19–24 May 2024
Music City Center
US/Central timezone

Impedance evaluation, mitigation, and measurement of ALS-U vacuum components.

TUPC13
21 May 2024, 16:00
2h
Country (MCC Exhibit Hall A)

Country

MCC Exhibit Hall A

Poster Presentation MC1.A04 Circular Accelerators Tuesday Poster Session

Speaker

Dan Wang (Lawrence Berkeley National Laboratory)

Description

The Advanced Light Source Upgrade (ALS-U) is a 4th generation diffraction-limited soft x-ray radiation source. Coupling-impedance-driven instabilities have been carefully evaluated to ensure meeting the machine’s high-performance goals during the design stage. At present, the focus of impedance modeling efforts primarily revolves around supporting beam tests of key components at ALS beamlines and the fabrication of various components. This paper presents impedance measurements of the main RF bellows with the Goubau-Line, as well as thermal evaluations on beam-induced heating on the RF bellows and the booster-to-accumulator ferrite (BTA) kicker on the ALS beamline. One challenge in the impedance modeling of the BTA kicker arises from a 4-micrometer-thick TiN coating, rendering direct modeling in CST challenging. To address this, we employed the ImpedanceWake2D (IW2D) code as an initial step to validate the efficacy of RF shielding. Subsequently, an equivalent model was constructed in CST to calculate the total impedance. We also show the impedance evaluation results and reduction strategies for the keyhole bellows and photon absorbers, incorporating thermal expansion considerations. Notably, the work is essential for successfully commissioning the ALS-U project.

Funding Agency

This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Region represented North America

Primary author

Dan Wang (Lawrence Berkeley National Laboratory)

Co-authors

Tianhuan Luo (Lawrence Berkeley National Laboratory) Ramiro Bereguer (Lawrence Berkeley National Laboratory) Tao Cui (Lawrence Berkeley National Laboratory) Qing Ji (Lawrence Berkeley National Laboratory) Sam Moy (Lawrence Berkeley National Laboratory) Tom Miller (Lawrence Berkeley National Laboratory) Nathan Millard (Lawrence Berkeley National Laboratory) Thomas Oliver (Lawrence Berkeley National Laboratory) Sol Omolayo (Lawrence Berkeley National Laboratory) Christoph Steier (Lawrence Berkeley National Laboratory) William Waldron (Lawrence Berkeley National Laboratory) Marco Venturini (Lawrence Berkeley National Laboratory) Guobin Wang (Lawrence Berkeley National Laboratory)

Presentation materials

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