gun
MOP7001
Upgrade of the arcing suppression system for the waveguides in the European XFEL
634
When planning the European XFEL, the decision was made to avoid using SF6 in the waveguide systems. Instead, air was used at slight to high overpressure. When slight overpressure is used, the air is also in motion. The air flow travels from the RF source towards the cavities and is released again before the coupler. This ensures that, in our non-gas-tight waveguide system, the air quality in the waveguides corresponds to the air quality supplied by the compressor. Particles and ionised air that could promote arcing are blown out. Originally, the air pressure was generated by local compressors and the air used came from the ambient atmosphere. Now, the accelerator’s central compressed air system is utilised. Locally, only the newly developed controls for air pressure and flow remain. The advantage of the central compressed air supply lies in the significantly better air quality and greater operational reliability.
Paper: MOP7001
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-MOP7001
About: Received: 07 May 2026 — Revised: 17 May 2026 — Accepted: 17 May 2026 — Issue date: 22 May 2026
MOP7192
Design of an RF-gridded gun for a high-efficiency tristron
1119
The RF gridded gun is a key component of the RF power sources chosen for the FCC-ee tristron. It enables the generation of bunched electron beams via the application of an RF voltage across the cathode-grid gap. The tristron allows a compact tube architecture and provides high RF power production efficiency. The emitted, grid intercepted, and transmitted beam currents are governed by the applied RF grid voltage and DC cathode voltage, providing additional degrees of freedom for controlling the bunch formation. For continuous wave tristron operation at an RF power level of 0.5 MW in the UHF band, particular attention must be paid to several critical design aspects, including beam grid interception, beam optics design, thermomechanical effects, and stress. These factors strongly influence the operational stability, device lifetime, and overall performance. The current status of the RF gridded gun design for the tristron is reported
Paper: MOP7192
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-MOP7192
About: Received: 12 May 2026 — Revised: 17 May 2026 — Accepted: 19 May 2026 — Issue date: 22 May 2026
MOP8303
Standard and microbeam LINATRONs by Varex Imaging Corporation
1141
At Varex Imaging Corporation, High Energy Systems (HES) Department staff with help and support of our Production and Imaging groups continue adding new features to our LINATRON linear accelerator (LINAC) systems and transitioning new developments to our products. HES is at the final stages of productizing our usual LINATRONs, equipped with our new, in-house developed and built Accelerator Beam Centerlines (ABC). The products we offer today match or exceed the older products specifications, which were offered before we established our own ABC development and production line. In addition, we are making good progress on our new Microbeam LINATRON (MBL) systems, and we present the latest results on our MBL production prototypes. Our 6 MeV MBL6 prototype has been packaged, and it is under extensive testing and qualification process, getting ready for demonstration to our customers and for delivery. The similar packaging of our 3 MeV and 9 MeV LINATRON systems offers options of Ultra Low Leakage (ULL) shielding and of an integrated design packaging, now both for our security LINACs and for NDT LINACs under development.
Paper: MOP8303
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-MOP8303
About: Received: 12 May 2026 — Revised: 17 May 2026 — Accepted: 18 May 2026 — Issue date: 22 May 2026
MOP8304
Measuring and characterizing beam energy of a compact medical linear accelerator
1144
Tong Chen* (RefleXion Medical Inc.) Liang Huo, Tong Li, Hao Tao, Zhen Feng, Liang Hu, Lin Zhou, Yongtao Liu* (Chengdu Elekom Vacuum Electron Technology Co. Ltd) Beam energy is an important parameter of linear accelerator. Compact linacs for medical or industrial applications are usually not equipped with beam monitors. The commonly used methods are “half value layer” (HVL) in industrial and “Percentage Depth Dose” (PDD) in medical to evaluate the beam energy of linac. However, these methods are not easily and accurately carried out, the HVL method needs big and heavy steel plates to prevent scattering x ray beams and PDD method need standard beam position and expensive 3d water tank to measure the beam energy. Most importantly, those methods cannot measure electron beam energy, but the photon distribution generated through Bremsstrahlung. This article introduced a method to measure and characterize the average electron beam energy when hitting the target by combining the external measurements and simulation beam profile results under different deflection magnetic field generated by steering coils. This method not only gives confidence in developing and operating the medical equipment but also reveals relation between beam energy and RF power settings. In addition, this paper provides energy and dose output variation across the RF pulse. This data provides guidance for proper setting of gun pulse width and timing.
Paper: MOP8304
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-MOP8304
About: Received: 30 Mar 2026 — Revised: 16 May 2026 — Accepted: 16 May 2026 — Issue date: 22 May 2026
TUP2316
Machine Learning based preventive maintenance and autonomous power control for RF cavities in a free-electron laser
1299
This project develops a machine learning–based system to prevent RF cavity trips in the free-electron laser by autonomously controlling the applied RF power. Sudden vacuum and current fluctuations within the cavities can cause reflections that trip the machine, and continuous manual monitoring throughout the conditioning process isn't feasible. To address this and potentially improve the conditioning efficiency, process-variable data was collected and analyzed to identify patterns in cavity behavior across operating power levels. A hybrid model combining clustering methods, linear regression, and a classifiers was designed to categorize current ranges, estimate baseline behavior, and detect anomalies. The resulting control program evaluates the machine state over short intervals, decreases power during unsafe conditions, increases it during prolonged stability, and can automatically reset the RF system after a trip. This approach enables faster and safer conditioning of the RF cavities, reduces operator workload, and provides a pathway toward fully autonomous preventive maintenance.
Paper: TUP2316
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP2316
About: Received: 01 Apr 2026 — Revised: 17 May 2026 — Accepted: 17 May 2026 — Issue date: 22 May 2026
TUP2330
RF conditioning and microwave gun simulations for the University of Hawai‘i Linac and FEL
1306
The S-band electron linac and free-electron-laser facility at the University of Hawai‘i at Manoa is being recommissioned after an extended period of inactivity. Following the restoration of vacuum and thermionic cathode systems, recent work focused on the high-power RF chain and on conditioning of the linac and microwave electron gun. We report RF conditioning measurements obtained during progressive power-up sessions at 1-4~Hz, including forward power delivered to the linac and forward and reflected power at the microwave gun. The linac RF response is stable and consistent with legacy calibrations, while the gun exhibits strong multipacting signatures. To guide the next conditioning campaign, we also present the developing RF-Track model of the thermionic TM010 gun, incorporating field maps, space charge, and beam loading.
Paper: TUP2330
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP2330
About: Received: 13 May 2026 — Revised: 18 May 2026 — Accepted: 20 May 2026 — Issue date: 22 May 2026
TUP2349
Finite element studies of the CANREB electron gun for a test stand setup
1351
The CANadian Rare isotope facility with Electron Beam ion source (CANREB) is an important component of the Advanced Rare IsotopE Laboratory (ARIEL) at TRIUMF. CANREB will deliver highly charged radioactive ion (HCI) beams for post-acceleration to nuclear physics experiments. Ion beams injected into CANREB are bunched using a ra- diofrequency quadrupole (RQB) cooler-buncher and energy adjusted using a pulsed drift tube for injection into an elec- tron beam ion source (EBIS) charge state breeder. Charge breeding occurs by collisions with an electron beam (up to 15 keV, 500 mA) produced by an electron gun. During EBIS commissioning, the electron gun became unstable at currents above 40 mA, with a large fraction of the beam intercepted by the anode. To address this issue, an electron gun with an updated design is planned to be fabricated and installed in CANREB. In order to characterise the new elec- tron gun, a test-stand will be built allowing for systematic testing. This paper describes a full simulation model of the test-stand using FEA software TRAK.
Paper: TUP2349
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP2349
About: Received: 12 May 2026 — Revised: 17 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
TUP2629
Generation and diagnostics of nanosecond-interval laser pulse trains with femtosecond-level timing control for the Korea-4GSR photocathode RF gun
1413
The Korea-4GSR (4th Generation Storage Ring) requires a highly stable and precisely synchronized laser pulse train to drive its photocathode RF gun in multi-bunch mode. To meet this requirement, we developed a laser system capable of generating nanosecond-interval pulse trains with femtosecond-level timing control. The pulse train is formed using a beam-split/delay-and-combine method, producing a 64-pulse sequence with 2 ns separation, synchronized to a 500 MHz RF reference. To further enhance synchronization accuracy and diagnose timing jitter at the femtosecond scale, a 500 MHz femtosecond oscillator is being developed and integrated into the system. This fs-oscillator enables precise timing diagnostics, long-term drift monitoring, and improved stability for multi-bunch operation. The combined system is designed to provide low-emittance, low-energy-spread electron bunches required for Korea-4GSR’s high-brightness injector and ensures reliable operation in both single-shot and multi-bunch modes.
Paper: TUP2629
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP2629
About: Received: 04 May 2026 — Revised: 20 May 2026 — Accepted: 20 May 2026 — Issue date: 22 May 2026
TUP2666
RF Commissioning Results in the SHINE
1463
SHINE is an 8 GeV continuous-wave (CW) free-electron laser (FEL) facility, mainly composed of an injector, a linear accelerator, an undulator segment, and experimental beamlines. Currently, for the accelerator section, the commissioning of the injector and the L1 segment of the linear accelerator has been completed. The RF structures in these two segments include a VHF electron gun, an L-band buncher, a dual-feed superconducting cavity, an injection eight-cavity module, two standard 1.3 GHz cryo-modules, and two 3.9 GHz cryo-modules. The RF specification of these accelerating structures have all met the design requirements. This paper will introduce the final parameters achieved through the commissioning of these accelerating structures and some problems encountered during the commissioning process.
Paper: TUP2666
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP2666
About: Received: 10 May 2026 — Revised: 22 May 2026 — Issue date: 22 May 2026
TUP2670
The collimator system for reducing the dark current in NSRRC photoinjector
1469
The NSRRC photoinjector generates ultrashort electron beams for the production of superradiant radiation in the 100–500 μm wavelength range using a gap tunable U100 planar undulator. The accelerator consists of an S band, laser driven photocathode RF gun equipped with a compensation solenoid, followed by a 5 m long linear accelerator. Sub picosecond electron bunches are achieved through velocity bunching in the linac. Under specific operating conditions, electrons emitted from the cathode surface may be accelerated to high energies independently of the main beam, which continues to gain energy in the linac. These stray electrons can impact the vacuum chamber, producing unwanted radiation that poses risks to both accelerator components and radiation safety. To suppress dark current, a collimator was installed between the photocathode gun and the linac to intercept these electrons prior to downstream transport. Experimental measurements and numerical simulations are presented, demonstrating the effectiveness of the collimator system in reducing dark current.
Paper: TUP2670
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP2670
About: Received: 11 May 2026 — Revised: 18 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
TUP2697
Analysis of beam loading effect of dark current in C-band photocathode electron gun
1520
In the research on high-gradient photocathode electron guns, the existence of dark current not only affects the measurement of photo-beam but also causes problems such as secondary electron multiplication and an increased difficult of condition. In this paper, the sources of dark current emission inside the electron gun and their impact duiring the power test are discussed through simulations. Additionally, combined with the test results from the C-band electron gun test platform in the pre-research project of the Southern Advanced Photon Source, the beam loading effect introduced by dark current is analyzed. The results show that when the dark current in the test is > 10 mA, it will increase the coupling parameters of the cavity and reduce the cathode accelerating field gradient.
Paper: TUP2697
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP2697
About: Received: 13 May 2026 — Revised: 18 May 2026 — Accepted: 19 May 2026 — Issue date: 22 May 2026
TUP3069
Multi-objective Bayesian optimisation (MOBO) for high-quality photoinjector optimisation
1650
Optimising SRF photoinjectors is a challenging task due to the high-dimensional, nonlinearly coupled parameters and competing objectives such as transverse emittance and bunch length. Conventional methods such as manual tuning or MOGA require thousands of evaluations and are impractical for routine operation or computationally expensive simulations. This work presents a multi-objective Bayesian optimisation (MOBO) approach that uses Gaussian-process surrogate models and tunable, uncertainty-aware acquisition functions to identify Pareto-optimal solutions in an order of magnitude fewer evaluations. When applied to the 1.4-cell SRF photoinjector at SEALab, and the 1.6-cell SRF gun and 20m injector beamline for EuXFEL, this optimisation outperforms MOGA in solution-efficiency and provides interpretable sensitivity information for injector tuning. These results demonstrate the potential of MOBO as an efficient, machine-ready strategy for SRF photoinjector optimisation.
Paper: TUP3069
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP3069
About: Received: 12 May 2026 — Revised: 20 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
TUP3073
Study and test of a triode gun for the FLASH electron LINAC at Sapienza
1658
A 24-MeV prototype LINAC is under development at Sapienza University of Rome for FLASH radiobiological studies. The injector is a 12-keV triode thermionic electron gun from HeatWave Labs, providing grid-controlled current modulation for high current, low perveance, and short-pulse operation. To optimize its integration with the 24 MeV C-band hybrid standing and travelling wave structure, extensive particle tracking simulations of electron gun were performed using CST Particle Studio. Parametric scans of the anode voltage and grid potential were used to evaluate beam current, perveance, and emittance, identifying operating points that balance beam stability and charge for FLASH applications. As the modern dispenser cathode requires stringent vacuum conditions below 1E-6 mbar, the LINAC was also modeled in Molflow+ to predict pressure profiles under realistic gas-load scenarios. Simulations revealed a potential vacuum limitation near the gun, leading to the design and implementation of an additional pumping port for better evacuation of gas molecules. These results are benchmarked with initial experimental tests performed on an electron gun test bench at Sordina IORT Technologies and with Flash LINAC at the department of Basic and Applied Sciences for Engineering in Sapienza. The combined simulation and experimental validation provides key requirements of an injector for a compact commercial LINACs for Flash applications.
Paper: TUP3073
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP3073
About: Received: 11 May 2026 — Revised: 16 May 2026 — Accepted: 19 May 2026 — Issue date: 22 May 2026
TUP3075
Evidence for RF breakdowns causing surface anomalies on caesium Telluride cathodes at Clara
1666
The Compact Linear Accelerator for Research and Applications (CLARA) at Daresbury Laboratory has recently undertaken an upgrade of its photocathodes from using a copper emission surface to using caesium telluride (Cs\textsubscript{2}Te). During the conditioning of the first Cs\textsubscript{2}Te cathode a significant number of RF breakdowns were detected, and so that cathode was replaced; subsequent inspection of the cathode following removal identified a number of surface defects. To better study the second cathode, a diagnostic camera was used to collect images of the surface \textit{in situ} during RF conditioning; the frequent formation over time of surface defects was observed. In this paper we present a statistical analysis of the breakdown events and surface image data, utilizing cross-correlation of the signal derivatives to account for cumulative trends. The analysis reveals a correlation between the rate of defect formation and the incidence of RF breakdowns, with a Pearson coefficient of $r = 0.59$ at zero time lag. These results provide quantitative evidence that RF breakdown events are the likely driver of surface morphology changes on Cs\textsubscript{2}Te cathodes.
Paper: TUP3075
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP3075
About: Received: 15 May 2026 — Revised: 18 May 2026 — Accepted: 20 May 2026 — Issue date: 22 May 2026
TUP3076
Recent dark current measurements on the CLARA S-band RF electron guns
1670
The CLARA accelerator at Daresbury Laboratory has recently commissioned a new electron gun as part of a larger upgrade to the machine. The new gun (‘HRRG’) is a high rep rate (400 Hz) 1.5 cell cavity (3 GHz fundamental frequency) designed to produce low emittance beams up to 5 MeV/c, with cathode fields up to 120 MV/m and RF pulse lengths of up to 3 us. The previous CLARA gun (‘LRRG’) was a similar 2.5 cell device but low rep rate (10 Hz). Dark current emitted from the gun is an important issue for several reasons, so is monitored and managed throughout CLARA commissioning and user operation. We present results from the dark current measurements from the new HRRG gun through its commissioning and early stage operation, and make a comparison to those taken from the previous LRRG gun.
Paper: TUP3076
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP3076
About: Received: 16 Apr 2026 — Revised: 18 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
TUP7623
Design and implementation of ridge waveguides for dual-mode microwave structure
1823
The dual-mode microwave structure is receiving increasing attention and research. In the application of dual-mode structures, it is necessary to solve the problem feeding microwave power at different frequencies. One method is to use complex waveguide components, such as first and second harmonic photocathode bimodal gun, which consists of the assembly of the directional coupler and the mode launcher. The structure combines the S-band and C-band power into a waveguide and feeds them into the dual-mode electronic gun. Another method is to use ridge waveguide to achieve selectable transmission or blocking of specific frequency. Currently, the ridge waveguide has been applied to dual-mode deflecting structure. This paper presents a X-band bandpass filter has been engineered to achieve a power reflection level of less than -30 dB at 12 GHz and a power transmission level of less than -40 dB at 24 GHz.
Paper: TUP7623
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP7623
About: Received: 10 May 2026 — Revised: 16 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
TUP7627
Beam test of C-band Compact accelerating structure made of longitudinally-split two halves
1838
Our 6 MeV medical C-band accelerating structure is assembles using the disk-stacked method, where multiple oxygen-free copper components are stacked along the beam axis. The design incorporates the side-coupled (SC) structure and the re-entrant structure with an accelerating gap at the center of the cavity. Due to the complex shape and the large number of components, there are difficulties in manufacturing efficiency. On the other hand, the longitudinally-split method divides the structure along a plane including the beam axis, independent of the number of cells, typically into only two halves or four quadrants, which significantly reduces the number of components. Building on the development experience of the quadrant-type X-band accelerating structure in the CLIC project, we have been working on the development of a compact, high-gradient, high-shunt impedance, SC-type C-band accelerating structure based on this configuration. We had reported previous work, fabrication of the full-scale structure, low-power RF test result, and preliminary first beam acceleration test at an energy level limited by the testing facility. In this presentation, we will report the progress of our work, RF conditioning and a high-power beam test in the actual operating conditions.
Paper: TUP7627
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-TUP7627
About: Received: 08 May 2026 — Revised: 19 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
WEO5M05
Low-emittance, Low-charge optimization of the Argonne Wakefield Accelerator for the Nanopatterned Microbunching Experiment
2188
Low-emittance microbunched electron beams are a key ingredient in free-electron lasers (FELs), facilitating gain and coherence in radiation production. It has been proposed, such as by the Compact X-ray FEL (CXFEL) group at Arizona State University, that nano-scale microbunching could be produced by rotating transverse beamlets into the longitudinal plane. Such a technique could make short-wavelength FELs much more compact, reducing cost. Thus, a collaboration has been formed to test this principle using the emittance exchange (EEX) beamline of the Argonne Wakefield Accelerator (AWA).* ** This experiment will take micro-scale transverse modulations on a TEM grid and produce mico-to-nano scale microbunches. Performing this with AWA’s 40 MeV electron beam will require low normalized emittance (~50 nm*rad), and low charge (~1pC) electron bunches that are not commonly produced at AWA. These proceedings will detail our work to produce and characterize this low emittance in the AWA beamline.
Paper: WEO5M05
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEO5M05
About: Received: 13 May 2026 — Revised: 19 May 2026 — Issue date: 22 May 2026
WEP1352
High-Average-Current, High-Brightness HVDC Electron Gun development for EIC Hadron Cooling
2314
The hadron cooler is an essential system for achieving high luminosity in the Electron-Ion Collider (EIC). The required electron source parameters exceed the current state of the art. We are conducting an electron-source R&D program aimed at producing an average current above 75 mA with bunch charges of 1–3 nC. This proceeding outlines the high-voltage design of a DC gun operating at 500 kV, with conditioning capability up to 600 kV. The design incorporates several unique features, including an inverted ceramic insulator at this voltage level, active cathode cooling, and large single-crystal multi-alkali photocathodes grown on silicon carbide substrates. This paper presents recent progress on gun construction, commissioning plans, and preliminary major components test results.
Paper: WEP1352
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEP1352
About: Received: 13 May 2026 — Revised: 17 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
WEP1353
Space Charge Effects on Spin Polarization in a High-Intensity Preinjector
2318
We are designing a high-charge, high-polarization preinjector for the EIC. Employing a Wien filter as the spin rotator immediately after the gun offers multiple advantages over the traditional dipole–solenoid spin rotator placed after the linac. However, this represents the first attempt to operate a Wien filter in a strong–space-charge environment. The energy spread and space-charge forces may influence spin dynamics. We analytical studied investigates space-charge effects on electron-beam polarization across the low-energy region, from the polarized electron gun to the linac entrance. We analyze spin degradation in the gun-to–Wien filter interface, within the Wien filter itself, and in the bunching section. A comprehensive evaluation of polarization-degradation mechanisms under space-charge conditions is presented. We further perform spin tracking through the full low-energy beamline using the space charging with spin tracking code General Particle Tracer (GPT) to validate the analytical model and incorporate higher-order effects.
Paper: WEP1353
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEP1353
About: Received: 13 May 2026 — Revised: 18 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
WEP4654
Synchronization of longitudinal hollow electron beam and ion beam in a storage ring
2564
In the cooling storage ring, a low-temperature electron beam from the electron cooling device overlaps with a high-temperature ion beam in the storage ring. The overlap occurs at the same average velocity for a certain distance. Through Coulomb interaction, electrons absorb excess energy from ions. This reduces the transverse emittance and longitudinal momentum spread of the ion beam, and increases its phase space density. When cooling a Gaussian-distributed pulsed ion beam with a longitudinal hollow electron beam, the pulses must align at the longitudinal center. This article introduces a synchronization scheme for longitudinal hollow electron beams and ion beams. The scheme includes pulse measurement, triggering delay, synchronization monitoring, and future feedback for automatic correction. This ensures the pulses are always synchronized. The scheme will be used in longitudinal hollow electron beam cooling experiments and will support future investigations into the cooling process.
Paper: WEP4654
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEP4654
About: Received: 01 Apr 2026 — Revised: 18 May 2026 — Issue date: 22 May 2026
WEP5081
Modelling of the HB2TF injector in COMSOL with benchmarking using Astra and RF-track
2748
A comprehensive electromagnetic and beam-dynamics model of the High Brightness Beam Test Facility (HB2TF) electron injector under development at INFN-LASA has been implemented using COMSOL Multiphysics. The model incorporates the DC photocathode gun and the low-energy transport line. Three-dimensional electric and magnetic field distributions were computed and employed for particle tracking within COMSOL, enabling analysis of field effects, mesh resolution impacts, and space-charge contributions. The resulting field maps were exported and imported into ASTRA and RF-Track simulation codes to perform cross-validation of beam dynamics. Comparative studies focus on transverse emittance, bunch length, energy spread, and sensitivity to field map resolution. This work establishes a validated modelling workflow for the HB2TF injector and provides crucial input for its optimisation and future commissioning.
Paper: WEP5081
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEP5081
About: Received: 12 May 2026 — Revised: 18 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
WEP5090
Status of the PERLE’s injector
2770
The ERL accelerator called PERLE is under construction on the campus of Paris-Saclay university. PERLE is an Energy Recovery Linac which aims to reach 250 MeV 20 mA cw, namely 5 MW of beam power. First brick of this accelerator is the injector whom the main components are the DC photo-injector and a booster holding 4 superconducting cavities. This paper will give an overview of the injector’s design, technical details about major components and the schedule of the construction.
Paper: WEP5090
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEP5090
About: Received: 12 May 2026 — Revised: 16 May 2026 — Accepted: 17 May 2026 — Issue date: 22 May 2026
WEP5120
Beam Dynamics Study for a Modified Low-Emittance RF Photogun
2854
High-brightness and low-emittance beams generated in RF-gun–based accelerators are essential for a number of applications, such as free-electron lasers (FELs), ultrafast electron Diffraction facilities and THz radiation sources. In these accelerators, the final beam characteristics are determined both, by the properties of the electron gun and by the influence of the electromagnetic system along the beamline. To meet the requirements imposed on beam characteristics, it is essential to identify the optimal parameters of the RF gun and the magnetic system. In this paper, beam dynamics studies of a modified RF photogun for the AREAL and REGAE accelerators are presented, with emphasis on transverse emittance compensation. Simulations were conducted by adjusting the parameters of the focusing and RF systems to identify the optimal configuration of the modified RF gun.
Paper: WEP5120
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEP5120
About: Received: 13 May 2026 — Revised: 21 May 2026 — Issue date: 22 May 2026
WEP5127
High-Level Applications for LINAC Commissioning at ELI-NP
2866
The ELI-NP (Extreme Light Infrastructure – Nuclear Physics) Gamma-ray Beam Source (ELI-GBS), currently under construction, employs an 800 MeV linear accelerator (LINAC) to generate high-brightness gamma rays through laser–electron interactions. Its control system is designed as a distributed, EPICS-based architecture, where engineering-level control is provided for devices such as LLRF, modulators, magnets, profile monitors, and current monitors. A set of high-level application tools is required for LINAC beam commissioning, tuning, and the measurement of key accelerator parameters. To meet the beam diagnostic capabilities and performance requirements of the commissioning process, we have developed Python-based high-level application software to support essential commissioning tasks, including gun phase scans, emittance measurements, and beam energy measurements. The software uses the pyepics package to interface with engineering-level device IOCs. To support visualization and offline simulation, a set of Python soft IOCs has also been implemented, enabling realistic emulation of device behavior and data acquisition workflows. The online measurement capabilities of the system will be validated during the upcoming RF Gun commissioning and the subsequent LINAC commissioning phases.
Paper: WEP5127
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEP5127
About: Received: 18 Apr 2026 — Revised: 15 May 2026 — Accepted: 22 May 2026 — Issue date: 22 May 2026
WEP6036
Beam positions monitors for PERLE injector
3006
PERLE is an Energy-Recovery Linac (ERL) to be constructed at IJCLab in Orsay. It will be the First ever multi-turn ERL with superconducting RF (SRF) acceleration, and the first ERL with the ambition to reach 5MW beam operation. Diagnostics are a key element for PERLE operation and among diagnostics, Beam position monitors (BPMs) cover a wide range of applications. We report BPM goals for a proper operation of PERLE, it also details the design of BPM detectors and eludes the steps for their realization. it finally discusses the design of BPM electronics to match the presence of multiple beams which need to be individually diagnosed and controlled.
Paper: WEP6036
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEP6036
About: Received: 06 May 2026 — Revised: 18 May 2026 — Accepted: 20 May 2026 — Issue date: 22 May 2026
WEP6148
Detuning estimation for a doubly-fed normal-conducting gun
3258
At the European Free-Electron Laser (EuXFEL) superconducting linac, a revised normal-conducting gun design with symmetrical feed was successfully installed and tested. Thermal expansion of the solid copper body dominantly affects the detuning transients of this cavity. To improve accuracy, and add time resolution over the duration of a pulse, we implemented and tested an observer that estimates the resonance frequency over time using a parameter-identified white-box model of the RF network. Results were validated against forward and reflected power couplers, cavity voltage, and an algebraic stationary approximation.
Paper: WEP6148
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-WEP6148
About: Received: 08 May 2026 — Revised: 18 May 2026 — Issue date: 22 May 2026
THP2049
Off-phase injection simulations for MAX 4U
3537
The MAX IV injector, including a full energy linac and a photo gun, offers a unique capability to deliver low- emittance, well-timed electron pulses suitable for injection. This makes on-axis, off-phase, on-energy injection an at- tractive option for future operation of the upgraded 3 GeV storage ring, MAX 4U, where stronger focusing, reduced magnet apertures, and narrow-gap undulators all limit the transverse acceptance and challenge the present off-axis MIK scheme. Additionally, the significantly reduced emittance makes injected beam perturbations less transparent to the beamlines. In this work, we investigate off-phase injection for the technical design lattice candidate (TDR-1) and show through simulations that stable capture is achievable despite the reduced dynamic aperture. We also evaluate how the characteristics of the photo gun beam support the longitu- dinal phase-space requirements of on-axis, off-phase, on- energy injection. These results indicate that the combination of a full energy linac, photo gun-based injector and off-phase injection provide a promising path forward for injection into a low-emittance storage ring at MAX IV
Paper: THP2049
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2049
About: Received: 13 May 2026 — Revised: 21 May 2026 — Issue date: 22 May 2026
THP2067
Investigation of thermal degradation and stability in multi-alkali antimonide photocathodes: NaKSb (Cs) vs KCsSb
3576
Multi-alkali antimonide photocathodes have emerged as promising photoemissive materials for electron sources in high-repetition-rate free-electron laser (FEL) applications due to their low thermal emittance and high quantum efficiency in the green wavelength region. To evaluate their feasibility for operation in high-gradient RF guns, a collaborative effort between DESY-PITZ and INFN-LASA was initiated to develop and characterize multi-alkali photocathode materials under operative condition. As part of this effort, a NaKSb(Cs) photocathode belonging to the multi-alkali antimonide family was grown on a molybdenum substrate using a sequential deposition method in the new preparation system at INFN-LASA. A thermal degradation study of this photocathode was conducted, and its behavior was compared with a KCsSb film. This contribution presents the experimental results of the NaKSb(Cs) photocathode, focusing on its thermal degradation behavior and comparative analysis with the KCsSb photocathode.
Paper: THP2067
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2067
About: Received: 18 Apr 2026 — Revised: 15 May 2026 — Accepted: 17 May 2026 — Issue date: 22 May 2026
THP2070
Simulation studies of SRF CW photoinjector brightness optimization for different RF gun gradients and photocathode laser pulse shapes
3584
Developments of a superconducting radio-frequency (SRF) photoinjector for future continuous-wave (CW) operation of the European XFEL are currently underway at DESY. A superconducting L-band 1.6-cell cavity is considered as a high-brightness electron source capable of supporting CW operation and meeting the stringent beam-quality requirements of cutting edge XFEL facilities. Given the limitations on the attainable gradient in the superconducting gun, photocathode laser pulse shaping provides an effective means of mitigating space-charge–driven emittance growth. In this study, 4D integral brightness; combining emittance, current profile, and longitudinal phase-space quality is used as the main optimization objective. Multi-objective optimization using ASTRA has been performed to minimize the electron beam emittance and maximize its brightness for various temporal and transverse profiles of the photocathode laser pulse in the European XFEL SRF photo injector. Gaussian, flat-top, ellipsoidal, and inverted-parabolic temporal profiles, along with radially uniform and truncated Gaussian transverse distributions, are compared in terms of achievable 4D beam brightness and their dependence on the attainable RF gradient in the SRF gun. The optimized photo injector working points will be propagated through start-to-end simulations to evaluate brightness preservation up to the undulator entrance.
Paper: THP2070
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2070
About: Received: 16 Apr 2026 — Revised: 21 May 2026 — Issue date: 22 May 2026
THP2104
High current photogun for the energy recovery linac PERLE
3640
In an Energy Recovery Linac (ERL), the beam, after acceleration and interaction, is recirculated and decelerated in the accelerating cavities of the linac. In such a scheme, the power of the beam is recovered within the SRF cavities, leading to substantial savings in electrical power. PERLE (Power Energy Recovery Linac for Experiments) is a high-power ERL demonstrator in Orsay, aiming to investigate multi-turn energy recovery. The electron beam can be recirculated in a superconducting linac up to 250 MeV (802 MHz). The high intensity electron beam (20 mA) is created by a photoinjector comprising a DC gun, a RF buncher, a SRF booster (7 MeV) and a merging section. The gun aims to produce 500 pC bunches at 40 MHz to inject the ERL ring with photocathodes of bi-alkali material (CsKSb). The photocathodes are deposited in a preparation facility (PPF) consisting of a molecular beam epitaxy (MBE) chamber for growth, linked via transfer lines to a glove box for precursor preparation and to the gun vacuum chamber. With this unique system, photocathodes can be prepared and loaded into the gun chamber under excellent vacuum conditions. Green light at 515 nm is used to produce electron bunch from the photocathode. The gun will be operated at 350 kV using as insulating gas N2 instead of SF6, a potent greenhouse effect gas. The photogun and its PPF, are installed at IJCLab- Orsay (France). The commissioning, currently underway, will be presented.
Paper: THP2104
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2104
About: Received: 12 May 2026 — Revised: 20 May 2026 — Accepted: 20 May 2026 — Issue date: 22 May 2026
THP2125
First demonstration of MeV electron diffraction using the superconducting RF photoinjector at the Helmholtz-Zentrum Dresden-Rossendorf
3679
Ultrafast electron diffraction (UED) allows for the characterization of structural and electronic dynamics in samples with sub-picosecond resolution. Utilizing a continuous wave photoinjector gives rise to MHz MeV UED, which has the benefits of better temporal resolution, higher beam coherence, higher resolution, and high repetition rates. A superconducting radiofrequency (SRF) photoinjector is part of the existing ELBE user facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), delivering electron beams in user operation since 2010. The HZDR is planning the construction of the Dresden Advanced Light Infrastructure (DALI), a source of positrons and IR and THz radiation. One of DALI's end stations will consist of the MeV UED facility, allowing to pump with IR and THz beams, and probe the samples with an electron beam, generated using an HZDR-type SRF photoinjector. In this proceeding, we present the first MeV electron diffraction results using the HZDR-type SRF photoinjector at ELBE.
Paper: THP2125
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2125
About: Received: 13 May 2026 — Revised: 21 May 2026 — Issue date: 22 May 2026
THP2126
A commercial MeV-UED instrument based on a 2.5 cell RF-Photogun
3683
Current research in quantum, nano, and energy materials requires information about material structure on the atomic scale in space and time. These materials show a variety of ultra-fast phenomena such as light absorption, structural changes, phase transitions, thermal or non-thermal melting, all of which happen on the ps or sub-ps scale and involve position changes on the Ångström scale. In this contribution we present the conceptual design for the RI-Bornite instrument, which allows ultra-fast electron diffraction using Mega-electron-volt electron beams (MeV-UED). For this instrument we use a warm (copper) 2.5-cell RF-photogun with a replaceable Cu photocathode. A single Ti:Sa fs-laser system drives both the pump beam (266 nm, ca. 1 µJ) and the probe beam (800 nm, several mJ/pulse). The system is designed to reliably reach 100 fs temporal resolution. The current sample chamber is optimized for solid-state samples and includes the option for sample cooling and a load-lock. Future versions shall allow experiments on liquid or gaseous samples. We present the main design considerations, electron beam dynamics simulations, and the engineering design.
Paper: THP2126
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2126
About: Received: 18 Apr 2026 — Revised: 20 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
THP2129
Options analysis of MHz injectors for the UK XFEL project
3690
The UK XFEL conceptual design and options analysis (CDOA) process has recently been completed. The UK XFEL design uses a superconducting linac operating with up to a 1 MHz repetition rate electron beam and demands beyond state of the art electron beam quality. This leads to strict requirements on the injector. The requirement for MHz repetition rates restricts the electron source technology to a number of operations: DC guns, VHF guns, L-band SRF guns, VHF SRF guns and DC-SRF guns. Two of these injector technologies were investigated in detail: a VHF gun and a high field L-band RF gun. In this proceeding the simulated beam dynamics performance and the technical readiness of the options will be compared and a number of conclusions will be drawn for the UK XFEL project.
Paper: THP2129
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2129
About: Received: 13 May 2026 — Revised: 21 May 2026 — Issue date: 22 May 2026
THP2131
Production and Initial Testing of a Nanostructured Copper Photocathode in an S-Band RF Gun
3698
A copper photocathode based on bulk Cu(100) substrate with a 50 𝜇m-diameter nanostructured region was fabricated and integrated into an S-band radio-frequency gun. We report the procedure for production and preparation of high- quality copper cathodes with nanostructured area compatible with state-of-the-art S-band RF gun. Experimental results indicate absence of increased dark current up to 70 MV/m at the cathode.
Paper: THP2131
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2131
About: Received: 12 May 2026 — Revised: 21 May 2026 — Issue date: 22 May 2026
THP2133
Development of a particle-free cathode loadlock system for SRF-Gun
3705
A prototype of SRF Gun has been built and successfully tested at MSU for LCLS-II HE project. This gun uses an HZDR-type cathode and required the development and implementation of a special cathode transfer and insertion system to ensure reliable operation. The main objectives were to prevent particle contamination, achieve a transverse alignment accuracy of less than 100 µm over a transfer distance of 1.3 m under ultra-high vacuum conditions (<10⁻⁹ Torr), and ensure the safe and repeatable insertion of the cathode into the cold cavity of the SRF gun. The cathode suitcase is used to transport a single cathode but can be upgraded in the future to accommodate high quantum efficiency (QE) semiconductor cathodes. To enable robust cathode exchanges, HZDR developed and built a special manipulation mechanism and an automated alignment system. The alignment concept was implemented using a translation rod equipped with contact electrodes and driven by precision stepper motors. Commissioning and final testing were successfully carried out at MSU to validate the transfer process. No change in RF performance was observed after the cathode exchange. The results confirmed that the system meets the design specifications and enables particle-free cathode exchange for the SRF gun at varying temperatures.
Paper: THP2133
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2133
About: Received: 13 May 2026 — Revised: 18 May 2026 — Accepted: 18 May 2026 — Issue date: 22 May 2026
THP2134
Photocathode development plan for DALI multifunctional facility
3708
DALI is an accelerator-based terahertz (THz) light source that uses multiple superconducting accelerators to drive CW electron bunches through undulators to emit ultra-intense THz pulses, including two ELBE SRF photo injects as the e- sources for high bunch charge beamline and for the UED, respectively. It requires a versatile portfolio of photocathodes to support diverse electron gun configurations and beam parameters targets. For the SRF gun commissioning, robust polycrystalline copper cathodes and magnesium cathodes will be employed, providing reliable performance and simplified handling during initial RF conditioning. Beam commissioning and routine user operation will firstly rely on the mature Cs₂Te photocathode, chosen for their proven robust, stability and realiable quantum efficiency. To enhance operational flexibility, especially in scenarios where UV laser generation presents challenges for special user appliations, we will consider to apply high-efficiency “green” photocathode optimized for visible-wavelength drive lasers. In parallel, an ultra-low-emittance photocathode in tens of micrometers will be under investigation to meet the stringent beam quality requirements of UED applications. This multi-cathode strategy ensures reliable commissioning, user-friendly operation, and state-of-the-art beam performance across all beamlines of the new accelerator facility.
Paper: THP2134
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2134
About: Received: 13 May 2026 — Revised: 18 May 2026 — Accepted: 18 May 2026 — Issue date: 22 May 2026
THP2137
Status of the hybrid electron gun development at ELSA
3718
A redesign of the injector beamline for the S-band linac at ELSA is underway, including the replacement of the existing electron gun by a hybrid gun that combines thermionic emission and thermally assisted photoemission in a single setup. The goal is to offer a new single-bunch injection mode alongside the long pulse mode already provided by the current gun. Measurements have been conducted to verify this emission technique using caesium dispenser cathodes. Another step in the scope of the project is the replacement of the current prebuncher cavity. A new design has been worked on and already undergone different tests of quality factor and bunching capabilities. The development of a dedicated test stand is currently being carried out to facilitate more detailed studies and serve as a prototype for the future injector section. Recent work has concentrated on the lattice and magnet design, as well as on evaluating suitable beam-diagnostic instrumentation.
Paper: THP2137
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP2137
About: Received: 13 May 2026 — Revised: 21 May 2026 — Issue date: 22 May 2026
THP3616
Cavity geometry optimization for multipactor suppression in a VHF CW electron gun
3833
VHF CW photocathode electron guns suffer from severe multipactor effects that significantly degrade their operational performance. In this work, the RF cavity geometry was optimized via CST simulations to suppress multipactor, employing a three-phase strategy with fixed key structural parameters. Compared with the SHINE gun baseline, the optimized cavity achieves a much lower multipactor growth rate $\alpha$ while preserving excellent high-performance RF characteristics. This demonstrates that geometry optimization is an effective approach to mitigate multipactor in VHF CW photocathode electron guns.
Paper: THP3616
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP3616
About: Received: 06 May 2026 — Revised: 19 May 2026 — Accepted: 20 May 2026 — Issue date: 22 May 2026
THP3617
Initial beam characterization from a cold field emitter in a VHF electron gun
3836
High-quality electron beams are critical for imaging experiments that provide detailed microscopic structural insights into materials. The Very-High-Frequency electron gun, capable of operating in continuous and pulsed modes, is a preferable option. In this paper, we employ a tungsten tip with an apex radius of curvature approximately 100nm as a cold field emission cathode in the VHF gun and measure the beam charge, transverse emittance, and energy spread to characterize the beam quality. In preliminary experiments, we have achieved a normalized transverse emittance of 54.01nm·rad. With an electron gun power of 37kW, we obtained astrongbeamcurrentofapproximately 6µA, which remained stable and continuous for several hours in a single experiment. By using an aperture to block electrons with large divergence angles and adjusting the solenoid’s focusing strength, we propose to converge the target-energy electron beam onto the aperture, increasing its transmission rate and optimizing the energy spread. Prior to optimization, the energy spread was approximately 3.57% at 536keV when using a 20µm diameter aperture.
Paper: THP3617
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP3617
About: Received: 13 May 2026 — Revised: 19 May 2026 — Issue date: 22 May 2026
THP3621
4K Superconducting RF electron gun
3843
A superconducting accelerator is an excellent technology that can efficiently accelerate high-current beams and is being applied to free electron lasers and next-generation linear electron-positron colliders such as ILC. Not only for the fundamental science, but also the high current electron beam plays a rather important role in industrial and medical applications. This is because the demand for high-current beams is also strong in these applications. While superconducting accelerators are becoming more widely used, there are not many examples in practical use of the superconducting RF gun, such as the ELBE RF Gun in HZDR. The entire accelerator should be superconducting for its energy efficiency and technical compatibility. To bridge this technical gap, we propose a superconducting RF gun utilizing the latest 4K superconducting technology, which can generate continuous, high-brightness beams.
Paper: THP3621
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP3621
About: Received: 16 Apr 2026 — Revised: 21 May 2026 — Issue date: 22 May 2026
THP4044
Consolidation of the Antiproton Decelerator Electron Cooler
3964
A new electron cooler, replacing the 40 year old one, will be installed starting in 2027, during Long Shutdown 3, in the CERN Antiproton Decelerator ring. The new electron cooler aims to improve reliability, cooling time and beam losses. The design of the new electron cooler, very similar in geometry, electron intensity and energies to the present device, will add electron beam magnetic expansion from the gun to the cooling section and enhance the field quality in the cooling section so to reduce electron transverse energy; approach the H/V orbit corrector magnets and improve relative position measurement of the antiproton and electron beams so to better center the two beam; allow faster switching of the electron beam on/off at the gun so to ease operations. Ultimately, the testing strategy will ensure highly reliable operations. This paper presents an overview of the status of the project.
Paper: THP4044
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP4044
About: Received: 12 May 2026 — Revised: 22 May 2026 — Issue date: 22 May 2026
THP4053
E-gun and test stand development for the pulsed electron lens for space charge compensation at GSI
3988
At GSI the design of a prototype electron lens to demonstrate space charge compensation in bunched ion beams is being continued. The ultimate goal is to increase the beam intensity for FAIR by compensating for the space charge forces in the synchrotrons operating with high intensity beams by overlapping with a pulsed electron beam in the electron lens. The development of the key components — e-gun and collector — is currently underway with the aim of installing them in the SIS18 e-cooler and demonstrating the concept for the first time. The conceptual design of the RF-modulated electron gun is completed, construction will start in mid 2026 and delivery is scheduled for autumn 2026. In the meantime, a test stand is being designed and will be set up at GSI to commission the e-gun and subsequently the collector. In this contribution, an overview of the ongoing activities regarding the details of the gun design, collector and the test stand set-up will be presented.
Paper: THP4053
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP4053
About: Received: 11 May 2026 — Revised: 19 May 2026 — Issue date: 22 May 2026
THP5337
LCLS-II Gun FPC window MP analysis
4243
The RF analysis of the LCLS-II Gun fundamental power coupler (FPC), including the ceramic window, has been analyzed using SLAC-developed 3D parallel finite-element electromagnetic code suite, ACE3P. Comprehensive multipacting (MP) simulations were carried out to investigate potential discharge regions within the FPC coaxial line and window assembly. The results reveal strong two-point MP between the ceramic disk and the window shielding sleeve at specific input power levels. In addition, the studies show that the external magnets mounted on the two FPC arms can only provide localized suppression of MP within regions influenced by their fringe magnetic fields. Therefore, effective MP mitigation in the LCLS-II FPC relies primarily on TiN coatings applied to the coaxial copper surfaces and ceramic disk, which reduce their secondary electron yield (SEY) below unity. Detailed analysis and findings from the LCLS-II Gun FPC RF simulations are presented.
Paper: THP5337
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP5337
About: Received: 12 May 2026 — Revised: 20 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
THP5638
Experimental design for validating relativistic ponderomotive dynamics via laser modulation of MeV electron beams
4349
We present a design for the experimental validation of relativistic ponderomotive dynamics on a realistic MeV electron-beam platform. The scheme combines an S-band gun with a co-propagating focused laser pulse to induce longitudinal momentum modulation in relativistic electrons. Using a nonparaxial laser-field model and beam-dynamics simulations, we evaluate the expected post-interaction energy signatures and their observability on a practical beamline. Particular attention is given to the dependence of the modulation on laser focusing, beam parameters, and synchronization errors. The analysis identifies the dominant force contributions governing the final energy distribution. These results provide a practical route for translating previously derived relativistic ponderomotive theory into a testable experiment.
Paper: THP5638
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP5638
About: Received: 15 Apr 2026 — Revised: 06 May 2026 — Accepted: 21 May 2026 — Issue date: 22 May 2026
THP5662
Time-of-flight control and passive compression in an Alpha-magnet beamline for MHz MeV UED
4386
We propose a novel MeV UED beamline design based on a normal-conducting very-high-frequency (VHF) electron gun that generates a high-quality electron beam at a megahertz (MHz) repetition rate. Beam compression and time-of-flight (TOF) control are achieved using an alpha-magnet. Simulations show compression of the 4.1 fC electron beam to a duration of 4.7 fs RMS, with a TOF jitter of 1.9 fs RMS, alongside normalized transverse emittances of 5.6 nm·rad in the x-direction and 5.2 nm·rad in the y-direction. This design substantially enhances both the signal-to-noise ratio and temporal resolution of the UED beamline, establishing a robust foundation for the future development of UED facilities.
Paper: THP5662
DOI: reference for this paper: 10.18429/JACoW-IPAC2026-THP5662
About: Received: 06 May 2026 — Revised: 22 May 2026 — Issue date: 22 May 2026