| Paper |
Title |
Page |
| MOPP042 |
RF Kick in the ILC Acceleration Structure
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637 |
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- V. P. Yakovlev, I. G. Gonin, A. Latina, A. Lunin, K. Ranjan, N. Solyak
Fermilab, Batavia, Illinois
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Detailed results of estimations and simulations for the RF kick caused by input and HOM couplers of the ILC acceleration structure are presented. Results of possible beam emittance dilution caused by RF kick are discussed for the main LINAC acceleration structure, and the RF structures of the ILC bunch compressors BC1 and BC2. Methods of the RF kick reduction are discussed.
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| MOPP043 |
Transverse Wake Field Simulations for the ILC Acceleration Structure
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640 |
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- V. P. Yakovlev, A. Lunin, N. Solyak
Fermilab, Batavia, Illinois
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Details of wake potential simulation in the acceleration structure of ILC, including the RF cavities and input/HOM couplers are presented. Transverse wake potential dependence is described versus the bunch length. Beam emittance dilution caused by main and HOM couplers is estimated, followed by a discussion of possible structural modifications allowing a reduction of transverse wake potential.
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| MOPP076 |
L-Band RF Gun with a Thermionic Cathode
|
727 |
| |
- S. Nagaitsev, R. Andrews, M. Church, A. Lunin, O. A. Nezhevenko, N. Solyak, D. Sun, V. P. Yakovlev
Fermilab, Batavia, Illinois
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In this talk we present a design for an L-band (1.3 GHz) rf gun with a two-grid thermionic cathode assembly. The rf gun is design to provide a 10-mA average beam current for 1ms at 5 Hz. These parameters match the requirements of both the ILC and Fermilab Project X test facilities. In our simulations we are able to attain the bunch length at 20-30 degrees (FW), while the output energy can vary 2-4 MeV. We will present the results of our simulations as well as preliminary designs.
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| MOPP093 |
Fast L-band Waveguide Phase Shifter
|
769 |
| |
- S. Kazakov, S. V. Shchelkunov
Omega-P, Inc., New Haven, Connecticut
- J. L. Hirshfield
Yale University, Physics Department, New Haven, CT
- A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio
- E. Nenasheva
Ceramics Ltd., St. Petersburg
- V. P. Yakovlev
Fermilab, Batavia, Illinois
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During the operation of accelerators it is often important to rapidly change the parameters of the RF system, such as cavity resonant frequency, coupling, or electrical length. For this purpose a fast L-band planar phase shifter has been designed, that has advantages compared to the coaxial scheme considered before by the authors (EPAC 06). The phase shifter is based on a new ferroelectric ceramic, whose permittivity changes with application of an external voltage. The switching time depends on only the external HV circuit and can by less than a few microseconds. The conceptual design and electrical parameters of the new phase shifter are presented, as are first results of low power measurements on a 1/3 model.
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| MOPP132 |
Progress Towards Development of an L-Band SC Traveling Wave Accelerating Structure with Feedback
|
871 |
| |
- A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio
- P. V. Avrakhov
LPI, Moscow
- S. Kazakov
KEK, Ibaraki
- N. Solyak, V. P. Yakovlev
Fermilab, Batavia, Illinois
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We describe an ongoing experimental program and progress towards development of a conceptual design for a superconducting traveling wave accelerating structure for the ILC. The accelerating gradient can be significantly improved by the use of an RF feedback system redirecting the accelerating wave that passed through the superconducting traveling wave accelerator (STWA) section back to the input of the accelerating structure. The conceptual design of the SC traveling wave accelerator has been considered by P. Avrakhov et al. [PAC07, pp.2538], where shape optimization, coupler cell design and tuning issues in the feedback loop were presented. The proposed TW structure design gives an overall 24% increase in gradient over the 1 m long standing wave structure and potentially can reach 46% if a longer structure is employed. Experimental investigation of the TW SC structure considers tests of a single cavity having the same shape as the regular cell of the full-sized STWA structure, and the same ratio of the RF fields. The details of the individual parts, joint configurations along with some developments on forming and welding of the proposed cavity shapes are discussed.
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| TUPP019 |
Wakefield and RF Kicks due to Coupler Asymmetry in TESLA-type Accelerating Cavities
|
1571 |
| |
- K. L.F. Bane, C. Adolphsen, Z. Li
SLAC, Menlo Park, California
- M. Dohlus, I. Zagorodnov
DESY, Hamburg
- E. Gjonaj, T. Weiland
TEMF, Darmstadt
- I. G. Gonin, A. Lunin, N. Solyak, V. P. Yakovlev
Fermilab, Batavia, Illinois
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In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate asymmetries in the fields that will kick the beam and tend to degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental and higher mode couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetries in) the fundamental RF fields and the other, due to transverse wakefields that are generated even when the beam is on axis. For the ILC configuration we numerically and analytically study both types of kicks and their effect on beam emittance. For the wakefield effect this is quite challenging since the bunches are very short (rms length of 300 microns), the cavity is very long (~1 m), and the distance to steady-state is even longer (~6 m). Finally, we study changes in the coupler design that can greatly reduce the effect.
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| TUPP046 |
Tunable Ferroelectric Based Technologies for Accelerator Components
|
1646 |
| |
- A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio
- S. Kazakov
KEK, Ibaraki
- E. Nenasheva
Ceramics Ltd., St. Petersburg
- A. Tagantsev
EPFL, Lausanne
- V. P. Yakovlev
Fermilab, Batavia, Illinois
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Low loss ferroelectric materials can be used as key elements in RF tuning and phase shifting components to provide fast, electronic control. These devices are under development for different accelerator applications in X, Ka and L - frequency bands. The exact design of these devices depends on the electrical parameters of the particular ferroelectric material to be used- its dielectric constant, loss tangent and tunability. BST based ferroelectric-oxide compounds have been found to be suitable materials for a fast electrically-controlled tuner for BNL and for high-power fast RF phase shifters to be used for SNS vector modulation applications. We present recent results on the development of BST based ferroelectric compositions synthesized for use in high power technology components. The BST(M) ferroelectrics have been tested using a transverse dc bias field. The tunability factor vs. dc field magnitude has been evaluated and the feasibility of transverse bias tuning for ferroelectric based accelerator components has been demonstrated.
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