{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:44:54Z","timestamp":1760150694536,"version":"build-2065373602"},"reference-count":48,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,12,24]],"date-time":"2023-12-24T00:00:00Z","timestamp":1703376000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Bundesanstalt f\u00fcr Materialforschung und Pr\u00fcfung (BAM) via the internal project SealWasteSafe"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The Large Aperture Ultrasound System (LAUS) developed at BAM is known for its ability to penetrate thick objects, especially concrete structures commonly used in nuclear waste storage and other applications in civil engineering. Although the current system effectively penetrates up to ~9 m, further optimization is imperative to enhance the safety and integrity of disposal structures for radioactive or toxic waste. This study focuses on enhancing the system\u2019s efficiency by optimizing the transducer spacing, ensuring that resolution is not compromised. An array of twelve horizontal shear wave transducers was used to find a balance between penetration depth and resolution. Systematic adjustments of the spacing between transmitter and receiver units were undertaken based on target depth ranges of known reflectors at depth ranges from 5 m to 10 m. The trade-offs between resolution and artifact generation were meticulously assessed. This comprehensive study employs a dual approach using both simulations and measurements to investigate the performance of transducer units spaced at 10 cm, 20 cm, 30 cm, and 40 cm. We found that for depths up to 5 m, a spacing of 10 cm for LAUS transducer units provided the best resolution as confirmed by both simulations and measurements. This optimal distance is particularly effective in achieving clear reflections and a satisfactory signal-to-noise ratio (SNR) in imaging scenarios with materials such as thick concrete structures. However, when targeting depths greater than 10 m, we recommend increasing the distance between the transducers to 20 cm. This increased spacing improves the SNR in comparison to other spacings, as seen in the simulation of a 10 m deep backwall. Our results emphasize the critical role of transducer spacing in achieving the desired SNR and resolution, especially in the context of depth imaging requirements for LAUS applications. In addition to the transducer spacing, different distances between individual sets of measurement positions were tested. Overall, keeping the minimal possible distance between measurement position offsets provides the best imaging results at greater depths. The proposed optimizations for the LAUS in this study are primarily relevant to applications on massive nuclear structures for nuclear waste management. This research highlights the need for better LAUS efficiency in applications such as sealing structures, laying the foundation for future technological advances in this field.<\/jats:p>","DOI":"10.3390\/s24010100","type":"journal-article","created":{"date-parts":[[2023,12,24]],"date-time":"2023-12-24T20:42:30Z","timestamp":1703450550000},"page":"100","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Enhancing the Performance of a Large Aperture Ultrasound System (LAUS): A Combined Approach of Simulation and Measurement for Transmitter\u2013Receiver Optimization"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2419-4287","authenticated-orcid":false,"given":"Prathik","family":"Prabhakara","sequence":"first","affiliation":[{"name":"Bundesanstalt f\u00fcr Materialforschung und -Pr\u00fcfung (BAM), 12205 Berlin, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3336-2350","authenticated-orcid":false,"given":"Vera","family":"Lay","sequence":"additional","affiliation":[{"name":"Bundesanstalt f\u00fcr Materialforschung und -Pr\u00fcfung (BAM), 12205 Berlin, Germany"}]},{"given":"Frank","family":"Mielentz","sequence":"additional","affiliation":[{"name":"Bundesanstalt f\u00fcr Materialforschung und -Pr\u00fcfung (BAM), 12205 Berlin, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2501-2249","authenticated-orcid":false,"given":"Ernst","family":"Niederleithinger","sequence":"additional","affiliation":[{"name":"Bundesanstalt f\u00fcr Materialforschung und -Pr\u00fcfung (BAM), 12205 Berlin, Germany"}]},{"given":"Matthias","family":"Behrens","sequence":"additional","affiliation":[{"name":"Bundesanstalt f\u00fcr Materialforschung und -Pr\u00fcfung (BAM), 12205 Berlin, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2023,12,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1016\/S0963-8695(98)00040-1","article-title":"Non-destructive investigation of sluices using radar and ultrasonic impulse echo","volume":"31","author":"Maierhofer","year":"1998","journal-title":"NDT E Int."},{"key":"ref_2","unstructured":"Krautkramer, J., and Krautkramer, H. (2009). Ultrasonic Testing of Materials, Springer."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Langenberg, K.-J., Marklein, R., and Mayer, K. (2012). Ultrasonic Nondestructive Testing of Materials: Theoretical Foundation, CRC Press Taylor & Francis Group.","DOI":"10.1201\/b11724"},{"key":"ref_4","unstructured":"Krause, M., and Wiggenhauser, H. (1997, January 8\u201311). Ultrasonic Pulse Echo Technique For Concrete Elements Using Synthetic Aperture. Proceedings of the Non-Destructive Testing in Civil Engineering (Proceedings), Liverpool, UK."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1061\/(ASCE)0899-1561(2003)15:3(235)","article-title":"Ultrasonic Imaging of Concrete Elements Using Reconstruction by Synthetic Aperture Focusing Technique","volume":"15","author":"Schickert","year":"2003","journal-title":"J. Mater. Civ. Eng."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1007\/s10921-008-0035-3","article-title":"Characterization of Reflector Types by Phase-Sensitive Ultrasonic Data Processing and Imaging","volume":"27","author":"Mayer","year":"2008","journal-title":"J. Nondestruct. Eval."},{"key":"ref_7","unstructured":"Mayer, K., Krause, M., Wiggenhauser, H., and Millmann, B. (2015, January 15\u201317). Investigations for the Improvement of the SAFT Imaging Quality of a Large Aperture Ultrasonic System. Proceedings of the International Symposium Non-Destructive Testing in Civil Engineering (NDT-CE), Berlin, Germany."},{"key":"ref_8","unstructured":"(2021). Pr\u00fcfung von Beton in Bauwerken. Teil 4, Bestimmung der Ultraschall-Impulsgeschwindigkeit: Testing Concrete in Structures. Part 4, Determination of Ultrasonic Pulse Velocity (Standard No. DIN EN 12504-4)."},{"key":"ref_9","unstructured":"(2023). Standard Test Method for Ultrasonic Pulse Velocity Through Concrete (Standard No. ASTM-C597-22)."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Breysse, D. (2012). Non-Destructive Assessment of Concrete Structures: Reliability and Limits of Single and Combined Techniques, Springer. State-of-the-Art Report.","DOI":"10.1007\/978-94-007-2736-6"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Epple, N., Sanchez-Trujillo, C.A., and Niederleithinger, E. (2023). Ultrasonic Monitoring of Large-Scale Structures\u2014Input to Engineering Assessment, CRC.","DOI":"10.1201\/9781003323020-221"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"B4016004","DOI":"10.1061\/(ASCE)IS.1943-555X.0000314","article-title":"Large Aperture Ultrasonic System for Testing Thick Concrete Structures","volume":"23","author":"Wiggenhauser","year":"2017","journal-title":"J. Infrastruct. Syst."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Prabhakara, P., Mielentz, F., Stolpe, H., Behrens, M., Lay, V., and Niederleithinger, E. (2022). Validation of Novel Ultrasonic Phased Array Borehole Probe by Using Simulation and Measurement. Sensors, 22.","DOI":"10.3390\/s22249823"},{"key":"ref_14","unstructured":"Bundesamt f\u00fcr Strahlenschutz (2015). Endlager Morsleben: Hintergr\u00fcnde, Ma\u00dfnahmen und Perspektiven der Stilllegung, Bundesamt f\u00fcr Strahlenschutz."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"127","DOI":"10.5194\/sand-1-127-2021","article-title":"SealWasteSafe: Materials technology, monitoring techniques, and quality assurance for safe sealing structures in underground repositories","volume":"1","author":"Lay","year":"2021","journal-title":"Saf. Nucl. Waste Disposal"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1002\/mawe.202000118","article-title":"Testing repository engineered barrier systems for cracks\u2014A challenge","volume":"52","author":"Effner","year":"2021","journal-title":"Mater. Werkst."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Lay, V., Effner, U., Niederleithinger, E., Arendt, J., Hofmann, M., and Kudla, W. (2022). Ultrasonic Quality Assurance at Magnesia Shotcrete Sealing Structures. Sensors, 22.","DOI":"10.3390\/s22228717"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1007\/s10921-021-00824-3","article-title":"Ultrasonic Echo Localization Using Seismic Migration Techniques in Engineered Barriers for Nuclear Waste Storage","volume":"40","author":"Niederleithinger","year":"2021","journal-title":"J. Nondestruct. Eval."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1792","DOI":"10.1190\/1.1635032","article-title":"Efficient acquisition, processing, and interpretation strategy for shallow 3D seismic surveying: A Case Study","volume":"68","author":"Spitzer","year":"2003","journal-title":"Geophysics"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"307","DOI":"10.3997\/1873-0604.2009015","article-title":"Ultra-shallow imaging using 3D seismic-reflection methods","volume":"7","author":"Sloan","year":"2009","journal-title":"Near Surf. Geophys."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"75A177","DOI":"10.1190\/1.3484194","article-title":"Recent advances in optimized geophysical survey design","volume":"75","author":"Maurer","year":"2010","journal-title":"Geophysics"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Kak, A.C., and Slaney, M. (2001). Principles of Computerized Tomographic Imaging, Society for Industrial and Applied Mathematics.","DOI":"10.1137\/1.9780898719277"},{"key":"ref_23","unstructured":"Gonzalez, R.C., and Woods, R.E. (2002). Digital Image Processing, Prentice Hall."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Tr\u00e4nkler, H.-R., and Reindl, L. (2014). Sensortechnik: Handbuch f\u00fcr Praxis und Wissenschaft, Springer.","DOI":"10.1007\/978-3-642-29942-1"},{"key":"ref_25","unstructured":"Maack, S. (2012). Untersuchungen zum Schallfeld Niederfrequenter Ultraschallpr\u00fcfk\u00f6pfe f\u00fcr die Anwendung im Bauwesen, Federal Institute for Materials Research and Testing. BAM-Dissertationsreihe; Band 95."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"WCA47","DOI":"10.1190\/1.3223187","article-title":"Fresnel volume migration of single-component seismic data","volume":"74","author":"Buske","year":"2009","journal-title":"Geophysics"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1046\/j.1365-246x.1999.00789.x","article-title":"Three-dimensional pre-stack Kirchhoff migration of deep seismic reflection data","volume":"137","author":"Buske","year":"1999","journal-title":"Geophys. J. Int."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Taheri, H., Ladd, K.M., Delfanian, F., and Du, J. (2014, January 14\u201320). Phased Array Ultrasonic Technique Parametric Evaluation for Composite Materials. Proceedings of the ASME 2014 International Mechanical Engineering Congress and Exposition, Montreal, QC, Canada.","DOI":"10.1115\/IMECE2014-36945"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"e975","DOI":"10.1016\/j.ultras.2006.05.218","article-title":"CIVA: An expertise platform for simulation and processing NDT data","volume":"44","author":"Calmon","year":"2007","journal-title":"Ultrasonics"},{"key":"ref_30","unstructured":"Dubois, P., Lonn\u00e9, S., Jenson, F., and Mahaut, S. (2010, January 7\u201311). Simulation of Ultrasonic, Eddy Current and Radiographic Techniques within the CIVA Software Platform. Proceedings of the 10th European Conference on Non-Destructive Testing, Moscow, Russia."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Yilmaz, O. (2001). Seismic Data Analysis: Processing, Inversion, and Interpretation of Seismic Data (Volume 1), Society of Exploration Geophysics.","DOI":"10.1190\/1.9781560801580"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Abood, S. (2020). Digital Signal Processing (Primer with Matlab), CRC Press.","DOI":"10.1201\/9781003010548"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Camina, A.R., and Janacek, G.J. (1984). Mathematics for Seismic Data Processing and Interpretation, Springer.","DOI":"10.1007\/978-94-011-7767-2"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Jones, I. (2014). Tutorial: Migration imaging conditions. First Break, 32.","DOI":"10.3997\/1365-2397.2014017"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Hill, S., and R\u00fcger, A. (2019). Illustrated Seismic Processing, Imaging; Society of Exploration Geophysicists.","DOI":"10.1190\/1.9781560803621"},{"key":"ref_36","unstructured":"B\u00fcttner, C. (2019). Application of Seismic Imaging Methods to Ultrasonic Echo Data from Underground Sealing Constructions. [Master\u2019s Thesis, Institut f\u00fcr Geophysik und Geoinformatik]."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1622","DOI":"10.1190\/1.1487107","article-title":"Seismic migration problems and solutions","volume":"66","author":"Gray","year":"2001","journal-title":"Geophysics"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1190\/1.1440828","article-title":"Integral Formulation for Migration in Two and Three Dimensions","volume":"43","author":"Schneider","year":"1978","journal-title":"Geophysics"},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Schleicher, J., Tygel, M., and Hubral, P. (2007). Seismic True Amplitude Imaging, Society of Exploration Geophysicists.","DOI":"10.1190\/1.9781560801672"},{"key":"ref_40","unstructured":"Claerbout, J.F. (1992). Earth Soundings Analysis: Processing Versus Inversion, Blackwell Scientific Publications."},{"key":"ref_41","unstructured":"Silva, R. (1992). SEG Technical Program Expanded Abstracts, Society of Exploration Geophysicists."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1007\/s00015-016-0241-4","article-title":"High-resolution mini-seismic methods applied in the Mont Terri rock laboratory (Switzerland)","volume":"5","author":"Schuster","year":"2017","journal-title":"Swiss J. Geosci. Suppl."},{"key":"ref_43","unstructured":"Eaglekumar, G.T., and PATANKAR, V. (2018, January 19\u201321). SNR Enhancement of Ultrasonic Pulse-Echo Signals using 1-D Anisotropic Diffusion Filter. Proceedings of the NDE 2018, Mumbai, India."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Roach, D.P., Walkington, P.D., and Rackow, K.A. (2005). Pulse-Echo Ultrasonic Inspection System for In-Situ Nondestructive Inspection of Space Shuttle RCC Heat Shields, Sandia National Laboratories. SAND2005-3429.","DOI":"10.2172\/923155"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"106550","DOI":"10.1016\/j.ultras.2021.106550","article-title":"Ultrasonic Signal Enhancement for Coarse Grain Materials by Machine Learning Analysis","volume":"117","author":"Xu","year":"2021","journal-title":"Ultrasonics"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1909","DOI":"10.1093\/gji\/ggx267","article-title":"Optimizing measurement geometry for seismic near-surface full waveform inversion","volume":"210","author":"Nuber","year":"2017","journal-title":"Geophys. J. Int."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"6943","DOI":"10.1002\/2015JB012330","article-title":"Improved structural characterization of the Earth\u2019s crust at the German Continental Deep Drilling Site using advanced seismic imaging techniques","volume":"120","author":"Hellwig","year":"2015","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s10921-023-01010-3","article-title":"Application of Iterative Elastic SH Reverse Time Migration to Synthetic Ultrasonic Echo Data","volume":"43","author":"Grohmann","year":"2023","journal-title":"J. Nondestruct. Eval."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/1\/100\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:41:19Z","timestamp":1760132479000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/1\/100"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,12,24]]},"references-count":48,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2024,1]]}},"alternative-id":["s24010100"],"URL":"https:\/\/doi.org\/10.3390\/s24010100","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2023,12,24]]}}}