Probing the absolute neutrino mass scale with 163Ho: The HOLMES project

De Gerone M.; Alpert B.; Becker D.; Bennett D.; Biasotti M.; Ceriale V.; Dressler R.; Faverzani M.; Ferri E.; Fowler J.; Gallucci G.; Gard J.; Gatti F.; Giachero A.; Hays-Wehle J.; Heinitz S.; Hilton G.; Koester U.; Lusignoli M.; Mates J.; Nucciotti A.; Nisi S.; Orlando A.; Pessina G.; Puiu A.; Ragazzi S.; Reintsema C.; Ribeiro Gomes M.; Schmidt D.; Schumann D.; Swetz D.; Ullom J.; Vale L.

doi:10.1016/j.nima.2018.10.108

The HOLMES project aims to directly measure the nu mass down to the eV scale using the electron capture decay (EC) of Ho-163. It will perform a precise calorimetric measurement of the end-point of the Ho energy spectrum looking for the deformation caused by a finite nu mass. The choice of Ho-163 as source is driven by the very low Q-value of the EC reaction, which allows for high sensitivity with low activities (O(10(2))Bq/detector), thus reducing the pile-up probability. A large array made by thousands of transition edge sensors based micro-calorimeters will be used. The calorimetric approach eliminates systematic uncertainties arising from the use of an external beta source, and minimizes the effect of the atomic de-excitation process. The commissioning of the first implanted sub-array is scheduled for the end of 2018. It will provide useful data about the EC decay of Ho-163 together with a first limit on nu mass.

Probing the absolute neutrino mass scale with 163Ho: The HOLMES project

De Gerone M.;Alpert B.;Becker D.;Bennett D.;Biasotti M.;Ceriale V.;Dressler R.;Faverzani M.;Ferri E.;Fowler J.;Gallucci G.;Gard J.;Gatti F.;Giachero A.;Hays-Wehle J.;Heinitz S.;Hilton G.;Koester U.;Lusignoli M.;Mates J.;Nucciotti A.;Nisi S.;Orlando A.;Pessina G.;Puiu A.;Ragazzi S.;Reintsema C.;Ribeiro Gomes M.;Schmidt D.;Schumann D.;Swetz D.;Ullom J.;Vale L.

2019

Abstract

The HOLMES project aims to directly measure the nu mass down to the eV scale using the electron capture decay (EC) of Ho-163. It will perform a precise calorimetric measurement of the end-point of the Ho energy spectrum looking for the deformation caused by a finite nu mass. The choice of Ho-163 as source is driven by the very low Q-value of the EC reaction, which allows for high sensitivity with low activities (O(10(2))Bq/detector), thus reducing the pile-up probability. A large array made by thousands of transition edge sensors based micro-calorimeters will be used. The calorimetric approach eliminates systematic uncertainties arising from the use of an external beta source, and minimizes the effect of the atomic de-excitation process. The commissioning of the first implanted sub-array is scheduled for the end of 2018. It will provide useful data about the EC decay of Ho-163 together with a first limit on nu mass.