1,721,016 research outputs found
Wakefields excited in the FCC-ee collimation system
Full text linkThe purpose of this paper is to calculate the longitudinal and transverse wakefields of the FCC collimators using the electromagnetic codes ECHO3D and IW2D. We cross-checked our results using CST particle studio for long bunches, and found them to be in good agreement. The obtained results show that the collimators give one of the highest contributions to the overall FCC-ee wake potentials. In particular, using the code PyHEADTAIL, we have found that the geometric contribution of the collimators' wakefield reduces significantly the transverse mode coupling instability threshold. Therefore, it is imperative to explore and implement solutions that effectively mitigate this wakefield source
A low-perveance electron gun for a high-efficiency Ka-band klystron
No full textSelf-consistent analytic and numeric design for a set of electron guns with a high beams quality to be used in high-power Ka-band klystrons is presented in this paper. The set of electron guns can be used in the high-power Ka-band klystrons in order to
feed linear accelerating structures at 36 GHz with an estimated 20 MW input power by achieving an effective accelerating electric
field in the (100–150) MV/m range. In the framework of the Compact Light XLS project, a short Ka-band linearizer by working at
36 GHz able to provide an integrated voltage of at least 15 MV is proposed for bunch-phase linearization. In order to optimize the Ka-band klystrons efficiency for achieving 20 MW RF output power, different electron guns, beam focusing channel designs and the RF beam dynamics are examined and discussed in this paper
A SW Ka-Band linearizer structure with minimum surface electric field for the compact light XLS project
No full textThere is a strong demand for accelerating structures able to achieve higher gradients and more compact dimensions for the next generation of linear accelerators for research, industrial and medical applications. In the framework of the Compact Light XLS project, an ultra-high gradient higher harmonic RF accelerating structure is needed for the linearization of the longitudinal phase space. In order to determine the maximum sustainable gradients in normal conducting RF powered particle beam accelerators with extremely low probability of RF breakdown, investigations are in progress for using short accelerating structures in the Ka-band regime. We here report an electromagnetic design of a compact linearizer standing wave (SW) accelerating structure. The cavity has a length of about 8 cm and operates on the π-mode at 35.982 GHz, which is the third harmonic with respect to the Linac frequency (11.994 GHz). The accelerating gradient is 100 MV/m and the cavity geometry is optimized in order to minimize the surface peak electric field
A novel exact analytical expression for the magnetic field of a solenoid
No full textIn this paper we present the analytical calculations to derive the magnetic field of a solenoid by solving exactly a fractional integral with the use of a novel method. Starting from the Biot-Savart law, we consider a coil of negligible thickness with a stationary electric current. We derive the expressions of the on- and off-axes magnetic field components. The results have been compared to some simplified and known analytical formulae as well as to a commercial numerical code showing a good agreement
Relativistic versus nonrelativistic approaches to a low perveance high quality matched beam for a high efficiency ka-band klystron
Full text linkAdvanced technical solution for the design of a low perveance electron gun with a high quality beam dedicated to high power Ka-band klystrons is presented in this paper. The proposed electron gun can be used to feed linear accelerating structures at 36 GHz with an estimated input power of 20 MW, thus achieving an effective accelerating electric field in the (100–150) MV/m range. Additionally, in the framework of the Compact Light XLS project, a short Ka-band accelerating structure providing an integrated voltage of at least 15 MV, has been proposed for bunch-phase linearization. For the klystron, a very small beam dimension is needed and the presented electron gun responds to this requirement. An estimate of the rotational velocity at beam edge indicates that the diamagnetic field due to rotational currents are small compared to the longitudinal volume. A detailed analysis of how this has been achieved, including compression of the beam, rotation in the magnetic field, and analysis of the subsequently generated diamagnetic field has been discussed
The Ka-band high power klystron amplifier design program of INFN
Full text linkIn the framework of the Compact Light XLS project, a short ultra-high gradient linearizer working on the
third harmonic of the main linac frequency is requested. Increasing gradients and reducing dimensions are
requirements for XLS and all next generation linear accelerators. Actually, ultra-compact normal conducting
accelerating structures, operating in the Ka-band are required to achieve ultra-high gradients for research,
industrial and medical applications, with electric field ranging from 100 to 150 MV/m. To fulfill these strong
requirements, the R&D of a proper Ka-band klystron with high RF power output and a high efficiency is
mandatory. This contribution reports the design of a possible klystron amplifier tube operating on the 010
mode at 36 GHz, the third harmonic of the 12 GHz linac frequency, with an efficiency of 42% and a 20 MW
RF power output. This contribution discusses also the high-power DC gun, the beam focusing channel and the
RF beam dynamics
A hard copper open X-band RF accelerating structure made by two halves
Full text linkThis communication focuses on the technological developments aiming to show the viability of novel welding techniques [1,2], and related applications, in order to benefit from the superior high-gradient performance of accelerating structures made of hard-copper alloys. The technological activity of testing high-gradient RF sections is related to the investigation of breakdown mechanisms, which limit the high gradient performance of these structures. In this content, our activity consists of the design, construction and high- power experimental tests of standing-wave (SW) 11.424 GHz (X-band) accelerating cavities with different materials and methods.
The goal is to assess the maximum sustainable gradients with extremely low probability of RF breakdown in normal-conducting high-gradient RF cavities
Multiphysics Design of High-Power Microwave Vacuum Window
Full text linkThis paper presents the Multiphysics Analysis of a High-
Power Microwave Window for a Ka-Band Klystron providing
16MW of peak power. After the optimization of the
electromagnetic performances, we analyze the effect of RF heating
effect and the stress of the pressure on the window. We also analyze
the multipactor effect, that is a common cause of window failure.
Using such approach, it is possible to realize a virtual prototype
capable to represent in a complete way the real prototype to be
manufactured
Studies of FCC-ee single bunch Instabilities with an updated impedance model
Full text linkThe design of the FCC-ee collider is ongoing with the goal of optimizing beam parameters and developing various accelerator systems. As a result, the modelling of coupling impedance is continuously evolving to take into account the design of the collider vacuum chamber and hardware components. Concurrently, estimates of collective effects and instabilities are being continually updated and refined. This paper presents the current FCC-ee impedance model and reports the findings of the single-bunch instability studies. Additionally, some potential mitigation techniques for these instabilities are discussed
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