The HOLMES experiment aims to directly measure the [Formula presented] mass with a calorimetric approach. The choice of 163 Ho isotope as source is driven by the very low decay Q-value ([Formula presented] 2.8 keV), which allows for high sensitivity with low activities (O(10[Formula presented])Hz/detector), thus reducing the pile-up probability. 163 Ho will be produced by neutron irradiation of 162 Er[Formula presented]O[Formula presented] then chemically separated; anyway, traces of others isotopes and contaminants will be still present. In particular [Formula presented]Ho has a beta decay ([Formula presented]1200y) which can induce background below 5 keV. The removal of the contaminants is critical so a dedicated system has been set up. It is designed to achieve an optimal mass separation @ 163 a.m.u. and consists of two main components: an evaporation chamber and an ion implanter. The first item is used to reduce Ho in metallic form providing a target for the ion implanter source. The implanter is made by the sputter source, an acceleration section, a magnetic dipole, a x–y scanning stage and a focusing electrostatic triplet. In this contribution we will describe the procedures for the Holmium “distillation” process and the status of the machine commissioning.

163 Ho distillation and implantation for the HOLMES experiment

De Gerone, M.;Biasotti, M.;Ceriale, V.;Gallucci, G.;Gatti, F.;Manfrinetti, P.;Orlando, A.;Provino, A.;
2018-01-01

Abstract

The HOLMES experiment aims to directly measure the [Formula presented] mass with a calorimetric approach. The choice of 163 Ho isotope as source is driven by the very low decay Q-value ([Formula presented] 2.8 keV), which allows for high sensitivity with low activities (O(10[Formula presented])Hz/detector), thus reducing the pile-up probability. 163 Ho will be produced by neutron irradiation of 162 Er[Formula presented]O[Formula presented] then chemically separated; anyway, traces of others isotopes and contaminants will be still present. In particular [Formula presented]Ho has a beta decay ([Formula presented]1200y) which can induce background below 5 keV. The removal of the contaminants is critical so a dedicated system has been set up. It is designed to achieve an optimal mass separation @ 163 a.m.u. and consists of two main components: an evaporation chamber and an ion implanter. The first item is used to reduce Ho in metallic form providing a target for the ion implanter source. The implanter is made by the sputter source, an acceleration section, a magnetic dipole, a x–y scanning stage and a focusing electrostatic triplet. In this contribution we will describe the procedures for the Holmium “distillation” process and the status of the machine commissioning.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/939971
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