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DOE OSTI2021

IoT Devices and Applications for Wire-Based Hybrid Manufacturing Machine Tools

Hybrid manufacturing machine tools have the potential to be a disruptive technology as they can leverage the benefits of both additive and subtractive manufacturing by incorporating both processes on the same machine while limiting the downsides of the individual processes. Since these machines use two very disparate manufacturing processes and hybrid manufacturing is an emerging technology, it will be useful to monitor data coming from the machine and apply it to improve the manufacturing process, the operation of the machine, and to integrate the machine into the larger digital framework of Industrial Internet of Things (IoT). The present work discusses IoT devices that would be beneficial to add to a hybrid machine tool as well as applications for those devices. The proposed methods discussed in this work have not been experimentally implemented on a hybrid machine tool and so there are no performance data available yet. The hybrid machine tool used as a basis to generate these IoT applications is the Mazak VC-500A/5x AM Hot Wire Deposition, which is a 5-axis machine tool incorporated with a wire feedstock 4kW laser deposition system. Methodologies and applications will be outlined for machine health and process monitoring. Other areas covered include process benchmarking, secure networking options for the proposed IoT framework, and hybrid process improvement. Limitations of these methods and future work for new sensor devices and application areas is also discussed.

Thien, Austen↗

DOE OSTI2016

Low-temperature atomic layer deposition of TiO{sub 2} thin layers for the processing of memristive devices

Atomic layer deposition (ALD) represents one of the most fundamental techniques capable of satisfying the strict technological requirements imposed by the rapidly evolving electronic components industry. The actual scaling trend is rapidly leading to the fabrication of nanoscaled devices able to overcome limits of the present microelectronic technology, of which the memristor is one of the principal candidates. Since their development in 2008, TiO{sub 2} thin film memristors have been identified as the future technology for resistive random access memories because of their numerous advantages in producing dense, low power-consuming, three-dimensional memory stacks. The typical features of ALD, such as self-limiting and conformal deposition without line-of-sight requirements, are strong assets for fabricating these nanosized devices. This work focuses on the realization of memristors based on low-temperature ALD TiO{sub 2} thin films. In this process, the oxide layer was directly grown on a polymeric photoresist, thus simplifying the fabrication procedure with a direct liftoff patterning instead of a complex dry etching process. The TiO{sub 2} thin films deposited in a temperature range of 120–230 °C were characterized via Raman spectroscopy and x-ray photoelectron spectroscopy, and electrical current–voltage measurements taken in voltage sweep mode were employed to confirm the existence of resistive switching behaviors typical of memristors. These measurements showed that these low-temperature devices exhibit an ON/OFF ratio comparable to that of a high-temperature memristor, thus exhibiting similar performances with respect to memory applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2025

Cryogenic optical beam steering for superconducting device calibration

We have developed a calibration system based on a micro-electromechanical systems (MEMS) mirror that is capable of delivering an optical beam over a wavelength range of 180 -- 2000 nm (0.62 -- 6.89 eV) in a sub-Kelvin environment. This portable, integrated system can steer the beam over a $\sim$3 cm $\times$ 3 cm area on the surface of any sensor with a precision of $\sim$100 $μ$m, enabling characterization of device response as a function of position. This fills a critical need in the landscape of calibration tools for sub-Kelvin devices, including those used for dark matter detection and quantum computing. These communities have a shared goal of understanding the impact of ionizing radiation on device performance, which can be pursued with our system. This paper describes the design of the first-generation calibration system and the results from successfully testing its performance at room temperature and 20 mK.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2015

Parallel transmit excitation at 1.5 T based on the minimization of a driving function for device heating

Purpose: To provide a rapid method to reduce the radiofrequency (RF) E-field coupling and consequent heating in long conductors in an interventional MRI (iMRI) setup. Methods: A driving function for device heating (W) was defined as the integration of the E-field along the direction of the wire and calculated through a quasistatic approximation. Based on this function, the phases of four independently controlled transmit channels were dynamically changed in a 1.5 T MRI scanner. During the different excitation configurations, the RF induced heating in a nitinol wire immersed in a saline phantom was measured by fiber-optic temperature sensing. Additionally, a minimization of W as a function of phase and amplitude values of the different channels and constrained by the homogeneity of the RF excitation field (B{sub 1}) over a region of interest was proposed and its results tested on the benchtop. To analyze the validity of the proposed method, using a model of the array and phantom setup tested in the scanner, RF fields and SAR maps were calculated through finite-difference time-domain (FDTD) simulations. In addition to phantom experiments, RF induced heating of an active guidewire inserted in a swine was also evaluated. Results: In the phantom experiment, heating at the tip of the device was reduced by 92% when replacing the body coil by an optimized parallel transmit excitation with same nominal flip angle. In the benchtop, up to 90% heating reduction was measured when implementing the constrained minimization algorithm with the additional degree of freedom given by independent amplitude control. The computation of the optimum phase and amplitude values was executed in just 12 s using a standard CPU. The results of the FDTD simulations showed similar trend of the local SAR at the tip of the wire and measured temperature as well as to a quadratic function of W, confirming the validity of the quasistatic approach for the presented problem at 64 MHz. Imaging and heating reduction of the guidewire were successfully performed in vivo with the proposed hardware and phase control. Conclusions: Phantom and in vivo data demonstrated that additional degrees of freedom in a parallel transmission system can be used to control RF induced heating in long conductors. A novel constrained optimization approach to reduce device heating was also presented that can be run in just few seconds and therefore could be added to an iMRI protocol to improve RF safety.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

TU-AB-201-10: Novel Conformal Skin Brachytherapy Device

Purpose: A novel conformal skin brachytherapy (CSBT) device was developed to provide patient specific treatment for small inoperable lesions and irregular surfaces that are not good candidates for electron external beam, e.g. eyelids, nose, lips, ears, etc. Methods: A prototype was built and tested using radioactive seeds spaced by 1.5 mm attached to a 3D printed template. Seeds were allowed to move independently at treatment surface to conform to target geometry. Beta-emitter Praseodymium-142 (half-life: 19.12 h, average beta energy: 809 keV) and Iodine-125 Model 6711 (half-life: 59.4 days, average gamma energy: 28 keV) seeds were used to test the feasibility of the device in solid water phantom for different prescription depths and surface areas. Percent depth doses and dose profiles were analyzed. MCNPX2.6 Monte Carlo Simulation and Gafchromic EBT3 film measurements were performed for a single Pr-142 seed. Treatment with nineteen I-125 seeds was planned in BrachyVision and measured experimentally for a total dose of 500 cGy at 5.0 mm depth. Results: For a single Pr-142 seed, dose was 500.0 cGy at surface and 17.4 cGy at 5.00 mm. BrachyVision planned and film doses for I-125 seed matrix were 500 cGy and 473.5 cGy at 5 mm depth and 171.0 cGy and 201.0 cGy at 10 mm depth. Total covered surface area for Pr-142 and I-125 were 2.35 mm{sup 2} and 88.24 mm{sup 2} respectively. Profile dose fall-off showed to be very conformal to contact area with 50% of the total surface dose from a single Pr-142 and array of I-125 seeds being deposited at 0.72 mm and 0.65 mm respectively from the central axis. Conclusion: CSBT device provides a high conformal dose to small surfaces. BrachyVision can be used to predict clinical dose distributions for multiple seeds matrix. Different radioactive seeds can be used to suit prescription depth and treatment area.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

TU-D-201-00: Use of End-Of-Life Brachytherapy Devices

Brachytherapy devices and software are designed to last for a certain period of time. Due to a number of considerations, such as material factors, wear-and-tear, backwards compatibility, and others, they all reach a date when they are no longer supported by the manufacturer. Most of these products have a limited duration for their use, and the information is provided to the user at time of purchase. Because of issues or concerns determined by the manufacturer, certain products are retired sooner than the anticipated date, and the user is immediately notified. In these situations, the institution is facing some difficult choices: remove these products from the clinic or perform tests and continue their usage. Both of these choices come with a financial burden: replacing the product or assuming a potential medicolegal liability. This session will provide attendees with the knowledge and tools to make better decisions when facing these issues. Learning Objectives: Understand the meaning of “end-of-life or “life expectancy” for brachytherapy devices and software Review items (devices and software) affected by “end-of-life” restrictions Learn how to effectively formulate “end-of-life” policies at your institution Learn about possible implications of “end-of-life” policy Review other possible approaches to “end-of-life” issue.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

TU-D-201-01: Definition and Purpose of End-Of-Life for Brachytherapy Devices and Software

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

TU-D-201-02: Physicist’s Responsibility On “End-Of-Life for Brachytherapy Devices and Software

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

SU-F-T-452: Influence of Dose Calculation Algorithm and Heterogeneity Correction On Risk Categorization of Patients with Cardiac Implanted Electronic Devices Undergoing Radiotherapy

Purpose: There is a lack of studies with significant cohort data about patients using pacemaker (PM), implanted cardioverter defibrillator (ICD) or cardiac resynchronization therapy (CRT) device undergoing radiotherapy. There is no literature comparing the cumulative doses delivered to those cardiac implanted electronic devices (CIED) calculated by different algorithms neither studies comparing doses with heterogeneity correction or not. The aim of this study was to evaluate the influence of the algorithms Pencil Beam Convolution (PBC), Analytical Anisotropic Algorithm (AAA) and Acuros XB (AXB) as well as heterogeneity correction on risk categorization of patients. Methods: A retrospective analysis of 19 3DCRT or IMRT plans of 17 patients was conducted, calculating the dose delivered to CIED using three different calculation algorithms. Doses were evaluated with and without heterogeneity correction for comparison. Risk categorization of the patients was based on their CIED dependency and cumulative dose in the devices. Results: Total estimated doses at CIED calculated by AAA or AXB were higher than those calculated by PBC in 56% of the cases. In average, the doses at CIED calculated by AAA and AXB were higher than those calculated by PBC (29% and 4% higher, respectively). The maximum difference of doses calculated by each algorithm was about 1 Gy, either using heterogeneity correction or not. Values of maximum dose calculated with heterogeneity correction showed that dose at CIED was at least equal or higher in 84% of the cases with PBC, 77% with AAA and 67% with AXB than dose obtained with no heterogeneity correction. Conclusion: The dose calculation algorithm and heterogeneity correction did not change the risk categorization. Since higher estimated doses delivered to CIED do not compromise treatment precautions to be taken, it’s recommend that the most sophisticated algorithm available should be used to predict dose at the CIED using heterogeneity correction.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

SU-F-T-515: Increased Skin Dose in Supine Craniospinal Irradiation Due to Carbon Fiber Couch and Vacuum Bag Immobilization Device

Purpose: To measure the surface dose for supine craniospinal irradiation employing posterior beams, treating through an imaging couch and BlueBag immobilization device. Methods: The percentage depth dose (PDD) in the buildup region of a clinical 6 MV photon beam was measured using an Advanced Markus parallel plate ionization chamber in a solid water phantom. The PDD from a 10×10 cm{sup 2} anterior beam was measured at 100 cm SSD, simulating a traditional prone craniospinal technique. The measurements were compared to commissioning and treatment planning system data. The PDD was also measured in a posterior setup with the phantom surface laying directly on the Brainlab carbon fiber imaging couch, with the phantom surface 100 cm from the source, simulating a supine craniospinal setup. The posterior measurements were repeated with a BlueBag vacuum immobilization device between the couch and phantom, with thicknesses of 1.7 cm and 5 cm. The PDD from a 10×10 cm{sup 2} field and a typical 6×30 cm{sup 2} craniospinal field were also compared. The PDDs were normalized at 5 cm to reflect typical craniospinal prescription dose normalization. Results: The measured PDD curve from the anterior setup agreed well with commissioning and treatment planning data, with surface doses of 19.9%, 28.8% and 27.7%, respectively. The surface doses of the 10×10 cm{sup 2} and 6×30 cm{sup 2} fields delivered through the imaging couch were both 122.4%. The supine setup yielded surface doses of 122.4%, 121.6%, and 119.6% for the couch only, 1.7 cm bag, and 5 cm bag setups, respectively. Conclusion: Delivering craniospinal irradiation through a carbon fiber couch removes the majority of skin sparing. The addition of a vacuum bag immobilization device restores some skin sparing, but the magnitude of this effect is negligible.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

SU-F-T-587: Quality Assurance of Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiation Therapy (SBRT) for Patient Specific Plans: A Comparison Between MATRIXX and Delta4 QA Devices

Purpose: Patient-specific quality assurance (QA) is necessary to accurately deliver high dose radiation to the target, especially for stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT). Unlike previous 2 dimensional (D) array QA devices, Delta{sup 4} can verify the dose delivery in 3D. In this study, the difference between calculated and measured dose distribution was compared with two QA devices (MATRIXX and Delta{sup 4}) to evaluate the delivery accuracy. Methods: Twenty-seven SRS/SBRT plans with VMAT were verified with point-dose and dose-map analysis. We use an ion chamber (A1SL, 0.053cc) for point-dose measurement. For verification of the dose map, the differences between the calculated and measured doses were analyzed with a gamma index using MATRIXX and Delta{sup 4} devices. The passing criteria for gamma evaluation were set at 3 mm for distance-to-agreement (DTA) and 3% for dose-difference. A gamma index less than 1 was defined as the verification passing the criteria and satisfying at least 95% of the points. Results: The mean prescribed dose and fraction was 40 ± 14.41 Gy (range: 16–60) and 10 ± 2.35 fractions (range: 1–8), respectively. In point dose analysis, the differences between the calculated and measured doses were all less than 5% (mean: 2.12 ± 1.13%; range: −0.55% to 4.45%). In dose-map analysis, the average passing rates were 99.38 ± 0.96% (range: 95.31–100%) and 100 ± 0.12% (range: 99.5%–100%) for MATRIXX and Delta{sup 4}, respectively. Even using criteria of 2%/2 mm, the passing rate of Delta{sup 4} was still more than 95% (mean: 99 ± 1.08%; range: 95.6%–100%). Conclusion: Both MATRIXX and Delta{sup 4} offer accurate and efficient verification for SRS/SBRT plans. The results measured by MATRIXX and Delta{sup 4} dosimetry systems are similar for SRS/SBRT performed with the VMAT technique.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

SU-G-201-12: Investigation of Beta-Emitter 90Sr-90Y Dose Distribution Using Gafchromic EBT3 Film for Application On Conformal Skin Brachytherapy Device

Purpose: To investigate {sup 90}Sr-{sup 90}Y as a high dose rate (HDR) source for application in a conformal skin brachytherapy (CSBT) device. The CSBT device has been previously developed to provide patient specific treatment for small inoperable lesions and irregular surfaces. Methods: A popular beta emitter, {sup 90}Sr-{sup 90}Y was tested for feasibility in a CSBT device. A 1 cm diameter plaque was used to deliver dose to a solid water phantom containing EBT3 Gafchromic films arranged at the surface and perpendicular to it. Additionally, a 1 cm diameter 6 MeV electron beam was used to irradiate EBT3 film at 100 cm SSD with a 0.5 cm bolus. Films were digitized with an Epson Expression 10000 XL scanner and calibrated with a 6 MeV electron specific dose curve. Normalized percent depth doses (PDD) and dose profiles for both techniques were analyzed using ImageJ. Results: Dose distributions achieved with the {sup 90}Sr-{sup 90}Y sources were compared with those of external electron beam radiation therapy (EBRT). Penumbra (20%- 80%) for EBRT and 90Sr-90Y were 4.3 mm and 1.6 mm, respectively. PDD values of 50% (normalized to 2 mm) were 10.1 mm and 2.8 mm for electron and {sup 90}Sr-{sup 90}Y, respectively. Flatness (80% of the central beam profile) was 14.1% at a 5 mm depth for EBRT and 4.0% at surface for the {sup 90}Sr-{sup 90}Y. Conclusion: As expected, the PDDs of {sup 90}Sr-{sup 90}Y in water are shallower than that of external electron beams for the same field size. {sup 90}Sr-{sup 90}Y can be used in CSBT to provide patient specific treatment where shallower depth doses than that provided by electron external beams may be required: e.g. eyelids, nose, lips, ears, etc. The customizability of EBRT could be replicated by using multiple adjacent {sup 90}Sr-{sup 90}Y plaque placements.

61 RADIATION PROTECTION AND DOSIMETRY↗

DOE OSTI2016

TH-EF-207A-03: Photon Counting Implementation Challenges Using An Electron Multiplying Charged-Coupled Device Based Micro-CT System

Purpose: To successfully implement and operate a photon counting scheme on an electron multiplying charged-coupled device (EMCCD) based micro-CT system. Methods: We built an EMCCD based micro-CT system and implemented a photon counting scheme. EMCCD detectors use avalanche transfer registries to multiply the input signal far above the readout noise floor. Due to intrinsic differences in the pixel array, using a global threshold for photon counting is not optimal. To address this shortcoming, we generated a threshold array based on sixty dark fields (no x-ray exposure). We calculated an average matrix and a variance matrix of the dark field sequence. The average matrix was used for the offset correction while the variance matrix was used to set individual pixel thresholds for the photon counting scheme. Three hundred photon counting frames were added for each projection and 360 projections were acquired for each object. The system was used to scan various objects followed by reconstruction using an FDK algorithm. Results: Examination of the projection images and reconstructed slices of the objects indicated clear interior detail free of beam hardening artifacts. This suggests successful implementation of the photon counting scheme on our EMCCD based micro-CT system. Conclusion: This work indicates that it is possible to implement and operate a photon counting scheme on an EMCCD based micro-CT system, suggesting that these devices might be able to operate at very low x-ray exposures in a photon counting mode. Such devices could have future implications in clinical CT protocols. NIH Grant R01EB002873; Toshiba Medical Systems Corp.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2025

Scalable fabrication of Chip-integrated 3D-nanostructured electronic devices via DNA-programmable assembly

DNA-based self-assembly methods have demonstrated powerful and unique capabilities to encode nanomaterial structures through the prescribed placement of inorganic and biological nanocomponents. However, the challenge of selectively growing DNA superlattices on specific locations of surfaces and their integration with conventional nanofabrication has hindered the fabrication of three-dimensional (3D) DNA-assembled functional devices. Here, we present a scalable nanofabrication technique that combines bottom-up and top-down approaches for selective growth of 3D DNA superlattices on gold microarrays. This approach allows for the fabrication of self-assembled 3D-nanostructured electronic devices. DNA strands are bound onto the gold arrays, which anchor DNA origami frames and promote ordered framework growth on the specific areas of the surface, enabling control of the lateral placement and orientation of superlattices. DNA frameworks selectively grown on the pads are subsequently templated to nanoscale silica and tin oxide (SnO x ) that follow the architecture, as confirmed by structural and chemical characterizations. The fabricated SnO x superlattices are integrated into devices that demonstrate photocurrent response.

36 MATERIALS SCIENCE↗

DOE OSTI2016

Asymmetric devices based on carbon nanotubes for terahertz-range radiation detection

Various asymmetric detecting devices based on carbon nanotubes (CNTs) are studied. The asymmetry is understood as inhomogeneous properties along the conducting channel. In the first type of devices, an inhomogeneous morphology of the CNT grid is used. In the second type of devices, metals with highly varying work functions are used as the contact material. The relation between the sensitivity and detector configuration is analyzed. Based on the data obtained, approaches to the development of an efficient detector of terahertz radiation, based on carbon nanotubes are proposed.

36 MATERIALS SCIENCE↗

DOE OSTI2017

Patterning approach for detecting defect in device manufacturing

Compact handheld devices which were a dream in the past are now a reality; this has been enabled by miniaturization of circuit architectures including power devices. Scaling down of the design feature sizes does come with a price with an increase in systematic defects during chip manufacturing. There are generally two methods of inline defect detection adopted to monitor the semiconductor device fabrication—optical inspection and electron beam inspection. The optical inspection uses ultra-violet and deep ultra-violet (UV/DUV) light to find patterning defects on the wafer. While the electron-beam inspection uses electron charge and discharge measurement to find electrical connection defects, both are a costly procedure in terms of resources and time. The physical limit of feature resolution of the optical source is now making the defect inspection job difficult in miniaturized application specific integrated circuit (ASIC). This study is designed to test the patterning optimization approach on both inspection platforms. Using hotspot analysis weak locations are identified in the full chip design, and then they are verified in the inline wafer inspection. The criterion for hot-spot determination is also discussed in this paper.

36 MATERIALS SCIENCE↗

DOE OSTI2016

(Invited) Comprehensive Assessment of Oxide Memristors As Post-CMOS Memory and Logic Devices

As CMOS technology approaches the end of its scaling, oxide-based memristors have become one of the leading candidates for post-CMOS memory and logic devices. In orderTo facilitate the understanding of physical switching mechanisms and accelerate experimental development of memristors, we have developed a three-dimensional fully-coupled electrical and thermal transport model, which captures all the important processes that drive memristive switching and is applicable for simulating a wide range of memristors. Moreover, the model is applied to simulate the RESET and SET switching in a 3D filamentary TaOx memristor. Extensive simulations show that the switching dynamics of the bipolar device is determined by thermally-activated field-dominant processes: with Joule heating, the raised temperature enables the movement of oxygen vacancies, and the field drift dominates the overall motion of vacancies. Simulated current-voltage hysteresis and device resistance profiles as a function of time and voltage during RESET and SET switching show good agreement with experimental measurement.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2023

Co-Design of Multijunction Photoelectrochemical Devices for Unassisted CO 2 Reduction to Multicarbon Products

Photoelectrochemical (PEC) CO 2 reduction (PEC CO 2 R) is a prospective approach for utilizing solar energy to synthesize a variety of carbon-containing chemicals and fuels, the most valuable of which are multicarbon (C 2+ ) products, such as ethylene and ethanol. While these products can be produced with high faradaic efficiency using Cu, this occurs over a relatively narrow potential range, which, in turn, imposes constraints on the design of a device for PEC CO 2 R. Herein, we used continuum-scale modeling to simulate the solar-to-C 2+ (STC 2+ ) efficiency of PEC CO 2 R devices fed with CO 2 -saturated, 0.1 M CsHCO 3 . We then explored how cell architecture and the use of single or dual photoelectrode(s) alters the optimal combination of photoelectrode bandgaps for high STC 2+ efficiency. Ultimately, this work provides guidance for the co-design of the device architecture and photoelectrode bandgaps required to achieve high STC 2+ efficiency. The insights gained are then used to identify systems that yield the highest amount of C 2+ products throughout the day and year.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗