Oakridge PPU Magnets: Results and Measurements

J. DiMarco; D. Harding; V. Kashikhin; O. Kiemschies; M. Kifarkis; A. Makulski; J. Nogiec; S. Stoynev; T. Strauss; M. Tartaglia; P. Thompson

arXiv · 2509.13455

Oakridge PPU Magnets: Results and Measurements

J. DiMarco·D. Harding·V. Kashikhin·O. Kiemschies·M. Kifarkis·A. Makulski·J. Nogiec·S. Stoynev·T. Strauss·M. Tartaglia·P. Thompson

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Abstract

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) is being upgraded from 1.0 GeV to 1.3 GeV (or 1.4 to 2.8 MW). Several water-cooled magnets have been upgraded to transport 30% higher beam energy. Fermilab contributed the magnet design for the new chicane magnets and injection/extraction septum. Designing the magnets was a challenging task because the new magnets required good combined integrated field quality and needed to occupy the old magnets space but with about 20% greater integrated magnetic field. Additional strong requirements applied to the magnets fringe field so as not to disturb the circulating beam. After fabrication of the magnets, an extensive measurement campaign was developed and performed at Fermilab's Magnet Test Facility. The measurements needed to assess magnet performance and provide comparison to design calculations. These included verification of field strength and harmonics along an 8 m length and 200 mm good field diameter for the chicane dipoles, end-field Hall probe mapping of these magnets, and measurements along two differently curved trajectories within the ~3 m septum gradient magnet. Details of the measurements and systems are presented along with results and comparison to field models.

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J. DiMarco, D. Harding, V. Kashikhin, O. Kiemschies, M. Kifarkis, A. Makulski, J. Nogiec, S. Stoynev, T. Strauss, M. Tartaglia, P. Thompson. 2025-09-16. Oakridge PPU Magnets: Results and Measurements. https://arxiv.org/abs/2509.13455

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