Calorimetric observation of single He2* excimers in a 100 mK He bath

Abstract

We report the first calorimetric detection of individual He2* excimers within a bath of superfluid 4He. The detector used in this work is a single superconducting titanium transition edge sensor (TES) with an energy resolution of ~1 eV, immersed directly in the helium bath. He2* excimers are produced in the surrounding bath using an external gamma-ray source. These excimers exist either as short-lived singlet or long-lived triplet states. We demonstrate detection of both states: in the singlet case the calorimeter records the absorption of a prompt 15 eV photon, and in the triplet case the calorimeter records a direct interaction of the molecule with the TES surface, which deposits a distinct fraction of the 15 eV, released upon decay, into the surface. We also briefly discuss the detector fabrication and characterization.

arXiv comment7 pages, 10 figures

References in corpus (6)

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• Probing Light Dark Matter with a Hadrophilic Scalar Mediator
• DELight: a Direct search Experiment for Light dark matter with superfluid helium
• First Demonstration of the HeRALD Superfluid Helium Detector Concept