Material and time dependence of the voltage noise generated bycathodic vacuum arcs
The high frequency fluctuations of the burning voltage of cathodic vacuum arcs have been investigated in order to extract information on cathode processes. Eight cathode materials (W, Ta, Hf, Ti, Ni, Au, Sn, Bi) were selected covering a wide range of cohesive energy. The voltage noise was recorded using both a broad-band voltage divider and an attenuator connected to a fast oscilloscope (limits 1 GHz analog and 5 GS/s digital). Fast Fourier transform revealed a power spectrum that is linear in log-log presentation, with a slope of 1/f{sup 2}, where f is the frequency (brown noise). The amplitude of the spectral power of the voltage noise was found to scale with the cohesive energy, in agreement with earlier measurements at lower resolution. These basic results do not depend on the time after arc initiation. However, lower arc current in the beginning of the pulse shows greater voltage noise, suggesting an inverse relation between the noise amplitude and number of emission sites (cathode spot fragments).
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE. Administrator for National Nuclear Security Admin.Nonproliferation and National Security Program Direction
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 891034
- Report Number(s):
- LBNL-58310; R&D Project: Z2N196; BnR: NN4101010; TRN: US0604888
- Journal Information:
- Journal of Physics D: Applied Physics, Vol. 38, Issue 23; Related Information: Journal Publication Date: 12/07/2005
- Country of Publication:
- United States
- Language:
- English
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