Ultracold neutron storage in a bottle coated with the fluoropolymer CYTOP

• Published in: The European physical journal. A, Hadrons and nuclei Hadrons and nuclei, 2022-07, Vol.58 (7), Article 141
• Main Authors: Neulinger, Thomas, Beck, Douglas, Connolly, Euan, Degenkolb, Skyler, Fierlinger, Peter, Filter, Hanno, Hingerl, Jürgen, Nordin, Pontus, Saerbeck, Thomas, Zimmer, Oliver
• Format: Article
• Language: English
• Subjects: Hadrons; Heavy Ions; Instrumentation and Detectors; Nuclear Fusion; Nuclear Physics; Nuclear Theory; Particle and Nuclear Physics; Physics; Physics and Astronomy; Special Article - New Tools and Techniques
• ISSN: 1434-601X; 1434-6001; 1434-601X
• DOI: 10.1140/epja/s10050-022-00791-x

The fluoropolymer CYTOP was investigated in order to evaluate its suitability as a coating material for ultracold neutron (UCN) storage vessels. Using neutron reflectometry on CYTOP-coated silicon wafers, its neutron optical potential was measured to be 115.2(2) neV. UCN storage measurements were carried out in a 3.8 l CYTOP-coated aluminum bottle, in which the storage time constant was found to increase from 311(9) s at room temperature to 564(7) s slightly above 10 K. By combining experimental storage data with simulations of the UCN source, the neutron loss factor of CYTOP is estimated to decrease from 1.1(1) × 10 - 4 to 2.7(2) × 10 - 5 at these temperatures, respectively. These results are of particular importance to the next-generation superthermal UCN source SuperSUN, currently under construction at the Institut Laue-Langevin, for which CYTOP is a possible top-surface coating in the UCN production volume.