Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userThe Study of Media Beta Elliptical Cavities for CADS
354
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The China Accelerator Driven Sub-critical System (CADS) is a high intensity proton facility to dispose of nuclear waste and generate electric power. CADS is based on 1.5GeV, 10mA CW superconducting (SC) linac as a driver. The high-energy section of the linac is compose of two families of SC elliptical cavities which are designed for the geometrical beta 0.63 and 0.82. In this paper, the 650 MHz b{eta}=0.63 SC elliptical cavity was studied including cavity optimization, multipacting, high order modes (HOMs) and generator RF power calculation. Keywords: high current, medium beta, ADS, superconducting cavity, HOMs
rate research
Read More
The European Spallation Source (ESS) accelerator is composed of superconducting elliptical cavities. When the facility is running, the cavities are fed with electrical field from klystrons. Parameters of this field are monitored and controlled by the Low-Level Radio Frequency (LLRF) system. Its main goal is to keep the amplitude and phase at a given set-point. The LLRF system is also responsible for the reference clock distribution. During machine operation the cavities are periodically experiencing strain caused by the Lorentz force, appearing when the beam is passing through the accelerating structures. Even small changes of the physical dimensions of the cavity cause a shift of its resonance frequency. This phenomenon, called detuning, causes significant power losses. It is actively compensated by the LLRF control system, which can physically tune lengths of the accelerating cavities with stepper motors (slow, coarse grained control) and piezoelements (active compensation during operation state). The paper describes implementation and tests of the software supporting various aspects of the LLRF system and cavities management. The Piezo Driver management and monitoring tool is dedicated for piezo controller device. The LO Distribution application is responsible for configuration of the local oscillator. The Cavity Simulator tool was designed to provide access to properties of the hardware device, emulating behaviour of elliptical cavities. IPMI Manager software was implemented to monitor state of MicroTCA.4 crates, which are major part of the LLRF system architecture. All applications have been created using the Experimental Physics and Industrial Control System (EPICS) framework and built in ESS EPICS Environment (E3).
Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.
We have been developing optical resonant cavities for laser-Compton scattering experiment at the Accelerator Test Facility in KEK. The main subject of the R&D is to increase laser pulse energy by coherently accumulating the pulses in an optical resonant cavity. We report previous results, current status and future prospects, including a new idea of an optical resonant cavity.
The proposed linear electron-positron collider TESLA is based on 1.3 GHz superconducting niobium cavities for particle acceleration. For a centre-of-mass energy of 500 GeV, an accelerating field of 23.4 MV/m is required which is reliably achieved with a niobium surface preparation by chemical etching. An upgrade of the collider to 800 GeV requires an improved cavity preparation technique. In this paper, results are presented on single-cell cavities which demonstrate that fields of up to 40 MV/m are accessible by electrolytic polishing of the inner surface of the cavity.
As a result of a collaboration between Jefferson Lab and niobium manufacturer CBMM, ingot niobium was explored as a possible material for superconducting radiofrequency (SRF) cavity fabrication. The first single cell cavity from large grain high purity niobium was fabricated and successfully tested at Jefferson Lab in 2004. This pioneering work triggered research activities in other SRF laboratories around the world. Large grain niobium became not only an interesting alternative material for cavity builders, but also material scientists and surface scientists were eager to participate in the development of this material. Most of the original expectations for this material of being less costly and allowing less expensive fabrication and treatment procedures at the same performance levels in cavities have been met. Many single cell cavities made from material of different suppliers have been tested successfully and several multi-cell cavities have shown the performances comparable to the best cavities made from standard poly-crystalline niobium. Several 9-cell cavities fabricated by Research Instruments and tested at DESY exceeded the best performing fine grain cavities with a record accelerating gradient of Eacc = 45.6 MV/m. Recently- at JLab- by using a new furnace treatment procedure a single cell cavity made of ingot niobium performed at a remarkably high Q0-value (~5x10^10) at an accelerating gradient of ~20 MV/m, at 2K. Such performance levels push the state-of-the art of SRF technology to new limits and are of great interest for future accelerators. This contribution reviews the development of ingot niobium technology and attempts to make a case for this material being the choice for future accelerators.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
