A summary is not available for this content so a preview has been provided. Please use the Get access link above for information on how to access this content.
Dynamic data from the MetalMapper electromagnetic induction sensor are analyzed using a fast inversion algorithm in order to obtain position information of buried anomalies. After validating the algorithm by comparing static and dynamic inversions from reference measurements at Camp San Luis Obispo, the algorithm is applied to realistic dynamic measurements from Camp Butner. A sequence of 939 data points are inverted as the MetalMapper travels along a calibration lane, flagging a few positions as corresponding to buried anomalies. An a posteriori comparison with field plots reveals a good agreement between the flagged positions and the field peak values, suggesting the efficacy of the algorithm at detecting a large variety of anomalies from dynamic data.
Abstract : SERDP project MR-1712 entitled Portable Electromagnetic Induction Sensor with Integrated Positioning is complete. This report contains the final design, engineering challenges, modeling advancements, data analysis, and results from Aberdeen Proving Ground tests which resulted from this project. The instrument developed under this project is call Pedemis (PortablE Decoupled Electromagnetic Induction Sensor). The instrument was conceived of as a sensor which combined the advantages of both the larger cart mounted sensors and the smaller handheld sensors. Pedemis is transported by one or two people and has nine transmitters and nine triaxial receivers with the receiver array being physically decoupled from the transmitter array leading to deployment and operational flexibility. The controlling electronics of Pedemis are lighter and more efficient than prior advanced electromagnetic induction instruments. We applied the Orthonormalized Volume Magnetic Source method (ONVMS) technique and the Joint Diagonalization (JD) method to data acquired with Pedemis at Aberdeen proving ground. Aberdeen Proving Ground blind grid results are better than any previous results from any group and instrument at APG.
Contemporary research and development of EMI systems for UXO detection and identification has suggested that a spatial array of receiver coils together with one or more transmitter coils can significantly improve target parameterization and, ultimately, target identification. Our system, the Advanced Ordnance Locator (AOL), has been funded by NAVEODTECHDIV and is a product of such research. The design of EMI systems that include multiple receiver arrays is typically based on the criterion of "optimal" recovery of target parameters using physics‐based inversion methods. However, that criterion overlooks an important aspect of the UXO survey problem, target Detection. Target detection involves locating a target by picking anomaly peaks on maps generated from dynamically acquired EM data. For a variety of reasons (e.g., motion‐induced EM noise, surface clutter, etc) dynamic‐mode EM data has significantly higher noise levels than the static data used for target parameter extraction, and these noise levels limit the depth of detection. In this paper, we study the AOL antenna array in the context of the simple detection problem as distinct from the problem of target classification. With data acquired at Blossom Point and Indian Head, we compare the detection performance of several detector responses derived from the 8 tri‐axial receivers in the AOL. Qualitatively, the results illustrate how a spatial receiver array can improve detection performance compared with single‐receiver antenna arrays such as the EM61, particularly in the presence of multiple near‐surface targets and/or clutter. Furthermore, the quality of the data from each individual cube as well as from their differences makes us optimistic that more complex detector algorithms can indicate not only the presence of a target but also can provide a better estimate of its 3‐D position and target size. We are pushing our investigations toward that end.
A 250 MeV superconducting compact cyclotron, based on an original concept from H. Blosser (NSCL) and to be designed and manufactured by ACCEL (D), is being developed for the proton therapy project PROSCAN at PSI. We have used the general purpose three dimensional particle tracking program TRACK, developed at PSI, in the configuration of the 250 MeV cyclotron to perform studies of the beam dynamics and to derive important parameters describing the beam properties. Detailed tracking studies have been performed in the central region and in the extraction region. Examples of our ongoing studies are discussed to demonstrate the capabilities of the program TRACK.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)
