We have been tested many CLIC prototype TW structures in Nextef-A.
We will review recent ones, TD24R05 and TD26CC-K1.
Also we have started the single-cell SW tests in Nextef-B.
We briefly discuss what we have done and what is being done.
In both test stands, we will discuss what we will chase in near future.
Much has been learned in the past decade regarding high gradient RF structures, in particular, thanks to the operation of the European X-band test facilities at CERN. The CLIC study needs to present to the European Strategy Group a case for a 380 GeV machine upgradable to higher energies and with a final aim of 3TeV centre of mass collisions. This case needs to address, design,...
The Argonne Wakefield Accelerator (AWA) facility is transforming into a dual function facility which is continuously working on its main mission of developing the dielectric structure based short pulse Two Beam Acceleration (TBA) technology while providing the full access of flexible multiple beamlines to users. In this talk, we report on the recent dielectric TBA experiments and the new...
An X-band high power test facility at a frequency of 11.424 GHz is under constructing in Tsinghua University. The system consists of a CPI klystron with maximum output power up to 50 MW and a ScandiNova solid-state pulse modulator which provides the pulsed high voltage with the maximum flat top of 1.5 μs. Ion pumps keep super high vacuum of the inside of the klystron and the high power...
There are 3 X-band test stands at CERN dedicated to the high gradient testing of prototype accelerating structures and RF components. This speech will cover the operational challenges, the upgrades in the algorithms for conditioning and the status of the stands during the last year.
An S-band High-Gradient (HG) Radio Frequency (RF) laboratory is under construction and commissioning at IFIC. The purpose of the laboratory is to perform investigations of high-gradient phenomena and to develop normal-conducting RF technology, with special focus on RF systems for hadron-therapy. The layout of the facility is derived from the scheme of the Xbox-3 test facility at CERN [1] and...
The new 400 Hz 120 MV/m photoinjector for CLARA will soon be conditioned. An automated RF conditioning program has been developed to perform the conditioning repeatably and with the minimum possible damage to the cavity. The program has been tested when re-conditioning on the current photoinjector, as well as on the first travelling wave linac. Conditioning method;differences for travelling...
At the high-gradient X-band test facility at CERN, prototype accelerating structures for the Compact Linear Collider (CLIC) are tested at high powers of up to 50 MW to achieve accelerating gradients of over 100 MV/m and peak surface electric fields of over 220 MV/m, and are conditioned to reach the highest possible gradient at low breakdown rate. The setup of the test stands will be presented,...
In order to further investigate field emission and vacuum arcs which limit the performance of the high gradient accelerating structures. New ways of measuring the properties of the plasma formed due to these processes are being developed. A novel experiment based on a microwave probe is discussed. The HOM damping waveguides of a TD24 CLIC structure are used to insert a low power RF signal,...
Portable 950 keV / 3.95 MeV X-band (9.3GHz) electron linac X-ray sources has been successfully applied to medicine and industrial/social infrastructure inspection. After the serious accident of old-tunnel wall collapse 5 years ago, the Japanese government has forced the bridge holders to perform regular inspection by eyes and hammering once for every 5 years. However, our X-ray sources have...
A number of initiatives to use linacs for proton therapy are underway and high-gradient technology may play an important role in making such linacs competitive with existing ring-based facilities. Collaborations between CLIC and both the Cockcroft Institute and the TERA foundation have designed high-gradient RF cavities for applications in hadron therapy. CLIC have established a field limiting...
Design and construction of S-band linear accelerator in Institute for research in fundamental science (IPM), is one of the successful experiences in design and construction of accelerators in Iran. Since brazing method has not been used for construction of such a system, copper remains hard during manufacturing process and hence this method would be a better candidate for construction of high...
CompactLight (XLS) is a three-years project, funded by EU in the context of the Horizon 2020 work Programme 2016-2017, Research Infrastructures, Design Studies. The project aims at designing the next generation of compact hard X-Rays FEL facilities, beyond today's state of the art, using the latest concepts for bright electron photo injectors, very high-gradient X-band structures, operating at...
The linac of the EuPRAXIA@SPARC_LAB project is based on an S-band Gun, three S-band TW structures and an X-band booster with a bunch compressor. The X-band technology allows reaching a high accelerating gradient and a high facility compactness, which are some of the goals of the projects. The accelerating structures are TW cavities fed by klystrons and pulse compressor systems. In the...
The company ADAM (Application of Detectors and Accelerators to Medicine), a CERN spin-off, is working on the construction and testing of its first linear accelerator for medical application: LIGHT (Linac for Image-Guided Hadron Therapy). LIGHT is an innovative high frequency proton linac designed to accelerate proton beams up to 230 MeV for protontherapy applications. A prototype of LIGHT is...
Tsinghua Thomson-scattering X-ray facility (TTX) has been successfully operating at beam energy of 50MeV and delivering photons at 25keV for the users. X-band high-gradient accelerating structures are proposed for energy upgrade of the beamline and a future project of compact gamma-ray source to generate ~MeV photons. A constant impedance structure, namely “XC72”, has been designed along with...
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, a feasibility study for increasing the Linac energy from 1.5 GeV to 1.8 GeV is actually ongoing. The design of new S-band accelerating structures, tailored for high gradient operation,...
ThomX is a Compton source project in the range of the hard X rays (40/90 keV). The machine is composed of a 50/70 MeV injector Linac and a storage ring where an electron bunch collides with a laser pulse accumulated in a Fabry-Perot resonator. The final goal is to provide an X-rays average flux of 1011-1013 ph/s. Different users are partners in the ThomX project, especially in the area of...
The choke-mode accelerating structure is one of the higher-order-mode (HOM) damping structures. It has the advantage of relatively simple fabrication and low surface magnetic field. The high-gradient performance of X-band choke-mode accelerating structures has been studied with six different single-cell prototypes. It was observed that high electric field and small choke dimension caused...
The Accelerator Laboratory of Tsinghua University has been carrying out research on radio frequency (RF) pulse compressors at both S-band and X-band. The S-band high-power test facility mainly consists of two S-band klystrons and a SLED-I type pulse compressor. Pulse modulations including the phase-to-amplitude modulation and high efficiency pulse compression have been demonstrated...
This report includes two sections. Section I focuses on RF breakdowns of Compact Pulsed Hadron Source（CPHS）RFQ. The conditioning history curve of CPHS RFQ has been recorded. After the post-processing of experiment data，the normalized curve of the conditioning history turned into a relatively smooth curve, which indicated that the empirical formula proposed by CERN for the high gradient...
The talk presents different aspects of the integration of high-gradient accelerating structures into modules that either exploit the classical CLIC two-beam acceleration scheme or that rely on klystron amplifiers to produce the beam acceleration.
This talk will describe the new developments in the structure and components for X-band technologies at CERN. The main issues covered in the talk will be the progress in the manufacturing of the structures made in halves as well as in structures made of rectangular discs. The talk will also include a brief update of possible future designs of other X-band components such as couplers.
Future colliders (FCC, ESS, CLIC) and high energy accelerators for scientific, industrial and medical applications require high power, high efficiency sources in wide range of frequencies. Novel bunching technology (BAC) together with transverse coupled cavities technology (TCC) allow to achieve efficiency up to 80% and peak output powers till 10 MW in X/C/S bands with long lifetime and low...
It has long been assumed that breakdown (BD) in vacuum cavities is initiated by field emission from localized surface irregularities causing localized field enhancement. However, the nature of these localized field enhancement region is unknown as of today, and remains as a missing part on the microscopic description of the BD process. This limits the ability to predict breakdown properties of...
The Argonne Cathode Test-stand (ACT) is a unique testbed to develop cathodes and to conduct fundamental surface study under ultra-high rf field (up to 700 MV/m with pin-shaped cathodes). The test-stand consists of an L-band 1.3 GHz single-cell photocathode rf gun and a field emission (FE) imaging system to locate emitters with a resolution of ~20 um. In the recent upgrade, UV laser has been...
The dynamics of dislocation activity under intense electric fields has been proposed as a potential cause of breakdowns. In this talk, results of searches for high-frequency fluctuations in field-emitted current that could arise as a consequence of these dynamics are presented for high-gradient RF accelerating structures at CERN. Measurements of spatial profiles of field emission in RF...
CLIC is focusing on the Compact Linear Collider. This work is to make an alternative design for CLIC pulse compression scheme. Using a spherical cavity, the new design can offer a higher Q factor compared with a cylindrical cavity. Besides, the use of degenerated "Whispering Gallery" mode makes the mode launcher much smaller.
Recently, a new technique for the realization of high gradient accelerating structures, based on the use of special gaskets has been implemented for the realization of the new SPARC_LAB and ELI-NP RF guns.
They have been successfully tested at high power leading to new perspectives in the realization of high gradient structures. The new technique has been developed at the Laboratories of...
An overview of potential consolidation and upgrades of the Xband test facilities at CERN and with collaborators, to increase the testing capability, reliability and expertise on high gradient structures.
High-power microwave sources play an important role in the applications of the radar system, controlled fusion plasma experiments, as well as particle accelerators. Currently, the conventional klystrons operating at S-, and X-band are the main driver in high-gradient accelerators. Klystrons with MW output power have been developed at CPI, SLAC, Thales, and so on. The most powerful klystron...
