SALER
Precision weak physics
Radioactive beams and superconducting sensors at FRIB.
A precision test of the weak interaction
I am the principal investigator for SALER at the Facility for Rare Isotope Beams (FRIB). Our team uses sensitive superconducting detectors to ask how precisely nuclear decay follows the Standard Model.
What the recoil reveals
When a nucleus decays, its recoil records how momentum is shared among the emitted particles. Measuring that recoil spectrum lets us test the weak interaction and search for additional scalar and tensor interactions beyond the Standard Model.
From beam to sensor
The Superconducting Array for Low-Energy Radiation (SALER) implants short-lived isotopes directly into superconducting tunnel-junction detectors while they are cold and operating. This connects FRIB’s radioactive beams with sensitive recoil spectroscopy.
The physics programme includes recoil correlations in mirror beta decays, which can contribute to tests of quark mixing, alongside broader searches for exotic weak currents.
Commissioning and next measurements
SALER’s 64-pixel array has undergone on-line commissioning with a stable nitrogen-14 beam at FRIB.
The October 2026 CPAD contribution describes tests of the cryogenic system and detector noise in the beamline environment. Preparations for the first aluminium-25 science run in early 2027 are underway.
These commissioning measurements establish the experimental conditions needed for precision spectroscopy with short-lived radioactive beams.
Further reading
First On-Beam Commissioning of SALER: STJ-Based Recoil Spectroscopy at FRIB
Glenn Richardson, CPAD 2026, October 2026.
Nuclear recoil spectroscopy with SALER
APS Global Physics Summit, March 2026.
Beta recoil spectroscopy as a Beyond Standard Model laboratory
Leendert Hayen, 2026 preprint.