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Han, S.

Publications and source records attributed to Han, S..

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Controlling T c of iridium films using the proximity effect

A superconducting Transition-Edge Sensor (TES) with low-$T_c$ is essential in a high resolution calorimetric detection. With a motivation of developing sensitive calorimeters for applications in cryogenic neutrinoless double beta decay searches, we have been investigating methods to reduce the $T_c$ of an Ir film down to 20 mK. Utilizing the proximity effect between a superconductor and a normal metal, we found two room temperature fabrication recipes of making Ir-based low-$T_c$ films. In the first approach, an Ir film sandwiched between two Au films, a Au/Ir/Au trilayer, has a tunable $T_c$ in the range of 20-100 mK depending on the relative thicknesses. In the second approach, a paramagnetic Pt thin film is used to create Ir/Pt bilayer with a tunable $T_c$ in the same range. We present detailed study of fabrication and characterization of Ir-based low-$T_c$ films, and compare the experimental results to theoretical models. We show that Ir-based films with predictable and reproducible critical temperature can be consistently fabricated for use in large scale detector applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Measurement of the absolute branching fraction of the inclusive decay $\Lambda _c^+ \rightarrow K_S^0X$: (BESIII Collaboration)

We report the first measurement of the absolute branching fraction of the inclusive decay Λ c + → K S 0 X . The analysis is performed using an e + e - collision data sample corresponding to an integrated luminosity of 567 pb - 1 taken at s = 4.6 GeV with the BESIII detector. Using eleven Cabibbo-favored Λ ¯ c - decay modes and the double-tag technique, this absolute branching fraction is measured to be B ( Λ c + → K S 0 X ) = ( 9.9 ± 0.6 ± 0.4 ) % , where the first uncertainty is statistical and the second systematic. The relative deviation between the branching fractions for the inclusive decay and the observed exclusive decays is ( 18.7 ± 8.3 ) % , which indicates that there may be some unobserved decay modes with a neutron or excited baryons in the final state.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗