Latest in physics.acc-ph

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Longitudinal phase-space manipulation with beam-driven plasma wakefieldsFeb 21 2019The development of compact accelerator facilities providing high-brightness beams is one of the most challenging tasks in field of next-generation compact and cost affordable particle accelerators, to be used in many fields for industrial, medical and ... More
Optimization of Undulator Parameters for 125 GeV Drive BeamFeb 20 2019In the baseline design of the International Linear Collider (ILC) an undulator-based source is foreseen for the positron source in order to match the physics requirements. The baseline parameters are optimized for the ILC at sqrt(s)=500 GeV, that means ... More
Self amplification of channeling radiation at Bragg diffraction conditionsFeb 19 2019X-ray radiation of relativistic electrons passing through the crystal lattice (in case of channeling radiation) requires electrons with energies just from tens up to hundreds MeV, but has a drawback: low number of emitted X-ray quanta. However, the brightness ... More
From self-organization in relativistic electron bunches to coherent synchrotron light: observation using a photonic time-stretch digitizerFeb 16 2019In recent and future synchrotron radiation facilities, relativistic electron bunches with increasingly high charge density are needed for producing brilliant light at various wavelengths, from X-rays to terahertz. In such conditions, interaction of electrons ... More
A magnetic spectrometer to measure electron bunches accelerated at AWAKEFeb 15 2019A magnetic spectrometer has been developed for the AWAKE experiment at CERN in order to measure the energy distribution of bunches of electrons accelerated in wakefields generated by proton bunches in plasma. AWAKE is a proof-of-principle experiment for ... More
Experimental demonstration of the correction of coupled transverse dynamics aberration in an rf photoinjectorFeb 14 2019The production of electron bunches with low transverse emittance approaches the thermal emittance of the photocathode as various aberrations are corrected. Recently, the coupled transverse dynamics aberration was theoretically identified as a significant ... More
Active Suppression of Microphonics Detuning in high $Q_L$ CavitiesFeb 13 2019Operation of Superconducting Radio Frequency (SRF) cavities with high loaded quality factors is becoming increasingly preferred for applications which involve low beam loading including Energy Recovery Linacs (ERL). Vibration induced microphonics detuning ... More
Improving performance of inverse Compton sources through laser chirpingFeb 12 2019We present a new paradigm for computation of radiation spectra in the non-linear regime of operation of inverse Compton sources characterized by high laser intensities. The resulting simulations show an unprecedented level of agreement with the experiments. ... More
Terahertz oscilloscope for recording time information of ultrashort electron beamsFeb 09 2019We propose and demonstrate a Terahertz (THz) oscilloscope for recording time information of an ultrashort electron beam. By injecting a laser-driven THz pulse with circular polarization into a dielectric tube, the electron beam is swept helically such ... More
Beam Commissioning Results from the CBETA Fractional Arc TestFeb 09 2019This work describes first commissioning results from the Cornell Brookhaven Energy Recovery Test Accelerator Fractional Arc Test. These include the recommissioning of the Cornell photo-injector, the first full energy operation of the main linac with beam, ... More
Beam Commissioning Results from the CBETA Fractional Arc TestFeb 09 2019Feb 12 2019This work describes first commissioning results from the Cornell Brookhaven Energy Recovery Test Accelerator Fractional Arc Test. These include the recommissioning of the Cornell photo-injector, the first full energy operation of the main linac with beam, ... More
Low RF power plasma ignition and detection for in-situ cleaning of 1.3 GHz 9-cell cavitiesFeb 08 2019Superconducting Radio Frequency (SRF) cavities performance preservation is crucial, from vertical test to accelerator operation. Field Emission (FE) is still one of the performance limiting factors to overcome and plasma cleaning has been proven successful ... More
Reduction of coherent betatron oscillations with RF fields in the Muon $g-2$ ExperimentFeb 08 2019Coherent betatron oscillations (CBO) of the beam centroid in the Muon $g-2$ storage ring modulates the radial decay position of the muons. This results in a modulation of the counted rate of the decay positrons due to the detector acceptance, asymmetry ... More
Magnetic design of twin aperture cos-theta superconducting dipoles with a semi-analytic approachFeb 06 2019The magnetic design is a basic aspect of the superconducting magnets for particle accelerators. When dealing with single aperture cos-theta type dipoles, at the first order, the design can be performed with an analytic approach based on a sector dipole ... More
Accurate Taylor transfer maps for large aperture iron dominated magnets used in charged particle separators and spectrometersFeb 01 2019For high-resolution separators like the projected Super-FRS at FAIR, an adapted and accurate ion-optical model considering realistic B-dependent magnet parameters is crucial in achieving the desired parameters (e.g. resolution) and to enable a fast optimization. ... More
Laser-Driven Electron Lensing in Silicon MicrostructuresFeb 01 2019We demonstrate a laser-driven, tunable electron lens fabricated in monolithic silicon. The lens consists of an array of silicon pillars pumped symmetrically by two 300 fs, 1.95 $\mu$m wavelength, nJ-class laser pulses from an optical parametric amplifier. ... More
The International Linear Collider. A Global ProjectJan 28 2019A large, world-wide community of physicists is working to realise an exceptional physics program of energy-frontier, electron-positron collisions with the International Linear Collider (ILC). This program will begin with a central focus on high-precision ... More
The International Linear Collider. A European PerspectiveJan 28 2019The International Linear Collider (ILC) being proposed in Japan is an electron-positron linear collider with an initial energy of 250 GeV. The ILC accelerator is based on the technology of superconducting radio-frequency cavities. This technology has ... More
Impact of ion dynamics on laser-driven electron acceleration and gamma-ray emission in structured targets at ultra-high laser intensitiesJan 27 2019We examine the impact of the ion dynamics on laser-driven electron acceleration in an initially empty channel irradiated by an ultra-high intensity laser pulse with $I > 10^{22}$ W/cm$^2$. The negative charge of the accelerated electrons inside the channel ... More
ALEGRO input for the 2020 update of the European StrategyJan 24 2019Jan 30 2019Advanced and Novel Accelerators (ANAs) can provide acceleration gradients orders of magnitude greater than conventional accelerator technologies, and hence they have the potential to provide a new generation of more compact, high-energy machines. In view ... More
Plasma Lenses for Relativistic Laser Beams in Laser Wakefield AcceleratorsJan 23 2019Focusing petawatt-level laser beams to a variety of spot sizes for different applications is expensive in cost, labor and space. In this paper, we propose a plasma lens to flexibly resize the laser beam by utilizing the laser self-focusing effect. Using ... More
Radiation rebound and Quantum Splash in Electron Laser CollisionJan 23 2019The radiation reaction is expected to play a critical role in light-matter interactions at extreme intensity. Knowing key characteristic of this effect will enable its experimental detection and, most importantly, allow to investigate the causality of ... More
Muon CollidersJan 18 2019Muon colliders have a great potential for high-energy physics. They can offer collisions of point-like particles at very high energies, since muons can be accelerated in a ring without limitation from synchrotron radiation. However, the need for high ... More
Low power commissioning of an innovative laser beam circulator for inverse Compton scattering Gamma-ray sourceJan 16 2019We report on the optical commissioning of the high power laser beam circulator (LBC) for the high brightness Compton {\gamma}-ray source Extreme Light Infrastructure for Nuclear Physics. Tests aiming at demonstrating the optical performances of the LBC ... More
Radiation of a Charge Moving in a Wire StructureJan 15 2019A theoretical approach for describing the electromagnetic radiation produced by prolonged electron bunch propagating in the lattice of metallic wires of finite length is presented. This approach is based on vibrator antenna theory and involves approximate ... More
muCool: A novel low-energy muon beam for future precision experimentsJan 15 2019Experiments with muons ($\mu^{+}$) and muonium atoms ($\mu^{+}e^{-}$) offer several promising possibilities for testing fundamental symmetries. Examples of such experiments include search for muon electric dipole moment, measurement of muon $g-2$ and ... More
A high precision neutrino beam for a new generation of short baseline experimentsJan 15 2019The current generation of short baseline neutrino experiments is approaching intrinsic source limitations in the knowledge of flux, initial neutrino energy and flavor. A dedicated facility based on conventional accelerator techniques and existing infrastructures ... More
All Optical Control of Beam Dynamics in a DLAJan 14 2019Dielectric laser acceleration draws upon nano-fabrication techniques to build photonic structures for high gradient electron acceleration. At the small spatial scales characteristic of these structures conventional accelerator techniques become ineffective ... More
Ultrafast Relativistic Electron NanoprobesJan 11 2019One of the frontiers in electron scattering is to couple ultrafast temporal resolution with highly localized probes to investigate the role of microstructure on material properties. Here, taking advantage of the unprecedented average brightness of the ... More
A New Approach for Measuring the Muon Anomalous Magnetic Moment and Electric Dipole MomentJan 10 2019This paper introduces a new approach to measure the muon magnetic moment anomaly $a_{\mu} = (g-2)/2$, and the muon electric dipole moment (EDM) $d_{\mu}$ at the J-PARC muon facility. The goal of this experiment is to measure $a_{\mu}$ and $d_{\mu}$ using ... More
Touschek with AdA in Orsay and the first direct observation of electron-positron collisionsDec 31 2018We describe how the first direct observation of electron-positron collisions took place in 1963-1964 at the Laboratoire de l'Acc\'el\'erateur Lin\'eaire d'Orsay, in France, with the storage ring AdA, which had been proposed and constructed in the Italian ... More
Measurement and modeling of electron-cloud-induced betatron tune shifts at CESRTADec 30 2018We report on extensive measurements at the Cornell Electron-positron Storage Ring of electron-cloud-induced betatron tune shifts for trains of positron bunches at 2.1 and 5.3 GeV with bunch populations ranging between 0.4x10^10 and 9.5x10^10. Measurements ... More
Procedure of simulations for Evaluations of Transient Parameters Stability for RF Cavities Due to Effects of Pulsed RF HeatingDec 26 2018The Pulsed RF Heating (PRFH) is the well known effect in the development of high gradient accelerating cavities. There is a lot of research dedicated to the tolerable strength of electromagnetic field and the corresponding temperature rise leading to ... More
Particle physics applications of the AWAKE acceleration schemeDec 22 2018The AWAKE experiment had a very successful Run 1 (2016-8), demonstrating proton-driven plasma wakefield acceleration for the first time, through the observation of the modulation of a long proton bunch into micro-bunches and the acceleration of electrons ... More
Achievement of Ultra-High Quality Factor in Prototype Cryomodule for LCLS-IIDec 21 2018Jan 08 2019Quality factor is a primary cost driver for high energy, continuous wave (CW) SRF linacs like the LCLS-II X-ray free electron laser currently under construction. Taking this into account, several innovations were introduced in the LCLS-II cryomodule design ... More
Beam break-up current limit in multi-turn ERLs and CBETADec 21 2018This paper uses theory and simulation of the Beam Break-Up instability (BBU) for multi-turn ERLs to determine and to optimize the current limit of the Cornell Brookhaven Energy-Recovery-Linac Test Accelerator (CBETA). Currently under construction at Cornell ... More
Feasibility Study for an EDM Storage RingDec 20 2018Jan 18 2019This project exploits charged particles confined as a storage ring beam (proton, deuteron, possibly $^3$He) to search for an intrinsic electric dipole moment (EDM, $\vec d$) aligned along the particle spin axis. Statistical sensitivities can approach ... More
Design and operation of a prototype interaction point beam collision feedback system for the International Linear ColliderDec 20 2018A high-resolution, intratrain position feedback system has been developed to achieve and maintain collisions at the proposed future electron-positron International Linear Collider (ILC). A prototype has been commissioned and tested with a beam in the ... More
Photonic Crystal-Based Compact High-Power Vacuum Electronic DevicesDec 19 2018This paper considers how the finite dimensions of a photonic crystal placed inside a resonator or waveguide affect the law of electron beam instability. The dispersion equations describing e-beam instability in the finite photonic crystal placed inside ... More
Backward wave oscillator with resonator made of metal foils (photonic BWO)Dec 19 2018Numerical and experimental analysis of high power microwave generation in photonic BWO, which uses foil photonic crystal, is presented. Single frequency excitation of the below cutoff modes in the photonic BWO is analyzed and demonstrated.
The Compact Linear e$^+$e$^-$ Collider (CLIC): Accelerator and DetectorDec 19 2018The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear e$^+$e$^-$ collider under development by international collaborations hosted by CERN. This document provides an overview of the design, technology, and implementation aspects of ... More
Electrostatic deflector studies using small prototypesDec 19 2018The search for electric dipole moments of particles in storage rings requires the development of dedicated deflector elements with electrostatic fields. In these rings, electric deflectors shall be used as bending elements for the charged particles. This ... More
Determination of the magnetic field dependence of the surface resistance of superconductors from cavity testsDec 14 2018We present a general method to derive the magnetic field dependence of the surface resistance of superconductors from the Q-curves obtained during the cryogenic tests of cavities. The results are applied to coaxial half-wave cavities, TM-like "elliptical" ... More
The Compact Linear $e^+e^-$ Collider (CLIC) - 2018 Summary ReportDec 14 2018Dec 17 2018The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear $e^+e^-$ collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and ... More
A doubly-magic storage ring EDM measurement methodDec 14 2018This paper discusses "doubly-magic trap" operation of storage rings with superimposed electric and magnetic bending, to allow the spins of beams of different particle type to be frozen (i.e. both magic) simultaneously. A few doubly-magic cases have been ... More
The Role of Magnetic Flux Expulsion to Reach Q0>3x10^10 in SRF CryomodulesDec 10 2018When a superconducting radiofrequency cavity is cooled through its critical temperature, ambient magnetic flux can become "frozen in" to the superconductor, resulting in degradation of the quality factor. This is especially problematic in applications ... More
A new energy spectrum reconstruction method for Time-Of-Flight diagnostics of high-energy laser-driven protonsDec 04 2018The Time-of-Flight (ToF) technique coupled with semiconductor-like detectors, as silicon carbide and diamond, is one of the most promising diagnostic methods for high-energy, high repetition rate, laser-accelerated ions allowing a full on-line beam spectral ... More
Prediction of Beam Losses during Crab Cavity Quenches at the HL-LHCDec 04 2018Studies of the crab cavities at KEKB revealed that the RF phase could shift by up to 50o within ~50 us during a quench; while the cavity voltage is still at approximately 75% of its nominal amplitude. If such a failure were to occur on the HL-LHC crab ... More
Correlated Energy Spread Compensation in Multi-Stage Plasma-Based AcceleratorsNov 19 2018The extreme electromagnetic fields sustained by plasma-based accelerators allow for energy gain rates above 100 GeV/m but are also an inherent source of correlated energy spread. This severely limits the usability of these devices. Here we propose a novel ... More
Opportunities in Machine Learning for Particle AcceleratorsNov 07 2018Machine learning (ML) is a subfield of artificial intelligence. The term applies broadly to a collection of computational algorithms and techniques that train systems from raw data rather than a priori models. ML techniques are now technologically mature ... More
First Commissioning Results of the Multicusp Ion Source at MIT (MIST-1) for H$_2^+$Nov 05 2018IsoDAR is an experiment under development to search for sterile neutrinos using the isotope Decay-At-Rest (DAR) production mechanism, where protons impinging on $^9$Be create neutrons which capture on $^7$Li which then beta-decays producing $\bar{\nu}_e$. ... More
Machine Parameters and Projected Luminosity Performance of Proposed Future Colliders at CERNOct 30 2018In response to a request from the CERN Scientific Policy Committee (SPC), the machine parameters and expected luminosity performance for several proposed post-LHC collider projects at CERN are compiled: three types of hadron colliders (HL-LHC upgrade, ... More
Muon Colliders, Neutrino Factories, and Results from the MICE ExperimentOct 24 2018Muon colliders and neutrino factories are attractive options for future facilities aimed at achieving the highest lepton-antilepton collision energies and precision measurements of parameters of the Higgs boson and the neutrino mixing matrix. The performance ... More
The new Felsenkeller 5 MV underground acceleratorOct 18 2018Nov 14 2018The field of nuclear astrophysics is devoted to the study of the creation of the chemical elements. By nature, it is deeply intertwined with the physics of the Sun. The nuclear reactions of the proton-proton cycle of hydrogen burning, including the 3He({\alpha},{\gamma})7Be ... More
Accelerator Design for the CHESS-U UpgradeOct 15 2018Jan 31 2019During the summer and fall of 2018 the Cornell High Energy Synchrotron Source (CHESS) is undergoing an upgrade to increase high-energy flux for x-ray users. The upgrade requires replacing one-sixth of the Cornell Electron Storage Ring (CESR), inverting ... More
External Electron Injection for the AWAKE ExperimentOct 09 2018We summarize and explain the realization of witness particle injection into wakefields for the AWAKE experiment. In AWAKE, the plasma wakefields are driven by a self-modulating relativistic proton bunch. To demonstrate that these wakefields can accelerate ... More
Polarized Proton Beams from Laser-induced PlasmasOct 04 2018Dec 21 2018We report on the concept of an innovative source to produce polarized proton/deuteron beams of a kinetic energy up to several GeV from a laser-driven plasma accelerator. Spin effects have been implemented into the PIC simulation code VLPL to make theoretical ... More
Multi-beam RF accelerators for ion implantationSep 23 2018We report on the development of a radio frequency (RF) linear accelerator (linac) for multiple-ion beams that is made from stacks of low cost wafers. The accelerator lattice is comprised of RF-acceleration gaps and electrostatic quadrupole focusing elements ... More
Generation of electron vortices using non-exact electric fieldsSep 20 2018Vortices in electron beams can manifest several types of topological phenomena, such as the formation of exotic structures or interactions with topologically structured electromagnetic fields. For instance, the wavefunction of an electron beam can acquire ... More
High throughput data streaming of individual longitudinal electron bunch profiles in a storage ring with single-shot electro-optical samplingSep 20 2018The development of fast detection methods for comprehensive monitoring of electron bunches is a prerequisite to gain comprehensive control over the synchrontron emission in storage rings with their MHz repetition rate. Here, we present a proof-of-principle ... More
Overestimation of thermal emittance in solenoid scans due to coupled transverse motionSep 17 2018Dec 25 2018The solenoid scan is a widely used method for the in-situ measurement of the thermal emittance in a photocathode gun. The popularity of this method is due to its simplicity and convenience since all rf photocathode guns are equipped with an emittance ... More
NbTi/Nb/Cu multilayer shield for the superconducting shield (SuShi) septumSep 12 2018A passive superconducting shield was proposed earlier to realize a high-field (3-4 T) septum magnet for the Future Circular Collider. This paper presents the experimental results of a potential shield material, a NbTi/Nb/Cu multilayer sheet. A cylindrical ... More
BDSIM: An Accelerator Tracking Code with Particle-Matter InteractionsAug 31 2018Beam Delivery Simulation (BDSIM) is a program that simulates the passage of particles in a particle accelerator. It uses a suite of standard high energy physics codes (Geant4, ROOT and CLHEP) to create a Geant4 model of a particle accelerator that mixes ... More
The FNAL Booster 2nd Harmonic RF CavityAug 28 2018A second harmonic RF cavity which uses perpendicularly biased garnet for frequency tuning is currently being constructed for use in the Fermilab Booster. The cavity will operate at twice the fundamental RF frequency, from ~76 - 106 MHz, and will be turned ... More
Residual orbit of BC bump for CSNS/RCSAug 22 2018In a beam cycle, there is a chicane bump (BC bump) in the injection region of China Spallation Neutron Source (CSNS). It is a core part of the injection system and the important guarantee that the Linac beam injecting into the rapid cycling synchrotron ... More
Dynamic simulations in SixTrackAug 19 2018The DYNK module allows element settings in SixTrack to be changed on a turn-by-turn basis. This document contains a technical description of the DYNK module in SixTrack. It is mainly intended for a developer or advanced user who wants to modify the DYNK ... More
Stable, predictable operation of racetrack coils made of high-temperature superconducting Bi-2212 Rutherford cable at the very high wire current density of more than 1000 A/mm2Aug 08 2018Oct 25 2018Uncertain performance and long training with many unpredictable quenches and slowly increasing quench currents are characteristic of the accelerator magnets needed for high energy particle accelerators, particularly the Nb3Sn magnets planned for future ... More
Slow Extraction of Charged Ion Pulses from the REXEBISAug 08 2018The Isotope mass Separator On-Line DEvice (ISOLDE) facility located at CERN, produces and transports Radioactive Ion Beams (RIBs) at low or high energy through the REX/HIE-ISOLDE linear accelerator, for nuclear physics, astrophysics, solid-state physics ... More
Vortex dynamics and losses due to pinning: Dissipation from trapped magnetic flux in resonant superconducting radio-frequency cavitiesAug 03 2018Oct 22 2018We use a model of vortex dynamics and collective weak pinning theory to study the residual dissipation due to trapped magnetic flux in a dirty superconductor. Using simple estimates, approximate analytical calculations, and numerical simulations, we make ... More
Online storage ring optimization using dimension-reduction and genetic algorithmsJul 27 2018Oct 19 2018Particle storage rings are a rich application domain for online optimization algorithms. The Cornell Electron Storage Ring (CESR) has hundreds of independently powered magnets, making it a high-dimensional test-problem for algorithmic tuning. We investigate ... More
Operation of normal-conducting RF cavities in multi-tesla magnetic fields for muon ionization cooling: a feasibility demonstrationJul 10 2018Ionization cooling is the preferred method for producing bright muon beams. This cooling technique requires the operation of normal conducting, radio-frequency (RF) accelerating cavities within the multi-tesla fields of DC solenoid magnets. Under these ... More
Systematic Studies of the Micro-Bunching Instability at Very Low Bunch ChargesJul 03 2018At KARA, the KArlsruhe Research Accelerator of the KIT synchrotron, the so called short bunch operation mode allows the reduction of the bunch length down to a few picoseconds. The micro- bunching instability resulting from the high degree of longitudinal ... More
RPC upgrade project for CMS Phase IIJun 29 2018Dec 14 2018The Muon Upgrade Phase II of the Compact Muon Solenoid (CMS) aims to guarantee the optimal conditions of the present system and extend the $\eta$ coverage to ensure a reliable system for the High Luminosity Large Hadron Collider (HL-LHC) period. The Resistive ... More
Few-femtosecond Electron Beam with THz-frequency Wakefield-driven CompressionJun 28 2018We propose and demonstrate a novel method to produce few-femtosecond electron beam with relatively low timing jitter. In this method a relativistic electron beam is compressed from about 150 fs (rms) to about 7 fs (rms, upper limit) with the wakefield ... More
Accelerating fields up to 49 MV/m in TESLA-shape superconducting RF niobium cavities via 75C vacuum bakeJun 26 2018In this paper we present the discovery of a new surface treatment applied to superconducting radio frequency (SRF) niobium cavities, leading to unprecedented accelerating fields of 49 MV/m in TESLA-shaped cavities, in continuous wave (CW); the corresponding ... More
Coherent Space-Charge to X-ray Up-Conversion in GasJun 25 2018We theoretically investigate the use of the intense transverse field created by a relativistic electron bunch to drive strong-field processes. Such bunches can be easily implemented from beam shaping in existing electron accelerators. We focus on the ... More
Passive Ballistic Microbunching of Non-Ultrarelativistic Electron Bunches using Electromagnetic Wakefields in Dielectric-Lined WaveguidesJun 25 2018Temporally-modulated electron beams have a wide array of applications ranging from the generation of coherently-enhanced electromagnetic radiation to the resonant excitation of electromagnetic wakefields in advanced-accelerator concepts. Likewise producing ... More
Alternating Phase Focusing for Dielectric Laser AccelerationJun 19 2018The concept of Dielectric Laser Acceleration (DLA) provides highest gradients among non-plasma particle accelerators. However, stable beam transport and staging have not been shown experimentally yet. We present a scheme that confines the beam longitudinally ... More
Garnet Ring Measurements For The Fermilab Booster 2nd Harmonic CavityJun 14 2018A perpendicularly biased tuneable 2nd harmonic cavity is being constructed for use in the Fermilab Booster. The cavity's tuner uses National Magnetics AL800 garnet as the tuning media. For quality control, the magnetic properties of the material and the ... More
Computation and Numerical Simulation of Focused Undulator Radiation for Optical Stochastic CoolingJun 14 2018Optical stochastic cooling (OSC) is a promising technique for the cooling of dense particle beams. Its operation at optical frequencies enables obtaining a much larger bandwidth compared to the wellknown microwave-based stochastic cooling. In the OSC ... More
The effect of air exposure on SEY and surface composition of laser treated copper applied in acceleratorsJun 11 2018In this paper, the effect of air exposure and acetone cleaning on the secondary electron yield (SEY) of laser treated copper were investigated and discussed. The SEY of laser treated copper samples after acetone cleaning and air exposure were measured. ... More
Testing the influence of acceleration on time dilation using a rotating MÖssbauer absorberMay 24 2018The aim of the experiment series was to test the influence of acceleration on time dilation by measuring the relative spectral shift between the resonance spectra of a rotating Mossbauer absorber with acceleration anti-parallel and parallel to the direction ... More
Optimizing Laser Wakefield Acceleration in the Nonlinear Self-Guided Regime for Fixed Laser EnergyMay 22 2018May 25 2018The scaling laws for laser wakefield acceleration in the nonlinear, self-guided regime [Lu et al. Phys. Rev. Spec. Top. Accel. Beams 10, 061301 (2007)] are examined in detail using the quasi-3D version of the particle-in-cell code OSIRIS. We find that ... More
Study of Collective Effects in the FCC-ee ColliderMay 22 2018The Future Circular Collider (FCC) study aims at designing different options of a post-LHC collider. The high luminosity electron-positron collider FCC-ee based on the crab waist concept is considered as an intermediate step on the way towards FCC-hh, ... More
A near-ideal dechirper for plasma-based electron and positron acceleration using a hollow channel plasmaMay 18 2018Nov 07 2018Plasma-based electron and positron wakefield acceleration has made great strides in the past decade. However one major challenge for its applications to coherent light sources and colliders is the relatively large energy spread of the accelerated beams, ... More
High efficiency laser-assisted H- charge exchange for microsecond duration beamsMay 11 2018Laser-assisted stripping is a novel approach to H- charge exchange that overcomes long-standing limitations associated with the traditional, foil-based method of producing high-intensity, time-structured beams of protons. This paper reports on the first ... More
Terahertz streaking of few-femtosecond relativistic electron beamsMay 10 2018Streaking of photoelectrons with optical lasers has been widely used for temporal characterization of attosecond extreme ultraviolet pulses. Recently, this technique has been adapted to characterize femtosecond x-ray pulses in free-electron lasers with ... More
Particle-in-cell simulation of x-ray wakefield acceleration and betatron radiation in nanotubesMay 09 2018Though wakefield acceleration in crystal channels has been previously proposed, x-ray wakefield acceleration has only recently become a realistic possibility since the invention of the single-cycled optical laser compression technique. We investigate ... More
Commissioning And First Results From The Fermilab Cryomodule Test StandMay 07 2018A new test stand dedicated to Superconducting Radiofrequency (SRF) cryomodule testing, CMTS1, has been commissioned and is now in operation at Fermilab. The first device to be cooled down and powered in this facility is the prototype 1.3 GHz cryomodule ... More
Terahertz-based attosecond metrology of relativistic electron beamsMay 05 2018Photons, electrons, and their interplay are at the heart of photonic devices and modern instruments for ultrafast science [1-10]. Nowadays, electron beams of the highest intensity and brightness are created by photoemission with short laser pulses, and ... More
Implementation of Design Changes Towards a More Reliable, Hands-off Magnetron Ion SourceMay 04 2018As the main $H^{-}$ ion source for the accelerator complex, magnetron ion sources have been used at Fermilab since the 1970s. At the offline test stand, new R&D is carried out to develop and upgrade the present magnetron-type sources of $H^{-}$ ions of ... More
Limitations on Energy Spread and Bunch Duration in Plasma-Based Accelerators Due to Betatron MotionApr 29 2018Plasma-based accelerators (PBAs) offer a path towards highly compact particle accelerators with GeV beams and short electron bunches that could drive a new generation of Free-Electron Lasers (FELs). However, a beam energy spread below current state-of-the-art ... More
Numerical Simulations to Evaluate and Compare the Performances of Existing and Novel Degrader Materials for Proton TherapyApr 28 2018The performance of the energy degrader in terms of beam properties directly impacts the design and cost of cyclotron-based proton therapy centers. The aim of this study is to evaluate the performances of different existing and novel degrader materials. ... More
Accelerating StructuresApr 23 2018In this lecture the basic concepts of electromagnetic waves in accelerating structures are discussed. After a short introduction on the propagation of electromagnetic waves and on the concept of travelling wave and standing wave structures, the most important ... More
XPS studies of nitrogen doping niobium used for accelerator applicationsApr 20 2018Nitrogen doping study on niobium (Nb) samples used for the fabrication of superconducting radio frequency (SRF) cavities was carried out. The samples' surface treatment was attempted to replicate that of the Nb SRF cavities, which includes heavy electropolishing ... More
Magnetic properties and hydrides precipitation observation of nitrogen doping niobium used for accelerator applicationsApr 20 2018Nitrogen doping study on niobium (Nb) samples used for the fabrication of the superconducting radio frequency (SRF) cavities has been carried out. The samples' surface treatment was attempted to replicate that of the SRF cavities, which includes heavy ... More
Generation and Measurement of Sub-Micrometer Relativistic Electron BeamsApr 11 2018The generation of low-emittance electron beams has received significant interest in recent years. Driven by the requirements of X-ray free electron lasers, the emittance of photocathode injectors has been reduced significantly, with a corresponding increase ... More
First storage of ion beams in the Double Electrostatic Ion-Ring Experiment - DESIREEMar 31 2018We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment; DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C$_n^-$, $n=1,2,3,4$) in a sputter ion source. ... More
Scaled Prototype of a Tantalum Target Embedded in Expanded Graphite for Antiproton Production: Design, Manufacturing and Testing under Proton Beam ImpactsMar 26 2018Aug 13 2018This study presents a further step within the ongoing R&D activities for the redesign of the CERN's Antiproton Decelerator Production Target (AD-Target). A first scaled target prototype, constituted of a sliced core made of ten Ta rods -8 mm diameter, ... More
The upgrade of J-PARC linac low-level radio frequency systemMar 24 2018The J-PARC linac was consist of 324MHz low-{\beta} section and 972MHz high-{\beta} section. There is a total of 48 stations. And each station was equipped with an independent LLRF (Low-Level Radio Frequency) system to realize an accelerating field stability ... More