| Paper | Title | Other Keywords | Page |
|---|---|---|---|
| MOPGW054 | Study on Spherical Aberration Correction of Solenoid Lens in Ultrafast Electron Diffraction | electron, solenoid, emittance, focusing | 213 |
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| High electron beam quality is required in Ultrafast Electron Diffraction (UED) to achieve high spatial resolution. However, aberrations mainly induced by solenoid lens will deteriorate the beam quality and limit the resolution. Spherical aberration introduces the largest distortion which is unavoidable in the case of static cylindrically symmetric electromagnetic fields on the basis of Scherzer’s theorem. In order to reduce the spherical aberrations, different models have been designed which are composed of three symmetrical lens and one asymmetrical lens. We obtain the magnetic field distribution and calculate the aberration of each model by OPERA, and the result is that the solenoid without poles has the minimum aberration and meets the design requirement best. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW054 | ||
| About • | paper received ※ 13 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019 | ||
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| MOPRB018 | Conceptual Design of Negative-Muon Decelerator for Material Science | cavity, experiment, impedance, power-supply | 610 |
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| In 2018, a Negative-Muon Spin Rotation and Relaxation technique was developed in J-PARC Material and Life Science Facility. It is a novel scheme to investigate the motion of hydrogens in the chemicals and materials. To study small samples, the surface of materials and thin foils, a low energy negative muon beam is required. To decelerate intense 300-keV muons to 15-keV, we propose a system which consists of pulse generators and multi-gap induction decelerators. In this design, an inductive adder scheme is considered to use for the high voltage pulse source. High impedance magnetic alloy ring cores will be loaded in the decelerator cells. The high impedance cores which have much larger size than those for public use were developed for J-PARC RF systems and used for many applications including CERN booster RF, anti-proton deceleration and medical accelerator. In this paper, we present a conceptual design of muon deceleration system. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB018 | ||
| About • | paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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| THPGW029 | Crucial Transverse Beam Dynamics of the Racetrack-shape Fixed Field Induction Accelerator for Giant Cluster Ions | acceleration, injection, space-charge, optics | 3643 |
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A racetrack-shape fixed field induction accelerator (RAFFIA) for high energy giant cluster ion acceleration was proposed in 2015*. The RAFFIA employs 4 bending magnets with gradient in the main pole face and reverse field strip at its front side which generate strong focusing in both planes. Beam dynamics properties of the RAFFIA of 140 MeV for C-60 have been evaluated by linear optics. The result has been confirmed with a help of 3D macro-particle computer simulation**. It is identified that the issue of COD generated from field non-uniformity associated with a finite size of the bending magnet is inherent. The programmed COD correction by steering magnets are discussed as well as the importance of uniformity in the magnet field profile. So far it has been unknown what beam current is acceptable in the RAFFIA. In order to estimate space-charge effects in the RAFFIA under design, the 2D core (σ) evolution equation has been derived from the envelope equation perturbed by space-charge fields. Resonant structures and chaotic motion in the phase space of (σ,σ’) have been clarified as a function of beam current. Those results were justified by macro-particle tracking based on a renormalized transfer matrix approach***. As a result, it turns out that the 8+ C-60 beam of 200 uA is acceptable.
* K.Takayama, et. al, Phys. Rev. ST Accel. Beams 18, 050101 (2015). ** Taufik, et. al, sub. to Phys. Rev. AB (2018). *** Taufik, K.Takayama, and T. Adachi, sub. Phys. Rev. AB (2019). |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW029 | ||
| About • | paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | ||