UV Excited Photoacoustic Raman
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
To summarize, our efforts and findings are as follows: we analyzed the theoretical system performance using known PARS theory coupled with an acoustic detector model to estimate the expected signal-to-noise ratio (SNR). The system model comprised a mathematical model of the Raman process leading to a prediction of the temperature change in the active region; a thermoacoustic gas prediction of the radiated pressure field (amplitude and pulse shape); and the receiver response for an acoustic microphone, including a simple model of the receiver circuitry (filters, integrators, etc.). Based on the PARS experimental parameters in Appendix B, the model predicted a PARS signal with pressure peak of 7 Pa and duration slightly longer than 2 ms at a distance of 7 mm from the focal spot when acoustic dissipation is not included. An analytical model of a PARS signal with acoustic dissipation was constructed but the numerical calculation is limited to gains of <1% of the experimental value. For these lower gains, the model predicts spreading of the signal.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 1113407
- Report Number(s):
- LLNL-TR-646859
- Country of Publication:
- United States
- Language:
- English
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