Reducing noise to the quantum limit over a large bandwidth is a fundamental requirement for future applications operating at millikelvin temperatures, such as the neutrino mass measurement, the ...next-generation X-ray observatory, the CMB measurement, the dark matter and axion detection, and the rapid high-fidelity readout of superconducting qubits. The read out sensitivity of arrays of microcalorimeter detectors, resonant axion-detectors, and qubits, is currently limited by the noise temperature and bandwidth of the cryogenic amplifiers. The Detector Array Readout with Traveling Wave Amplifiers project has the goal of developing high-performing innovative traveling wave parametric amplifiers with a high gain, a high saturation power, and a quantum-limited or nearly quantum-limited noise. The practical development follows two different promising approaches, one based on the Josephson junctions and the other one based on the kinetic inductance of a high-resistivity superconductor. In this contribution, we present the aims of the project, the adopted design solutions and preliminary results from simulations and measurements.
The HOLMES experiment will perform a precise calorimetric measurement of the end point of the Electron Capture (EC) decay spectrum of 163 Ho in order to extract information on neutrino mass with a ...sensitivity below 2 eV. 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 SiN x membrane with gold absorbers. Considering the large number of pixels and an event rate of about 300 Hz/pixel, a large multiplexing factor and a large bandwidth are needed. To fulfill this requirement, HOLMES will exploit recent advances on microwave multiplexing. In this contribution we present the status of the activities in development, the performances of the developed microwave-multiplexed readout system, and the results obtained with the detectors specifically designed for HOLMES in terms of noise, time and energy resolutions.
The HOLMES experiment aims to directly measure the
ν
mass studying the
163
Ho electron capture decay spectrum developing arrays of TES-based microcalorimeters implanted with O(300 Bq/detector) Ho ...atoms. The embedding of the source inside detectors is a crucial step of the experiment. Because the
163
Ho production process (neutron irradiation of a
162
Er sample) is not perfectly free from impurities, Ho source must be separated from a lot of contaminants. A chemical processing removes every species other than Ho, but it is not sufficient to remove all isotope-related background sources: Indeed,
166
m
Ho beta decay can produce fake signal in the region of interest. For this reason, a dedicated implantation system was set up. It is designed to achieve the separation power better than 5
σ
at 163/166 a.m.u. allowing an efficient Ho ions implantation inside microcalorimeter absorbers. Its main components are a 50 kV sputter-based ion source, a magnetic dipole and a target chamber. A specially designed co-evaporation system was designed to “grow” the gold microcalorimeter absorber during the implantation process, increasing the maximum achievable activity which can be implanted. The machine performances were evaluated by means of calibration runs using
63
Cu/
65
Cu and Mo beams. A special care was given to the study of the more effective way to populate source plasma with Ho ions obtained from different Ho compounds by sputtering process. In this work, the machine development and commissioning are described.
HOLMES Faverzani, M.
Journal of physics. Conference series,
09/2017, Letnik:
888, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The experiment HOLMES, founded by the European Research Council, will perform a calorimetric measurement of the energy released in the electron capture of 163Ho to directly measure the neutrino mass ...with a sensitivity of ∼ 1 eV. This approach allows to eliminate the problematics connected to the use of external sources and the systematic uncertainties arising from decays on excited states. Such measurement will be performed with low temperature thermal detectors, where the decay energy is converted into a temperature signal measured by sensitive thermometers. HOLMES, besides of being an important step forward in the direct neutrino mass measurement with a calorimetric approach, will also establish the potential of this approach to extend the sensitivity down to 0.1 eV and lower. The best configuration has been defined with Monte Carlo simulations: HOLMES will collect about 3 × 1013 decays with 1000 detectors characterized by an instrumental energy resolution of the order of the eV and a time resolution of few microseconds. For a measuring time of 3 years, this translates in a total required 163Ho activity of about 300 kBq, equivalent to about 6.5 × 1016 163Ho nuclei, or 18 µg. The HOLMES detectors will have 163Ho implanted into Gold absorber coupled to Transition Edge Sensors, which will be read using microwave multiplexed rf-SQUIDs in combination with a ROACH2 based acquisition system. An extensive R&D activity is in progress in order to maximize the multiplexing factor while preserving the performances of the individual detectors. R&D activities aimed at optimizing the single detector performances, the 163Ho isotope production and embedding are in progress and will converge in a preliminary measurement of an array of 16 detectors planned by the end of 2016. We outline here the HOLMES project with its technical challenges, its status and perspectives.
Abstract
The PTOLEMY transverse drift filter is a new concept to
enable precision analysis of the energy spectrum of electrons near
the tritium
β
-decay endpoint. This paper details the
...implementation and optimization methods for successful operation of
the filter for electrons with a known pitch angle. We present the
first demonstrator that produces the required magnetic field
properties with an iron return-flux magnet. Two methods for the
setting of filter electrode voltages are detailed. The challenges of
low-energy electron transport in cases of low field are discussed,
such as the growth of the cyclotron radius with decreasing magnetic
field, which puts a ceiling on filter performance relative to fixed
filter dimensions. Additionally, low pitch angle trajectories are
dominated by motion parallel to the magnetic field lines and
introduce non-adiabatic conditions and curvature drift. To minimize
these effects and maximize electron acceptance into the filter, we
present a three-potential-well design to simultaneously drain the
parallel and transverse kinetic energies throughout the length of
the filter. These optimizations are shown, in simulation, to achieve
low-energy electron transport from a 1 T iron core (or 3 T
superconducting) starting field with initial kinetic energy of
18.6 keV drained to < 10 eV (< 1 eV) in about 80 cm. This
result for low field operation paves the way for the first
demonstrator of the PTOLEMY spectrometer for measurement of
electrons near the tritium endpoint to be constructed at the Gran
Sasso National Laboratory (LNGS) in Italy.
Noise at the quantum limit over a broad bandwidth is a fundamental requirement for future cryogenic experiments for neutrino mass measurements, dark matter searches, and Cosmic Microwave Background ...(CMB) measurements as well as for fast high-fidelity read-out of superconducting qubits. In the last years, Josephson Parametric Amplifiers (JPA) have demonstrated noise levels close to the quantum limit, but due to their narrow bandwidth, only few detectors or qubits per line can be read out in parallel. An alternative and innovative solution is based on superconducting parametric amplification exploiting the travelling-wave concept. Within the Detector Array Readout with Travelling Wave AmplifieRS (DARTWARS) project, we develop Kinetic Inductance Travelling-Wave Parametric Amplifiers (KI-TWPAs) for low temperature detectors and qubit read-out. KI-TWPAs are typically operated in a three-wave mixing (3WM) mode and are characterised by a high gain, a high saturation power, a large amplification bandwidth, and nearly quantum limited noise performance. The goal of the DARTWARS project is to optimise the KI-TWPA design, explore new materials, and investigate alternative fabrication processes in order to enhance the overall performance of the amplifier. In this contribution we present the advancements made by the DARTWARS collaboration to produce a working prototype of a KI-TWPA, from the fabrication to the characterisation.
This study presents recent advancements in Josephson Traveling Wave Parametric Amplifiers (JTWPAs) developed and tested at Istituto Nazionale di Ricerca Metrologica within the Detector Array Readout ...with Traveling Wave AmplifieRS project framework. Combining Josephson junctions with superconducting coplanar waveguides, JTWPAs offer advanced capabilities for quantum-limited broadband microwave amplification and the emission of non-classical microwave radiation. The work delves into the architecture, optimization, and experimental characterization of a JTWPA with a Resonant Phase-Matching mechanism, highlighting signal gains and idler conversion factors in relation to pump power and signal frequency.
The advent of ultra-low noise microwave amplifiers revolutionized several research fields demanding quantum-limited technologies. Exploiting a theoretical bimodal description of a linear ...phase-preserving amplifier, in this contribution we analyze some of the intrinsic properties of a model architecture (i.e., an rf-SQUID based Josephson Traveling Wave Parametric Amplifier) in terms of amplification and noise generation for key case study input states (Fock and coherent). Furthermore, we present an analysis of the output signals generated by the parametric amplification mechanism when thermal noise fluctuations feed the device.
Ultralow-noise microwave amplification and detection play a central role in different applications, going from fundamental physics experiments to the deployment of quantum technologies. In many ...applications the necessity of reading multiple detectors, or cavities or qubits, calls for large bandwidth amplifiers with the lowest possible noise. Current technologies are based on High Electron Mobility Transistors and Josephson Parametric Amplifiers. Both have limitations, the former in terms of the minimum noise, the latter in terms of bandwidth. Superconducting Traveling Wave Parametric Amplifiers (TWPAs) have the potential of offering quantum limited noise and large bandwidth. These amplifiers are based on the parametric amplification of microwaves traveling along a transmission line with embedded nonlinear elements. We are developing superconducting TWPAs based both on Josephson junction arrays (Traveling Wave Josephson Parametric Amplifiers) and on nonlinear kinetic inductance (Dispersion Engineered Traveling Wave Kinetic Inductance Amplifiers). Our goal is to achieve large bandwidth (in the 5 to 10 GHz range), large gain (more than 20 dB), large saturation power (more than −50 dBm), and near quantum limited noise (noise temperature less than 600 mK). Current achievements in the design and development of the high performance TWPAs are here reported and discussed, together with current limitations and possible future developments.
For experiments with high arrival rates, reliable identification of nearly-coincident events can be crucial. For calorimetric measurements to directly measure the neutrino mass such as HOLMES, ...unidentified pulse pile-ups are expected to be a leading source of experimental error. Although Wiener filtering can be used to recognize pile-up, it suffers from errors due to pulse shape variation from detector nonlinearity, readout dependence on subsample arrival times, and stability issues from the ill-posed deconvolution problem of recovering Dirac delta-functions from smooth data. Due to these factors, we have developed a processing method that exploits singular value decomposition to (1) separate single-pulse records from piled-up records in training data and (2) construct a model of single-pulse records that accounts for varying pulse shape with amplitude, arrival time, and baseline level, suitable for detecting nearly-coincident events. We show that the resulting processing advances can reduce the required performance specifications of the detectors and readout system or, equivalently, enable larger sensor arrays and better constraints on the neutrino mass.
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