Conveners
Morning session: General & Highlights 1
- Alessandro Gallo (Istituto Nazionale di Fisica Nucleare)
Morning session: General & Highlights 2
- Emilio Nanni (SLAC Natinoal Accelerator Laboratory)
Morning session: Projects
- Walter Wuensch (CERN)
Morning session: Klystrons, LLRF and equipment
- Gerardo D'Auria (Elettra)
Morning session: Injectors & C-band
- Tetsuo ABE (High Energy Accelerator Research Organization (KEK))
Morning session: C-band & Cryogenics
- LUIGI PALUMBO (UNIVERSITA' LA SAPIENZA ROMA)
Morning session: X-band and beyond
- Jiaru Shi (Tsinghua University)
Morning session: HG in the context of the European Strategy Accelerator R&D and CONCLUSIONS
- Valery Dolgashev (SLAC National Accelerator Laboratory)
Presentation materials
A broad overview is given of our current understanding of the effects that limit gradient in copper structures. Both experiments and theory from published literature are reviewed.
The linac energy booster of the EuPRAXIA@SPARC_LAB project foresees the use of 16, 1 m long, travelling wave X-Band structures, with a field phase advance per cell of 2ฯ/3 and a repetition rate of 100 Hz. To reach the 1 GeV required by the linac these structures have been designed to work at 60 MV/m. An optimization of the electromagnetic and mechanical design has been done to simplify the...
The Argonne Wakefield Accelerator (AWA) facility supports an extensive research portfolio along three themes: electron beam production, electron beam manipulation, and electron beam-driven structure wakefield acceleration (SFWA). This talk presents efforts at AWA to explore and exploit short RF pulses (sub-10 ns) to drive accelerating structures to higher gradients. The talk begins with an...
In the past ten years, the high gradient technolog team of SSRF has been working on the research of high gradient RF structures. Here will gives some results of the recent RF activities, including dual-mode variable polarization deflector, cold electron guns and accelerarting structures. In the mean time, the X-band deflecting structures that have been successfully used on SXFEL will also...
FERMI is the seeded Free Electron Laser (FEL) user facility at Elettra laboratory in Trieste, operating in the VUV to soft X-rays spectral range. In order to extend the FEL spectral range to shorter wavelengths, an upgrade plan for increasing the Linac energy from 1.5 GeV to 2.0 GeV is actually going on. After the successful testing of the short prototype of the new high gradient (HG) S-band...
We will present the design of a compact, highly efficient, pulse-to-pulse energy-tunable 9.3 GHz linac to generate up to 500 W of 10 MeV electron beam power for medical and security applications. This linac will employ a patented travelling wave accelerating structure which combines the advantages of high efficiency with energy tunability of traveling wave cavities. One of the advantages of...
This contribution summarizes some results obtained so far during the set-up of the two X-band TDSs with variable polarization (PolariX) installed downstream the Athos undulators in SwisFEL. The method used to avoid a beam kick in the plane orthogonal to the streaking plane and a study of the dependence of the deflecting voltage on the shape of the klystron pulse are described in more detail.
In this paper we will discuss the challenges that are open today in getting high gradients in nomral conductive cavities.
Particular enphasis will be devoted to the Muon Collider case.
New proposed and under development facilites will be presented and discussed.
The presentation starts with an overview of the solutions adopted by different labs around the world to develop LLRF systems driving a X-band power station.
Then, specifications for a user facility linac will be pointed out, especially referring to modern machines designed for plasma acceleration R&D that have demanding requests on amplitude and phase jitter of the accelerating fields.
The...
Currently SSRF/SXFEL is ongoing to develop the advanced transverse deflecting structure TTDS๏ผTwo-mode operation transverse deflecting structure) to carry out variable polarization based on the design of dual-mode RF structure. Driven by two different RF power sources, this novel TDS can work on both HEM11 and HEM12 modes in vertical and horizontal deflecting directions simultaneously, and...
The Compact Linear Collider (CLIC) beam-based acceleration baseline uses high-gradient traveling wave accelerating structures at a frequency of 12 GHz. To demonstrate the performance of these structures at high peak power and short pulse width RF, two klystron-based test facilities will be put into operation this year.
The X-band Laboratory for Accelerators and Beams (X-LAB) at the...
After a long recovery process from the fire in 20219, we have recently re-started high-power testing at the X-band test stand Nextef2. We will report the status and update.
Increasing energy of proton beam at the Los Alamos Neutron Science Center (LANSCE) from 800 MeV to 3 GeV will improve radiography resolution ten-fold. This energy boost can be achieved with a compact cost-effective linac based on normal conducting high-gradient (HG) RF accelerating structures. Such an unusual booster is feasible for proton radiography (pRad), which operates with short beam...
Advances in high-gradient accelerating technologies have facilitated commercial interest in producing compact, pulsed, electron-driven neutron facilities. Here we present studies undertaken for the design of an accelerator, optimised for cost and compactness, that delivers 30 nC trains in < 1 ยตs timescales.
The Very-compact Inverse Compton gamma source (VIGAS) is underconstructing in Tsinghua University in Beijing. It is based on a 350-MeV electron linac and to generate up to 4.8MeV photon by head-on interaction between the electron bunch and the laser pulse. The accelerator consists of S-band photo-injector and X-band main linac. The six 630-mm-long x-band accelerating structures will provide...
The CXFEL Project encompasses the Compact X-ray Light Source (CXLS) that is now commissioning in the hard x-ray energy range 4-20 keV, and the Compact X-ray Free-Electron Laser (CXFEL) designed to lase in the soft x-ray range 300-2500 eV. CXFEL has recently completed a 3-year design phase and just received NSF funding for construction over the next 5 years. These instruments are housed in...
Inverse Compton Scattering (ICS) sources are becoming more popular as future lab-based x-ray sources. Smart*Light is one such facility, under commissioning at Eindhoven University of Technology (TU/e). This compact X-ray source aims at bridging the gap between conventional lab X-ray sources and synchrotrons.
A 100 kV DC photo electron gun is used in combination with a bunching cavity to...
In this talk we will present an update on the design and R&D plans for C3 (Cool Copper Collider). C3 is a Higgs factory concept based on cryogenic copper distributed-coupling accelerator technology. An update on the accelerator complex design, cryogenics and cryomodule design will be presented. Ongoing R&D (high gradient testing, vibrations, beam dynamics, etc.) and future R&D needs...
To reduce energy consumption and cost has become a prime objective of the development and operation of high energy particle accelerators. RF sources are major energy consumption components of any RF system for the particle colliders. The 30 GeV injector linear accelerator (LINAC) for the CEPC (Circular Electron and Positron Collider) requires S-band klystrons with higher efficiency to reduce...
Several types of X-band accelerating tubes for varies applications have been developed in Tsinghua University, with beam energy from 6MeV to 12MeV. Beam-break-up was also observed in a 6MeV tube with 10microsecond 200mA pulse. A backward-travelling-wave strcuture was developed as an injector for VHEE beamline. This presentaton will talk about the research and develop of these X-band linac tubes.
After the discovery of the Higgs particle at Large Hadron Collider (LHC) in 2012, a 240 GeV circular electron positron collider (CEPC) was proposed in China. The beam power of CEPC is about 60 MW. To reduce the energy demand and operation cost for CEPC, a 800 kW CW klystron with efficiency of more than 80% are being developed as a priority key technology at Institute of High Energy Physics,...
Operation of high-gradient structures require the delivery of extremely high RF power---from hundreds of kW to MW---by klystrons, usually at the expense of high overall energy consumptions. A collaboration between CERN and Canon Electron Tubes and Devices has been established to optimise the efficiency of commercially available klystrons, resulting in the proposal of novel technological...
Recently๏ผa soft X-ray FEL facility, Shenzhen Superconducting Soft-X-ray Free Electron Laser(S3FEL), has been approved by the national government of China. SยณFEL is a high repetition rate soft-X-ray super-conducting free-electron laser facility that consists of a 2.5 GeV CW superconducting linear accelerator and four initial undulator lines, which aims at generating X-Rays between 40 eV and 1...
The new C-Band RF gun, developed in the context of the European I.FAST and INFN Commission V TUAREG projects, has been realized. It is a 2.6 cell standing wave cavity with a four-port mode launcher, designed to operate with short rf pulses (300 ns) and cathode peak field larger than 160 MV/m. The gun has been realized with the new technology without brazing, developed at INFN, that allows to...
The current trend in accelerator facilities is to increase the beam brightness, which places higher demands on both the electron gun and the acceleration unit. With high shunt impedance and expected gradient, cryogenic structure has the ability to provide beam with high peak brightness and has the potential to operate at a higher repetition rate. In SSRF/SXFEL, the scheme and preliminary...
HB2TF is a project funded by INFN CSN5 related to the development of a High Brightness Beams Test Facility (HB2TF) at the INFN-LASA laboratory. The Test Facility will allow to perform developments in different accelerator technologies and to carry out experiments with a high current CW electron beam in frontier areas of accelerator physics.
The Test Facility setup will comprise a...
Nowadays, production of ultrashort and high-current electron bunches of few fs to hundred fs with several pc charge is a very attractive subject in the context of many recent applications, specially, in light sources, free electron lasers and plasma wake field accelerators. In the light sources and free electron lasers, the radiation gain is directly proportional to the beam pick current and...
In this talk we will present results from high gradient structure testing of single and multi-cell accelerating structures and components at C-band. Structures were tested with a variety of fabrication techniques including brazing, diffusion bonding and clamped plated structures. Target gradients of 120 MeV/m were achieved and exceeded. Designs and performance of rf components (loads, windows,...
This talk will report on the status high gradient C-band accelerator structure research at Los Alamos National Laboratory (LANL). Current activities at LANL include construction of the Cathodes And Radio-frequency Interactions in Extremes (CARIE) high gradient C-band RF photoinjector test stand and research on the higher order mode (HOM) absorbers for high gradient cavities. We are putting...
FLASH Therapy represents a revolutionary advancement in cancer treatment, offering the potential to spare healthy tissue from ionizing radiation damage while maintaining its efficacy in tumor control. The practical clinical integration of FLASH therapy, particularly for treating deep-seated tumors, requires the attainment of Very High Electron Energy (VHEE) levels within the 50-150 MeV range....
A dielectric assist accelerating (DAA) structure, a type of dielectric loaded accelerating structures, is greatly superior in power efficiency compared with the conventional disk-loaded copper structures. The advantage of DAA structure is that it has an extremely high quality (Q0 > 10^5@C-band) factor and a high shunt impedance at room temperature since the electromagnetic field distribution...
With high shunt impedance and expected gradient, cryogenic structure has the ability to reduce accelerators' length and has the potential to operate at a higher repetition rate. In SSRF/SXFEL, the scheme and preliminary experimental studies about the cryogenic RF structure have been developed. Foremost, theoretical and experimental studies of the RF characteristics in cryogenic environments...
Abstract: In electron linear accelerators, the improvement of the acceleration gradient of the acceleration structure has been a continuous research topic for scientists, which can reduce the construction cost of the entire accelerator by increasing the acceleration gradient. Normally, large acceleration structures work on traveling wave made of ordinary conductive material oxygen free copper...
A cryogenic DC HV system integrated in a stand-alone cryocooler has been constructed at Uppsala University in order to investigate the fundamental mechanisms of field emission and breakdown nucleation. A series of high-field measurements has been carried out with pairs of copper and niobium electrodes at temperatures ranging from ambient down to 4K. We observed a significant increase in the...
Recently, much work has been directed at R&D a ultra-compact X-ray FEL (UC-XFEL) based on rapidly emerging techniques in high field cryogenic acceleration, attendant dramatic improvements in beam brightness, and state-of-the-art concepts in beam dynamics, magnetic undulators, and X-ray optics. A full conceptual design of a 1 nm XFEL with a length and cost over an order of magnitude below...
Hollow-core dielectric Electromagnetic Band Gap (EBG) microstructures powered by lasers represent a new and promising area of accelerator research thanks to the dielectric higher damage threshold and greater accelerating gradients with respect to the metallic counterparts. In this paper, we present MeV-scale 3D beam-dynamics simulations and fabrication results relative to a silicon,...
The exploration of procedures, materials, technological methods, and welding techniques applied in the production of high-acceleration components to achieve an exceeding accelerating gradient (>100 MV/m) and minimal occurrence of RF breakdown, has guided us towards proposing the utilization of hard-copper structures composed of multiple segments in the Ka-Band spectrum. Among research...
The operational principles and the approach to mitigate electromagnetic field breakdowns in a corrugated structure of a sub-THz wakefield accelerator will be discussed. A design of the structure and its test using an electron beam will be presented. The analysis of an impulse heating of the structure with a high charge electron bunch will be shown. The results of calculations using COMSOLโs...
High intensity THz pulsed radiation was used to investigate the damage induced on low roughness copper substrates and thin films deposed on copper. Using the THz Free Electron Laser available at the ISIR facility of the Osaka University [1], we irradiated samples in air at different angles, with an energy density of ~100 GW/cm
Hefei Advanced Light Facility (HALF) is a fourth-generation low-energy synchrotron radiation light source which will be started from September 2023 to August 2028. It consists of a 2.2 GeV full energy linac and a storage ring. This contribution presents optimizations on the C-band accelerating structures and pulse compressors for HALF linac. A new design method for matching couplers to an...
Linear accelerators used in high-energy physics, industry, and medicine need compact, durable, and cost-effective accelerating structures. To achieve a smaller footprint, linacs require high accelerating gradients. Currently, stable operating gradients exceeding 100 MV/m have been successfully demonstrated at SLAC National Accelerator Laboratory, CERN, and KEK, particularly at X-band...
Various working groups have been set up in the context of the European Strategy for Particle Physics. We report on surveys carried out by two of the working groups; Normal conducting high-gradient RF and high-efficiency power sources. The surveys give an overview of the status of development initiatives, infrastructure at the European and international level.
