| Paper |
Title |
Page |
| MOPP036 |
Dark Current Model for ILC Main Linac
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625 |
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- N. Solyak, N. V. Mokhov, G. V. Romanov
Fermilab, Batavia, Illinois
- Y. I. Eidelman
BINP SB RAS, Novosibirsk
- W. M. Tam
IUCF, Bloomington, Indiana
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In the ILC Main Linac the dark current electrons, generated in SRF cavity can be accelerated to hundreds of MeV before being kicked out by quadrupoles and thus will originate electromagnetic cascade showers in the surrounding materials. Some of the shower secondaries can return back into vacuum and re-accelerated again. The results of simulation of the dark current dynamics and energy deposition along the linac are discussed in paper.
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| MOPP042 |
RF Kick in the ILC Acceleration Structure
|
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
|
640 |
| |
- 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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| 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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| MOPP135 |
Vertical and Horizontal Test Results of 3.9 GHz Accelerating Cavities at FNAL
|
874 |
| |
- T. N. Khabiboulline, H. T. Edwards, M. H. Foley, E. R. Harms, A. Hocker, D. V. Mitchell, A. M. Rowe, N. Solyak
Fermilab, Batavia, Illinois
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The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve the beam performance of the electron/positron linear accelerators. In the frame of a collaborative agreement, Fermilab will provide DESY with a cryomodule containing a string of four cavities. Several 9-cell Nb cavities were tested and they did reach accelerating gradient up to 24 MV/m almost twice more than design value of 14 MV/m. Two of these cavities are with new HOM couplers with improved design. In this paper we present all results of the vertical and horizontal tests.
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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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| WEPP102 |
Design of the ILC RTML Extraction Lines
|
2752 |
| |
- S. Seletskiy, P. Tenenbaum, D. R. Walz
SLAC, Menlo Park, California
- N. Solyak
Fermilab, Batavia, Illinois
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The Damping Ring to the Main Linac beamline (RTML) is equipped with three extraction lines (EL). Each EL can be used both for an emergency abort dumping of the beam and the tune-up continual train-by-train extraction. Two of the extraction lines are located downstream of the first and second stages of the RTML bunch compressor, and must accept both compressed and uncompressed beam with energy spread of 2.5 % and 0.15 % respectively. In this paper we report optical design that allowed us to minimize the length of the extraction lines while offsetting the beam dumps from the main line by the distance required for acceptable radiation level in the service tunnel. Proposed extraction lines can accommodate beams with different energy spreads at the same time providing the beam size suitable for the aluminum dump window.
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| THPC037 |
Studies of Orthogonal Bumps for ILC Main Linac
|
3059 |
| |
- N. Solyak
Fermilab, Batavia, Illinois
- S. A. Glukhov
BINP SB RAS, Novosibirsk
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To preserve small vertical emittance of the beam in ILC main linac a few beam-based alignment techniques were proposed and studied in recent years. Dispersion and wakefield bumps are one of the effective tool for final tuning of the machine. One of the modifications of bumps is so called orthogonal (or SVD) bumps, proposed for CLIC. In paper we present study of orthogonal bumps performances for final alignment of the ILC main linac.
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