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Laser-driven neutron sources are routinely produced by the interaction of laser-accelerated protons with a converter. They present complementary characteristics to those of conventional accelerator-based neutron sources (e.g. short pulse durations, enabling novel applications like radiography). We present here results from an experiment aimed at performing a global characterization of the neutrons produced using the Titan laser at the Jupiter Laser Facility (Livermore, USA), where protons were accelerated from 23 m thick plastic targets and directed onto a LiF converter to produce neutrons. For this purpose, several diagnostics were used to measure these neutron emissions, such as CR-39, activation foils, time-of-flight detectors and direct measurement of residual activity in the LiF converters. The use of these different, independently operating diagnostics enables comparison of the various measurements performed to provide a robust characterization. These measurements led to a neutron yield of neutrons per shot with a modest angular dependence, close to that simulated.

We propose an effective scheme to sense charged particles by employing two-color second-order sidebands (TSSs) in a hybrid optomechanical system. This is realized in an optomechanical cavity with a double-oscillator structure, where the Coulomb force acting on two charged oscillators participates in nonlinear optomechanical interaction. With the aid of mechanical mode splitting induced by the Coulomb force, we report that the TSS spectrum can be generated and enhanced when the strong absorption in the transmission spectrum allows the TSS generated pathways to be readily accessed. More importantly, after seeking two correlations between the TSS spectra and the charged particles deposited on the oscillator, we design a dual-parameter sensor to measure the mass and the charge of the external particles simultaneously. Through evaluating the influence of the thermomechanical noise on the optomechanical sensing device, the resolution for detecting the mass and the charge of the measured particles can be identified as δ m ≈ 1.7 × 10 − 18 g and δ Q ≈ 1.6 × 10 − 18 C , respectively. [ABSTRACT FROM AUTHOR]

Superconducting cyclotron can generate high-energy proton beams and are mainly used for radiation therapy of tumors and cancers. In the superconducting cyclotron SC200, the maximum magnetic induction intensity can typically reach up to 4.6 T, and the magnetic field accuracy is 1e-4. Hall probes are commonly used tools for measuring high-intensity magnetic fields. Through comprehensive consideration, this study selects the SENIS Low-Noise Teslameter 3MH5 and Hall probe C to measure the magnetic field. When the magnetic field exceeds the range of 2 T, the measurement accuracy of the Hall probe is less than 1e-4, and the Hall probe needs to be calibrated to improve its measurement accuracy. The Hall probes are calibrated using Swiss METROLAB PT2025 nuclear magnetic resonance (NMR) Tesla instrument and 1062 probe. Based on the calibration principle, a calibration system platform was built, test data were collected, and calibration curves were obtained. At the same time, the calibration data were analyzed through cross-validation experiments using the cubic polynomial fitting method. The results indicate that the test deviation range is from −0.1 g to 0.1 g, and the measurement accuracy can reach 1e-4. In summary, the Hall probe can accurately measure the magnetic field distribution of the superconducting cyclotron. It can provide accurate and important data for the calculation and analysis of particle beam dynamics. [ABSTRACT FROM AUTHOR]

Optical turbidity and acoustic sensors have been widely used in laboratory experiments and field studies to investigate suspended particulate matter concentration over the last four decades. Both methods face a serious challenge as laboratory and in‐situ calibrations are usually required. Furthermore, in coastal and estuarine environments, the coexistence of mud and sand often results in multimodal particle size distributions, amplifying erroneous measurements. This paper proposes a new approach of combining a pair of optical turbidity‐acoustic sensors to estimate the total concentration and sediment composition of a mud/sand mixture in an efficient way without an extensive calibration. More specifically, we first carried out a set of 54 bimodal size regime experiments to derive empirical functions of optical‐acoustic signals, concentrations, and mud/sand fractions. The functionalities of these relationships were then tested and validated using more complex multimodal size regime experiments over 30 optical‐acoustic pairs of 5 wavelengths (420, 532, 620, 700, 852 nm) and six frequencies (0.5, 1, 2, 4, 6, 8 MHz). In the range of our data, without prior knowledge of particle size distribution, combinations between optical wavelengths 620–700 nm and acoustic frequencies 4–6 MHz predict mud/sand fraction and total concentration with the variation <10% for the former and <15% for the later. The results also suggest that acoustic‐acoustic signals could be combined to produce meaningful information regarding concentration and mud/sand fraction, while no useful knowledge could be extracted from a combination of optical‐optical pairs. This approach therefore enables the robust estimation of suspended sediment concentration and composition, which is particularly practical in cases where calibration data is insufficient. Plain Language Summary: Crucial decisions to govern the development of an estuary, delta, or coastal zone often rely heavily on the knowledge of where sediment accumulates. Such knowledge primarily comes from long‐term, high‐frequency monitoring of the transport of mud and sand particles in the water column. Optical or acoustic sensors are usually used for this task. Optical/acoustic sensors emit a light/sound beam to the particles and then measure the strength of the reflecting signals to estimate the concentration of the suspension. Since particles with different shape, size, and density respond differently to the light/sound signals, intensive calibrations are required whenever there is a significant change in the water column, for example, during a tidal cycle, seasonal variations between summer and winter. To avoid these tedious calibrations processes, we experimentally show that combination of optical and acoustic sensors in one measurement will help to derive empirical functions which in turn allow us to estimate the ratio of mud/sand and total concentration. Key Points: A new approach of coupling uncalibrated optical and acoustic signals to predict mud/sand fraction and total concentration was proposedWe experimentally show that without knowledge of the suspension estimations of mud/sand ratio and concentration can be as accurate as 10%–15%The new approach is particularly useful in cases where calibration data is insufficient or impractical [ABSTRACT FROM AUTHOR]

The possibility of increasing the current density of a charged particle beam (focusing) by means of tapered glass channels without the use of external energy sources is actively translated into action today for positively charged ions. For electron beams, this possibility is not realized due to the lack of experimental data on the sliding interaction between electron beams and a dielectric surface. It is necessary to examine the compression of an electron beam by tapered capillaries depending on their geometrical parameters, as well as to study the temporal characteristics of the focusing process. In this work, the authors experimentally studied the compression of a 10 keV electron beam using a 15-mm-long tapered glass channel with an inlet-to-outlet inside diameter ratio of 1.15 mm/0.30 mm. The beam current density is shown to increase at the outlet of the capillary with the specified parameters by up to a factor of 2.7 for the position where the channel axis is parallel to that of the initial beam. This density increase is estimated for electrons that have lost no more than 1 keV of initial energy. It is also shown that the process of electron transmission by a tapered capillary is stable regardless of the orientation of the capillary with respect to the direction of the initial beam. [ABSTRACT FROM AUTHOR]

The numerical simulation of boundary value problems involving a high number of pile-type structures, such as pile foundation systems of high-rise buildings, represents a standard task in computational geotechnics. Due to their ability to simplify the underlying pile modeling process and decrease the simulation runtime embedded beam formulations (EBFs) have attracted widespread interest from the geotechnical community. State-of-the art EBFs are typically equipped with nonlinear interface constitutive models to capture the soil–structure interaction behavior with reasonable accuracy. However, reliable information concerning the calibration of related parameters is limited, which decreases the confidence in the results obtained with EBFs. The present work addresses this research aspect for the first time, along with a theoretical discussion of inherent simplifications in the numerical description of the soil–structure contact associated with EBFs. The significance of selecting adequate embedded interface constitutive model parameters to ensure EBF predictions with high credibility is demonstrated by means of parametric studies. This has motivated the development of an automatic calibration software, leveraged by particle swarm optimization, that provides guidance in selecting suitable values. The effectiveness of the calibration software is confirmed by back-calculation of different pile problems with default and calibrated parameter sets. Likewise, the results provide insight into crucial factors driving the calibration framework, with a view to increasing its potential for take-up in engineering practice. Potential lines of research in the context of the automatic calibration software are explored throughout this work and may serve as valuable reference in future research. Practical Applications: The design of geotechnical problems involving a high number of pile-type structures, such as pile foundation systems of high-rise buildings or wind turbines, is routinely assisted by finite-element analyses. The computational expense of these simulations is significantly influenced by the pile modeling technique. Due to their exceptional ability to simplify the underlying modeling process and reduce the runtime to an acceptable limit, embedded beam formulations have therefore attracted widespread interest for geotechnical design tasks. As with all soil–structure interaction problems, it is essential in embedded beam formulations to accurately describe the interface behavior between the soil and the structure. This work presents the first attempt to highlight the relevance of this concern and visually describes relevant limitations resulting from an inadequate selection of interface constitutive model parameters. This observation has motivated the development of an automatic calibration software to increase the confidence in the parameter selection. The high potential of this software to increase the credibility of numerical predictions obtained with embedded beam formulations is demonstrated based on pile problems with different soil stratification layers, pile geometries, and pile arrangements. In all cases considered, the results confirm that the numerical fidelity could be significantly increased by employing calibrated parameter sets. [ABSTRACT FROM AUTHOR]

Using high-speed laser melt injection (HSLMI), it is possible to generate wear-resistant metal matrix composite (MMC) surfaces on tools with great productivity. Since high laser intensities are required for reaching high process speeds, strong interactions can occur between powder particles and the laser beam. In order to reduce the interaction time and gain a better understanding of the role of particle transport in the HSLMI process, trajectories of spherical fused tungsten carbide (SFTC) particles were analyzed using high-speed imaging. The trajectories were divided into a path outside the laser beam and a path inside the laser beam. The identified interaction mechanisms were particle deformations, the formation of agglomerates, and particle disintegration. The volume flow rate of the feeding gas was found to have a decisive influence on the travel time of the particles, whereas the powder feed rate and the working distance of the powder nozzle only had a minor influence. Consequently, an increased volume flow rate led to a significant reduction of interactions between SFTC particles and the laser beam. [ABSTRACT FROM AUTHOR]

A dilute plasma is continuously maintained in the troposphere by ionising particle radiation from galactic cosmic rays and radon decay. Small ions in the 1–2 nm size range play an important role in atmospheric processes such as ion-induced nucleation of aerosol particles. Consequently there is a need for precise and robust instruments to measure small ions both for atmospheric observations and for laboratory experiments that simulate the atmosphere. Here we describe the design and performance of the Cluster Ion Counter (CIC, Airel OÜ), which simultaneously measures the number concentrations of positively- and negatively-charged ions and particles below 5 nm mobility diameter, with low noise and fast time response. The detection efficiency is above 80 % for ions and charged particles between 1.2 and 2.0 nm, and above 90 % between 2.0 and 3.0 nm. The ion concentrations measured by the CIC agree well with reference instruments. The noise level (1 σ of background measurements) is typically between 20 and 30 ions cm-3 at 1 Hz sampling rate and an air flow rate of 7 l min-1 per analyzer. The noise level improves when higher flow rates and longer sampling periods are used. The CIC responds rapidly with 1 s time resolution to pulses of ionisation produced in the CLOUD chamber by a CERN particle beam. [ABSTRACT FROM AUTHOR]

Relativistic charged particle beam can be used as a destructive beam weapon in space for debris removal tasks. The trajectories of charged particles are affected by both electric and magnetic forces in the Earth's magnetic field. In this paper, we firstly analyzed the correlation parameters of the charged particle beam as a weapon when it is propagated in the geomagnetic field. Then, the models were constructed based on COMSOL Multiphysics, and the IGRF model was adopted in the simulation. The gyroradius and the related uncertainty were analyzed by simulation of the charged particle transport in the geomagnetic field at different altitudes. The charged beam spot radius divergency was also simulated. The geomagnetic field can inhibite the diffusion of the electron beam. [ABSTRACT FROM AUTHOR]

The joint use of hourly resolution sampling and analyses with accelerated ion beams such as Particle Induced X-ray Emission (PIXE) technique has allowed the measurement of hourly temporal patterns of particulate matter (PM) composition at many sites in different parts of the world. The demand within the scientific community for this type of analysis has been continuously increasing in recent years, but hourly resolution samplers suitable for PIXE analysis are now discontinued and/or suffer from some technical limitations. In this framework, a new hourly sampler, STRAS (Size and Time Resolved Aerosol Sampler), was developed for the collection of PM10, PM2.5 or PM1. It allows automatic sequential sampling of up to 168 hourly samples (1 week), it is mechanically robust, compact, and easily transportable. To increase PIXE sensitivity, each sample is concentrated on a small surface area on a polycarbonate membrane. The comparison between the elemental concentrations retrieved by STRAS samples and samples collected using a standard sequential sampler operated in parallel shows a very good agreement; indeed, if both the samplers use the same kind of membrane, the concentrations of all detected elements are in agreement within 10 %. [ABSTRACT FROM AUTHOR]

Solar type V radio bursts are associated with type III bursts. Several processes have been proposed to interpret the association, electron distribution, and emission. We present the observation of a unique type V event observed by e-CALLISTO on 7 May 2021. The type V radio emission follows a group of U bursts. Unlike the unpolarized U bursts, the type V burst is circularly polarized, leaving room for a different emission process. Its starting edge drifts to higher frequency four times slower than the descending branch of the associated U burst. The type V processes seem to be ruled by electrons of lower energy. The observations conform to a coherent scenario where a dense electron beam drives the two-stream instability (causing type III emission) and, in the nonlinear stage, becomes unstable to another instability, previously known as the electron firehose instability (EFI). The secondary instability scatters some beam electrons into velocities perpendicular to the magnetic field and produces, after particle loss, a trapped distribution prone to electron cyclotron masering (ECM). A reduction in beaming and the formation of an isotropic halo are predicted for electron beams continuing to interplanetary space, possibly observable by Parker Solar Probe and Solar Orbiter. [ABSTRACT FROM AUTHOR]

In the centre of mass frame, we have investigated the electroweak process e + e - → μ + μ - in the presence of a plane and monochromatic laser wave of linear polarization. We provide the theoretical calculations of the differential cross-section for this process by using the scattering-matrix approach and Dirac-Volkov formalism. The laser-assisted cross-section is computed, and its dependence on the laser parameters is analyzed. We have found that this cross-section increases significantly inside a linearly polarized laser wave co-propagating with the incident particle's beam, and it passes its corresponding laser-free cross-section by several orders of magnitude. [ABSTRACT FROM AUTHOR]

This article provides an overview of the concept of quark/gluon plasma (QGP), a state of matter that existed in the early universe and can be recreated in high-energy particle collisions. It explains that QGP can be observed through experimental signatures such as enhanced strange quark production and suppressed jet production. The article also discusses the history of QGP research, from its announcement in 2000 to ongoing measurements at accelerators like RHIC and LHC. It concludes by acknowledging that there is still much to be learned about QGP and its properties. [Extracted from the article]

We outline a method of beamed power for propulsion that utilizes relativistic electron beams. The physics of charged particle beam propagation in the space plasma environment is discussed and the long-range (> 100 AU) advantage of relativistic electron beams is emphasized. A preliminary statite-based beam emitter for powering probes to 0.1c is proposed and the challenges in beamed-power uses are explored. • The potential for a relativistic electron beam to have dramatically longer beam ranges than other forms of beam-driven propulsion is revealed • The propagation of the beam through the space plasma is discussed and areas for further work identified • It is shown that the longer range of the beam permits interstellar probes to be driven to relevant speeds above 0.1c with feasible power levels in the GW class for implementation. • The key remaining obstacle, the conversion from the electron beam to rocket thrust, is identified and some possible approaches discussed • A path to implementation, using plasma sailing to hover the beam platform near the sun, and thermoelectric power conversion to generate the power for the beam, is presented. [ABSTRACT FROM AUTHOR]

Space debris poses a great threat to space stations. When a collision hazard is detected, the space station's orbit should be adjusted. An alternative approach is to apply collision avoidance measures that consist in creating an external impact on the space debris object to change its orbit and increase the miss distance slightly. Such an impact can be carried out using a ground-based or orbital laser, through the use of nano-tugs thrusters, or by placing a cloud of particles in the path of the object. This study proposes to use the plume of a thruster of an active spacecraft called an Ion Beam Interceptor. When a potential collision is detected, the interceptor undocks from the space station, approaches the space debris object and directs an ion beam, which is generated by the spacecraft's thrusters, at it. Hitting into the surface of the object, the particles of the ion beam exert a force effect on it, which leads to the required change in the orbit. After the completion of the maneuver, the interceptor returns to the space station for refueling and servicing. The objective of the study is a preliminary assessment of the feasibility and effectiveness of the proposed approach of protecting a space station from space debris impact using an active spacecraft. A mission profile of the space station protection is proposed. A series of numerical simulations are performed to determine mission parameters and fuel costs. Based on an analysis of the orbits of space objects located near the space station, the maximum angle between the orbital planes of the dangerous object and the station are determined at which it is advisable to use the Ion Beam Interceptor. The developed concept also allows to implement just-in-time collision avoidance measures for space debris objects whose orbital planes are close to the plane of the space station. • The concept of the Ion Beam Interceptor spacecraft designed to protect the space station from a predicted collision is developed. • A series of calculations were carried out to analyze the possibility of protecting the international space station from potentially dangerous objects. • The developed mission can be effectively used to protect the International Space Station from objects whose orbit is deviated from the station's orbit by no more than 0.23 rad. • The concept makes it possible to implement just-in-time collision avoidance measures for space debris objects in the above range of orbits in LEO. [ABSTRACT FROM AUTHOR]

In various electron-optical and ion-beam devices and vacuum electronics installations, emission elements and units are used to extract and form beams of charged particles. Their focusing properties significantly affect the quality parameters and technical characteristics of the analytical devices and technological installations in which they are used. Due to the specificity of the initial conditions during the formation of the beams of charged particles in the area of charged particle extraction, the methods of studying single and conventional immersion electron lenses are not suitable for the high quality theoretical and numerical studies of the properties of immersion objectives. In this paper, theoretical and numerical studies were conducted on the problems in analyzing the focusing parameters of charged particles in emission elements and units when solving problems of designing and upgrading devices and installations of vacuum electronics. As a result of the studies, a theoretical method for studying cathode lenses with a curved optical axis was developed and options for solving problems in correcting aberrations of emission elements and units were proposed. [ABSTRACT FROM AUTHOR]

The goal of this work is to characterize the secondary neutron spectra produced by 1 GeV/u56Fe beam colliding with a thick cylindric aluminum target and to perform a quantitative comparison with simulated results obtained with Monte Carlo codes. The measurements were performed using extended-range Bonner sphere spectrometers at two positions (15° and 40°) with respect to the beam direction. The secondary radiation field was simulated using four Monte Carlo codes (FLUKA, MCNP6, Geant4 and PHITS) and several physical models of nuclei transport and interaction. Neutron and proton energy distributions were simulated for the experimental measurement positions. The simulated neutron spectra, together with data measured with Bonner sphere spectrometers, after carrying out the correction of the contributions induced by the secondary protons, were used as input for the MAXED spectrum unfolding code to obtain the measured neutron spectra. Unfolded neutron spectra were compared with simulated ones to carry out a quantitative analysis of the performance of the chosen Monte Carlo codes and their corresponding physical models. This comparison showed that, because of experimental uncertainties and physical models, there are no unique solutions for each measurement location, but a range of solutions where the true experimental neutron spectra probably lie. The results showed deviations between 4.23% and 8.42% for some simulated spectra. Regarding the total integral values of neutron fluence and ambient equivalent dose, the unfolded neutron spectra showed deviations lower than 2%. [ABSTRACT FROM AUTHOR]

We present a brief survey of problem formulations related to high-speed beams with emphasis on analytical solutions. Additionally, numerical solutions for some problems of this class are described. Within the framework of kinetic theory, the analytical method is used to consider the interaction of groups of particles (molecules) assuming that the particles' velocities are highly correlated (delta function is used as a distribution density). The problems of beam interaction with and without loss of particles are studied numerically using direct statistical Monte Carlo simulation. For the problem with loss of particles (intersection and interaction of thin beams), good agreement with the analytical solution is obtained. For the problem without loss of particles (collision of flows), we obtain a numerical solution of the type of a traveling shock wave of limiting compression that is formed when the flow collides with a wall. The role of collision transforms at the initial stage of the process is shown. The problem of beam penetration into a stationary gas up to the stage of plume formation is considered, and a similarity of its initial stage with the problem of thin beams is noted. It is emphasized that analytical methods are fruitful as applied to primary analysis of problems and to the verification of numerical solutions. [ABSTRACT FROM AUTHOR]

Background: In radiotherapy, it is essential to deliver prescribed doses to tumors while minimizing damage to surrounding healthy tissue. Accurate measurements of absorbed dose are required for this purpose. Gafchromic® external beam therapy (EBT) radiochromic films have been widely used in radiotherapy. While the dosimetric characteristics of the EBT3 model film have been extensively studied for photon and charged particle beams (protons, electrons, and carbon ions), little research has been done on α$\alpha$‐particle dosimetry. α$\alpha$‐emitting radionuclides have gained popularity in cancer treatment due to their high linear energy transfer, short range in tissue, and ability to spare surrounding organs at risk, thereby delivering a more localized dose distribution to the tumor. Therefore, a dose‐calibration film protocol for α$\alpha$‐particles is required. Purpose: This study aimed to develop a dose‐calibration protocol for the α$\alpha$‐particle emitting radionuclide 241Am, using Monte Carlo (MC) simulations and measurements with unlaminated EBT3 films. Methods: In this study, a MC‐based user code was developed using the Geant4 simulation toolkit to model and simulate an 241Am source and an unlaminated EBT3 film. Two simulations were performed: one with voxelized geometries of the EBT3 active volume composition and the other using water. The dose rate was calculated within a region of interest in the voxelized geometries. Unlaminated EBT3 film pieces were irradiated with the 241Am source at various exposure times inside a black box. Film irradiations were compared to a 6‐MV photon beam from a Varian TrueBeam machine. The simulated dose rate was used to convert the exposure times into absorbed doses to water, describing a radiochromic‐film‐based reference dosimetry protocol for α$\alpha$‐particles. The irradiated films were scanned and through an in‐house Python script, the normalized pixel values from the green‐color channel of scanned film images were analyzed. Results: The 241Am energy spectra obtained from the simulations were in good agreement with IAEA and NIST databases, having differences <$<$0.516% for the emitted γ$\gamma$‐rays and produced characteristic x‐rays and <$<$0.006% for the α$\alpha$‐particles. Due to the short range of α$\alpha$‐particles, there was no energy deposition in the voxels outside the active 241Am source region projected onto the film surface. Thus, the total dose rate within the voxels covering the source was 0.847 ±$\pm$ 0.003 Gy/min within the sensitive layer of the film (LiPCDA) and 0.847 ±$\pm$ 0.004 Gy/min in water, indicating that the active volume can be considered water equivalent for the 241Am beam quality. A novel approach was employed in α$\alpha$‐film dosimetry using an exponential fit for the green channel, which showed promising results by reducing the uncertainty in dose estimation within 5%. Although the statistical analysis did not reveal significant differences between the 6‐MV photon beam and the α$\alpha$ calibration curves, the dose–response curves exhibited the expected behavior. Conclusions: The developed MC user code simulated the experimental setup for α$\alpha$‐dosimetry using radiochromic film with acceptable uncertainty. Unlaminated EBT3 film is suitable for the dosimetry of α$\alpha$‐radiation at low doses and can be used in conjunction with other unlaminated GafChromic® films for quality assurance and research purposes. [ABSTRACT FROM AUTHOR]

There are numerous instabilities present in charged particle beams that undergo exponential growth and reach saturation. In various applications, such as free-electron lasers or micro-bunching light sources, achieving saturation is desirable. Conversely, there are applications where these instabilities are utilized as linear broad-band amplifiers for signals embedded in the charged beam. In the latter scenario, the saturation of an instability induces non-linear distortions in the imprinted signal, thereby limiting the useful range of such amplifiers. Accurate evaluation of these instabilities necessitates a complete and comprehensive modeling approach that includes shot noise within the beam. Unfortunately, such modeling is not always feasible or practical. In this paper, we introduce a methodology utilizing the frequency and bandwidth of the instability as key parameters. Through this, we derive an estimation for the range of linear instability growth. Our derivation is conducted in a model-independent manner, making it applicable to a broad spectrum of instabilities. To validate our approach, we employ established and thoroughly benchmarked simulations with a free electron laser (FEL) code as well as self-consistent 3-dimensional simulation of plasma-cascade instability using code SPACE. [ABSTRACT FROM AUTHOR]

We present theoretical estimates of the electrical charge and electrostatic surface potentials on debris objects orbiting in the LEO and GEO regions of the Earth's ionosphere. The estimates are obtained using analytic calculations based on an improved Orbital Motion Limited model as well as through numerical Particle-In-Cell simulations using the open-source SPIS code. A variety of shapes, sizes, and material compositions of the debris objects are considered, including HAMR objects with a high area-to-mass ratio and objects composed of insulating and conducting material patches. In the GEO region, we consider the charging arising from photo-emission effects and the impact of energetic charged particle beams associated with solar flares. We discuss the nature of the debris-induced collective excitations in the plasma and their potential use for debris detection. • Measurement of charge and surface potential on space debris in LEO and GEO regions. • Comparison of debris charging using OML theory and Particle-In-Cell simulations. • Collective excitations due to charged debris. [ABSTRACT FROM AUTHOR]

Plasma focus devices represent a class of hot and dense plasma sources that serve a dual role in fundamental plasma research and practical applications. These devices allow the observation of various phenomena, including the z-pinch effect, nuclear fusion reactions, plasma filaments, bursts, shocks, jets, X-rays, neutron pulses, ions, and electron beams. In recent years, considerable efforts have been directed toward miniaturizing plasma focus devices, driven by the pursuit of both basic studies and technological advancements. In this paper, we present the design and construction of a compact, portable pulsed plasma source based on plasma focus technology, operating at the ~2–4 Joule energy range for versatile applications (PF-2J: 120 nF capacitance, 6–9 kV charging voltage, 40 nH inductance, 2.16–4.86 J stored energy, and 10–15 kA maximum current at short circuit). The components of the device, including capacitors, spark gaps, discharge chambers, and power supplies, are transportable within hand luggage. The electrical characteristics of the discharge were thoroughly characterized using voltage and current derivative monitoring techniques. A peak current of 15 kiloamperes was achieved within 110 nanoseconds in a short-circuit configuration at a 9 kV charging voltage. Plasma dynamics were captured through optical refractive diagnostics employing a pulsed Nd-YAG laser with a 170-picosecond pulse duration. Clear evidence of the z-pinch effect was observed during discharges in a deuterium atmosphere at 4 millibars and 6 kilovolts. The measured pinch length and radius were approximately 0.8 mm and less than 100 μm, respectively. Additionally, we explore the potential applications of this compact pulsed plasma source. These include its use as a plasma shock irradiation device for analyzing materials intended for the first wall of nuclear fusion reactors, its capability in material film deposition, and its utility as an educational tool in experimental plasma physics. We also show its potential as a pulsed plasma thruster for nanosatellites, showcasing the advantages of miniaturized plasma focus technology. [ABSTRACT FROM AUTHOR]

Advanced accelerator-based light sources such as free electron lasers (FEL) accelerate highly relativistic electron beams to generate incredibly short (10s of femtoseconds) coherent flashes of light for dynamic imaging, whose brightness exceeds that of traditional synchrotron-based light sources by orders of magnitude. FEL operation requires precise control of the shape and energy of the extremely short electron bunches whose characteristics directly translate into the properties of the produced light. Control of short intense beams is difficult due to beam characteristics drifting with time and complex collective effects such as space charge and coherent synchrotron radiation. Detailed diagnostics of beam properties are therefore essential for precise beam control. Such measurements typically rely on a destructive approach based on a combination of a transverse deflecting resonant cavity followed by a dipole magnet in order to measure a beam's 2D time vs energy longitudinal phase-space distribution. In this paper, we develop a non-invasive virtual diagnostic of an electron beam's longitudinal phase space at megapixel resolution (1024 × 1024) based on a generative conditional diffusion model. We demonstrate the model's generative ability on experimental data from the European X-ray FEL. [ABSTRACT FROM AUTHOR]

The emerging technique of neutral beam microscopy offers a non-perturbative way of imaging surfaces of various materials which cannot be studied using conventional microscopes. Current neutral beam microscopes use either diffractive focusing or pin-hole scanning to achieve spatial resolution, and are characterised by a strong dependence of the imaging time on the required resolution. In this work we introduce an alternative method for achieving spatial resolution with neutral atom beams which is based on manipulating the magnetic moments of the beam particles in a gradient field, and is characterised by a much weaker dependence of the imaging time on the image resolution. The validity of the imaging approach is demonstrated experimentally by reconstructing one dimensional profiles of the beam which are in good agreement with numerical simulation calculations. Numerical simulations are used to demonstrate the dependence of the signal to noise on the scan resolution and the topography of the sample, and assess the broadening effect due to the spread of velocities of the beam particles. The route towards implementing magnetic encoding in high resolution microscopes is discussed. An alternative approach for achieving resolution in neutral beam microscopes is presented. The reciprocal space approach involves magnetically manipulating the spin of the beam atoms to encode their position and offers favourable scaling of the measurement time with the image resolution. [ABSTRACT FROM AUTHOR]

Particle accelerators are complex systems that focus, guide, and accelerate intense charged particle beams to high energy. Beam diagnostics present a challenging problem due to limited non-destructive measurements, computationally demanding simulations, and inherent uncertainties in the system. We propose a two-step unsupervised deep learning framework named as Conditional Latent Autoregressive Recurrent Model (CLARM) for learning the spatiotemporal dynamics of charged particles in accelerators. CLARM consists of a Conditional Variational Autoencoder transforming six-dimensional phase space into a lower-dimensional latent distribution and a Long Short-Term Memory network capturing temporal dynamics in an autoregressive manner. The CLARM can generate projections at various accelerator modules by sampling and decoding the latent space representation. The model also forecasts future states (downstream locations) of charged particles from past states (upstream locations). The results demonstrate that the generative and forecasting ability of the proposed approach is promising when tested against a variety of evaluation metrics. [ABSTRACT FROM AUTHOR]

In the present work, we extend the results of a previous investigation on the dynamics of electrons under the action of an inverse free-electron-laser scheme (Almansa et al. , Phys. Plasmas , vol. 26, 2019, 033105). While the former work examined electrons as single test particles subject to the combined action of a modulated wiggler plus a laser field, we now look at electrons as composing a particle beam, where collective space-charge effects are relevant and included in the analysis. Our previous work showed that effective acceleration is achieved when the initial velocities of the particles are close enough to the phase velocity of the beat-wave mode formed by the laser and the wiggler fields. Electrons are then initially accelerated by a ponderomotive uphill effect generated by the beat mode and, once reaching the phase velocity of the beat, undergo a final strong resonant acceleration step resembling a catapult effect. The present work shows that, under proper conditions, space-charge effects play a similar role as the initial (or injected) velocity of the beam. Even if acceleration is absent when space charge is neglected, it may be present and effective when charge effects are taken into account. We also discuss how far the space charge can grow without affecting the sustainability of the acceleration process. [ABSTRACT FROM AUTHOR]

This study documents several correlations observed during the first run of the plasma wakefield acceleration experiment E300 conducted at FACET-II, using a single drive electron bunch. The established correlations include those between the measured maximum energy loss of the drive electron beam and the integrated betatron X-ray signal, the calculated total beam energy deposited in the plasma and the integrated X-ray signal, among three visible light emission measuring cameras and between the visible plasma light and X-ray signal. The integrated X-ray signal correlates almost linearly with both the maximum energy loss of the drive beam and the energy deposited into the plasma, demonstrating its usability as a measure of energy transfer from the drive beam to the plasma. Visible plasma light is found to be a useful indicator of the presence of a wake at three locations that overall are two metres apart. Despite the complex dynamics and vastly different time scales, the X-ray radiation from the drive bunch and visible light emission from the plasma may prove to be effective non-invasive diagnostics for monitoring the energy transfer from the beam to the plasma in future high-repetition-rate experiments. [ABSTRACT FROM AUTHOR]

The High-Luminosity Large Hadron Collider (HL-LHC) project aims to improve the performance of the LHC by increasing the proton–proton collision luminosity. New physics discoveries will be possible starting in 2027. The HL-LHC aims to improve the integrated luminosity by a factor of 10 concerning the current running LHC's design value. The HL-LHC project foresees delivering proton–proton collisions at 14 TeV CM (Center of Mass) energy providing the integrated luminosity to a value of 3 ab−1 for the ATLAS and CMS experiments, 50 fb−1 for LHCb, and 5 fb−1 for ALICE. The increased integrated luminosity for the above LHC experiments will provide the potential to discover rare processes while improving these measurements' signal-to-noise (S/N) ratio statistics. The ATLAS muon spectrometer has been upgraded to face the challenges of the luminosity at the HL-LHC run. The new sub-detectors are as follows: The New Small Wheel (NSW) has replaced the Cathode Strip Chambers (CSC) discs at the internal part of the ATLAS end cups. The new integrated small Monitored Drift Chambers (sMDT) with the Resistive Plate Chambers (RPC) are installed at the outer end of the ATLAS BI (Barrel Inner) layer, in the barrel–endcap transition region, at 1.0 < |η| < 1.3, where η is the pseudo-rapidity (pseudo-rapidity η is a commonly used spatial coordinate describing the angle of a particle relative to the beam axis, defined as η = − l n t a n θ 2 , where θ is the angle between the vector momentum p → and the positive direction of the beam axis). The NSW is an innovative technological achievement, including the MicroMegas (MM) gas detectors in large areas and small-strip Thin Gap Chambers (sTGC), enabling high pT (high pT is the high value of the particles' transverse momentum versus the beam collision axis) trigger and muon detection. The muon reconstruction, the background rate, other spectrometer parameters, and the NSW performance are also presented. [ABSTRACT FROM AUTHOR]

The evaluation and deduction of recommended cross section values allowing extension of the database to monitor energy and intensity parameters of charged particle beams is presented. Included are 53 charged particle (p, d, 3He, 4He) induced reactions on suited C, Al, Ti, Fe, Ni, Cu, Nb and Au targets. The new data allow more systematic simultaneous use of multiple reactions on the same target and promote the backings of electrodeposited and sedimented targets as monitoring aids. Where possible the energy range is extended to above 100 MeV. Integral yield curves over the studied energy range are derived and compared to experimentally measured yields at specific energy points. A comparison with the theoretical excitation curve prediction of the TALYS-code as available in the TENDL 2021–2023 libraries is shown. [ABSTRACT FROM AUTHOR]

Damages induced on the tungsten surface at two different operating conditions of a kilojoule plasma focus device are studied. In one condition, the tungsten samples were exposed to axial plasma shocks that are formed after pinch disruption, and in the other condition, the pinch phenomenon was absent or weak. Melting, craters, and cracking on the surfaces were observed in both cases. In the former case, the charged particle beams and post-pinch material ejection will play a role in impacting the surface; however, in the latter case those phenomena will have small contributions because of the absence or weak formation of the pinch. A damage factor of ∼ 10 9 W m−2 s0.5 was estimated at a distance of 3 cm from the pinch exit using the method given in Akel et al. [J. Fusion Energy 35, 694–701 (2016)] and Klimov et al. [J. Nucl. Mater. 390, 721–726 (2009)] for the former case. The present work suggests that at pressures lower than the pinch-occurring pressure, only axial plasma shock effects on the targeted surface can be studied and that they can be separated from the effects produced by the charged particle beams mixed with axial plasma shocks in the case of pinch occurrence. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Electromagnetic scattering is a routine tool for rapid, non-contact characterization of particle media. In previous work, the interaction targets of scattering intensity, scattering efficiency, and extinction efficiency of Bessel pincer light-sheet beams were all aimed at dielectric spheres. However, most particles in nature are charged. Considering the boundary condition on a charged sphere, the beam shape coefficients (BSCs) ( p m n , q m n ) of the charged spherical particle illuminated by a Bessel pincer light-sheet beam are obtained. The extinction, scattering, and absorption efficiencies are derived under the generalized Lorenz–Mie theory (GLMT) framework. This study reveals the significant differences in scattering characteristics of Bessel pincer light-sheet beams on a charged particle compared to traditional beams. The simulations show a few apparent differences in the far-field scattering intensity and efficiencies between charged and natural spheres under the influence of dimensionless size parameters. As dimensionless parameters increase, the difference between the charged and neutral spheres decreases. The effects of refractive index and beam parameters on scattering, extinction, and absorption coefficients are different but tend to converge with increasing dimensionless parameters. When applied to charged spheres with different refractive indices, the scattering, extinction, and absorption efficiencies of Bessel pincer light-sheet beams change with variations in surface charge. However, once the surface charge reaches saturation, these efficiencies become stable. This study is significant for understanding optical manipulation and super-resolution imaging in single-molecule microbiology. [ABSTRACT FROM AUTHOR]

The selective control and manipulation of nanoparticles require developing and researching new methods for designing optical tweeters, mainly based on a photonic hooks (PHs) effect. This paper first proposes a tunable PH in which a structured beam illuminates an anisotropic cutting liquid crystal microcylinder based on the Finite-DifferenceTime-Domain (FDTD) method. The PHs generated by plane wave, Gaussian, and Bessel beam are analyzed and compared. The impact of beams and LC particle parameters on the PHs are discussed. Where the influence of the extraordinary refractive index ( n e ) on PHs is emphasized. Our results reveal that introducing birefringence can change the bending direction of PH. Besides, the maximum intensity of the PHs increases as n e increases regardless of the beam type. The PH generated by a plane wave has a higher maximum intensity and smaller FWHM than that generated by the Gaussian and Bessel beams. The smallest FWHM and maximum intensity of the PHs generated by the Gaussian falls between that generated by the plane wave and the Bessel beam. The PH generated by a Bessel beam has the minor maximum intensity and the largest FWHM. Still, it exceeds the diffraction limit and exhibits bending twice due to its self-recovery property. This paper provides a new way to modulate PH. This work offers novel theoretical models and the degree of freedom for the design of PHs, which is beneficial for the selective manipulation of nanoparticles. It has promising applications in Mesotronics and biomedicine. [ABSTRACT FROM AUTHOR]

Modern science is dependent on imaging on the nanoscale, often achieved through processes that detect secondary electrons created by a highly focused incident charged particle beam. Multiple types of measurement noise limit the ultimate trade-off between the image quality and the incident particle dose, which can preclude useful imaging of dose-sensitive samples. Existing methods to improve image quality do not fundamentally mitigate the noise sources. Furthermore, barriers to assigning a physically meaningful scale make the images qualitative. Here, we introduce ion count-aided microscopy (ICAM), which is a quantitative imaging technique that uses statistically principled estimation of the secondary electron yield. With a readily implemented change in data collection, ICAM substantially reduces source shot noise. In helium ion microscopy, we demonstrate 3x dose reduction and a good match between these empirical results and theoretical performance predictions. ICAM facilitates imaging of fragile samples and may make imaging with heavier particles more attractive. [ABSTRACT FROM AUTHOR]

Vibration is always present in our environment at some level. It can have a deleterious effect on all types of microscopes and should always be considered when installing a microscope in a facility. Some microscope manufacturers, particularly those who make charged electron or particle beam microscopes, have detailed vibration specifications; others do not. In this article we discuss sources of vibration, techniques for mitigating vibration, and some general rules about which types of vibration control to use based on the type of microscope being used. [ABSTRACT FROM AUTHOR]

Vector Lommel beams are a class of non-diffracting laser beams, characterized by their ability to propagate without any changes in their intensity profile. Understanding, the effect of the polarization state on the interaction between these beams and particles is of significant interest. In this context, we use the polarization states that obey Maxwell's equations to investigate the scattering of vector Lommel beams by a dielectric homogeneous spherical particle within the framework of generalized Lorenz-Mie theory (GLMT). The quadrature method is employed to derive closed-form expressions for the beam shape coefficients of both linearly and circularly polarized Lommel beams. These coefficients are then used to compute the differential scattering cross section of the scattered intensity of vector Lommel beams by spherical particles. The results of this study indicate that the scattered intensity is heavenly influenced by the polarization states of vector Lommel beams. Additionally, these findings offer significant benefits for applications across various fields, including the scattering of non-diffracting beams by objects, laser light scattering, optical tweezers, and the trapping and manipulation of particles through the optical forces exerted by such beams. Analytical theories of scattering, such as GLMT, play a crucial role in comprehending these phenomena. [ABSTRACT FROM AUTHOR]

Slits have been widely used in laser–plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle beams. Here, we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser pulse. The fundamental physics of intense laser interaction with thin slits is studied, and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing regime. In addition, the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional waveguides. These results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications. [ABSTRACT FROM AUTHOR]

Copyright of Spal: Revista de Prehistoria y Arqueologia de la Universidad de Sevilla is the property of Spal. Revista de Prehistoria y Arqueologia de la Universidad de Sevilla and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We utilize a Fourier transformation-based representation of Maxwell's equations to develop physics-constrained neural networks for electrodynamics without gauge ambiguity, which we label the Fourier–Helmholtz–Maxwell neural operator method. In this approach, both of Gauss's laws and Faraday's law are built in as hard constraints, as well as the longitudinal component of Ampère–Maxwell in Fourier space, assuming the continuity equation. An encoder–decoder network acts as a solution operator for the transverse components of the Fourier transformed vector potential, A ^ ⊥ (k , t) , whose two degrees of freedom are used to predict the electromagnetic fields. This method was tested on two electron beam simulations. Among the models investigated, it was found that a U-Net architecture exhibited the best performance as it trained quicker, was more accurate and generalized better than the other architectures examined. We demonstrate that our approach is useful for solving Maxwell's equations for the electromagnetic fields generated by intense relativistic charged particle beams and that it generalizes well to unseen test data, while being orders of magnitude quicker than conventional simulations. We show that the model can be re-trained to make highly accurate predictions in as few as 20 epochs on a previously unseen data set. [ABSTRACT FROM AUTHOR]

In breast cancer radiation therapy, minimizing radiation-related risks and toxicity is vital for improving life expectancy. Tailoring radiotherapy techniques and treatment positions can reduce radiation doses to normal organs and mitigate treatment-related toxicity. This study entailed a dosimetric comparison of six different external beam whole-breast irradiation techniques in both supine and prone positions. We selected fourteen breast cancer patients, generating six treatment plans in both positions per patient. We assessed target coverage and organs at risk (OAR) doses to evaluate the impact of treatment techniques and positions. Excess absolute risk was calculated to estimate potential secondary cancer risk in the contralateral breast, ipsilateral lung, and contralateral lung. Additionally, we analyzed the distance between the target volume and OARs (heart and ipsilateral lung) while considering the treatment position. The results indicate that prone positioning lowers lung exposure in X-ray radiotherapy. However, particle beam therapies (PBTs) significantly reduce the dose to the heart and ipsilateral lung regardless of the patient's position. Notably, negligible differences were observed between arc-delivery and static-delivery PBTs in terms of target conformity and OAR sparing. This study provides critical dosimetric evidence to facilitate informed decision-making regarding treatment techniques and positions. [ABSTRACT FROM AUTHOR]

Background: Nasopharyngeal adenoid cystic carcinoma (NACC) is a relatively rare salivary gland tumor that is generally associated with poor outcomes. High-dose radiotherapy is a key treatment for patients with NACC. This study reported the long-term efficacy and safety of particle beam radiation therapy (PBRT) for NACC. Methods and materials: Twenty-six patients with nonmetastatic NACC who received definitive PBRT alone were included in this retrospective study. The majority of patients (92.3%) had locally advanced disease. Twenty-five (96.15%) patients received intensity-modulated proton radiotherapy (IMPT) followed by a carbon ion radiotherapy (CIRT) boost, and one patient received CIRT alone. Overall survival (OS), local control (LC), regional control (RC), and distant metastasis control (DMC) rates were calculated via the Kaplan-Meier method. Results: The median follow-up time was 46.95 months for the entire cohort. Seven patients experienced local recurrence, and one patient experience neck lymph node recurrence. The 3- and 4-year OS, LC, RC, and DMC rates were 100% and 91.7%, 92.3% and 84.6%, 95.8% and 87.8%, and 90.2% and 71.3%, respectively. A total of 91.3% of the patients achieved complete remission of gross tumors at 1 year after PBRT. Severe acute toxicity was observed in only two patients. A grade 4 decrease in visual acuity was observed in one patient with orbital apex invasion. No late grade 3 or 5 toxicity was observed. Conclusion: Definitive PBRT provided a satisfactory 4-year OS for patients with locally advanced NACC. The toxicity was acceptable and mild. Further follow-up is necessary to confirm the efficacy and safety of definitive PBRT for patients with NACC. [ABSTRACT FROM AUTHOR]

This study introduces numerical advancements in an alternative design for the Super Proton Synchrotron (SPS) Beam Dump Facility (BDF) at the European Laboratory for Particle Physics (CERN). The design envisions a high-power operation target made of flowing liquid lead. The proposed BDF is a versatile facility for both beam-dump-like and fixed-target experiments. The target behavior is studied, assuming a proton beam with a momentum of 400 GeV/c, a pulse frequency of 1/7.2 Hz, and an average beam power of 355 kW. Using various Computational Fluid Dynamics (CFD) codes, we evaluate the behavior of liquid lead and predict the thermal stress on the target vessel induced by the pulsed heat source generated by the charged particle beam. The comparison increases the reliability of the results, investigating the dependencies on the CFD modeling approach. The beam is a volumetric heat source with data from the beam-lead interaction simulations provided by the European Laboratory for Particle Physics and obtained with a Monte Carlo code. Velocity field and stress profiles can enhance the design of the lead loop and verify its viability and safety when operated with a liquid metal target. [ABSTRACT FROM AUTHOR]

Nuclear photonics is a emerging field of science which combines research with new generation γ -ray sources based on traditional and laser-based electron accelerators. Here, we discuss isomeric studies carried out with γ -ray beams having either continuous, or quasi-monochromatic photon spectra. In experiments with high-power lasers, intense secondary radiation sources are generated. Such experiments explore isomer population or de-excitation in plasma environments. Laser-accelerated particle beams with high charge also facilitate high-energy nuclear excitations, leading to efficient production of nuclear isomers with higher lying isomeric state (reaching MeV energy level) within very-short time scales. The population of isomeric states is a sensitive diagnostic method for characterization of the laser-driven secondary radiation sources. [ABSTRACT FROM AUTHOR]

A theoretical analysis is made of the formation of longitudinal and transverse emittance of beams of charged particles in photoguns under the influence of repulsive forces of Coulomb fields. In numerical calculations, the characteristics of bunches of charged particles with uniform and Gaussian charge density distributions are compared. The efficiency of the proposed numerical-analytical model is compared with calculations using the Astra program. The obtained numerical and analytical results can be useful in the design of photoinjectors to select the optimal parameters that determine the main characteristics of photoguns. [ABSTRACT FROM AUTHOR]

Background/Objectives: Particle beam therapy (PBT) was approved in April 2018 for head and neck malignancies and has since been introduced as a radical therapy for parotid malignancies. However, its prevalence and effectiveness in relation to surgical treatment have not been investigated. Methods: In this study, we evaluated 36 patients with parotid malignancy who underwent surgery (n = 26) or PBT (n = 10) and then analyzed the annual changes in the number of patients, survival rates, and clinical factors affecting prognosis. Results: Of the ten patients who opted for PBT, two and eight patients underwent PBT before and after 2018, respectively. There was a significant difference between these two groups of patients (p = 0.04). Of the ten patients who underwent PBT, five patients were recurrent cases; meanwhile, all twenty-six patients who underwent surgery were receiving initial treatment. Only one patient in each group had local recurrence after the treatment. Conclusions: The use of PBT as a radical therapy for parotid malignancies has been increasing since 2018, and patients with recurrent tumors tended to choose PBT. The outcome of the patients who underwent PBT did not seem to be inferior compared with those of the patients who underwent surgery. The histopathological type was a crucial issue in the outcomes of patients who underwent radical therapy for parotid malignancies. [ABSTRACT FROM AUTHOR]

Non-destructive measurements of low-intensity charged particle beams are particularly challenging for beam diagnostics. At the Heavy Ion Accelerator Facility in Lanzhou (HIRFL), beams with weak currents below 1 µA are often provided for experiments. The detection of such low beam current is below the threshold of typical standard beam current transformers. Therefore, a low-intensity monitoring system is developed by using a sensitive capacitive pick-up (PU) and low-noise electronics. This device measures beam currents by digitally analyzing the amplitude of the PU signals using a homodyne detection scheme. During lab tests, the amplitude nonlinearity is <0.5% in the operational range of 1 nA–45 µA and the amplitude resolution is 0.94 nA. At present, four measurement systems for low beam currents are installed at HIRFL for the monitoring of standard operating conditions with low beam currents below 1 µA. After an absolute calibration with a Faraday cup, it can be used for accurate beam intensity measurement with a current resolution of about 1 nA. [ABSTRACT FROM AUTHOR]

Needs arising at both current and future accelerator facilities call for the development of radiation-hardened position-sensing diagnostics that can operate with multi-GHz repetition rates. Such instruments are likely to also have applications in the diagnosis of rapid plasma behavior. Building on the recent work of our Advanced Accelerator Diagnostics Collaboration, we are exploring the development of integrated multi-GHz ionizing particle detection systems based on chemical-vapor deposition diamond sensors, with the initial goal of producing a quadrant detector that can determine the intensity and centroid position of a particle beam at a repetition rate between 5 and 10 GHz. Results from our initial high-speed characterization work are presented, including those from a single-channel sensor with a GHz response. Approaches to achieving multi-GHz (5–10 GHz) rate capability, including the design of a dedicated Application Specific Integrated Circuit and the use of 3D RF-solver computer aided design software, are presented and discussed in more detail. 3D RF simulations suggest clean pulses of duration less than 250 ps (FWHM less than 125 ps) can be achieved with the approaches developed by this work. [ABSTRACT FROM AUTHOR]