18-22 October 2021
Matsue, Shimane Prefecture, Japan
Asia/Tokyo timezone

The precision nEDM measurement with UltraCold Neutrons at TRIUMF

22 Oct 2021, 09:40
Room 403 (Kunibiki Messe)

Room 403

Kunibiki Messe

Parallel Session Presentation Future facilities and experiments Joint BSM - Lowenergy - Future Session US timezone


Dr Ryohei Matsumiya (TRIUMF)


The TRIUMF Ultra-Cold Advanced Neutron (TUCAN) collaboration aims at a precision neutron electric dipole moment (nEDM) measurement with an uncertainty of 10$^{-27}$ e$\cdot$cm, which is an order-of-magnitude better than the current nEDM upper limit [1] and enables us to test Supersymmetry. To achieve this precision, our collaboration has been developing a new high-intensity ultracold neutron (UCN) source and a nEDM spectrometer at TRIUMF, Canada.

Recent nEDM experiments are performed by measuring the Larmor precession frequency of polarized UCNs confined in a spin precession chamber where static magnetic and electric fields are applied. The spin precession of the UCNs in the chamber is observed by Ramsey's technique of separately oscillating magnetic field [2]. Our nEDM spectrometer polarizes UCNs with a 3.5 T magnetic field generated by a superconducting magnet, and then transports them through UCN guides to a spin precession chamber. The chamber is placed in a magnetically shielded room where the internal magnetic field is controlled with high precision Cs magnetometers and compensation coils. After flipping the UCN spin by Ramsey's technique, the UCNs are guided from the chamber to UCN detectors. The polarization of the UCNs is analyzed by counting the number of UCNs transmitting through magnetized iron thin films placed before the detectors.

We have been developing these sub-systems of the nEDM spectrometer. In this talk, the overview of our project and the current development status will be presented.

[1] C. Abel et al., Phys. Rev. Lett. 124, 081803 (2020).
[2] N. F. Ramsey, Phys. Rev. 78, 695 (1950).

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