Pulser for arbitrary width and position square pulse trains generation

Svilainis, Linas; Dumbrava, V.; Chaziachmetovas, Andrius; Aleksandrovas, Arturas

doi:10.1109/ultsym.2012.0438

Cited by 8 publications

(5 citation statements)

References 10 publications

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“…More details on the pulser can be found in Ref. [25]. In order to be able to compare the reflection and transmission test results, two acquisition channels and two reception preamplifiers were used.…”

Section: Resultsmentioning

confidence: 99%

High frequency focused imaging for ultrasonic probe integrity inspection

Svilainis

Kybartas

Aleksandrovas

et al. 2020

NDT & E International

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Most ultrasonic probes present a layered structure that may comprise delay lines, acoustic lens, wear plates, matching layers, electrodes, piezoelectric layers, and a backing block. Probe integrity can be compromised by different defects, such as deficient bonding, presence of air bubbles or porosity, lack of electrical conductivity in electrodes, and deviations in the layers' acoustic thicknesses, impedances or attenuation values. Conventional testing procedures are based on the integral properties of the probe, such as acoustic directivity, sensitivity, and electrical impedance. An alternative technique for the non-destructive inspection of the probe's integrity is presented in this study. The proposed technique is based on imaging of the internal structure using a higher frequency focused ultrasound. Scanning the probe's surface using this focused beam provides two imaging modes: reflection and transmission. In the reflection mode, the higher intensity of the echoes indicates the presence of the defects, such as disbonds, poor acoustic matching or porosity. The main novelty of the proposed technique is in the transmission mode: the probe's electric response to the high frequency focused beam is used to get a 2D distribution of transduction efficiency. Moreover, the probe's response can be gated to separate, both front and back side, responses in the time domain, so the local integrity of an electroacoustic structure is evaluated. To verify the proposed technique, a focused 20 MHz transducer with a focal spot diameter of 0.35 mm was mounted on an ultrasonic scanner and immersed in water above the surface of the probe to be tested. Signals were gated by the layers' thickness, giving the C-scan images corresponding to the different material interfaces inside the tested probes: front face, matching layers, piezoelement and backing. It was demonstrated that the resulting C-scan images are informative in evaluating probe's integrity and layers' acoustic thickness. Comparison of the C-scan images obtained in the reflection and transmission modes shows a good agreement in the structure deficiencies evaluation. The technique proposed is attractive due to its simplicity. It can be useful in several applications: i) the probes already in use can be verified and if any deficiencies are detected, the information obtained can be used to evaluate and guide repair; ii) fabrication quality can be verified by confirming the adhesion of layers and parameters in 2D; and iii) the development of new fabrication routes can be guided, where adherence, compatibility, homogeneity, etc. of new materials or new technologies can be evaluated.

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Section: Resultsmentioning

confidence: 99%

High frequency focused imaging for ultrasonic probe integrity inspection

Svilainis

Kybartas

Aleksandrovas

et al. 2020

NDT & E International

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“…Sonovue MBs were prepared in 0.9% NaCl solution, as indicated in the instruction sheet US signals were generated and registered by an arbitrary signal generator/oscilloscope (Picoscope 5242B, Picotech, Eaton Socon, UK). A push-pull transformer (SE-TX02-00, Kaunas University of Technology, Kaunas, Lithuania) [30,31], powered by a high-voltage supply (MCP Lab Electronics, Shanghai, China), was utilized for the amplification of electrical signals. US pulses were generated by an 18 mm diameter unfocused transducer (0.9-1.2 MHz at −6 dB bandwidth) operating at a center frequency of 1 MHz (Medelkom, Vilnius, Lithuania).…”

Section: Methodsmentioning

confidence: 99%

The Assessment of Calcium and Bleomycin Cytotoxic Efficiency in Relation to Cavitation Dosimetry

et al. 2023

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Microbubble (MB)- and ultrasound (US)-facilitated intracellular Ca2+ delivery, known as sonoporation (SP), is a promising anticancer treatment modality, since it allows a spatio-temporally controllable and side-effect-free alternative to conventional chemotherapy. The current study provides extensive evidence that a 5 mM concentration of Ca2+ in combination with US alone or US and Sonovue MBs can be an alternative to the conventional 20 nM concentration of the anticancer drug bleomycin (BLM). Ca2+ application together with SP induces a similar level of death in Chinese hamster ovary cells to the combination of BLM and SP but does not cause systemic toxicity, as is inherent to conventional anticancer drugs. In addition, Ca2+ delivery via SP alters three vital characteristics essential for viable cells: membrane permeability, metabolic activity and proliferation ability. Most importantly, Ca2+ delivery via SP elicits sudden cell death—occurring within 15 min—which remains similar during 24–72 h and 6 d periods. The extensive study of US waves side-scattered by MBs led to the quantification of the cavitation dose (CD) separately for subharmonics, ultraharmonics, harmonics and broadband noise (up to 4 MHz). The CD was suitable for the prognostication of the cytotoxic efficiency of both anticancer agents, Ca2+ and BLM, as was indicated by an overall high (R2 ≥ 0.8) correlation (22 pairs in total). These extensive analytical data imply that a broad range of frequencies are applicable for the feedback-loop control of the process of US-mediated Ca2+ or BLM delivery, successively leading to the eventual standardization of the protocols for the sonotransfer of anticancer agents as well as the establishment of a universal cavitation dosimetry model.

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“…In integrity inspection experiments, the focused transducer was excited by transformer push-pull pulser SE-TX02-02 (Kaunas University of Technology, Kaunas, Lithuania) [ 34 ] using bipolar 60 Vpp rectangular spread spectrum signal (0.7–1.1 MHz range, 40 µs chirp).…”

Section: Methodsmentioning

confidence: 99%

Air-Coupled Ultrasonic Probe Integrity Test Using a Focused Transducer with Similar Frequency and Limited Aperture for Contrast Enhancement

Svilainis

Chaziachmetovas

Kybartas

et al. 2020

Sensors

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Air-coupled ultrasonic probes require a special design approach and handling due to the significant mismatch to the air. Outer matching layers have to be soft so can be easily damaged and excitation voltages might cause the degradation of electrodes or bonding between the layers. Integrity inspection is desired during design, manufacturing, and exploitation. Spatial distribution of a transduction efficiency over piezoelement surface is proposed as a convenient means for the air-coupled probe integrity inspection. Focused transducer of similar center frequency is used to scan the surface of the inspected probe. However, such approach creates a challenge, i.e., area of the scanning beam is much smaller than the total receiving area of the inspected probe, therefore, contrast and imaging resolution are significantly degraded. Masking aperture made from cardboard and felt, placed at the focal point was proposed as solution. Far-range sidelobes were suppressed down to the noise floor (−50 dB) and the near-range sidelobes were reduced down to −17 dB. The proposed modification allows to use a similar frequency focused transducer. Probe integrity inspection can be carried out at significantly enhanced contrast and lateral resolution. Natural and artificial defects can be detected by the use of the proposed method.

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Pulser for arbitrary width and position square pulse trains generation

Cited by 8 publications

References 10 publications

High frequency focused imaging for ultrasonic probe integrity inspection

High frequency focused imaging for ultrasonic probe integrity inspection

The Assessment of Calcium and Bleomycin Cytotoxic Efficiency in Relation to Cavitation Dosimetry

Air-Coupled Ultrasonic Probe Integrity Test Using a Focused Transducer with Similar Frequency and Limited Aperture for Contrast Enhancement

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