Speaker
Angelo Enrico Lodovico Nucciotti
(MIB)
Description
HOLMES is a new experiment to directly measure the neutrino mass with a sensitivity as low as 0.4 eV. HOLMES will perform a calorimetric measurement of the energy released in the electron capture decay of $^{163}$Ho.
The calorimetric measurement eliminates systematic uncertainties arising from the use of external beta sources, as in experiments with beta spectrometers.
HOLMES will deploy a large array of low temperature microcalorimeters with implanted $^{163}$Ho nuclei.
The detectors used for the HOLMES experiment will be Mo/Cu superconducting Transition Edge Sensors (TES) on SiN$_x$ membrane with bismuth absorbers. The detectors require a special two step fabrication process to allow the $^{163}$Ho nuclei embedding. The signals from the microcalorimeter array will be read-out with a microwave multiplexing system combined with an FPGA based digital acquisition system which implements a Software Designed Radio.
HOLMES baseline detector is an array of 1000 microcalorimeters each with an implanted $^{163}$Ho activity of about 300 Bq, an energy resolution FWHM of about 1 eV at the spectrum end-point ($Q\approx 2.5$\,keV), and a time resolution of about 1\,$\mu$s.
Matching these performances requires a careful optimization of all components, from the microcalorimeters to the signal processing algorithms.
We outline here the project technical challenges and the present status of the development.
HOLMES is funded by the European Research Council (GA n. 340321).
Collaboration
The HOLMES collaboration
NIST, Boulder, Colorado, USA
LNGS, INFN, Assergi (AQ), Italy
Dipartimento di Fisica, Universit`a di Genova, Genova, Italy
INFN, Sezione di Genova, Genova, Italy
Dipartimento di Fisica, Universit`a di Milano-Bicocca, Milano, Italy
INFN, Sezione di Milano-Bicocca, Milano, Italy
JPL, Caltech, Pasadena, California, USA
PSI, Villigen, Switzerland
INFN, Sezione di Roma 1, Roma, Italy
ILL, Grenoble, France
CENTRA-IST, University of Lisbon, Lisbon, Portugal
Primary author
Angelo Enrico Lodovico Nucciotti
(MIB)
