Measuring the neutrino mass is one the most compelling issues in modern particle physics. HOLMES experiment aims at directly measuring the neutrino mass with a sensitivity as low as 1 eV exploiting the calorimetric approach: HOLMES will extract information on neutrino mass through a precise measurement of the end-point of the Electron Capture decay spectrum of 163Ho. HOLMES, in its final configuration, will deploy a 1000-pixel array of low temperature microcalorimeters: each detector is composed of a gold absorber, where the 163Ho nuclei will be ion implanted, coupled to a Transition Edge Sensor which acts as thermometer. The detectors will be kept at their operating temperature of 70 mK in a dilution refrigerator. In order to easily read out the 1000 detectors of HOLMES, a multiplexed readout is required: the choice is to couple the Transition Edge Sensors to multiplexed rf-SQUIDs operated in flux ramp modulation for linearization purposes. The rf-SQUIDs, in turn, are coupled to superconducting quarter wavelength resonators in the GHz range, from which the modulated signal is finally recovered using Software-Defined Radio techniques. This allows to readout multiple detectors with a common readout line, heavily simplifying the experimental set-up.
In this contribution, we outline the status and perspective of HOLMES: the target time and energy resolution have been reached while the final detector array design is being finalized. A first 64 detectors measurement is planned to start by the beginning of 2018: this will allow to evaluate crucial parameters, such as the relevance of shake-up and shake-off second order processes, which could be relevant in affecting the spectral shape close to the end-point. From this preliminary measurement, with a two-month long exposure time, it will be possible to set a limit below 10 eV on the neutrino mass.