| Paper | Title | Page |
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| TU1C3 | Beam-Based Calibration of Sextupole Magnet Displacement with Betatron Tune Shift | 192 |
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| The alignment of sextupole magnets is one of the critical issues for the upcoming 4th generation light sources and future colliders. The alignment error of magnets and the beam offsets in sextupoles should be within a few 10 µm rms to ensure enough dynamic aperture for stable operation and minimize deterioration of beam quality. Considering that the quadrupole field in a sextupole is proportional to the displacement (normal Q for horizontal and skew Q for vertical), we propose a beam-based calibration (BBC) method to measure the sextupole centers by observing the betatron tune shift. The magnetic center is the point where the tune does not change regardless of the sextupole field strength. The key is increasing the XY coupling to obtain a tune shift large enough for the vertical calibration. We studied experimentally the feasibility of the sextupole BBC at SPring-8 and successfully demonstrated the principle for both horizontal and vertical calibration. The tune shift was monitored by bunch-by-bunch feedback electronics with approximately 1e-5 resolution. The measurement resolution of the sextupole center was approximately 10 µm std., which was sufficient for our requirement. | ||
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Slides TU1C3 [4.150 MB] | |
| DOI • | reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TU1C3 | |
| About • | Received ※ 31 August 2022 — Revised ※ 10 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 27 November 2022 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUP32 | Differential Current Transformer for Beam Charge Monitoring in Noisy Environments | 304 |
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We developed a differential current transformer (CT) for electron beam charge measurement in noisy environments, such as near high-power pulse sources. This CT has four pickup wires coiled at equal intervals (90 deg.) on a toroidal core and each coil is wound for two turns. The midpoint of the coil is connected to the body ground so that a balanced differential signal is generated at both ends. A beam pipe with a ceramics insulation gap is inserted into the toroidal core to obtain a signal from a charged-particle beam. The four pairs of signals are transmitted through a CAT6 differential cable and fed into differential amplifiers. The common-mode noise from the noisy ground at the CT is canceled out by the amplifier. The four signals are then summed and digitized by an AD converter. We produced differential CTs and installed them into the new injector linac of NewSUBARU (*). Before the installation, the frequency response was measured in a laboratory and a flat response of up to 100 MHz was obtained as expected. Common-mode noise cancellation was also confirmed at NewSUBARU and the CTs have been utilized for beam charge monitoring stably.
*: T. Inagaki et al., ’Construction of a Compact Electron Injector Using a Gridded RF Thermionic Gun and a C-Band Accelerator’, in Proc. IPAC’21, pp. 2687-2689. doi:10.18429/JACoW-IPAC2021-WEPAB039 |
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Poster TUP32 [1.393 MB] | |
| DOI • | reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TUP32 | |
| About • | Received ※ 07 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 26 October 2022 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |