Gießen 2024 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 28: Instrumentation VII
HK 28.2: Talk
Tuesday, March 12, 2024, 18:00–18:15, HBR 19: C 2
Development of an improved adiabatic spin flipper unit for the neutron lifetime experiment tauspect — •Viktoria Ermuth1, Martin Fertl1, and Dieter Ries2 for the tauSPECT collaboration — 1Institute of Physics, Johannes Gutenberg- Universität Mainz, Mainz, Germany — 2Paul Scherrer Institute, Villigen PSI, Switzerland
To measure the free neutron lifetime the τSPECT experiment stores ultracold neutrons (UCN) using magnetic field gradients. High-field-seeking (HFS) neutrons can overcome higher magnetic potentials whereby low-field-seeking neutrons (LFS) loose kinetic energy when moving to higher magnetic fields. Therefore, the magnetic trap of τSPECT is filled by flipping the spin of HFS neutrons transforming them to the LFS state. For the spin flip an adiabatic fast passage spin flipper unit (SFU) is used which consists of a coil producing a radiofrequency field resonant with the neutron spin precession frequency. The radiofrequency field is perpendicular to the main magnetic field and the neutron spin precession frequency is made position dependent by a small magnetic gradient. With a second SFU UCNs with higher kinetic energies, available in larger numbers, can be made storable. In the next generation of this SFU optimisations are implemented to increase the efficiency of the double spin flip. The optimised design must combine challenging constraints like little available space, cryogenic temperatures and ultra high vacuum compatibility.
This talk will show simulations and first tests on possible spin flipper designs as well as the current status of the development.