Accelerator Components Research Articles

DANSEN: Database Acceleration on Native Computational Storage by Exploiting NDP

This article introduces DANSEN , the hardware accelerator component for neoDBMS, a full-stack computational storage system designed to manage on-device execution of database queries/transactions as a Near-Data Processing (NDP)-operation. The proposed system enables Database Management Systems (DBMS) to offload NDP-operations to the storage while maintaining control over data through a native storage interface . DANSEN provides an NDP-engine that enables DBMS to perform both low-level database tasks, such as performing database administration, as well as high-level tasks like executing SQL, on the smart storage device while observing the DBMS concurrency control. Furthermore, DANSEN enables the incorporation of custom accelerators as an NDP-operation (e.g., to perform hardware-accelerated ML inference directly on the stored data). We built the DANSEN storage prototype and interface on an UltraScale+HBM FPGA and fully integrated it with PostgreSQL 12. Experimental results demonstrate that the proposed NDP approach outperforms software-only PostgreSQL using a fast off-the-shelf NVMe drive and significantly improves the end-to-end execution time of an aggregation operation (similar to Q6 from CH-benCHmark, 150 million records) by ≈ 10.6×. The versatility of the proposed approach is also validated by integrating a compute-intensive data analytics application with multi-row results, outperforming PostgreSQL by ≈ 1.5×.

Damage localization using low-frequency bridge acceleration component under a moving vehicle

Monitoring the health of short-span and medium-span bridges in urban transportation systems is a crucially important issue in civil engineering, as is locating damage. Earlier studies have attempted to use bridge deflection or acceleration to locate damage. However, the deflection is not so sensitive to enable damage location. Few studies have investigated low-frequency acceleration responses. For this study, a proposed model-free method is evaluated for damage localization using low-frequency bridge acceleration under a moving vehicle. First, the bridge dynamic responses in a vehicle–bridge interaction (VBI) system are derived theoretically, where the bridge is modeled as a simply supported beam, the vehicle as a moving sprung mass, and damage as a reduction of the beam’s bending stiffness. A partially moving loading model is proposed to explain the influence of the structural damage on the dynamic behavior of the beam. A simple relation was found between low-frequency bridge acceleration and the damage location. Specifically, an abnormal “bump” occurred on the low-frequency bridge acceleration when a vehicle passes over the damaged area. Using this relation, one can directly locate potential damage from the low-pass filtered acceleration time history of the beam. A series of numerical analyses and laboratory and field experiments were conducted to validate the proposed damage localization method.

Tangential and Normal Acceleration Components in Projectile Motion

Tangential and Normal Acceleration Components in Projectile Motion

Development of a novel bunch oscillation recorder with RFSoC technology

The SuperKEKB accelerator is designed to achieve unprecedented luminosity levels, but this goal is currently hindered by Sudden Beam Loss (SBL) events. These events not only obstruct luminosity improvement but also pose a significant risk to accelerator components, the Belle II detectors, and the superconducting focusing system, potentially leading to severe damage and quenching of the superconducting system. To address this critical challenge, we have developed a novel Bunch Oscillation Recorder (BOR) based on RFSoC technology. The BOR has demonstrated high precision with a position resolution of 0.03 mm, making it a powerful tool for real-time beam monitoring. In its initial deployment, the BOR successfully recorded multiple SBL events, providing valuable data for further analysis. By strategically positioning BORs at the suspected points of SBL origin, we aim to directly identify sources of beam instability. We anticipate that this portable, high-speed BOR monitor will play a crucial role in resolving the SBL issue, ultimately helping achieve SuperKEKB's luminosity targets.

Meta-analyses of epigenetic age acceleration and GrimAge components of schizophrenia or first-episode psychosis

Schizophrenia is a common chronic psychiatric disorder that causes age-related dysfunction. The life expectancy in patients with schizophrenia is ≥10 years shorter than that in the general population because of the higher risk of other diseases, such as cardiovascular diseases. Aging studies based on DNA methylation status have received considerable attention. Several epigenetic age accelerations and predicted values of aging-related proteins (GrimAge and GrimAge2 components) have been analyzed in multiple diseases. However, no studies have investigated up to GrimAge and GrimAge2 components between patients with schizophrenia and controls. Therefore, we aimed to conduct multiple regression analyses to investigate the association between schizophrenia and epigenetic age accelerations and GrimAge and GrimAge2 components in seven cohorts. Furthermore, we included patients with first-episode psychosis whose illness duration was often shorter than schizophrenia in our analysis. We integrated these results with meta-analyses, noting the acceleration of GrimAge, GrimAge2, and DunedinPACE, and increase in adrenomedullin, beta-2 microglobulin, cystatin C, and plasminogen activation inhibitor-1 levels, in patients with schizophrenia or first-episode psychosis. These results corroborated the finding that patients with schizophrenia had an increased risk of diabetes, cardiovascular disease, and cognitive dysfunction from a biological perspective. Patients with schizophrenia and first-episode psychosis showed differences in the results when compared with controls. Such analyses may lead to the development of novel therapeutic targets to patients with schizophrenia or relevant diseases from the perspective of aging in the future.

Green upgrading of SPring-8 to produce stable, ultrabrilliant hard X-ray beams.

SPring-8-II is a major upgrade project of SPring-8 that was inaugurated in October 1997 as a third-generation synchrotron radiation light source. This upgrade project aims to achieve three goals simultaneously: achievement of excellent light source performance, refurbishment of aged systems, and significant reduction in power consumption for the entire facility. A small emittance of 50 pm rad will be achieved by (1) replacing the existing double-bend lattice structure with a five-bend achromat one, (2) lowering the stored beam energy from 8 to 6 GeV, (3) increasing the horizontal damping partition number from 1to 1.3, and (4) enhancing horizontal radiation damping by installing damping wigglers in long straight sections. The use of short-period in-vacuum undulators allows ultrabrilliant X-rays to be provided while keeping a high-energy spectral range even at the reduced electron-beam energy of 6 GeV. To reduce power consumption, the dedicated, aged injector system has been shut down and the high-performance linear accelerator of SACLA, a compact X-ray free-electron laser (XFEL) facility, is used as the injector of the ring in a time-shared manner. This allows the simultaneous operation of XFEL experiments at SACLA and full/top-up injection of the electron beam into the ring. This paper overviews the concept of the SPring-8-II project, the system design of the light source and the details of the accelerator component design.

Effects of liquid accelerators on long-term mechanical strength development and microstructural changes of wet-mixed shotcrete

The significant long-term strength loss of shotcrete can greatly affect the safety and stability of underground shotcrete structures. Developing high-quality liquid accelerators remains an indispensable research direction and a viable approach to mitigate challenge. This study synthesizes three distinct kinds of liquid accelerators - alkali-free fluorine-free (GJ), alkali-free fluorine-containing (MJ), and low-alkaline (JJ) and investigates their effects on the long-term mechanical strength of wet-mixed shotcrete. Moreover, changes in the phase composition and microstructure of accelerated shotcrete were explored utilizing X-ray diffraction, thermogravimetric analysis, mercury intrusion porosimetry, and scanning electron microscopy techniques to reveal underlying mechanisms. Results indicate that accelerated cement paste and mortar with a 6 wt% fixed dosage of liquid accelerators exceeded the prescribed basic performance indices (setting time and 28-day compressive strength ratio) for shotcrete applications. Among the accelerators, the alkali-free fluorine-containing type exhibited the most beneficial effect on long-term strength, attributed to increased C-(A)-S-H formation from added Al and Si into the system. Morphological and crystal composition changes in hydrate phases, notably the transformation of ettringite to AFm and additional formation of monosulfate and hemicarbonate, increased the solid volume, refined pore structure and reduced total porosity, thus enhancing long-term strength. This study offers valuable insights into the synthesis and optimization of main accelerator components to mitigate long-term strength loss in shotcrete for practical engineering applications.

A perspective on Varian edge live view calibration

Modern radiotherapy relies heavily on precise, real-time monitoring of both the patient and the linear accelerator (linac) components. However, current commercial surface scanning systems often overlook the monitoring of linac components, such as the gantry, collimator, and couch, focusing solely on the patient. This study aims to address this issue by developing a comprehensive understanding of the Varian TrueBeam Edge system using a live view calibration method. This method ensures accurate alignment between the machine's 3D model and live camera images, improving the precision and reliability of radiotherapy treatments.

Shielded Pair Method for Beam Screen Surface Resistance Measurement at Cryogenic Temperature

The shielded pair resonator method is a useful tool in the measurement of accelerator components, such as the beam screens used in the Large Hadron Collider (LHC), the High-Luminosity (HL) LHC, or future accelerators. It can measure the resistive losses at several frequency points by separating the resistive losses on the sample from other sources of losses. We built a new resonator to be inserted into a superconducting dipole magnet (peak magnetic field of 9.5 T) and to measure the surface resistance of beam screens, such as LHC beam screens coated with amorphous carbon (a-C). The device can measure surface resistance at any temperature between 4.2 K and 300 K, in the frequency range of 400 MHz to 1600 MHz. We conducted the first surface resistance measurements of two a-C coated beam screens at 4.2 K and showed that the 200 nm to 400 nm titanium underlayer plus 50 nm a-C only has a limited effect on the surface resistance. This first result supports the choice of this coating as baseline for the HL-LHC triplets magnets upgrade. The resonator will have an important role in the characterization of next-generation beam screens, such as a beam screen with laser-engineered surface structure (LESS). Further measurements of the LHC beam screen in the presence of magnetic fields up to 9.5 T and throughout the full temperature range are going to be reported separately.

Limitations in Maximum Intensity Front Crawl in Swimmers with Down Syndrome

Individuals with Down Syndrome exhibit deficits in muscle strength and cardiovascular adaptation, which limit athletic performance. We compared a maximum-intensity 50 m front crawl test between competitive male swimmers with Down Syndrome (SDS; n = 11; 26.5 ± 5.6 years; m ± SD) and a control group of swimmers (CNT; n = 11; 27.1 ± 4.0 years) with similar training routines (about 5 h/week). Wearable sternal sensors measured their heart rate and 3D accelerometry. The regularity index Sample Entropy (SampEn) was calculated using the X component of acceleration. The total times (SDS: 58.91 ± 13.68 s; CNT: 32.55 ± 3.70 s) and stroke counts (SDS: 66.1 ± 9.6; CNT: 51.4 ± 7.4) were significantly higher in the SDS group (p < 0.01). The heart rate was lower in the SDS group during immediate (SDS: 129 ± 15 bpm; CNT: 172 ± 11 bpm) and delayed recovery (30 s, SDS: 104 ± 23 bpm; CNT: 145 ± 21 bpm; 60 s, SDS: 79 ± 27 bpm; CNT: 114 ± 27 bpm) (p < 0.01 for all the comparisons). The SampEn of sternal acceleration showed no differences between the groups and between 0–25 m and 25–50 m. Body pitch correlated strongly with performance in the SDSs (R2 = 0.632, p < 0.01), but during the first 25 m only. The high-intensity front crawl performances differed between the SDS and CNT athletes in terms of time, biomechanics, and training adaptation, suggesting the need for tailored training to improve swimming efficiency in SDSs.

Open LEARN: Open access linear accelerator education and augmented reality Navigator

PurposeTo create an open-access Linear Accelerator Education and Augmented Reality Navigator (Open LEARN) via 3D printable objects and interactive augmented reality assets. MethodsThis study describes an augmented reality linear accelerator (linac) model accessible through a QR code and a smartphone to address the challenges of medical physics and radiation oncology trainees in low-to-middle-income countries. ResultsMajor components of a generic linear accelerator are modeled as individual objects. These objects can be 3D printed for hands-on learning and used as interactive 3D assets within the augmented reality app. In the AR app, descriptions are displayed to navigate the components spatially and textually. Items modeled include the treatment couch, klystron, circulator, RF waveguides, electron gun, waveguide, beam steering assemblies, target, collimators, multi-leaf collimators, and imaging systems. The linear accelerator is rendered at nearly 100% of its actual size, allowing users to change magnification and view objects from different angles. ConclusionsThe augmented reality linear accelerators and 3D-printed objects make these complex machines easily accessible with smartphones and 3D-printing technologies, facilitating education and training through physical and virtual interaction.

Pathology diagnosis of intraoperative frozen thyroid lesions assisted by deep learning

BackgroundThyroid cancer is a common thyroid malignancy. The majority of thyroid lesion needs intraoperative frozen pathology diagnosis, which provides important information for precision operation. As digital whole slide images (WSIs) develop, deep learning methods for histopathological classification of the thyroid gland (paraffin sections) have achieved outstanding results. Our current study is to clarify whether deep learning assists pathology diagnosis for intraoperative frozen thyroid lesions or not.MethodsWe propose an artificial intelligence-assisted diagnostic system for frozen thyroid lesions that applies prior knowledge in tandem with a dichotomous judgment of whether the lesion is cancerous or not and a quadratic judgment of the type of cancerous lesion to categorize the frozen thyroid lesions into five categories: papillary thyroid carcinoma, medullary thyroid carcinoma, anaplastic thyroid carcinoma, follicular thyroid tumor, and non-cancerous lesion. We obtained 4409 frozen digital pathology sections (WSI) of thyroid from the First Affiliated Hospital of Sun Yat-sen University (SYSUFH) to train and test the model, and the performance was validated by a six-fold cross validation, 101 papillary microcarcinoma sections of thyroid were used to validate the system’s sensitivity, and 1388 WSIs of thyroid were used for the evaluation of the external dataset. The deep learning models were compared in terms of several metrics such as accuracy, F1 score, recall, precision and AUC (Area Under Curve).ResultsWe developed the first deep learning-based frozen thyroid diagnostic classifier for histopathological WSI classification of papillary carcinoma, medullary carcinoma, follicular tumor, anaplastic carcinoma, and non-carcinoma lesion. On test slides, the system had an accuracy of 0.9459, a precision of 0.9475, and an AUC of 0.9955. In the papillary carcinoma test slides, the system was able to accurately predict even lesions as small as 2 mm in diameter. Tested with the acceleration component, the cut processing can be performed in 346.12 s and the visual inference prediction results can be obtained in 98.61 s, thus meeting the time requirements for intraoperative diagnosis. Our study employs a deep learning approach for high-precision classification of intraoperative frozen thyroid lesion distribution in the clinical setting, which has potential clinical implications for assisting pathologists and precision surgery of thyroid lesions.

Quantitative assessment of human motion for health and rehabilitation: A novel fuzzy comprehensive evaluation approach

In the pursuit of advancing health and rehabilitation, the quintessence of human motion recognition technology has been underscored through its quantitative contributions to physical performance assessment. This research delineates the inception of a novel fuzzy comprehensive evaluation-based recognition method that stands at the forefront of such innovative endeavours. By synergistically fusing multi-sensor data and advanced classification algorithms, the proposed system offers a granular quantitative analysis with implications for health and fitness monitoring, particularly rehabilitation processes. Our methodological approach, grounded in the modal separation technique and Empirical Mode Decomposition (EMD), effectively distills the motion acceleration component from raw accelerometer data, facilitating the extraction of intricate motion patterns. Quantitative analysis revealed that our integrated framework significantly amplifies the accuracy of motion recognition, achieving an overall recognition rate of 90.03 %, markedly surpassing conventional methods, such as Support Vector Machines (SVM), Decision Trees (DT), and K-Nearest Neighbors (KNN), which hovered around 80 %. Moreover, the system demonstrated an unprecedented accuracy of 97 % in discerning minor left-right swaying motions, showcasing its robustness in evaluating subtle movement nuances—a paramount feature for rehabilitation and patient monitoring. This marked precision in motion recognition heralds a new paradigm in health assessment, enabling objective and scalable analysis pertinent to individualized therapeutic interventions. The experimental evaluation accentuates the system's adeptness at navigating the dichotomy between complex, intense motions and finer, subtler movements with a high fidelity rate. It substantiates the method's utility in delivering sophisticated, data-driven insights for rehabilitation trajectory monitoring.

The Continuous Electron Beam Accelerator Facility at 12 GeV

This review paper describes the energy-upgraded Continuous Electron Beam Accelerator Facility (CEBAF) accelerator. This superconducting linac has achieved 12 GeV beam energy by adding 11 new high-performance cryomodules containing 88 superconducting cavities that have operated cw at an average accelerating gradient of 20 MV/m. After reviewing the attributes and performance of the previous 6 GeV CEBAF accelerator, we discuss the upgraded CEBAF accelerator system in detail with particular attention paid to the new beam acceleration systems. In addition to doubling the acceleration in each linac, the upgrade included improving the beam recirculation magnets, adding more helium cooling capacity to allow the newly installed modules to run cold, adding a new experimental hall, and improving numerous other accelerator components. We review several of the techniques deployed to operate and analyze the accelerator performance and document system operating experience and performance. In the final portion of the document, we present much of the current planning regarding projects to improve accelerator performance and enhance operating margins, and our plans for ensuring CEBAF operates reliably into the future. For the benefit of potential users of CEBAF, the performance and quality measures for the beam delivered to each of the experimental halls are summarized in the Appendix. Published by the American Physical Society 2024

A rapid method for prediction of the non-resonant ultra-fast multipactor regime in high gradient RF accelerating structures

The purpose of this work is to present an analytical method that allows to estimate in an approximate and fast way the presence of the non-resonant and ultra-fast multipactor effect in RF accelerating structures in the presence of high gradient electromagnetic fields. This single-surface multipactor regime, which has been little studied in the scientific literature, is characterised by appearing only under conditions of very strong RF electric fields (of the order of tens or hundreds of MV/m), where it is predominant over other types of single- or dual-surface resonance described in classical multipactor theory. This type of multipactor causes a rapid growth of the electron population and poses a serious drawback in the operation of RF accelerator components operating under high gradient conditions. Specifically, in dielectric-assist accelerating structures (DAA) it has been experimentally found that the presence of multipactor limits the maximum operating gradient of these components due to a significant increase in the reflected power due to the discharge, being this phenomenon the main problem to overcome. In a previous work, we found and described in detail by means of numerical simulations the presence of this non-resonant and ultra-fast multipactor regime in a DAA structure design for hadrontherapy. Here we aim to present a simple and fast method to predict the presence of this non-resonant and ultra-fast multipactor regime in RF accelerator structures with cylindrical revolution symmetry around the acceleration axis. This method is especially useful in the design stages of accelerating structures as it provides much faster results than numerical simulations of the multipactor, with quite good accuracy in a wide range of cases as shown in this paper.

Impact pressure coefficient and object mobilization length in mass flows

As the impact force of a flow overcomes the frictional resistance of an object, the object moves as long as the pressure exerted by the flow is greater than its shear resistance. With this concept, here, we develop simple analytical models for the mechanical description of the coefficient of impact pressure Cp0 and the mobilization length L when a mass flow impacts a movable object. We invented the obstacle mobilization number Cp0, a dimensionless number, which is expressed as the ratio of the obstacle shear resistance to the kinetic energy of the flow, per unit length. We also relate it to the obstacle Froude number Fr0. When the object moves through the length L against the basal friction, after consuming its kinetic energy, the object eventually stops. This balance between the kinetic energy and friction yields an analytical model for the mobilization length of the object. Equivalently, if the mobilization length is known, the impact velocity can be calculated. This is very important in estimating the flow velocity of any large-scale natural mass flows. Our model predicts that Cp0 decreases strongly to weakly non-linearly with the impact velocity, density ratio between the granular particle and the mobile object, and the area ratio between the grain covered area of the object and its base. Moreover, Cp0 increases linearly with the basal friction coefficient. However, the dynamic response of Cp0 to the shape of the object may vary immensely between objects of different shapes. Our model also predicts that the mobilization length L of the mobile object varies with the square of the impact velocity of flowing mass, but decreases with basal friction of the obstacle and the component of gravitational acceleration in the direction normal to the flow depth. We conduct several laboratory chute experiments with different native Nepalese complex fruit seeds and food grains to validate the physical significance and scope of Cp0 and L. Our simple analytical models very well describe the coefficient of impact pressure and the mobilization length of the mobile object impacted by the laboratory granular flows. We discuss the applicability of Cp0 and L to real flow situations in designing protective civil defense structures as well as mitigating from natural disasters, and industrial transports of complex granular flows.

Kinematics of nonlinear waves over variable bathymetry. Part I: Numerical modelling, verification and validation

Fluid particle kinematics due to wave motion (i.e. orbital velocities and accelerations) at and beneath the free surface is involved in many coastal and ocean engineering applications, e.g. estimation of wave-induced forces on structures, sediment transport, etc. This work presents the formulations of these kinematics fields within a fully nonlinear potential flow (FNPF) approach. In this model, the velocity potential is approximated with a high-order polynomial expansion over the water column using an orthogonal basis of Chebyshev polynomials of the first kind. Using the same basis, original analytical expressions of the components of velocity and acceleration are derived in this work. The estimation of particle accelerations in the course of the simulation involves the time derivatives of the decomposition coefficients, which are computed with a high-order backward finite-difference scheme in time. The capability of the numerical model in computing the particle kinematics is first validated for regular nonlinear waves propagating over a flat bottom. The model is shown to be able to predict both the velocity and acceleration of highly nonlinear and nearly breaking waves with negligible error compared to the corresponding stream function wave solution. Then, for regular waves propagating over an uneven bottom (bar-type bottom profile), the simulated results are confronted with existing experimental data, and very good agreement is achieved up to the sixth-order harmonics for free surface elevation, velocity and acceleration.

A Novel Friction Compensation Method for Machine Tool Drive Systems in Insufficient Lubrication.

Friction is the dominant factor restricting tracking accuracy and machining surface quality in mechanical systems such as machine tool feed-drive. Hence, friction modeling and compensation is an important method in accurate tracking control of CNC machine tools used for welding, 3D printing, and milling, etc. Many static and dynamic friction models have been proposed to compensate for frictional effects to reduce the tracking error in the desired trajectory and to improve the surface quality. However, most of them focus on the friction characteristics of the pre-sliding zone and low-speed sliding regions. These models do not fully describe friction in the case of insufficient lubrication or high acceleration and deceleration in machine tool systems. This paper presents a new nonlinear friction model that includes the typical Coulomb-Viscous friction, a nonlinear periodic harmonic friction term for describing the lead screw property in insufficient lubrication, and a functional component of acceleration for describing the friction lag caused by the acceleration and deceleration of the system. Experiments were conducted to compare the friction compensation performance between the proposed and the conventional friction models. Experimental results indicate that the root mean square and maximum absolute tracking error can be significantly reduced after applying the proposed friction model.

Generalized threshold of longitudinal multibunch instability in synchrotrons

Beam stability is a crucial requirement for all particle accelerators. Coupled-bunch instability (CBI) is driven by beam interaction with narrowband impedance of the resonant accelerator components. Loss of Landau damping (LLD) for a single bunch is mainly determined by broadband impedance and can lead to undamped bunch oscillations. For the first time, we solve numerically the longitudinal stability problem in a self-consistent way for a general case of two impedance types and propose a simple analytical criterion describing how the obtained LLD and CBI thresholds are combined. We demonstrate that LLD can modify the CBI mechanism and reduce the instability threshold even below the LLD threshold. These findings allow the existing beam observations in CERN Super Proton Synchrotron and Large Hadron Collider to be explained and should be considered in design of the future accelerators. Published by the American Physical Society 2024

The Linac Extension Area at the Advanced Photon Source

The Linac Extension Area has been developed into a beamline area for testing accelerator components and techniques. Beginning commissioning activities in February 2023, we have delivered the first electron beam to the Linac Extension Area at the Advanced Photon Source at 425 MeV. In the present work, we summarise the principal accelerator components and review safety controls of the Linac Extension Area.