditions of the superconductor, and thus an array of several super conductors with an array of differing related energy gaps may provide a wide-range phonon spectrum analyzer.

This phonon spectrometer (Fig. 1) is based on the energy gap reduction due to pair center-of-mass motion and on the energy-dependent phonon attenuation in superconductors. High resolution can be obtained at low temperatures.

Fig. 2 is a graph showing the phonon attenuation coefficient in superconductors at T=O, as a function of energy. Alpha(S) (E) approachs Attenuation coefficient in the superconducting state. Alpha(N) approaches Attenuation coefficient in the normal state.

The energy-dependent phonon attenuation coefficient in superconductors has a sharp discontinuity at phonon energy h Omega=2 Delta. It is also known that the energy gap of a superconductor can be lowered by about approx. 15 percent g without altering the sharpness of the energy gap, by a supercurrent.

By varying the current I, the energy gap of the superconductor can be varied. Phonons are injected at one end of the superconductor 1 and detected at the other end. A superconducting tunnel junction 2 may be used to detect the phonons. Phonons with energy h Omega above 24 are sharply attenuated because of the sharp increase in attenuation coefficient. By varyin...