| Paper |
Title |
Other Keywords |
Page |
| TUP050 |
Microwave Helical Undulator-Based Production of Polarized Photons and Positrons
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undulator, positron, radiation, linear-collider |
361 |
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- A. Smirnov, D. Yu
DULY Research Inc., Rancho Palos Verdes, California
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Linac-driven undulator technology and capabilities are considered for production of polarized positrons and polarized high-brightness X-rays. Challenging requirements for polarized positron production reveal a number of benefits of a microwave undulator compared with a conventional magnetic undulator: larger gap, simpler construction, shorter length, reduced requirements on tolerances and alignment. Two novel approaches are introduced for open and closed structures: cross-polarized excitation of a circular waveguide and a twisted structure. For the CLIC project the microwave undulator becomes an integral part of the TBA, and as it is naturally powered by the same decelerator. Other applications include emittance dampers, synchrotron radiation sources, and FELs. Additionally the twisted undulator provides unique opportunity for studies of circular dichroism and multi-photon anomalous diffraction (MAD) in protein crystallography.
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| TUP065 |
Longitudinal Beam Dynamic Simulation of S-DALINAC Polarized Injector
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electron, gun, simulation, emittance |
400 |
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- B. Steiner, W. F.O. Müller, N. Somjit, T. Weiland
TEMF, Darmstadt
- R. Eichhorn, J. Enders, C. Heßler, A. Richter, M. Roth
TU Darmstadt, Darmstadt
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In future, a polarized gun will extend the experiment possibilities of the superconducting recirculating linear electron accelerator S-DALINAC. Therefore a new injector has to be designed where a new 100 keV polarized source SPIN will be added to the present unpolarized thermionic source. A polarization degree of 80%, a mean current of 60 uA and a 3 GHz cw structure are required. All features of the new source will be tested and measured at an offset beam line. The longitudinal beam dynamics of the injector are studied. The electron bunch length behind the gun is about 50 ps. The electrons has to be bunched to 5 ps for capturing the electrons to the main linac. Therefore a chopper/prebuncher system based on the devices used at MAMI is designed. The system consists of a harmonic chopper cavity, a slit, a first and a second harmonic prebuncher. The recent simulation results will be presented here.
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| THP032 |
A Variable Directional Coupler for an Alternate ILC High-Power RF Distribution Scheme
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coupling, klystron, quadrupole, linac |
643 |
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- C. D. Nantista, C. Adolphsen
SLAC, Menlo Park, California
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We describe the design and functionality of an RF directional coupler for which the power division between the output ports is mechanically variable. In an alternate power distribution scheme for the ILC, power is delivered to cavities in pairs, through hybrids. Four pairs, or eight cavities, are fed from one waveguide feed, from which one fourth, one third, and one half of the power is coupled out at consecutive directional couplers. Three such feeds are powered by a single 10 MW klystron. Experience suggests that cavities considered useable will display some variation in the operational accelerating gradient they can sustain. With fixed distribution, the klystron power must be kept below the level at which the weakest cavity out of 24 receives its power limit. This problem can be solved by installing variable attenuators, but that means wasting precious power. With adjustable coupling, distribution can be optimized for more efficient use both of available power and of the accelerating cavities. This novel device, feeding cavities paired by similar performance, can provide such benefit to the ILC.
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