Jul 22 – 26, 2019
Europe/Rome timezone

A New Measurement of the 60 keV Transition in Am-241 Decays using Metallic Magnetic Calorimeters

Jul 23, 2019, 5:45 PM
1h 15m
Piazza Città di Lombardia (Milano)

Piazza Città di Lombardia


Piazza Città di Lombardia, 1, 20124 Milano MI
Poster Low Temperature Detector Applications Poster session


Geon-Bo Kim (Lawrence Livermore National Laboratory)


The 60 keV transition in Am-241 decay is one of the most important calibration standards for low energy gamma-rays. The current literature value of 59.5409(1) keV is based on measurements with high-purity Ge detectors and a Tb-161 reference source in 1993, and its 0.1 eV uncertainty gives it significant weight for cryogenic detector calibration. We have re-measured the energy of this transition in Am-241 decays with metallic magnetic calorimeter (MMC) gamma detectors with an energy resolution of 80 eV and demonstrated high linearity and reproducibility. For calibration, we have made a Yb-169 source, whose gamma emissions are known extremely accurately from measurements using crystal spectrometers, through Tm-169(d,2n)Yb-169 at the 88” Cyclotron. We will discuss statistical and systematic uncertainties of the measurements and provide a preliminary recommendation for an improved value of the Am-241 gamma-ray energy.

Student (Ph.D., M.Sc. or B.Sc.) N
Less than 5 years of experience since completion of Ph.D Y

Primary authors

Geon-Bo Kim (Lawrence Livermore National Laboratory) Prof. Stephen Boyd (University of New Mexico) Dr Robin Cantor (STAR Cryoelectronics) Prof. Lee Bernstein (Lawrence Berkeley National Laboratory) Dr Stephan Friedrich (Lawrence Livermore National Laboratory)

Presentation materials