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Ferella, Alfredo D.ORCID iD iconorcid.org/0000-0002-6006-9160
Alternative names
Publications (10 of 33) Show all publications
Antochi, V. C., Baudis, L., Bollig, J., Brown, A., Budnik, R., Cichon, D., . . . Wulf, J. (2021). Improved quality tests of R11410-21 photomultiplier tubes for the XENONnT experiment. Journal of Instrumentation, 16(8), Article ID P08033.
Open this publication in new window or tab >>Improved quality tests of R11410-21 photomultiplier tubes for the XENONnT experiment
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2021 (English)In: Journal of Instrumentation, E-ISSN 1748-0221, Vol. 16, no 8, article id P08033Article in journal (Refereed) Published
Abstract [en]

Photomultiplier tubes (PMTs) are often used in low-background particle physics experiments, which rely on an excellent response to single-photon signals and stable long-term operation. In particular, the Hamamatsu R11410 model is the light sensor of choice for liquid xenon dark matter experiments, including XENONnT. The same PMT model was also used for the predecessor, XENON1T, where issues affecting its long-term operation were observed. Here, we report on an improved PMT testing procedure which ensures optimal performance in XENONnT. Using both new and upgraded facilities, we tested 368 new PMTs in a cryogenic xenon environment. We developed new tests targeted at the detection of light emission and the degradation of the PMT vacuum through small leaks, which can lead to spurious signals known as afterpulses, both of which were observed in XENON1T. We exclude the use of 26 of the 368 tested PMTs and categorise the remainder according to their performance. Given that we have improved the testing procedure, yet we rejected fewer PMTs, we expect significantly better PMT performance in XENONnT.
Keywords
Photon detectors for UV, visible and IR photons (vacuum), visible and IR photons (vacuum) (photomultipliers, HPDs, others), Dark Matter detectors (WIMPs, axions, etc, ), Noble liquid detectors (scintillation, ionization, double-phase)
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-198396 (URN)10.1088/1748-0221/16/08/P08033 (DOI)000696805000001 ()
Available from: 2021-11-11 Created: 2021-11-11 Last updated: 2024-07-04Bibliographically approved
Betti, M. G., Biasotti, M., Boscá, A., Calle, F., Carabe-Lopez, J., Cavoto, G., . . . Zurek, K. M. (2019). A design for an electromagnetic filter for precision energy measurements at the tritium endpoint. Progress in Particle and Nuclear Physics, 106, 120-131
Open this publication in new window or tab >>A design for an electromagnetic filter for precision energy measurements at the tritium endpoint
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2019 (English)In: Progress in Particle and Nuclear Physics, ISSN 0146-6410, E-ISSN 1873-2224, Vol. 106, p. 120-131Article, review/survey (Refereed) Published
Abstract [en]

We present a detailed description of the electromagnetic filter for the PTOLEMY project to directly detect the Cosmic Neutrino Background (CNB). Starting with an initial estimate for the orbital magnetic moment, the higher-order drift process of E x B is configured to balance the gradient-B drift motion of the electron in such a way as to guide the trajectory into the standing voltage potential along the mid-plane of the filter. As a function of drift distance along the length of the filter, the filter zooms in with exponentially increasing precision on the transverse velocity component of the electron kinetic energy. This yields a linear dimension for the total filter length that is exceptionally compact compared to previous techniques for electromagnetic filtering. The parallel velocity component of the electron kinetic energy oscillates in an electrostatic harmonic trap as the electron drifts along the length of the filter. An analysis of the phase-space volume conservation validates the expected behavior of the filter from the adiabatic invariance of the orbital magnetic moment and energy conservation following Liouville's theorem for Hamiltonian systems.
Keywords
PTOLEMY, Relic neutrino, Cosmic Neutrino Background, CNB, Neutrino mass, Transverse drift filter
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-168315 (URN)10.1016/j.ppnp.2019.02.004 (DOI)000464490900003 ()2-s2.0-85062806646 (Scopus ID)
Available from: 2019-05-22 Created: 2019-05-22 Last updated: 2022-11-02Bibliographically approved
Aprile, E., Aalbers, J., Agostini, F., Alfonsi, M., Althueser, L., Amaro, F. D., . . . Zopounidis, J. P. (2019). Constraining the Spin-Dependent WIMP-Nucleon Cross Sections with XENON1T. Physical Review Letters, 122(14), Article ID 141301.
Open this publication in new window or tab >>Constraining the Spin-Dependent WIMP-Nucleon Cross Sections with XENON1T
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2019 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, no 14, article id 141301Article in journal (Refereed) Published
Abstract [en]

We report the first experimental results on spin-dependent elastic weakly interacting massive particle (WIMP) nucleon scattering from the XENON1T dark matter search experiment. The analysis uses the full ton year exposure of XENON1T to constrain the spin-dependent proton-only and neutron-only cases. No significant signal excess is observed, and a profile likelihood ratio analysis is used to set exclusion limits on the WIMP-nucleon interactions. This includes the most stringent constraint to date on the WIMP-neutron cross section, with a minimum of 6.3 x 10(-42) cm(2) at 30 GeV/c(2) and 90% confidence level. The results are compared with those from collider searches and used to exclude new parameter space in an isoscalar theory with an axial-vector mediator.
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-168287 (URN)10.1103/PhysRevLett.122.141301 (DOI)000463902500001 ()31050482 (PubMedID)2-s2.0-85064270730 (Scopus ID)
Available from: 2019-04-30 Created: 2019-04-30 Last updated: 2022-11-02Bibliographically approved
Aprile, E., Aalbers, J., Agostini, F., Alfonsi, M., Althueser, L., Amaro, F. D., . . . Schwenk, A. (2019). First Results on the Scalar WIMP-Pion Coupling, Using the XENON1T Experiment. Physical Review Letters, 122(7), Article ID 071301.
Open this publication in new window or tab >>First Results on the Scalar WIMP-Pion Coupling, Using the XENON1T Experiment
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2019 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, no 7, article id 071301Article in journal (Refereed) Published
Abstract [en]

We present first results on the scalar coupling of weakly interacting massive particles (WIMPs) to pions from 1 t yr of exposure with the XENON1T experiment. This interaction is generated when the WIMP couples to a virtual pion exchanged between the nucleons in a nucleus. In contrast to most nonrelativistic operators, these pion-exchange currents can be coherently enhanced by the total number of nucleons and therefore may dominate in scenarios where spin-independent WIMP-nucleon interactions are suppressed. Moreover, for natural values of the couplings, they dominate over the spin-dependent channel due to their coherence in the nucleus. Using the signal model of this new WIMP-pion channel, no significant excess is found, leading to an upper limit cross section of 6.4 x 10(-46) cm(2) (90% confidence level) at 30 GeV/c(2) WIMP mass.
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-167516 (URN)10.1103/PhysRevLett.122.071301 (DOI)000459311800003 ()30848617 (PubMedID)
Available from: 2019-04-21 Created: 2019-04-21 Last updated: 2022-02-26Bibliographically approved
Aprile, E., Aalbers, J., Agostini, F., Alfonsi, M., Althueser, L., Amaro, F. D., . . . Zopounidis, J. P. (2019). Light Dark Matter Search with Ionization Signals in XENON1T. Physical Review Letters, 123(25), Article ID 251801.
Open this publication in new window or tab >>Light Dark Matter Search with Ionization Signals in XENON1T
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2019 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 123, no 25, article id 251801Article in journal (Refereed) Published
Abstract [en]

We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22 +/- 3) tonne day. Above similar to 0.4 keV(ee), we observe <1 event/(tonne day keV(ee)), which is more than 1000 times lower than in similar searches with other detectors. Despite observing a higher rate at lower energies, no DM or CEvNS detection may be claimed because we cannot model all of our backgrounds. We thus exclude new regions in the parameter spaces for DM-nucleus scattering for DM masses m(chi) within 3-6 GeV/c(2), DM-electron scattering for m(chi) > 30 MeV/c(2), and absorption of dark photons and axionlike particles for m(chi) within 0.186-1 keV/c(2).
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-177437 (URN)10.1103/PhysRevLett.123.251801 (DOI)000503050000004 ()
Available from: 2020-01-15 Created: 2020-01-15 Last updated: 2022-03-23Bibliographically approved
Betti, M. G., Biasotti, M., Bosca, A., Calle, F., Canci, N., Cavoto, G., . . . Zurek, K. M. (2019). Neutrino physics with the PTOLEMY project: active neutrino properties and the light sterile case. Journal of Cosmology and Astroparticle Physics (7), Article ID 047.
Open this publication in new window or tab >>Neutrino physics with the PTOLEMY project: active neutrino properties and the light sterile case
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2019 (English)In: Journal of Cosmology and Astroparticle Physics, E-ISSN 1475-7516, no 7, article id 047Article in journal (Refereed) Published
Abstract [en]

The PTOLEMY project aims to develop a scalable design for a Cosmic Neutrino Background (CNB) detector, the first of its kind and the only one conceived that can look directly at the image of the Universe encoded in neutrino background produced in the first second after the Big Bang. The scope of the work for the next three years is to complete the conceptual design of this detector and to validate with direct measurements that the non-neutrino backgrounds are below the expected cosmological signal. In this paper we discuss in details the theoretical aspects of the experiment and its physics goals. In particular, we mainly address three issues. First we discuss the sensitivity of PTOLEMY to the standard neutrino mass scale. We then study the perspectives of the experiment to detect the CNB via neutrino capture on tritium as a function of the neutrino mass scale and the energy resolution of the apparatus. Finally, we consider an extra sterile neutrino with mass in the eV range, coupled to the active states via oscillations, which has been advocated in view of neutrino oscillation anomalies. This extra state would contribute to the tritium decay spectrum, and its properties, mass and mixing angle, could be studied by analyzing the features in the beta decay electron spectrum.
Keywords
cosmological neutrinos, neutrino detectors, particle physics - cosmology connection, physics of the early universe
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-171776 (URN)10.1088/1475-7516/2019/07/047 (DOI)000478735300006 ()
Available from: 2019-08-27 Created: 2019-08-27 Last updated: 2023-03-28Bibliographically approved
Aprile, E., Aalbers, J., Agostini, F., Alfonsi, M., Althueser, L., Amaro, F. D., . . . Zopounidis, J. P. (2019). Observation of two-neutrino double electron capture in 124Xe with XENON1T. Nature, 568(7753), 532-535
Open this publication in new window or tab >>Observation of two-neutrino double electron capture in 124Xe with XENON1T
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2019 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 568, no 7753, p. 532-535Article in journal (Refereed) Published
Abstract [en]

Two-neutrino double electron capture (2νECEC) is a second-order weak-interaction process with a predicted half-life that surpasses the age of the Universe by many orders of magnitude. Until now, indications of 2νECEC decays have only been seen for two isotopes, 78Kr and 130Ba, and instruments with very low background levels are needed to detect them directly with high statistical significance. The 2νECEC half-life is an important observable for nuclear structure models and its measurement represents a meaningful step in the search for neutrinoless double electron capture—the detection of which would establish the Majorana nature of the neutrino and would give access to the absolute neutrino mass. Here we report the direct observation of 2νECEC in 124Xe with the XENON1T dark-matter detector. The significance of the signal is 4.4 standard deviations and the corresponding half-life of 1.8 × 1022 years (statistical uncertainty, 0.5 × 1022 years; systematic uncertainty, 0.1 × 1022 years) is the longest measured directly so far. This study demonstrates that the low background and large target mass of xenon-based dark-matter detectors make them well suited for measuring rare processes and highlights the broad physics reach of larger next-generation experiments. 
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-169103 (URN)10.1038/s41586-019-1124-4 (DOI)000465594200047 ()31019319 (PubMedID)2-s2.0-85064937084 (Scopus ID)
Available from: 2019-06-10 Created: 2019-06-10 Last updated: 2022-11-02Bibliographically approved
Aprile, E., Aalbers, J., Agostini, F., Alfonsi, M., Althueser, L., Amaro, F. D., . . . Zopounidis, J. P. (2019). Search for Light Dark Matter Interactions Enhanced by the Migdal Effect or Bremsstrahlung in XENON1T. Physical Review Letters, 123(24), Article ID 241803.
Open this publication in new window or tab >>Search for Light Dark Matter Interactions Enhanced by the Migdal Effect or Bremsstrahlung in XENON1T
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2019 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 123, no 24, article id 241803Article in journal (Refereed) Published
Abstract [en]

Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above similar to 5 GeV/c(2), but have limited sensitivity to lighter masses because of the small momentum transfer in dark matter-nucleus elastic scattering. However, there is an irreducible contribution from inelastic processes accompanying the elastic scattering, which leads to the excitation and ionization of the recoiling atom (the Migdal effect) or the emission of a bremsstrahlung photon. In this Letter, we report on a probe of low-mass dark matter with masses down to about 85 MeV/c(2) by looking for electronic recoils induced by the Migdal effect and bremsstrahlung using data from the XENON1T experiment. Besides the approach of detecting both scintillation and ionization signals, we exploit an approach that uses ionization signals only, which allows for a lower detection threshold. This analysis significantly enhances the sensitivity of XENON1T to light dark matter previously beyond its reach.
Keywords
Dark matter, Particle dark matter
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-177446 (URN)10.1103/PhysRevLett.123.241803 (DOI)000502798200004 ()
Available from: 2020-01-15 Created: 2020-01-15 Last updated: 2022-03-23Bibliographically approved
Aprile, E., Aalbers, J., Agostini, F., Alfonsi, M., Althueser, L., Amaro, F. D., . . . Tintori, C. (2019). The XENON1T data acquisition system. Journal of Instrumentation, 14, Article ID P07016.
Open this publication in new window or tab >>The XENON1T data acquisition system
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2019 (English)In: Journal of Instrumentation, E-ISSN 1748-0221, Vol. 14, article id P07016Article in journal (Refereed) Published
Abstract [en]

The XENON1T liquid xenon time projection chamber is the most sensitive detector built to date for the measurement of direct interactions of weakly interacting massive particles with normal matter. The data acquisition system (DAQ) is constructed from commercial, open source, and custom components to digitize signals from the detector and store them for later analysis. The system achieves an extremely low signal threshold by triggering each channel independently, achieving a single photoelectron acceptance of (93 +/- 3)%, and deferring the global trigger to a later, software stage. The event identification is based on MongoDB database queries and has over 98% efficiency at recognizing interactions at the analysis threshold in the center of the target. A readout bandwidth over 300 MB/s is reached in calibration modes and is further expandable via parallelization. This DAQ system was successfully used during three years of operation of XENON1T.
Keywords
Data acquisition concepts, Front-end electronics for detector readout, Trigger concepts and systems (hardware and software), Control and monitor systems online
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-171785 (URN)10.1088/1748-0221/14/07/P07016 (DOI)000477726900004 ()
Available from: 2019-08-28 Created: 2019-08-28 Last updated: 2024-07-04Bibliographically approved
Aprile, E., Aalbers, J., Agostini, F., Alfonsi, M., Althueser, L., Amaro, F. D., . . . Zopounidis, J. P. (2019). XENON1T dark matter data analysis: Signal and background models and statistical inference. Physical Review D: covering particles, fields, gravitation, and cosmology, 99(11), Article ID 112009.
Open this publication in new window or tab >>XENON1T dark matter data analysis: Signal and background models and statistical inference
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2019 (English)In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 99, no 11, article id 112009Article in journal (Refereed) Published
Abstract [en]

The XENON1T experiment searches for dark matter particles through their scattering off xenon atoms in a 2 metric ton liquid xenon target. The detector is a dual-phase time projection chamber, which measures simultaneously the scintillation and ionization signals produced by interactions in target volume, to reconstruct energy and position, as well as the type of the interaction. The background rate in the central volume of XENON1T detector is the lowest achieved so far with a liquid xenon-based direct detection experiment. In this work we describe the response model of the detector, the background and signal models, and the statistical inference procedures used in the dark matter searches with a 1 metric ton x year exposure of XENON1T data, that leads to the best limit to date on WIMP-nucleon spin-independent elastic scatter cross section for WIMP masses above 6 GeV/c(2).
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-170843 (URN)10.1103/PhysRevD.99.112009 (DOI)000473026500001 ()2-s2.0-85069721847 (Scopus ID)
Available from: 2019-07-26 Created: 2019-07-26 Last updated: 2022-11-04Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6006-9160

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