Large-mass bolometers are today extensively used for dark matter and double beta decay searches, in both cases the ultimate experimental sensitivity is defined by the background level reached in such ...devices. The most common background sources and the techniques used for their identification and reduction are here reviewed, with a particular focus on double beta decay searches. The relevant role played by Monte Carlo simulations in this field is discussed. As a real case, the background optimization in the MiDBD experiment is described.
In recent years, the progress on low temperature detector technologies has allowed design of large scale experiments aiming at pushing down the sensitivity on the neutrino mass below 1 eV. Even with ...outstanding performances in both energy (~eV on keV) and time resolution (~ 1 μs) on the single channel, a large number of detectors working in parallel is required to reach a sub-eV sensitivity. HOLMES is a new experiment to directly measure the neutrino mass with a sensitivity as low as 2eV. HOLMES will perform a calorimetric measurement of the energy released in the electron capture (EC) decay of 163 Ho. In its final configuration, HOLMES will deploy 1000 detectors of low temperature microcalorimeters with implanted 163 Ho nuclei. The baseline sensors for HOLMES are Mo/Cu TESs (Transition Edge Sensors) on SiNx membrane with gold absorbers. The readout is based on the use of rf-SQUIDs as input devices with flux ramp modulation for linearization purposes; the rf-SQUID is then coupled to a superconducting lambda/4-wave resonator in the GHz range, and the modulated signal is finally read out using the homodyne technique. The TES detectors have been designed with the aim of achieving an energy resolution of a few eV at the spectrum endpoint and a time resolution of a few micro-seconds, in order to minimize pile-up artifacts.
Microwave multiplex readout for superconducting sensors Ferri, E.; Becker, D.; Bennett, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2016, Letnik:
824
Journal Article
Recenzirano
Odprti dostop
The absolute neutrino mass scale is still an outstanding challenge in both particle physics and cosmology. The calorimetric measurement of the energy released in a nuclear beta decay is a powerful ...tool to determine the effective electron-neutrino mass. In the last years, the progress on low temperature detector technologies has allowed to design large scale experiments aiming at pushing down the sensitivity on the neutrino mass below 1eV. Even with outstanding performances in both energy (~ eV on keV) and time resolution (~ 1μs) on the single channel, a large number of detectors working in parallel is required to reach a sub-eV sensitivity. Microwave frequency domain readout is the best available technique to readout large array of low temperature detectors, such as Transition Edge Sensors (TESs) or Microwave Kinetic Inductance Detectors (MKIDs). In this way a multiplex factor of the order of thousands can be reached, limited only by the bandwidth of the available commercial fast digitizers. This microwave multiplexing system will be used to readout the HOLMES detectors, an array of 1000 microcalorimeters based on TES sensors in which the 163Ho will be implanted. HOLMES is a new experiment for measuring the electron neutrino mass by means of the electron capture (EC) decay of 163Ho. We present here the microwave frequency multiplex which will be used in the HOLMES experiment and the microwave frequency multiplex used to readout the MKID detectors developed in Milan as well.
Microresonator detectors for neutrino physics in Milano Faverzani, M.; Day, P.; Ferri, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Letnik:
718
Journal Article
Recenzirano
Superconducting microwave microresonators are low temperature detectors compatible with large-scale multiplexed frequency domain readout. We aim to develop detector arrays for calorimetric ...measurement of the energy spectra of 163Ho EC decay (Q∼2–3keV) for a direct measurement of the neutrino mass. We plan to investigate nitrides of high-Z materials, like TaN and HfN, that are appropriate for containing the energy of keV decay events, exploring the properties relevant to our detectors, such as quality factor, penetration depth and recombination time.
HOLMES is aiming at a direct measurement of neutrino mass by performing a calorimetric measurement of the energy released in the decay of
163
Ho. In such approach, the
163
Ho source, with the ...required activity, needs to be embedded in the detector. HOLMES will deploy a large array of transition-edge sensor microcalorimeters with implanted
163
Ho ions. While good progress has been made in optimizing single pixel design and fabrication to achieve the target resolution, a major challenge is the fabrication of arrays of such microcalorimeters with the required amount of
163
Ho ions embedded in the detectors absorber. We describe the multi-step microfabrication process implemented to produce the detector arrays for HOLMES. One crucial part of such process is the ability to perform co-deposition of gold during the
163
Ho implantation process on the detectors absorber. We describe the UHV target chamber, with integrated gold deposition system, we have built to achieve this goal.
The European Research Council has recently funded HOLMES, a project with the aim of performing a calorimetric measurement of the electron neutrino mass measuring the energy released in the electron ...capture decay of
163
Ho. The baseline for HOLMES are microcalorimeters coupled to transition edge sensors read-out with rf-SQUIDs, for microwave multiplexing purposes. A promising alternative solution is based on superconducting microwave resonators that have undergone rapid development in the last decade. These detectors, called Microwave Kinetic Inductance Detectors (MKIDs), are inherently multiplexed in the frequency domain and suitable for even larger-scale pixel arrays, with theoretical high energy resolution and fast response. The aim of our activity is to develop arrays of microresonator detectors for X-ray spectroscopy and suitable for the calorimetric measurement of the energy spectra of
163
Ho. Superconductive multilayer films composed by a sequence of pure Titanium and stoichiometric TiN layers show many ideal properties for MKIDs, such as low loss, large sheet resistance, large kinetic inductance, and tunable critical temperature
T
c
. We developed Ti/TiN multilayer microresonators with
T
c
within the range from 70 mK to 4.5 K and with good uniformity. In this contribution, we present the design solutions adopted, the fabrication processes, and the characterization results.
We present our current progress on the design and test of Ti/TiN multilayer for use in kinetic inductance detectors. Sensors based on sub-stoichiometric TiN film are commonly used in several ...applications. However, it is difficult to control the targeted critical temperature
T
c
, to maintain precise control of the nitrogen incorporation process and to obtain a production uniformity. To avoid these problems we investigated multilayer Ti/TiN films that show a high uniformity coupled with high quality factor, kinetic inductance and inertness of TiN. These features are ideal to realize superconductive microresonator detectors for astronomical instruments application but also for the field of neutrino physics. Using pure Ti and stoichiometric TiN, we developed and tested different multilayer configurations, in terms of number of Ti/TiN layers and in terms of different interlayer thicknesses. The target was to reach a critical temperature
T
c
around
(
1
÷
1.5
)
K in order to have a low energy gap and slower recombination time (i.e. low generation–recombination noise). The results prove that the superconductive transition can be tuned in the
(
0.5
÷
4.6
)
K temperature range by properly choosing the Ti thickness in the
(
0
÷
15
)
nm range, and the TiN thickness in the
(
5
÷
100
)
nm range.
AbstractThe search for neutrinoless double beta decay (DBD-0ν) is a powerful tool to establish the correct neutrino mass hierarchy and whether the neutrino is a Majorana or Dirac particle. The Milano ...group has run several experiments using thermal detectors to search for the 130Te DBD-0ν. The Cuoricino experiment consists of an array of 62 TeO2 thermal detectors for a total mass of about 40 kg, by far the largest cryogenic experiment in the world. The detector installation in the Gran Sasso Underground Laboratory has been recently completed. After a test phase the experiment is now taking data and we report here the preliminary results. Cuoricino is the first step toward the CUORE experiment, which will consists of 1000 TeO2 thermal detectors for a total mass of about 760 kg: in this paper we discuss also the physics potential of both stages for what concerns the DBD-0ν search. PACS: 11.30.Fs Lepton number – 14.60.Pq Neutrino mass and mixing – 23.40.Bw Weak interactions in beta decay
Measuring the neutrino mass is one the most compelling issue in particle physics. HOLMES is an experiment funded by the European Research Council for a direct measurement of neutrino mass. HOLMES ...will perform a precise measurement of the end point of the Electron Capture decay spectrum of 163Ho in order to extract information on neutrino mass with a sensitivity as low as 1 eV. HOLMES, in its final configuration will deploy a 1000 pixel array of low temperature microcalorimeters: each calorimeter consists of an absorber, where the Ho atoms will be implanted, coupled to a Transition Edge Sensor thermometer. The detectors will be kept at the working temperature of ∼70 mK using a dilution refrigerator. In order to gather the required 3 × 1013 events in a three year long data taking with a pile up fraction as low as 10−4, detectors must fulfill rather high speed and resolution requirements, i.e. 10 µs rise time and 4 eV resolution. To ensure such performances with an efficient read out technique for very large detectors array kept at low temperature inside a cryostat is no trivial matter: at the moment, the most appealing read out technique applicable to large arrays of Transition Edge Sensors is rf-SQUID multiplexing. It is based on the use of rf-SQUIDs as input devices with flux ramp modulation for linearisation purposes; the rf-SQUID is then coupled to a super-conductive λ/4-wave resonator in the GHz range, and the modulated signal is finally read out using the homodyne technique.
A powerful tool to determine the effective electron-neutrino mass is the calorimetric measurement of the energy released in a nuclear beta decay. Performing a precision measurement of the end point ...of the Electron Capture decay spectrum of 163Ho, HOLMES aims at pushing down the sensitivity on the neutrino mass below 1 eV. In its final configuration HOLMES will deploy an array of 1000 microcalorimeters based on Transition Edge Sensors with gold absorbers in which the 163Ho will be ion implanted. The best technique to easily read out such a number of detector with a common readout line is the microwave frequency domain multiplexing. Therefore, the TESs are coupled to multiplexed rf-SQUIDS operated in flux ramp modulation for linearization purposes. The rf-SQUIDS are then coupled to superconducting quarter wavelength resonators in the GHz range, from which the modulating signal is finally recovering using software defined radio techniques. In the last two years an extensive R&D activity has been carried out in order to maximize the multiplexing factor while preserving the performances of each detector which fulfil the HOLMES requirements ( i.e. an energy resolution of few eV and a time-resolution of a few microseconds). We report here the progress made towards the characterization of the multiplexing system together with the results of the characterization of the HOLMES detectors.
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