| Paper | Title | Page | 
    
        | WE4P36 | The Cryogenic Undulator Upgrade Programme at Diamond Light Source | 211 | 
    
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                Z. Patel, W. Cheng, A. George, S.H. Hale, R. Mercado, A. Ramezani Moghaddam, M. Reeves, G. Sharma, S. TripathiDLS, Oxfordshire, United Kingdom
M.V. MarzianiUniversity of Cape Town, Cape Town, South Africa
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        |  | Diamond Light Source has installed four 2 m long, 17.6 mm period Cryogenic Permanent Magnet Undulators (CPMUs) as upgrades for crystallography beamlines since 2020, with two more planned within the next year. The CPMUs provide 2 - 3 times more brightness and 2 - 4 times more flux than the pure permanent magnet (PPM) devices they are replacing. They have been designed, built, and measured in-house. All four have a 4 mm minimum operating gap and are almost identical in their construction: the main difference being an increase in the number of in-vacuum magnet beam support points from four to five, between CPMU-1 and CPMUs 2 - 4, to better facilitate shimming, particularly at cold temperatures. The ability to shim at cryogenic temperatures necessitated the development of an in-vacuum measurement system. The details of the measurement system will be presented alongside the mechanical and cryogenic design of the undulators; including issues with the magnet foils, and the shimming procedures and tools used to reach the tight magnetic specifications at room temperature and at 77 K. |  | 
    
        |   | Poster WE4P36 [1.656 MB] |  | 
    
    	  | DOI • | reference for this paper 
              ※ doi:10.18429/JACoW-FLS2023-WE4P36 |  | 
    
    	  | About • | Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023 | 
    
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