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| MOPRI065 | The Development of a Low Energy Neutron Accelerator for Rebunching Pulsed Neutrons | 751 |
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| Low energy neutrons can be accelerated or decelerated by the technique of AFP-NMR with RF in a gradient magnetic fields. The neutrons have magnetic moments, hence their potential energy are not cancelled before and after passage of magnetic fields and their kinetic energy change finally when their spins are flipped in the fields. Nowadays most measurements of the neutron electric dipole moment (nEDM) are carried out with ultra cold neutrons (UCN), whose kinetic energies are lower than about 300 neV, and with a small storage bottle to reduce the systematic errors. In such experiments highly dense UCNs are desired. The spallation neutron sources generate high-density neutrons at the target, however, the pulsed neutrons with spread velocities are diffused in guide tubes during long beam transport. It is necessary to concentrate UCN temporally upon the bottle by controlling their velocities for nEDM experiments at those facilities. We demonstrated such rebuncher and have been developed the advanced apparatus which makes it possible to handle broader energy range UCN. The design, measured specification of the new rebuncher is described in detail. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI065 | |
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| TUPRO094 | Magnetic Field Evaluation of Multipole Permanent Magnets by Harmonic Coil with Novel Calibration Technique | 1259 |
| SUSPSNE097 | use link to see paper's listing under its alternate paper code | |
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| Quadrupole magnets for ILC final focus should be strong enough with the restriction on the external radius to let the disrupted out-going beam pass by, while vibration of the magnetic center has to be highly avoided to keep the nm sized beam focusing stable at the interaction point a few meter downstream from the lens. Gluckstern's 5-ring PMQ singlet seems a good candidate for this point of view. In order to fabricate a good 5-ring singlet, property of each ring has to be good enough. A harmonic coil system, which has 24-bit ADC’s for high resolution, was developed. Current noise level of the system is less than 10-5, which is supposed to be improved by reducing mechanical vibration of the ball bearings. We demonstrated the evaluation method of coil wire position with magnetic field from pin point magnet, so that the accuracy of the method was comparable to um scale. We measured the prototype 5-ring PMQ singlet and evaluated harmonic components. This result was compared with the data measured at KEK. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO094 | |
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| WEPRO005 | Development of Superconducting Spoke Cavity for Laser Compton Scattered Photon Sources | 1946 |
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Funding: This work is supported by Photon and Quantum Basic Research Coordinated Development Program. We have launched a 5-year research program to develop superconducting spoke cavity for laser Compton scattered (LCS) photon sources. For realizing a wide use of LCS X-ray and gamma-ray sources in academic and industrial applications, we adopt 325-MHz superconducting spoke cavity to electron beam drivers for the LCS sources. The spoke cavity, originally invented for ion and proton acceleration, can be used for electron accelerators, in which we can make best use of features of spoke cavity: relative compactness in comparison with a TM cavity of the same frequency, robustness with respect to manufacturing inaccuracy due to its strong cell-to-cell coupling, couplers on outer conductor for the better packing in a linac, and so on. In this paper, we present our research plan and results of cavity shape optimization. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO005 | |
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| WEPRI023 | Review of the Multilayer Coating Model | 2522 |
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Structures of alternating layers of superconducting (Sc) and insulating films formed on a bulk Sc proposed by A. Gurevich in 2006 are actively discussed these years, because of their great possibility in reducing power consumptions and in enhancing RF breakdown field of the Sc RF cavity. On Apr. 2013, we submitted general formulae for the vortex penetration field of the Sc layer and the shielded magnetic field on the bulk Sc for a structure with a single Sc layer and a single insulator layer formed on a bulk Sc, by which a combination of the thicknesses of Sc and insulator layers that can realize the enhanced RF breakdown field can be found for any given materials. In this contribution, we will show progresses during the last year. Comparisons between the formulae and experimental results, and extended formulae for more realistic models, such as a model with surface defects, will be shown.
T. Kubo, Y. Iwashita, and T. Saeki, Appl. Phys. Lett. 104, 032603 (2014); arXiv:1304.6876 [physics.acc-ph]; arXiv:1306.4823 [physics.acc-ph]; arXiv:1307.0583 [physics.acc-ph]. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI023 | |
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| WEPRI025 | Studies of Fabrication Procedure of 9-cell SRF Cavity for ILC Mass-production at KEK. | 2528 |
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| We had been constructing a new facility for the fabrication of superconducting RF cavity at KEK from 2009 to 2011. In the facility, we have installed a deep-drawing machine, a half-cup trimming machine, an electron-beam welding machine, and a chemical etching room in one place. We started the studies on the fabrication of 9-cell cavity for International Linear Collier (ILC) using this facility. The studies are focusing on the cost reduction with keeping high performance of cavity, and the goal is the establishment of mass-production procedure for ILC. We already finished the fabrication of two 9-cell cavities in this facility. This article reports the current status of the studies. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI025 | |
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| WEPRI030 | Multipactor Simulation on Superconducting Spoke Cavity for Laser Compton Scattered Photon Sources | 2543 |
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Funding: This work is supported by Photon and Quantum Basic Research Coordinated Development Program. Superconducting spoke cavity for laser Compton scattered (LCS) photon sources is under development. The operating frequency is 325-MHz to accelerate electron beam for the LCS sources, where the size of the spoke cavity is less than a elliptical cavities with the same frequency. Because of the complicated shape of the cavity, it may be suffered from a strong multipactor effect. The recent results on the multipactor analysis will be presented. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI030 | |
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