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Results for “Spectrum Analysis”

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At least 217 records · Page 12Linked to original sources
PubMed2001

Full-spectrum analysis of natural gamma-ray spectra.

In this paper, a new system to measure natural gamma-radiation in situ will be presented. This system combines a high-efficiency BGO scintillation detector with full-spectrum data analysis (FSA). This technique uses the (nearly) full spectral shape and the so-called 'standard spectra' to calculate the activity concentrations of 40K, 232Th and 238U present in a geological matrix (sediment, rock, etc.). We describe the FSA and the determination of the standard spectra. Standard spectra are constructed for various geometries and a comparison in intensity and shape will be made. The performance of such a system has been compared to a more traditional system, consisting of a NaI detector in combination with the 'windows' analysis. For count rates typically encountered in field experiments, the same accuracy is obtained 10-20 times faster using the new system. This allows for shorter integration times and hence shorter measurements or a better spatial resolution. The applicability of such a system will be illustrated via an example of an airborne experiment in which the new system produced results comparable to those of much larger traditional systems. This paper will conclude with a discussion of the current status of the system and an outlook for future research.

Air Pollution, Radioactive↗
PubMed1985

Spectrum analysis of large toe plethysmographic waveshape.

To assess plethysmographic waveform diagnostic utility in peripheral vascular disease, a spectrum analyzer was attached to the output of a conventional mercury strain gauge sensor. The resulting quantified waveforms were compared with geometrically determined waveform characteristics and resting ankle pressure ratios for a group of 16 men who ranged from healthy to severely occluded (lower extremities). Of the various harmonics contained within the waveform, second harmonic magnitude best correlated with those geometric waveform characteristics believed to possess diagnostic value. Second harmonic magnitude was positively related (0.9 correlation coefficient) to the 1.33 power of resting ankle pressure ratio. Because it does not require exercise or pressure cuffs, spectrum analyzer waveform based diagnosis may be suited for mass screening purposes.

Ankle Joint↗