Download Free Next Linear Collider Test Accelerator Book in PDF and EPUB Free Download. You can read online Next Linear Collider Test Accelerator and write the review.

At SLAC, the authors are pursuing the design of a Next Linear Collider (NLC) which would begin with a center-of-mass energy of 0.5 TeV, and be upgradable to at least 1.0 TeV. To achieve this high energy, they have been working on the development of a high-gradient 11.4-GHz (X-band) linear accelerator for the main linac of the collider. In this paper, they present the design of a {open_quotes}Next Linear Collider Test Accelerator{close_quotes} (NLCTA). The goal of the NLCTA is to incorporate the new technologies of X-band accelerator structures, RF pulse compression systems and klystrons into a short linac which will then be a test bed for beam dynamics issues related to high-gradient acceleration.
During the past several years, there has been tremendous progress on the development of the RF system and accelerating structures for a Next Linear Collider (NLC). Developments include high-power klystrons, RF pulse-compression systems and damped/detuned accelerator structures to reduce wakefields. In order to integrate these separate development efforts into an actual X-band accelerator capable of accelerating the electron beams necessary for an NLC, we plan to build an NLC Test Accelerator (NLCTA). The goal of the NLCTA is to bring together all elements of the entire accelerating system by constructing. and reliably operating an engineered model of a high-gradient linac suitable for the NLC. The NLCTA win serve as a test-bed as the design of the NLC evolves and will provide a model upon which a reliable cost estimate can be based. In addition to testing the RF acceleration system, the NLCTA will be able to address many questions related to the dynamics of the beam during acceleration. In this paper, we will report on the status of the design and component development for the NLC Test Accelerator.
The design for the Next Linear Collider (NLC) at SLAC is based on two 11.4 GHz linacs operating at an unloaded acceleration gradient of 50 MV/m increasing to 85 MV/m as the energy is increased from 1/2 TeV to 1 TeV in the center of mass. During the past several years there has been tremendous progress on the development of 11.4 GHz (X-band) RF systems. These developments include klystrons which operate at the required power and pulse length, pulse compression systems that achieve a factor of four power multiplication and structures that are specially designed to reduce long-range wakefields. Together with these developments, we have constructed a 1/2 GeV test accelerator, the NLC Test Accelerator (NLCTA). The NLCTA will serve as a test bed as the design of the NLC is refined. In addition to testing the RF system, the NLCTA is designed to address many questions related to the dynamics of the beam during acceleration, in particular the study of multibunch beam loading compensation and transverse beam break-up. In this paper we present the status of the NLCTA and the results of initial commissioning.
The Next Linear Collider Test Accelerator (NLCTA) being built at SLAC will integrate the new technologies of X-band accelerator structures and RF systems for the Next Linear Collider, demonstrate multibunch beam-loading energy compensation and suppression of higher-order deflecting modes, measure transverse components of the accelerating field, and measure the dark current generated by RF field emission in the accelerator Injector design and simulation results for the NLCTA injector are discussed.
The Next Linear Collider Test Accelerator (NLCTA) being built at SLAC will integrate the new technologies of X-band Accelerator structures and RF systems for the Next Linear Collider, demonstrate multibunch beam-loading energy compensation and suppression of higher-order deflecting modes, and measure the dark current generated by RF field emission in the accelerator. The current injector being constructed for phase 1 of the NLCTA tests is a simple injector consisting of a gun with a 150 ns long pulse and X-band bunching and accelerating system. While the injector will provide average currents comparable to what is needed for NLC it will not provide the bunch structure since every X-band RF bucket will be filled. The injector upgrade will produce a similar bunch train as planned for NLC mainly a train of bunches 1.4 ns apart with 3 nC in each bunch up to 50 to 60 MeV. The bunching system for the upgrade is more elaborate than the current injector and the plan is to produce a bunch train right at the gun. The difference between the NLCTA injector upgrade and the planned injector for NLC is that the NLCTA injector will not have polarized beam and the accelerator sections are X-band rather than S-band. If the authors are able to produce beams comparable to the NLC requirements with the X-band injector then it should be easier to do with the S-band.
The Stanford Linear Collider (SLC) was built to collide single bunches of electrons and positrons head-on at a single interaction point with single beam energies up to 55 GeV. The small beam sizes and high currents required for high luminosity operation have significantly pushed traditional beam quality limits. The Polarized Electron Source produces about 8 × 101° electrons in each of two bunches with up to 28% polarization, . The Damping Rings provide coupled invariant emittances of 1.8 × 10−5 r-m with 4.5 × 101° particles per bunch. The 57 GeV Linac has successfully accelerated over 3 × 101° particles with design invariant emittances of 3 × 10−5 r-m. Both longitudinal and transverse wakefields affect strongly the trajectory and emittance corrections used for operations. The Arc systems routinely transport decoupled and betatron matched beams. In the Final Focus, the beams are chromatically corrected and demagnified producing spot sizes of 2 to 3 [mu]m at the focal point. Spot sizes below 2 [mu]m have been made during special tests. Instrumentation and feedback systems are well advanced, providing continuous beam monitoring and pulse-by-pulse control. A luminosity of 1.6 × 1029 cm−2sec−1 has been produced. Several experimental tests for a Next Linear Collider (NLC) are being planned or constructed using the SLC accelerator as a test facility. The Final Focus Test Beam will demagnify a flat 50 GeV electron beam to dimensions near 60 nm vertically and 900 nm horizontally. A potential Emittance Dynamics Test Area has the capability to test the acceleration and transport of very low emittance beams, the compression of bunch lengths to 50 [mu]m, the acceleration and control of multiple bunches, and the properties of wakefields in the very short bunch length regime.
The Next Linear Collider (NLC) Collaboration is planning to construct an Engineering Test Facility (ETF) at Fermilab. As presently envisioned, the ETF would comprise a fundamental unit of the NLC main linac to include X-band klystrons and modulators, a delay-line power-distribution system (DLDS), and NLC accelerating structures that serve as loads. The principal purpose of the ETF is to validate stable operation of the power-distribution system, first without beam, then with a beam having the NLC pulse structure. This paper concerns the possibility of configuring and using the ETF to accelerate beam with an NLC pulse structure, as well as of doing experiments to measure beam-induced wakefields in the rf structures and their influence back on the beam.
Preliminary design for the SLAC Next Linear Collider Test Accelerator (NLCTA) requires a pulse power source to produce a 600 kV, 600 A, 1.4 [mu]s, 0.1% flat top pulse with rise and fall times of approximately 100 ns to power an X-Band klystron with a microperveance of 1.25 at H"100 MW peak RF power. The design goals for the modulator, including those previously listed, are peak modulator pulse power of 340 MW operating at 120 Hz. A three-stage darlington pulse-forming network, which produces a>100 kV, 1.4 [mu]s pulse, is coupled to the klystron load through a 6:1 pulse transformer. Careful consideration of the transformer leakage inductance, klystron capacitance, system layout, and component choice is necessary to produce the very fast rise and fall times at 600 kV operating continuously at 120 Hz.