bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Efficiency of New Self-driven Fault Current Limiter Based on the Improved Genetic Algorithm
Authors: Feng Zeming , Wang Rufan , Xie Dongze , Liao Minfu , Duan Xiongying , Ma Hui
Published: January 2023

To study the current limiting characteristics and system efficiency of the new fault short-circuit current limiter, an equivalent geometric model based on the rectangular guide rail, an algorithm analysis model of electromagnetic drive equation and a self-driven process is established. The effect of the geometric size and skin effect of the current limiter on the current limiting characteristics and system efficiency of the current limiter is analyzed. At the same time, the two goals of the initial time of current limiting and system efficiency are considered, and the important parameters of the new fault limiter are optimized by the improved genetic algorithm. The results show that the cross-sectional area of the rectangular guide and the width of the metal slider have a comprehensive effect on the performance. The algorithm model can optimize and analyze the target in a shorter time and a smaller algebra, which provides the theoretical basis and technical support for improving the current limiting characteristics and system efficiency of the new current limiter.
Research on Gear Surface Damage Identification Based on the ResNet Network
Authors: Qin Jiayin , Sun Yibo , Wu Luji
Published: January 2023

Gear damage will directly affect the normal operation of the whole transmission system. Aiming at the problem of gear surface damage recognition, a gear surface damage recognition model based on the improved ResNet-34 network is proposed. Firstly, the most suitable network model is selected by training the official describable textures dataset. Secondly, channel pruning, decomposition of the large convolutional kernel, application of global average pooling and transfer learning operations are performed on the primitive network to reduce the computational and parametric quantities and accelerate the training. Finally, experiments are conducted to compare the training effects of the improved network by introducing different pruning methods and scaling factors to the dataset. The experiments show that for the gear surface image dataset, the Slim Pruning (20% Pruned) method results in a 20.78% reduction in computation, a 21.71% compression in the number of parameters, and a 7.38% reduction in the average time per training epoch at a relative error rate of only 1.17%, thus showing that channel pruning can effectively compress the model within the accuracy error and reduce the training cost.
Rolling bearing fault diagnosis method based on dynamic convolution capsule network
Authors: Yang Aoyu , Zhong Zhidan , Zhao Yao , Zhang Zhihui
Published: January 2023

Aiming at the weak generalization ability of traditional rolling bearing fault diagnosis methods, a rolling bearing diagnosis method based on dynamic convolutional capsule networks (DC-CapNets) was proposed. First, one-dimensional vibration signals are preprocessed and divided into a training set and a test set. Then the fast Fourier transform (FFT) is used to convert the training set and the test set. In this model, two dynamic convolution layers and pooling layers are used to extract the features of the input frequency signals, and the feature information is transmitted to the capsule network to obtain the diagnosis results. The CWRU (Western Reserve University) data set validation shows that the proposed method still has high fault diagnosis accuracy under noise and variable load conditions, and has good anti-noise and generalization performance, which is superior to the convolutional neural network (CNN) and deep neural network (DNN).
Technology and Practice of Automatic Verification of Electric (Thermal) Instrument
Authors: Cao De-kun , Wang Shao-ran , Liu Yan-wen , Ni Hong-wei , Liu Shuai
Published: January 2023

To meet the need for peak regulating, large unit sets have put forward new and higher requirements for a thermal automatic control system, and the degree of automation has become an important symbol to measure the level of modernization of enterprises. In industrial production, the automatic verification technology of thermal measurement is becoming more and more mature and plays an important role in the industry. The automatic verification technology of thermal metrology is the manifestation of the development of automation, and it has also improved in the aspect of testing equipment. The use of automatic verification technology in thermal measurement can not only improve work efficiency but also reduce labor costs, which provides a basic guarantee for safe and reliable operations of equipment.
Unsupervised Learning Based Soil-film Recognition System for Electric Film Uncovering Machine
Authors: Ren Zhenyu , He Peixiang , Wang Jianping , Sun Yuhong
Published: January 2023

To reduce the damage to the edge film of the soil ridge during the uncovering process of the film uncovering machine, the soil-film recognition system of the film uncovering machine is designed in this paper. Firstly, the overall structure and working principle of the electric film uncovering machine are analyzed. Then the aberration correction of the camera of the machine is performed. Subsequently, multiple processing methods for field soil-film images are compared and analyzed. The image segmentation method most suitable for this system is determined to be the K-means++ method. The acquired images are also filtered and noise is reduced, and the contour information of the film is finally extracted and identified. The range of feature values of the experimentally measured images is area 4500~20,000 mm2, area share 4%~22%, and perimeter 250~950mm. When the three conditions are satisfied at the same time, it is a soil-film image. The system is combined with the experimental film uncovering machine in the soil consolidation state. The average film recognition rate of the system is greater than 95%. At the same time, the damage rate of the film is below 5%, and the soil removal rate on the side film reaches 82%.
Multi-index joint node selection protocol in UAV ad hoc network
Authors: Liang Jingyuan , Zhang Chuanbin , Dang Shuai , Wu Pengfei
Published: January 2023

In the application scenario of a UAV ad hoc network, aiming at the problems of low packet forwarding success rate and premature death of some nodes in greedy perimeter stateless routing (GPSR) protocol, a multi-index joint node selection-GPSR protocol (MT-GPSR) is proposed. Based on greedy forwarding, MT-GPSR protocol comprehensively considers the link holding time of adjacent nodes, the residual energy of adjacent nodes, and the node degree to jointly select the next hop node, and proposes an AHP maximum entropy criterion weighting algorithm, which reasonably weights the node index value, adds the weighted index values to obtain the selection priority value, and selects the neighbor node whose priority value is the best under the weighting condition as the next hop node for data forwarding, so as to improve the efficiency of data forwarding. At the same time, the network life is prolonged. The simulation results show that compared with the GPSR algorithm and GPSR-NMP algorithm, this algorithm ensures stable communication between UAVs, improves the network communication quality, and improves the network lifetime.
Error Correction Method of Transformer Harmonic Detection Based on the Improved BP Neural Network
Authors: Dai Chen , Zhuang Gewei , Wang Jin , Chen Daihu , Gu Zhen
Published: January 2023

In the case that the harmonic problem has threatened the safe operation of user equipment, the requirements of power quality are constantly improving, and the error correction method of harmonic detection has become a key concern in the field of power. Due to the complexity of the power structure, some of the transformer harmonic detection error correction methods have the defect of too large an error. In this demand, a transformer harmonic detection error correction method based on an improved BP neural network is designed. The open-circuit mode of the damper is converted into the connected mode, and the key parameters of the transformer are obtained. Based on the improved BP neural network, the harmonic voltage content is extracted, and the transfer relationship between the currents is obtained. The reverse propagation path of the fault component is clarified, and the detection error correction method is designed. The experimental results show that the average error rate of the error correction method of transformer harmonic detection is 37. 437%, which proves that it has more advantages in accuracy after combining with the improved BP neural network. The research results not only have high academic value but also help improve the user’s electricity experience.
Near Surface Layer Meteorological Observation System Based on Programmable Unmanned Aerial Vehicles
Authors: Peng Jiakai , Lu Jun , Yang Hong , Liang Lei , Tang Ran , Zhang Wei , Zhao Min
Published: January 2023

With the rapid development of UAV (Unmanned Aerial Vehicle) technology, to give full play to the spatial flexibility of multi-rotor UAV, this paper designs and develops a programmable UAV-based near-surface layer meteorological observation system to achieve the measurement of meteorological data such as temperature, humidity, air pressure, wind, wind direction and particle concentration in the near-surface layer environment. The data obtained from the measurements are accurate and reliable, and have positive implications for scientific research in meteorology. The system makes good use of the portability and intelligence of the UAV, and can work in different environments and adapt well to all kinds of weather. In addition, the use of a microcontroller realizes the real-time transmission of detection data and ensures the timeliness and reliability of the data. And the ground station can also monitor and intelligently control the whole process of the UAV and complete a variety of different tasks.
Analysis of Multi-Robot Patrolling Algorithms
Authors: Li Xiang , Ma Yuxuan
Published: January 2023

This article is dedicated to analyzing the common problems of robots when patrolling indoors and the corresponding solution algorithms. In the article, four problems of patrol robots (whether centralized or non-centralized) during operation are listed: the overload of data to be processed when the robotic sensors are transmitting the data, the repetitiveness and simultaneity of the robot work, the incorrect execution of the algorithm and how to deal with the inevitable unknown external factors. The simultaneity of the robots is to be eliminated because robots need to explore independently in the patrol task. Subsequently, four algorithms and functionalities are introduced (Monte Carlo Tree Planning Algorithm, Rapid Exploring Random Tree Planning, Mutual Exclusion Algorithm, and Kalman Filter Algorithm). The question of how the four algorithms address the corresponding factors will be illustrated by an elaboration of the process by which the algorithms solve the problem.
Structural and Passability Analysis of Dual Detection Mode Pipeline Robot
Authors: Yang Zhiqian , Xue Junfang , Li Weiguo
Published: January 2023

A new pipeline robot with a dual detection mode is built in order to address the issues with the current oil and gas pipeline inspection robots, such as single detection mode, small pipe diameter adaptation range, poor passing ability, and adaptability of the robots in pipelines. The general design of the robot is presented in this paper and the robot’s general construction and operation principles are discussed. The support system, which combines the main and auxiliary springs to achieve common preloading and force analysis, is organized to meet these goals. This paper designs the detection structure with an angle adjustable function. The robot’s motion and dimension restrictions through the bend pipe are examined concurrently. Experimental verification is then completed. The results of the experiments demonstrate that the robot’s structure design and calculations are reasonable, that the robot’s size and motion constraints analysis in the bend pipe is accurate, and that the robot can successfully pass the bend pipe with R ≥ 1.5D. The study’s findings serve as a guide for the development of prototype robots and subsequent robot simulation experiments.
An Adaptive Fault-Tolerant Control Algorithm for Underwater Vehicle Propulsion System
Authors: Jiang Jun , Li Bo Hao , Ding Meng Lei
Published: January 2023

Underwater navigation plays an important role in the exploration of current marine resources. But the underwater environment is complicated, traditional fault-tolerant control of the unmanned underwater vehicle has a high dependence on the accuracy of the dynamic model in the design of the control rate, which is difficult to deal with the uncertainty and external disturbance of this system. Therefore, an adaptive fault-tolerant control algorithm based on the residual drive is proposed. The motion state reference model is generated by BP neural network, and the residual between the reference model and the actual state is used as a feedback parameter. The thrust distributor is established with a simple dynamic model, and the control strategy is reconstructed by adjusting distribution weight to achieve the purpose of adaptive fault-tolerant control. Taking a typical fixed-angle propulsion system as an example, the algorithm is modeled, analyzed, and simulated. Simulation results show that the algorithm can track target parameters well without relying on an accurate dynamic model and automatically adapt to a variety of abnormal working conditions.
Numerical Simulation of Wake Magnetic Field in Pitch Motion of an Underwater Vehicle
Authors: Huang Bo , Liu Zhongyan , Xu Yujing , Ding Qiaochu , Pan Mengchun , Hu Jiafei , Zhang Qi
Published: January 2023

The underwater vehicle produces a complex hydrodynamic wake during its mission, which will generate the induced magnetic field. With the development of acoustic stealth technology for underwater vehicles, the wake-induced magnetic field is of great significance to detecting and tracking underwater vehicles. This paper combines the numerical simulation of the wake flow field and magnetic field. The magnetic field of the wake during the motion of the underwater vehicle is numerically simulated by using dynamic overlapping mesh technology. The results show that a strong magnetic field centered on the shedding vortex is formed at the wake during the floating movement of the underwater vehicle. With an increase in pitch movement time, the strength and range of the wake magnetic field gradually increase. The vertical range of the wake magnetic field is obviously affected by the upward trim angle, but the horizontal range is basically not affected. The range and strength of the wake magnetic field increase when the upward trim angle increases.
The Method for Analyzing the Pitching Motion Pattern of a New Surface Unmanned Wing-sliding Boat
Authors: Yang Zhaolong , Zou Zaojian , Wang Xuegang
Published: January 2023

In this paper, a new surface unmanned wing skate (NUSV) is taken as the research object, and the free decay model test under different drafts and different initial pitch angles is completed. In the case of specially selected regular waves, typical swaying tests against waves and waves were carried out. Four mathematical models for system identification of pitch motion modes are established. Based on the system identification theory and the programming idea of the improved genetic algorithm, the NUSV pitch motion mode system identification software is written in C# language. The system identification software is developed based on experimental technology and an analysis method of ship motion patterns is developed based on the optimization theory. This paper completed the following: (1) compared and calculated the mathematical models of system identification based on four-pitch motion modes and determining their motion modes, (2) based on the results of pitch motion mode identification, the predicted values and the test results are in good agreement, which verifies the rationality of the method and the reliability of the self-compiled software, (3) analyzed the variation law of the relative value of each moment that affects the NUSV pitch decay motion with the draft and initial pitch angle, (4) analyzed the influence of the NUSV in the regular wave. The variation law of each moment of the rocking motion with the draught, wave height, and encounter period, and (5) proposed the idea of establishing a rocking motion pattern map based on the rocking test and optimal identification theory. The method and research results proposed in this paper can provide a reliable motion model for the pitch motion control of this type of boat, and provide technical support for its effective regulation of the adverse effect of the pitch on the boat’s stability. It also provides a reference for the seakeeping of this type of boat and the optimization design of the subsequent boat type. The system identification software written can also be used for system identification of the rocking motion mode of this type of unmanned boat in other directions.
Acceleration and crossing of transition energy investigation using an RF structure of the barrier bucket type in the NICA accelerator complex
Authors: Kolokolchikov S , Senichev Y , Melnikov A , Syresin E
Published: January 2023

The dynamic of longitudinal motion in Barrier Bucket RF structure is considered. To preserve the stability of the proton beam during the acceleration to the experiment energy it is necessary to cross the transition energy and a rapid jump of transition energy is possible. The influence of the second-order slip factor is taking into account. The dynamic aperture is investigated for various gradients of focusing quadrupoles and corresponding working points which is necessary for transition crossing.
WITHDRAWN: Investigation of polarized proton spin coherence time at storage rings
Authors: Melnikov A , Aksentyev A , Senichev Y , Syresin E
Published: January 2023

This article has been withdrawn by IOP Publishing following the request by the authors to augment their affiliation by an institution. Upon reviewing the matter, IOP Publishing found that the institution (Moscow Institute of Physics and Technology) is subject to sanctions by the UK government.

To ensure compliance with sanctions regulations, this article has been withdrawn from IOPscience.
Study of hydrodynamic-tunnelling effects induced by high-energy proton beams in graphite
Authors: Wiesner C , Carra F , Don J , Kolthoff I , Lechner A , Rasile R , Wollmann D
Published: January 2023

The design and assessment of machine-protection systems for existing and future high-energy accelerators comprises the study of accidental beam impact on machine elements. In case of a direct impact of a large number of high-energy particle bunches in one location, the damage range in the material is significantly increased due to an effect known as hydrodynamic tunnelling. The effect is caused by the beam-induced reduction of the material density along the beam trajectory, which allows subsequent bunches to penetrate deeper into the target. The assessment of the damage range requires the sequential coupling of an energy-deposition code, like FLUKA, and a hydrodynamic code, like Autodyn. The paper presents the simulations performed for the impact of the nominal LHC beam at 7 TeV on a graphite target. It describes the optimisation of the simulation setup and the required coupling workflow. The resulting energy deposition and the evolution of the target density are discussed.
Beam loading compensation of standing wave linac with off-crest acceleration
Authors: Kuriki M , Konno S , Tajino H , Liptak Z , Takahashi T , Fukuda M , Omori T , Seimiya Y , Urakawa J , Yokoya K , Kashiwagi S
Published: January 2023

In E-Driven positron source of ILC, the generated positron is captured by a standing wave cavity. Because the deceleration capture method is employed, the positron is off-crest over the linac. Because the beam-loading is expected to be more than 1A in a multi-bunch format, the compensation is essential to obtain uniform intensity over the pulse. A conventional method for the compensation controlling the timing doesn’t work because RF and Beam induced field are in different phase. In this manuscript, we discuss the compensation with the off-crest acceleration case. A simple phase modulation on the input RF is a solution.
Fine decoupling test and simulation study to maintain a large transverse emittance ratio in hadron storage rings
Authors: Luo Y , Blackler I , Blaskiewicz M , Fischer W , Marusic A , Montag C , Shrey T , Xu D
Published: January 2023

In previous and existing hadron storage rings, the horizontal and vertical emittances are normally the same or very close. For the Hadron Storage Ring (HSR) of the Electron-Ion Collider (EIC), the design proton transverse emittance ratio is 10:1. To maintain this large emittance ratio, we need to have an online fine decoupling system to prevent transverse emittance exchange. For this purpose, we carried out fine decoupling experiments in the Relativistic Heavy Ion Collider (RHIC) and reviewed its previous operational data. Analytical prediction and numerical simulation are preformed to estimate how small the global coupling coefficient should be to maintain a 10:1 emittance ratio.
Designing the EIC electron storage ring lattice for a wide energy range
Authors: Marx D , Berg JS , Cai Y , Gamage BRP , Hoffstaetter GH , Kewisch J , Li Y , Montag C , Morozov V , Nosochkov Y , Ptitsyn V , Sagan D , Signorelli MG , Tepikian S , Unger J , Willeke F , Xu D
Published: January 2023

The Electron-Ion Collider (EIC) will collide electrons with hadrons at center-of-mass energies up to 140 GeV (in the case of electron-proton collisions). A 3.8-kilometer electron storage ring is being designed, which will store electrons with a range of energies up to 18 GeV for collisions at one or two interaction points. At energies up to 10 GeV the arcs will be tuned to provide 60 degree phase advance per cell in both planes, whereas at top energy of 18 GeV a 90 degree phase advance per cell will be used, which largely compensates for the horizontal emittance increase with energy. The optics must be matched at three separate energies, and the different phase-advance requirements in both the arc cells and the straight sections make this challenging. Moreover, the spin rotators must fulfill requirements for polarization and spin matching at widely different energies while satisfying technical constraints. In this paper these challenges and proposed solutions are presented and discussed.
Beam-beam interaction for tilted storage rings
Authors: Xu D , Luo Y , Holmes D , Montag C , Willeke F , Hao Y , Qiang J
Published: January 2023

In the Electron-Ion Collider (EIC) design, to avoid vertical orbit bumps in the Electron Storage Ring (ESR) at some crossing points with Hadron Storage Ring (HSR) to preserve the electron polarization, we plan to tilt the ESR plane by 200 μrad with an axis connecting IP6 and IP8. In this article, we study the beam-beam interaction when two rings are not in the same plane. The Lorentz boost formula is derived and the required vertical crabbing strength is calculated to compensate the dynamic effect. The beam-beam simulations are performed to validate the theory.
Status and powering test results of HTS undulator coils at 77 K for compact FEL designs
Authors: Richter S C , Ballarino A , Nes T H , Schoerling D , Bernhard A , Müller A-S
Published: January 2023

The production of low emittance positron beams for future linear and circular lepton colliders, like CLIC or FCC-ee, requires high-field damping wigglers. Just as compact free-electron lasers (FELs) require high-field but as well short-period undulators to emit high energetic, coherent photons. Using high-temperature superconductors (HTS) in the form of coated ReBCO tape superconductors allows higher magnetic field amplitudes at 4 K and larger operating margins as compared to low-temperature superconductors, like Nb-Ti.

This contribution discusses the development work on superconducting vertical racetrack (VR) undulator coils, wound from coated ReBCO tape superconductors. The presented VR coils were modularly designed with a period length of 13 mm. Powering tests in liquid nitrogen of multiple vertical racetrack coils were performed at CERN. The results from the measurements are presented for three VR coils and compared with electromagnetic simulations.
Lifetime correction using fast-off-energy response matrix measurements
Authors: Liuzzo S M , Carmignani N , Carver L R , Hoummi L , Perron T , Roche B , White S
Published: January 2023

Following the measurements done at MAX-IV [1], we try to exploit for the ESRF-EBS Storage Ring (SR) off-energy response matrix measurement for the optimization of Touschek lifetime. The measurements performed with fast AC steerers on- and off-energy are analyzed and fitted producing an effective model including quadrupole and sextupole errors. Several alternatives to extrapolate sextupoles strengths for correction are compared in terms of lifetime. For the time being none of the corrections could produce better lifetime than the existing empirically optimized set of sextupoles.
Virtual commissioning of the European XFEL for advanced user experiments at photon energies beyond 25 keV using low-emittance electron beams
Authors: Chen Ye , Brinker Frank , Decking Winfried , Scholz Matthias , Winkelmann Lutz , Zhu Zihan
Published: January 2023

Growing interests in ultra-hard X-rays are pushing forward the frontier of commissioning the European X-ray Free-Electron Laser (XFEL) for routine operation towards the sub-ångström regime, where a photon energy of 25 keV (0.5 Å) and above is desired. Such X-rays allow for larger penetration depths and enable the investigation of materials in highly absorbing environments. Delivering the requested X-rays to user experiments is of crucial importance for the XFEL development. Unique capabilities of the European XFEL are formed by combining a high energy linac and the long variable-gap undulator systems for generating intense X-rays at 25 keV and pushing the limit even further to 30 keV. However, the FEL performance relies on achievable electron bunch qualities. Low-emittance electron bunch production, and the associated start-to-end modelling of beam physics thus becomes a prerequisite to dig into the XFEL potentials. Here, we present the obtained simulation results from a virtual commissioning of the XFEL for the user experiments at 25 keV and beyond, including the optimized electron bunch qualities and corresponding FEL lasing performance. Experimental results at 30 keV from the first test run are presented.
Twin delayed deep deterministic policy gradient for free-electron laser online optimization
Authors: Cai M , Zhu Z H , Zhang K Q , Feng C , Tu L J , Gu D , Zhao Z T
Published: January 2023

X-ray free-electron lasers (FEL) have contributed to many frontier applications of nanoscale science which benefit from its extraordinary properties. During FEL commissioning, the beam status optimization especially orbits correction is particularly significant for FEL amplification. For example, the deviation between beam orbit and the magnetic center of undulator can affect the interaction between the electron beam and the FEL pulse. Usually, FEL commissioning requires a lot of effort for multi-dimensional parameters optimization in a time-varying system. Therefore, advanced algorithms are needed to facilitate the commissioning procedure. In this paper, we propose an online method to optimize the FEL power and transverse coherence by using a twin delayed deep deterministic policy gradient (TD3) algorithm. The algorithm exhibits more stable learning convergence and improves learning performance because the overestimation bias of policy gradient methods is suppressed.
Studies of a Ka-band high power klystron amplifier at INFN-LNF
Authors: Behtouei M , Spataro B , Faillace L , Leggieri A , Di Paolo F , Marrese F , Valletti L , Fantauzzi S , Torrisi G , Carillo M , Bosco F , Mostacci A , Palumbo L , Migliorati M
Published: January 2023

In the framework of the Compact Light XLS project [1], a Ka-band linearizer with electric field ranging from 100 to 150 MV/m is requested [2, 3, 4]. In order to feed this structure, a proper Ka-band high power klystron amplifier with a high efficiency is needed. This paper reports a possible solution for a klystron amplifier operating on the TM010 mode at 36 GHz, the third harmonic of the 12 GHz linac frequency, with an efficiency of 44% and 10.6 MW radiofrequency output power. We discuss also here the high-power DC gun with the related magnetic focusing system, the RF beam dynamics and finally the multiphysics analysis of a high-power microwave window for a Ka-band klystron providing 16 MW of peak power.
Investigation, simulation and first measurements of a 2 m long electron column trapped in a Gabor-Lens device
Authors: Thoma K I , Droba M , Meusel O
Published: January 2023

Various Gabor-Lenses (GL) were investigated at Goethe University. Confinements of sufficient electron densities (ne ∼ 1 · 1015 m3) were reached without any external source of electrons. Focusing of ion beams by low energy was demonstrated, long term stability and reproducibility were approved. Main differences compared to experiments and investigations of the pure non-neutral in Penning-Malmberg traps [1] are higher residual gas pressure and therefore higher collision rates, higher bulk temperatures, self-sustaining electron production process, much higher evaporation cooling rate. GL2000 is a new 2 m long device and was mainly designed for focusing of ion beams in energy ranges up to GeV but also for investigation of non-neutral plasma parameters. The confined electron column is much longer compared to previous constructed Lenses. This makes ion and hadron beam focussing much more efficient, in addition new physical phenomena can be expected and investigated. Simulation results of steady-and thermal equilibrium states with various external parameters and first measurements will be presented. The first operational tests show that it is possible to confine a two-meter long electron column.
Status of the development of the electron lens for space charge compensation at GSI
Authors: Schulte-Urlichs K , Droba M , Dönges T , Meusel O , Ondreka D , Podlech H , Spiller P , Thoma K I
Published: January 2023

At GSI a prototype electron lens for space charge (SC) compensation is currently being designed and main components as the RF-modulated electron gun are already under commissioning. The goal of this project is the (partial) compensation of SC forces within the ion beam by an overlapping electron beam. This may help to increase the intensity of primary beams, especially in the FAIR facility and potentially all large synchrotrons operated at the SC limit. For an effective SC compensation, the generated electron beam needs to follow the transverse and longitudinal beam profile of the ion bunch structure. The requirements are maximum currents of 10 A and grid modulation to cover a broad frequency range from 400 kHz to 1 MHz. The RF-modulated electron gun was designed and manufactured in the scope of the ARIES collaboration and is currently being tested at the E-Lens Lab of Goethe-University Frankfurt. A dedicated test bench was built for commissioning of the major e-lens components and diagnostics. In this contribution the overall set-up will be presented putting special emphasis on the beam dynamics and collector design as well as simulation results of the electron gun.
Simulating quasi-integrable optics with space charge in the IBEX Paul trap
Authors: Flowerdew J A D , Kelliher D J , Machida S , Sheehy S L
Published: January 2023

The intensity frontier has called for new initiatives in hadron accelerator design in order to accommodate space charge dominated beams. Octupoles are often used to damp beam instabilities caused by space charge, however the insertion of octupole magnets leads to a nonintegrable lattice which reduces the area of stable particle motion. One proposed solution is Quasi-Integrable optics (QIO), where the octupoles are inserted between sections of a specific lattice insertion called a T-insert. An octupole with a strength that scales as 1/β
3(s) is applied in the drift region, where the horizontal and vertical beta functions are equal, to create a time independent octupole field. This leads to a lattice with a time-independent Hamiltonian which is robust to small perturbations. IBEX is a Paul trap which allows the transverse dynamics of a collection of trapped particles to be studied, mimicking the propagation through multiple quadrupole lattice periods, whilst remaining stationary in the laboratory frame. In order to test QIO at the IBEX experiment, it has recently undergone an upgrade to allow for the creation of octupole fields. We present our design of the IBEX experiment upgrade along with simulation results of our proposed experiment to test QIO with space charge.
Excitation of the σl_l = 90° resonance by the cavity rf accelerating fields
Authors: Lagniel J -M
Published: January 2023

In rf linacs the longitudinal focalization is done by si-nusoidal forces and at high accelerating fields the zero-current longitudinal phase advance per longitudinal fo-cusing period σ0l_l can be high. The nonlinear compo-nents of the sinusoidal rf field (sextupolar, octupolar and higher order components) can then excite parametric resonances, including the 4th-order resonance (σl_l = 90°) when σ0l_l is higher than 90°, inducing strong longitudinal emittance growths and acceptance reductions. As pointed out in previous papers, the longitudinal beam dynamics is therefore complex, even when the space-charge forces are ignored. The parametric resonance excitation by the rf field is analyzed before discussing the additional effect of the space-charge forces, in particular to explain why the zero-current longitudinal phase advance per trans-verse focusing period σ0l_t is not a relevant parameter. Examples are given in the SPIRAL2 linac case.
Reverse bend option for a 6 GeV storage ring lattice
Authors: Hoummi L , Carmignani N , Carver L R , Cianciosi F , Liuzzo S M , Perron T , White S
Published: January 2023

Several high-energy synchrotron facilities adopted the Hybrid Multi-Bend Achromat scheme (HMBA) developed for the ESRF-EBS [1]. The considered lattice has been developed for a generic 6 GeV storage ring (SR) of 1100 m circumference [2]. It includes a short bending (SB) magnet at the center of the cell, and achieves a ~70 pm rad equilibrium horizontal emittance. The optics of such SR are modified introducing reverse bending magnets [3, 4] to further reduce the natural horizontal emittance to 53 pm rad. The impact of such modification on dynamic aperture and lifetime is assessed and optimized.
Generalisation and longitudinal extension of the Genetic Lattice Construction (GLC) algorithm
Authors: Reimann S , Droba M , Meusel O , Podlech H J
Published: January 2023

The GLC algorithm [1] allows the construction of efficient transfer lines with defined imaging properties using a minimum number of quadrupole elements. This work describes a generalisation of this algorithm to make it applicable to the use of arbitrary beam optical elements. This includes an extension to longitudinal phase space.
WITHDRAWN: Quasi-frozen spin concept of magneto-optical structure of NICA adapted to study the electric dipole moment of the deuteron and to search for the axion
Authors: Senichev Y , Aksentyev A , Kolokolchikov S , Melnikov A , Ladygin V , Syresin E , Nikolaev N
Published: January 2023

This article has been withdrawn by IOP Publishing following the request by the authors to augment their affiliation by an institution. Upon reviewing the matter, IOP Publishing found that the institution (Moscow Institute of Physics and Technology) is subject to sanctions by the UK government.

To ensure compliance with sanctions regulations, this article has been withdrawn from IOPscience.
Investigation of RF heating for the multipole injection kicker installed at SOLEIL
Authors: Gamelin A , Alexandre P , Fekih R Ben El , Castro J Da Silva , Ajjouri M El , Letresor A , Nadolski L S , Ollier R , Thoraud S , Sacko M , Taurines S
Published: January 2023

During the commissioning of the new Multipole Injection Kicker (MIK) pulsed magnet at SOLEIL synchrotron, an anomalously high heating of the MIK chamber and flanges was found. To better manage the heat load, fans directed toward the MIK were added to improve the air-cooling flow. This allowed the nominal current to be reached in all operation modes while keeping reasonable temperatures on the MIK. Post-installation investigations subsequently showed that the initial estimate of the maximal heat load was in agreement with the measured temperature in several operation modes both with and without the additional fans. In this article, we present the complete study, starting from the impedance calculation to thermal simulations, and comparison with the measured data with beam.
Concrete shielding activation for proton therapy systems using BDSIM and FISPACT-II
Authors: Ramoisiaux E , Hernalsteens C , Tesse R , Gnacadja E , Pauly N , Vanwelde M , Stichelbaut F
Published: January 2023

Proton therapy systems are used worldwide for patient treatment and fundamental research. The generation of secondary particles when the beam interacts with the beamline elements is a well known issue. In particular, the energy degrader is the dominant source of secondary radiation. This poses new challenges for the concrete shielding of compact systems and beamline elements activation computation. We use a novel methodology to seamlessly simulate all the processes relevant to the activation evaluation. A realistic model of the system is developed using Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code that allows a single model to simulate primary and secondary particle tracking and all particle-matter interactions. The secondary particle fluxes extracted from the simulations are provided as input to FISPACT-II to compute the activation by solving the rate equations. This approach is applied to the Ion Beam Applications (IBA) Proteus®ONE (P1) system and the shielding of the proton therapy research centre of Charleroi, Belgium. Proton loss distributions are used to model the production of secondary neutrals inside the accelerator structure. Two models for the distribution of proton losses are compared for the computation of the clearance index at specific locations of the design. Results show that the variation in the accelerator loss models can be characterised as a systematic error.
Characterization of the electron beam visualization stations of the ThomX accelerator
Authors: Moutardier Alexandre , Bruni Christelle , Cayla Jean-Noël , Chaikovska Iryna , Chance Sophie , Delerue Nicolas , Guler Hayg , Monard Hugues , Omeich Maher , Williams Scott David
Published: January 2023

We present an overview of the diagnostics screens stations - named SSTs - of the ThomX compact Compton source. ThomX is a compact light source based on Compton backscattering. It features a linac and a storage ring in which the electrons have an energy of 50 MeV. Each SST is composed of three screens, a YAG:Ce screen and an Optical Transition Radiation (OTR) screen for transverse measurements and a calibration target for magnification and resolution characterisation. The optical system is based on commercial lenses that have been reverse-engineered. An Arduino is used to control both the aperture and the focus remotely, while the magnification must be modified using an external motor. We report on the overall performance of the station as measured during the first steps of beam commissioning and on the optical system remote operations.
6D Phase space diagnostics based on adaptively tuned physics-informed generative convolutional neural networks
Authors: Scheinker Alexander , Filippetto Daniele , Cropp Frederick
Published: January 2023

A physics-informed generative convolutional neural network (CNN)-based 6D phase space diagnostic is presented which generates all 15 unique 2D projections (x, y), (x, y′),...,(z, E) of a charged particle beam’s 6D phase space (x, y, z, x′, y′, E). The CNN is trained by supervised learning over a wide range of input beam distributions, accelerator parameters, and the associated 6D beam phase spaces at multiple accelerator locations. The CNN is applied in an un-supervised adaptive manner without knowledge of the input beam distribution or accelerator parameters and is robust to their unknown time variation. Adaptive feedback automatically tunes the low-dimensional latent space of the encoder-decoder CNN to predict the 6D phase space based only on 2D (z, E) longitudinal phase space measurements from a device such as a transverse deflecting RF cavity (TCAV). This method has the potential to provide diagnostics beyond the existing state of the art at many accelerator facilities. Studies are presented for two very different accelerators: the 5-meter-long ultra-fast electron diffraction (UED) HiRES compact accelerator at LBNL and the kilometer long plasma wakefield accelerator FACET-II at SLAC.
A machine learning approach to electron orbit control at the 1.5 GeV synchrotron light source DELTA
Authors: Schirmer D
Published: January 2023

Machine learning (ML) methods have found their application in a wide range of particle accelerator control tasks. Among other possible use cases, neural networks (NNs) can also be utilized for automated beam position control (orbit correction). ML studies on this topic, which were initially based on simulations, were successfully transferred to real accelerator operation at the 1.5–GeV electron storage ring of the DELTA accelerator facility. For this purpose, classical fully connected multi-layer feed-forward NNs were trained by supervised learning on measured orbit data to apply local and global beam position corrections. The supervised NN training was carried out with various conjugate gradient backpropagation learning algorithms. Afterwards, the ML-based orbit correction performance was compared with a conventional, numerical-based computing method. Here, the ML-based approach showed a competitive orbit correction quality in a fewer number of correction steps.
A data-driven anomaly detection on SRF cavities at the European XFEL
Authors: Sulc A , Eichler A , Wilsken T
Published: January 2023

The European XFEL is currently operating with hundreds of superconducting radio frequency cavities. To be able to minimize the downtimes, prevention of failures on the SRF cavities is crucial. In this paper, we propose an anomaly detection approach based on a neural network model to predict occurrences of breakdowns on the SRF cavities based on a model trained on historical data. We used our existing anomaly detection infrastructure to get a subset of the stored data labeled as faulty. We experimented with different training losses to maximally profit from the available data and trained a recurrent neural network that can predict a failure from a series of pulses. The proposed model is using a tailored architecture with recurrent neural units and takes into account the sequential nature of the problem which can generalize and predict a variety of failures that we have been experiencing in operation.
New generation of very low noise beam position measurement system for the LHC transverse feedback
Authors: Valuch Daniel , Stopjakova Viera
Published: January 2023

Recent studies showed that the transverse feedback system noise floor in the Large Hadron Collider (LHC) must be reduced by at least factor of two in order to operate the machine with large beam-beam tune shift as foreseen in the High Luminosity (HL) LHC. Also, the future feedback system foreseen to suppress the LHC Crab Cavity noise relies on improved noise performance of the beam position measurement system. An upgrade program was launched to lower the LHC transverse feedback system noise floor during the LHC Long Shutdown II. A new generation, very low noise beam position measurement module was developed and tested with beam. Innovative methods in the RF receiver, digital signal processing, thorough optimization of every element in the signal chain from pickup to the kickers allowed to achieve a significant reduction of the system noise floor. This unprecedented noise performance opens also new possibilities for auxiliary instruments, using the position data from the transverse feedback. The paper presents the new system, notable implementation details and measured performance.
Online correction of laser focal position using FPGA-based ML models
Authors: Einstein-Curtis J , Coleman S J , Cook N M , Edelen J P , Barber S , Berger C , Tilborg J van
Published: January 2023

Ultrafast lasers play an increasingly critical role in the generation, manipulation, and acceleration of electron beams for High Energy Physics applications. Laser plasma accelerators enable order of magnitude improvements in accelerating gradient and promise compact tunable GeV electron beam sources, while novel photocathode systems permit fundamental advances in electron beam manipulation for accelerator and radiation applications Advances in fast feedback systems are required to stabilize laser performance at kHz repetition rate operation against environmental fluctuations. A field programmable gate array (FPGA) based digital control system, coupled with responsive optics, can provide rapid and precise stabilization of ultrafast lasers. A collaboration between RadiaSoft and the Lawrence Berkeley National Laboratory BELLA Center to develop, test, and deploy these systems across a range of beamlines operating at >1 Hz repetition rate, including 1 kHz systems, was created.
A Python Framework for High-level Applications in Accelerator Operations
Authors: Chrin J , Erçağlar V , Schietinger T
Published: January 2023

A Python graphical framework providing reusable components to facilitate the development of accelerator applications, that meet the basic requirements of experts and operators alike, is presented. Such a collective approach serves to bridge the gap between the expert developer and the operational team, resulting in applications that are inherently cohesive, durable and easily navigable. The operational advantages and underlying principles are exemplified in a reference application that provides executable examples of customary practices, and further highlights a number of composite and control system-enabled widgets.
The new eddy current type septum magnet for upgrading of fast extraction in main ring of J-PARC
Authors: Shibata T , Ishii K , Iwata S , Sugimoto T , Matsumoto H , Fan K
Published: January 2023

As part of the goal of increasing the beam power of the Main Ring for Fast eXtraction (FX) in J-PARC to 750 kW, we have been evaluating new FX low-field septa of induced eddy current type (Eddy-septum) since 2014. To reduce the leakage field in the circulating line of the eddy-septa, new pure iron duct-type magnetic shields were produced in July 2021, and in March 2022 we verified that the leakage field was greatly reduced. The construction of the two eddy-septa and their power supplies was completed in May 2022. Beam operation with a new 1.3-s cycle will be started in June 2022.
Spallation target optimization for ADS by Monte Carlo codes
Authors: Mumyapan M , Ghergherehchi M , Ha D H , Namgoong H , Chai J S
Published: January 2023

Accelerator Driven System are advanced system for the use of Thorium as fuel, aiming to reduce nuclear waste through transmutation. The spallation target, which is responsible for producing neutrons, is one of the main parts of the ADS system. In this research, neutronic parameters of spallation targets consisting of several materials LBE, Mercury, and Lead, on the cylindrical and conic shapes using Monte Carlo codes (FLUKA, PHITS, MCNPX) were investigated. Energy deposition and spallation neutron yield of spallation target with different shapes and dimensions have been calculated to optimization of the target. According to the results, the neutron yield values from MCNPX and PHITS are similar and it’s close to the experimental result. On the other hand, the error rate of the values in FLUKA is higher.