Shot Rate Research Articles

Ocular and the whole body radiation exposure during endoscopic retrograde cholangiopancreatography

Objective: This study aimed to analyze the average whole body radiation exposure, which changes significantly according to during endoscopic retrograde cholangiopancreatography (ERCP) difficulty and to determine whether an ocular protection device must be used by analyzing applied ocular radiation. Material and Methods: Patients >18 years of age in whom an ERCP had been indicated were prospectively included in the study. Results: A total of 1173 patients were included. Increased applied radiation dose significantly correlated with increased shot rate (Rho= 0.789, p< 0.001), ERCP duration (Rho= 0.487, p< 0.001), cost (Rho= 0.129, p< 0.001), and LOS (Rho= 0.109, p< 0.001). The whole body, skin, and eye radiation exposure doses were found to be lower than the recommended limit per year (20 mSv/year). Conclusion: Limit of ocular radiation exposure during ERCP did not exceed the recommended annual limit (20 mSv/year), and it was also detected to be much lower than that. Therefore, the use of ocular visors is not recommended.

An analysis of the waning effect of COVID-19 vaccinations.

Vaccine development is one of the key efforts to control the spread of coronavirus disease 2019 (COVID-19). However, it has become apparent that the immunity acquired through vaccination is not permanent, known as the waning effect. Therefore, monitoring the proportion of the population with immunity is essential to improve the forecasting of future waves of the pandemic. Despite this, the impact of the waning effect on forecasting accuracies has not been extensively studied. We proposed a method for the estimation of the effective immunity (EI) rate which represents the waning effect by integrating the second and booster doses of COVID-19 vaccines. The EI rate, with different periods to the onset of the waning effect, was incorporated into three statistical models and two machine learning models. Stringency Index, omicron variant BA.5 rate (BA.5 rate), booster shot rate (BSR), and the EI rate were used as covariates and the best covariate combination was selected using prediction error. Among the prediction results, Generalized Additive Model showed the best improvement (decreasing 86% test error) with the EI rate. Furthermore, we confirmed that South Korea's decision to recommend booster shots after 90 days is reasonable since the waning effect onsets 90 days after the last dose of vaccine which improves the prediction of confirmed cases and deaths. Substituting BSR with EI rate in statistical models not only results in better predictions but also makes it possible to forecast a potential wave and help the local community react proactively to a rapid increase in confirmed cases.

Demonstration of neutron-yield enhancement by laser preheating and magnetization of laser-driven cylindrical implosions

Magnetized liner inertial fusion (MagLIF) is a fusion concept that uses magnetized, preheated fuel to reduce the implosion velocities and convergence ratios required for ignition. A scaled, laser-driven experimental platform to study MagLIF has been demonstrated on the OMEGA laser system, providing comprehensive experimental data on MagLIF scaling, utilizing the higher shot rate on OMEGA compared to the Z machine. Using this platform, a broader experimental space for MagLIF has been studied. Presented in this article are experimental results that demonstrate that the combination of preheat and magnetization enhances the neutron yield by 470% compared to a reference implosion, significantly more than the yield enhancement by the field or preheat alone. These results are achieved while maintaining a relatively low convergence ratio (<20). The experiments were supported by one-, two-, and three-dimensional radiation-hydrodynamics simulations, all of which suggest that multiple sources of mix play different key roles depending on the scale of the MagLIF experiment.

MODELO DE TREINAMENTO ASSISTIDO PARA APERFEIÇOAMENTO DA CESTA DE TRÊS PONTOS NO BASQUETEBOL

ABSTRACT Introduction The outcome of basketball games is based on scoring, and basketball rules are discussed from a qualitative point of view. The three-point basket is the key to the game's success; improving this shot's percentage will ensure success. Objective Explore the key elements of a successful three-point shot, discussing its effective improvements. Methods This paper randomly selects 26 students from a particular basketball class as volunteers for the research. Before starting the experiment, the subjects were divided into control and experimental groups; they were grouped according to their test scores. Four data of three-point shot rate, jump shot, and shot after dribbling are analyzed according to the grouping of players. The data were statistically treated for better appreciation of the results. Results Although the throws improved in both groups, the improvement was insignificant (P>0.05). After nine weeks of exercise, the success rate of three-point baskets in both the experimental and control groups improved. The improvement in the three-point basket was the greatest in the experimental group (P<0.05). Conclusion Functional strength training can significantly improve the rate of long-range 3-point baskets in basketball players. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

EdgeAI: Machine learning via direct attached accelerator for streaming data processing at high shot rate x-ray free-electron lasers

We present a case for low batch-size inference with the potential for adaptive training of a lean encoder model. We do so in the context of a paradigmatic example of machine learning as applied in data acquisition at high data velocity scientific user facilities such as the Linac Coherent Light Source-II x-ray Free-Electron Laser. We discuss how a low-latency inference model operating at the data acquisition edge can capitalize on the naturally stochastic nature of such sources. We simulate the method of attosecond angular streaking to produce representative results whereby simulated input data reproduce high-resolution ground truth probability distributions. By minimizing the mean-squared error between the decoded output of the latent representation and the ground truth distributions, we ensure that the encoding layers and resulting latent representation maintains full fidelity for any downstream task, be it classification or regression. We present throughput results for data-parallel inference of various batch sizes, some with throughput exceeding 100 k images per second. We also show in situ training below 10 s per epoch for the full encoder–decoder model as would be relevant for streaming and adaptive real-time data production at our nation’s scientific light sources.

THE EFFECT OF PROPRIOCEPTIVE TRAINING ON HIGH-INTENSITY ACTIONS AND TECHNIQUE IN FOOTBALL PLAYERS: A TRAINING PROGRAM

It is aimed to determine the level of influence of proprioceptive training applied to young football players on high-intensity actions and footballspecific skills of football players. The research group consists of 30 male football players (age = 15.86 ± 0.69). The participants were divided into 2 groups as proprioceptive training group (PTG) and control group, each consisting of 15 football players. The body height and body weight of the participants were measured. Hand-eye coordination, vertical jump, sprint, agility, and core endurance tests, which are defined as high-intensity actions, were applied to the participants. Dynamic balance performances of the participants were also determined. Passing, ball control and dribbling were measured by international tests to determine the participants' football-specific skills. No significant differences were found between the groups in the comparison of PTG and CG in terms of high-intensity actions (p>0.05). There was also no significant difference in the comparison of the dynamic balance performance of both dominant and non-dominant feet (p>0.05). Significant differences were determined in favor of the PTG group in the variables of football-specific skills such as pass shot rate and the number of ball control (p0.05). As a result, it can be stated that in addition to football training, proprioceptive training contributes positively to the development of skills such as passing and ball control, which we can show among the basic football skills.

Large area ion beam sputtered dielectric ultrafast mirrors for petawatt laser beamlines.

The latest advances in petawatt laser technology within the ELI Beamlines project have stimulated the development of large surface area dielectrically coated mirrors meeting all demanding requirements for guiding the compressed 30 J, 25 fs HAPLS laser beam at 10 Hz repetition rate and a center wavelength of 810 nm entirely in vacuum. We describe the production and evaluation of Ta2O5/HfO2/SiO2 ion beam sputtered coated (440 × 290 × 75) mm3 beam transport mirrors. No crazing was observed after thirty vacuum-air cycles. A laser induced damage threshold of 0.76 J/cm2 (fluence on mirror surface) was achieved and maintained at high shot rates.

Accelerating the rate of discovery: toward high-repetition-rate HED science

As high-intensity short-pulse lasers that can operate at high-repetition-rate (HRR) (>10 Hz) come online around the world, the high energy density (HED) science they enable will experience a radical paradigm shift. The >103 increase in shot rate over today’s shot-per-hour drivers translates into dramatically faster data acquisition, more experiments, and the ability to exploit machine learning, and thus the potential to significantly accelerate the advancement of HED science. A wide range of HED experiments, from opacity investigations to secondary source generation to plasma nuclear physics, will benefit from the increased statistics, precision, and exploration of phase space. Besides increasing the rate at which scientific experiments can be performed, HRR also allows for the rapid delivery of optimal experiments supported by simulations and modeling augmented by close coupling to empirical data. To fully realize such an HRR framework, numerous subsystems must be developed and brought together, including feedback laser control loops, high-throughput targetry and diagnostics, cognitive simulation, enhanced HED codes, and advanced data analytics. This paper describes the vision for an integrated HRR laser experimental HED system and outlines some of the major considerations and challenges for realizing it.

Optimized monolithic edge-cladding glass for N31-type Nd-doped high power laser glass

In this paper, six edge-cladding glasses are prepared and analyzed, which are designed to clad the elliptical disk of N31-type Nd-doped phosphate laser glass by monolithic edge-cladding technique. The transition temperatures, soften temperatures, thermal expansion coefficients, high temperature viscosities and refractive indices of the prepared edge-cladding glasses are determined, which must be consistent with these parameters of N31 glass as possible. The residual stresses and residual reflectivities are determined for the cladded N31 elliptical disks and slab samples, which are the most important parameters for the monolithic edge-cladding technique and must be as low as possible to meet the index requirements for high power laser applications. The interface bubbles, edge-cladding interface and the controllability of divalent Cu2+ ions are also discussed. By the optimized edge-cladding glass, it is verified that the elliptical disk of N31-type Nd-doped phosphate laser glass can be successfully cladded by the optimized monolithic edge-cladding glass, which can be utilized securely in a strong liquid cooling to pursue a better high-power laser performance with a higher laser shot rate.

Review: Production of nuclear medicine radioisotopes with ultra-intense lasers

In the last two decades, there has been a strong research interest in producing radioisotopes with ultra-intense lasers, as an application of laser-driven accelerators in nuclear medicine. Encouraging progress has been obtained in both experiments and simulations. This Review presents the results of several intense studied radioisotopes in detail, i.e., 18F, 11C, 13N, 15O, 99mTc, 64Cu, and 62Cu. As for other less studied radioisotopes, the results are summarized in Sec. II G. The results are listed in Tables I–VII along with laser intensities, maximum ion/photon energies, number of ions/photons per shot, reactions, and laser repetition rates and facilities. For research based on high repetition rate lasers, both single-shot and multi-shot productions are provided for the purpose of comparison. With key technologies implemented in new commissioning ultra-intense lasers, further experiments will definitely help moving this area forward, which will bring the realization of laser-driven radioisotope production closer.

Automated Delivery of Microfabricated Targets for Intense Laser Irradiation Experiments.

Described is an experimental procedure that enables high-power laser irradiation of microfabricated targets. Targets are brought to the laser focus by a closed feedback loop that operates between the target manipulator and a ranging sensor. The target fabrication process is explained in detail. Representative results of MeV-level proton beams generated by irradiation of 600 nm thick gold foils at a rate of 0.2 Hz are given. The method is compared with other replenishable target systems and the prospects of increasing the shot rates to above 10 Hz are discussed.

Plasma-Jet-Driven Magneto-Inertial Fusion

Plasma-jet-driven magneto-inertial fusion (PJMIF) is the only embodiment of magneto-inertial fusion that has the unique combination of stand-off implosion and high implosion velocity (50 to 150 km/s). It uses inexpensive plasma guns for all plasma formation and implosion and has potential for a relatively high repetition rate from 1 to 2 Hz. Its configuration is compatible with the use of a thick liquid wall that doubles as a tritium breeding blanket as well as a coolant for extracting the heat out of the fusion reactor. The PJMIF operational parameter-space allows for the possibility of using a sufficiently dense target plasma for the target plasma to have a high . If such a high- plasma could be realized, it would help to suppress micro and magnetohydrodynamic instabilities, giving its target plasma classical transport and energy confinement characteristics. Its open geometry and moderate time and spatial scales provide convenient diagnostics access. Diagnostics accessibility, high shot rate, and low cost per shot should enable quick resolution of technical issues during development, thus the potential for enabling rapid research and development of PJMIF. There are a number of challenges for PJMIF, however, including being at a very early stage of development, developing the required plasma guns, dealing with potential liner nonuniformities, clearing the chamber of residual high-Z gas between shots, and developing the repetitive pulsed-power component technologies. Over the last 3 years, the development of the Plasma Liner Formation Experiment (PLX-) has been undertaken to explore the physics and demonstrate the formation of a spherical liner by the merging of a spherical array of plasma jets. Two- and three-jet merging experiments have been conducted to study the interactions of the jets. Six- and seven-jet experiments have been performed to form a piece of the plasma liner. A brief status report on this development is provided in this paper.

A gatling-gun target delivery system for high-intensity laser irradiation experiments

Abstract Intense laser irradiation experiments of sub-micrometer scale targets are currently performed at slow shot rates. This limitation is the result of the inability to place such targets quickly and accurately in the focus of the laser. Here we present a target setup that enables irradiation at a high rate and sub-wavelength positioning accuracy. Three hundred targets were micro-machined and mounted on a single Si wafer. The system implements a closed feedback loop between a triangulation displacement sensor and a motorized manipulator. Using this setup, we demonstrate repeatable stable proton acceleration from 600 nm thick Au foils at a rate of 0.2 Hz. This system will enable studies that require a large overall dose, high statistical significance, or a fine scan of target geometric attributes.

Experimental Testing of Targets for a High Accuracy Microtarget Supply (HAMS) System on the Gemini Laser System

It is widely understood within the high-power laser community that recent developments in diode pumped and high repetition rate laser systems will give unprecedented access to laser shots. This will provide a challenge for target fabrication in making enough experimental samples. While in the past access to facilities and shot rates during access periods have been the limiting factor for high power laser experiments this will soon not be the case. There has already been a shift in development of the user base from fundamental science experiments to industrial applications using the laser experiment as a reliable source for secondary aims. The Astra Gemini laser system has been operating at a high repetition rate for high intensity (0.5PW) experiments for a number of years and the Central Laser Facility has developed a target methodology to deliver to the user community the maximum number of solid targets and to fully utilise the available time on the laser. Targets for the High Accuracy Microtarget Supply (HAMS) system have been tested and have been proven to survive in a manner to allow shot rates comparable with the available laser repetition rate (0.1Hz). Investigations into target geometry have been carried out and debris production has been studied by high frame rate camera imaging. The study of the relationship between target geometry and debris production has allowed the design of optimal target support infrastructure, such as aperture size and structure, for high rep rate experiments on the Gemini system.

Process Developments in the Fabrication of Depleted Uranium Hohlraums

Research at General Atomics and Lawrence Livermore National Laboratory has been focused on evaluating depleted uranium (DU) hohlraum fabrication over the past 10 years to improve the yield, thereby increasing the availability of DU hohlruams required to support the increased shot rate at the National Ignition Facility. The more straightforward gold (Au) hohlraum fabrication involves four basic steps: mandrel fabrication, electroplating, back machining and milling, and leaching. For Au, the overall fabrication yield of this process approaches 98% [H. Streckert and K. Blobaum, Fusion Sci. Technol., Vol. 63, p. 213 (2013)] Depleted uranium lined hohlraum fabrication, however, requires deposition of a multilayer of thin films after the mandrel fabrication step. These thin film deposition processes have historically proven difficult to execute on a complex cylindrical geometry of a hohlraum, resulting in unacceptable stress-driven delamination, with net yields ranging 20% to 35% [H. L. Wilkens et al., Phys. Plasmas, Vol. 14, 056310 (2007)]. Recent hohlraum design and fabrication process changes, as well as material selections implemented between 2014 and 2016, have improved the fabrication yield to over 60%. These changes are discussed here as well as plans for future improvements.

Fast gated imaging of the collisionless interaction of a laser-produced and magnetized ambient plasma

The collisionless interaction between a laser-produced carbon plasma (LPP) and an ambient hydrogen plasma in a background magnetic field was studied in a high shot rate experiment which allowed large planar data sets to be collected. Plasma fluorescence was imaged with a fast-gated camera with and without carbon line filters. The resulting images were compared to high-resolution two dimensional (2D) data planes of measured magnetic field and electric potential. Several features in the fluorescence images coincide with features in the field data. Relative intensity was used to determine the initial angular velocity distribution of the LPP and the growth rate of instabilities. These observations may be applied to understand fluorescence images from similar experiments where 2D planes of field data are not available.

Automation of NIF Target Fabrication

The National Ignition Facility (NIF) is on schedule to increase its shot rate after a congressionally mandated efficiency study was enacted to develop strategies for increasing the number of experiments fielded on NIF. The study set an ambitious goal to double the number of shots over a short 2-year period. Through a variety of higher-efficiency means, NIF has geared up and is on track to meet this goal. General Atomics (GA), as a major target and component supplier for NIF, has pursued a number of higher-efficiency studies and enabled higher-throughput systems on its own in order to meet the target requests for the increased shot rate while maintaining the same high-precision level required for every target. Five automation processes have recently been implemented at GA, adding to a large suite of automated metrology, robotics, and laser-machining capabilities.

Unspanned Stochastic Volatility & Conformal Symmetry (Presentation Slides)

We employ conformal symmetries to provide a generic tractable framework for interest rate modelling. The approach combines calibration flexibility of market models with tractability and computational efficiency of shot rate models. The methodology enables robust calibration to the whole variety of caps and swaptions with various expirations, strikes and tenors. In the same time, low dimensionality enables backward induction allowing efficient valuation of bermudan swaptions without resorting to suboptimal American Monte Carlo.

Increasing shot and data collection rates of the Shock/Shear experiment at the National Ignition Facility

Updates to the Los Alamos laser-driven high-energy-density Shock/Shear mixing- layer experiment are reported, which have collectively increased the platform's shot and data acquisition rates. The strategies employed have included a move from two-strip to four-strip imagers (allowing four times to be recorded per shot instead of two), the implementation of physics-informed rules of engagements allowing for the maximum flexibility in a shot's total energy and symmetry performance, and splitting the laser's main drive pulse from a monolithic single pulse equal to all beams into a triply-segmented pulse which minimizes optics damage.

ICStatus and progress of the National Ignition Facility as ICF and HED user facility

Since its completion in 2009, the National Ignition Facility has been operated in support of NNSA's Stockpile Stewardship mission, providing unique experimental data in the high energy density regime. We will describe the progress made by the National Ignition facility in the user office and management, facility capabilities, target diagnostics and diagnostics development. We will also discuss the results of a major effort to increase the shot rate on NIF. An extensive set of projects, developed in conjunction with the HED community and drawing on best practices at other facilities, improved shot rate by over 80% and recently enabled us to deliver 356 target experiments in FY15 in support of the users. Through an updated experimental set-up and review process, computer controlled set-up of the laser and diagnostics and disciplined operations, NIF also continued to deliver experimental reliability, precision and repeatability. New and complex platforms are introduced with a high success rate. Finally we discuss how new capabilities and further efficiency improvements will enable the successful execution of ICF and HED experimental programs required to support the quest for Ignition and the broader Science Based Stockpile Stewardship mission