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| MOPAB162 | The First Trial of XY-Coupled Beam Phase Space Matching for Three-Dimensional Spiral Injection | 553 |
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Funding: Work supported by "Grant in Aid" for Scientific Research, JSPS (KAKENHI# 26287055, KAKENHI#19H00673) The most recent measurement of muon g-2 results in a 3.8σ discrepancy with the equally precise theoretical prediction. The J-PARC muon g-2/EDM experiment (E34) is in preparation to decipher this discrepancy and unravel the new physics beyond the standard model. The precision goal for g-2 is 0.1 ppm. To achieve this precision goal a novel 3-D spiral injection scheme has been devised to inject and store the beam into a small diameter MRI-type storage magnet for E34. The new injection scheme features smooth injection with high storage efficiency for the compact magnet. However, the spiral injection scheme is an unproven idea, therefore, a Spiral Injection Test Experiment (SITE) at KEK Tsukuba Campus is underway to establish this injection scheme. Due to the axial symmetric field of the solenoid magnet, a strongly XY-coupled beam is required. To produce the required phase space for the solenoid-type storage magnet, a beam transport line consisting of three rotatable quadrupole magnets has been designed and built for SITE. The vertical beam size reduction by means of phase space matching and other geometrical information has been successfully measured by the wire scanners. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB162 | |
| About • | paper received ※ 20 May 2021 paper accepted ※ 28 May 2021 issue date ※ 01 September 2021 | |
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| MOPAB163 | First Synchronous Measurement of Single-Bunched Electron and Positron Beams with a Wideband Feedthrough-BPM at the Positron Capture Section of the SuperKEKB Injector Linac | 557 |
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| The SuperKEKB is an asymmetric e−/e+ collider with 40 times higher luminosity than the KEKB project, to explore the new physics beyond the standard model. For the SuperKEKB, the positrons are created by striking the accelerated electrons at a tungsten target. The secondary electrons are also produced during the positron creation process and accelerated in the capture section. Because of phase slipping in the capture section, the secondary electron bunch is only ∼ 180 ps away from the positron. Conventional stripline-type BPM cannot detect such closely spaced and opposite polarity signals due to slow frequency response and high cable losses. Therefore, a new wideband feedthrough-type beam position monitor was developed. It was successfully employed at the positron capture section of the SuperKEKB injector linac for the first synchronous measurement of the electron and positron beams. The cable losses effect also has been de-embedded to reveal correct signal properties. This paper describes the initial results of synchronous measurement of e−/e+ transverse position. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB163 | |
| About • | paper received ※ 20 May 2021 paper accepted ※ 27 May 2021 issue date ※ 16 August 2021 | |
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| MOPAB221 | Developments of a Pulse Kicker System for the Three-Dimensional Spiral Beam Injection of the J-PARC Muon g-2/EDM Experiment | 726 |
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| The J-PARC muon g-2/EDM experiment aims to perform ultra-precise measurements of anomalous magnetic moments (g-2) and electric dipole moments (EDM) from the spin precession of muons in a precise magnetic field and to explore new physics beyond the Standard Model. On experimental requirements, the beam must be stored in a compact storage orbit with a diameter of 66 cm, which is about 1/20th smaller than that of the previous experiment. To be realized, we adopt an unprecedented injection technique called the three-dimensional spiral injection scheme. In this scheme, the beam is injected from upward of the solenoidal storage magnet. The vertical beam motion along the solenoid axis is controlled by a few 100 ns pulse kicker. Once the beam is guided into the center fiducial storage volume, the muon beam is stored by the weak focusing magnetic field. Therefore, stable and accurate control of the pulse kicker is one of the major technical challenges to realize the ultra-precise measurement of the muon spin precession. In this presentation, we discuss the performance of the prototype pulse kicker device and future plan for installation of it to our test bench with an electron beam. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB221 | |
| About • | paper received ※ 20 May 2021 paper accepted ※ 31 May 2021 issue date ※ 15 August 2021 | |
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| MOPAB256 | Development of Pulsed Beam System for the Three Dimensional Spiral Injection Scheme in the J-PARC muon g-2/EDM Experiment | 809 |
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| The J-PARC muon g-2/EDM experiment aims to measure the anomalous magnetic moment(g-2) and electric dipole moment(EDM) of the muon with higher precision than the previous BNL E821 experiment. A brand-new three-dimensional spiral injection scheme is employed to inject and store muon beam into a 66 cm diameter of storage magnet. Feasibility studies are ongoing by use of 80 keV electron beam at KEK test bench, to develop skills on control transverse beam motion; so-called X-Y coupling, with DC beam. As a next step, towards store the beam by use of a kicker system, a pulsed beam should be generated from the DC beam with an intended time structure to meet a pulse kicker’s duration time, without changing transverse phase space characteristics. In this presentation, the development of a beam chopper device and the evaluation of pulse beam profile are discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB256 | |
| About • | paper received ※ 20 May 2021 paper accepted ※ 15 June 2021 issue date ※ 16 August 2021 | |
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