Estimating source position accuracy of a large-aperture hydrophone array for bioacoustics

2001 ◽  
Vol 109 (1) ◽  
pp. 397-406 ◽  
Author(s):  
Magnus Wahlberg ◽  
Bertel Møhl ◽  
Peter Teglberg Madsen
Keyword(s):  
Source Position ◽  
Position Accuracy ◽  
Large Aperture ◽  
Hydrophone Array

Acoustic performance of a large-aperture, seabed, fiber-optic hydrophone array

2004 ◽  
Vol 115 (6) ◽  
pp. 2848-2858 ◽  
Author(s):  
G. A. Cranch ◽  
R. Crickmore ◽  
C. K. Kirkendall ◽  
A. Bautista ◽  
K. Daley ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Acoustic Performance ◽  
Large Aperture ◽  
Hydrophone Array

scholarly journals Restoring the Suzaku Source Position Accuracy and Point-Spread function

2008 ◽  
Vol 60 (sp1) ◽  
pp. S35-S41 ◽  
Author(s):  
Yasunobu Uchiyama ◽  
Yoshitomo Maeda ◽  
Masatoshi Ebara ◽  
Ryuichi Fujimoto ◽  
Yoshitaka Ishisaki ◽  
...  
Keyword(s):  
Point Spread Function ◽  
Source Position ◽  
Position Accuracy ◽  
Point Spread ◽  
Spread Function

scholarly journals Accurate azimuth estimates from a large aperture hydrophone array using T-phase waveforms

1998 ◽  
Vol 25 (3) ◽  
pp. 365-368 ◽  
Author(s):  
Jeffrey A. Hanson ◽  
Holly K. Given
Keyword(s):  
Large Aperture ◽  
Hydrophone Array ◽  
T Phase

scholarly journals Locating Thunder Source Using a Large-Aperture Micro-Barometer Array

2021 ◽  
Vol 9 ◽  
Author(s):  
Jan Rusz ◽  
Jaroslav Chum ◽  
Jiří Baše
Keyword(s):  
Electrostatic Field ◽  
Signal To Noise Ratio ◽  
Rapid Change ◽  
Low Frequency ◽  
Thunderstorm Activity ◽  
Sound Waves ◽  
Source Position ◽  
Spherical Waves ◽  
Large Aperture ◽  
Wide Range

Lightning generates sound waves across a wide range of frequencies, including infrasonic waves below 20 Hz. Source mechanism for these low frequency pulses is still area for debate. Infrasound pulses detected after rapid changes of electrostatic field during the thunderstorm activity were analyzed. The measurements were done by large aperture array of absolute microbarometers located in the Western part of the Czech Republic. Distances between four measuring sites are in the range of 4–10 km. The infrasound source position was calculated from time delays between the rapid change of electrostatic field and infrasound signal arrival to the individual microbarometers assuming propagation of spherical waves from the source. Only cases with a sufficient signal-to-noise ratio on all four microbarometers were analyzed. The variation of sound speed with height due to temperature height profile was taken into account. For most of the analyzed cases, the calculated infrasound source position corresponds to the lightning location determined by European lightning detection network (EUCLID). The calculated height of infrasound source is most often 3–5 km.

Development of a conical anode Fe-gun for low voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 978-979
Author(s):  
T. Miyokawa ◽  
S. Norioka ◽  
S. Goto
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Low Voltage ◽  
Irradiation Damage ◽  
Cold Cathode ◽  
Virtual Source ◽  
Source Position ◽  
Electrostatic Lens ◽  
Electrostatic Lenses ◽  
Wide Range

Field emission SEMs (FE-SEMs) are becoming popular due to their high resolution needs. In the field of semiconductor product, it is demanded to use the low accelerating voltage FE-SEM to avoid the electron irradiation damage and the electron charging up on samples. However the accelerating voltage of usual SEM with FE-gun is limited until 1 kV, which is not enough small for the present demands, because the virtual source goes far from the tip in lower accelerating voltages. This virtual source position depends on the shape of the electrostatic lens. So, we investigated several types of electrostatic lenses to be applicable to the lower accelerating voltage. In the result, it is found a field emission gun with a conical anode is effectively applied for a wide range of low accelerating voltages.A field emission gun usually consists of a field emission tip (cold cathode) and the Butler type electrostatic lens.

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