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1.
Phys Rev Lett ; 131(22): 221801, 2023 Dec 01.
Article in English | MEDLINE | ID: mdl-38101357

ABSTRACT

Using an 185-kg NaI[Tl] array, COHERENT has measured the inclusive electron-neutrino charged-current cross section on ^{127}I with pion decay-at-rest neutrinos produced by the Spallation Neutron Source at Oak Ridge National Laboratory. Iodine is one the heaviest targets for which low-energy (≤50 MeV) inelastic neutrino-nucleus processes have been measured, and this is the first measurement of its inclusive cross section. After a five-year detector exposure, COHERENT reports a flux-averaged cross section for electron neutrinos of 9.2_{-1.8}^{+2.1}×10^{-40} cm^{2}. This corresponds to a value that is ∼41% lower than predicted using the MARLEY event generator with a measured Gamow-Teller strength distribution. In addition, the observed visible spectrum from charged-current scattering on ^{127}I has been measured between 10 and 55 MeV, and the exclusive zero-neutron and one-or-more-neutron emission cross sections are measured to be 5.2_{-3.1}^{+3.4}×10^{-40} and 2.2_{-0.5}^{+0.4}×10^{-40} cm^{2}, respectively.

2.
Phys Rev Lett ; 130(5): 051803, 2023 Feb 03.
Article in English | MEDLINE | ID: mdl-36800477

ABSTRACT

The COHERENT Collaboration searched for scalar dark matter particles produced at the Spallation Neutron Source with masses between 1 and 220 MeV/c^{2} using a CsI[Na] scintillation detector sensitive to nuclear recoils above 9 keV_{nr}. No evidence for dark matter is found and we thus place limits on allowed parameter space. With this low-threshold detector, we are sensitive to coherent elastic scattering between dark matter and nuclei. The cross section for this process is orders of magnitude higher than for other processes historically used for accelerator-based direct-detection searches so that our small, 14.6 kg detector significantly improves on past constraints. At peak sensitivity, we reject the flux consistent with the cosmologically observed dark-matter concentration for all coupling constants α_{D}<0.64, assuming a scalar dark-matter particle. We also calculate the sensitivity of future COHERENT detectors to dark-matter signals which will ambitiously test multiple dark-matter spin scenarios.

3.
Phys Rev Lett ; 129(8): 081801, 2022 Aug 19.
Article in English | MEDLINE | ID: mdl-36053683

ABSTRACT

We measured the cross section of coherent elastic neutrino-nucleus scattering (CEvNS) using a CsI[Na] scintillating crystal in a high flux of neutrinos produced at the Spallation Neutron Source at Oak Ridge National Laboratory. New data collected before detector decommissioning have more than doubled the dataset since the first observation of CEvNS, achieved with this detector. Systematic uncertainties have also been reduced with an updated quenching model, allowing for improved precision. With these analysis improvements, the COHERENT Collaboration determined the cross section to be (165_{-25}^{+30})×10^{-40} cm^{2}, consistent with the standard model, giving the most precise measurement of CEvNS yet. The timing structure of the neutrino beam has been exploited to compare the CEvNS cross section from scattering of different neutrino flavors. This result places leading constraints on neutrino nonstandard interactions while testing lepton flavor universality and measures the weak mixing angle as sin^{2}θ_{W}=0.220_{-0.026}^{+0.028} at Q^{2}≈(50 MeV)^{2}.

4.
Phys Rev Lett ; 126(1): 012002, 2021 Jan 08.
Article in English | MEDLINE | ID: mdl-33480779

ABSTRACT

We report the first measurement of coherent elastic neutrino-nucleus scattering (CEvNS) on argon using a liquid argon detector at the Oak Ridge National Laboratory Spallation Neutron Source. Two independent analyses prefer CEvNS over the background-only null hypothesis with greater than 3σ significance. The measured cross section, averaged over the incident neutrino flux, is (2.2±0.7)×10^{-39} cm^{2}-consistent with the standard model prediction. The neutron-number dependence of this result, together with that from our previous measurement on CsI, confirms the existence of the CEvNS process and provides improved constraints on nonstandard neutrino interactions.

5.
Radiol Med ; 115(6): 962-74, 2010 Sep.
Article in English, Italian | MEDLINE | ID: mdl-20352357

ABSTRACT

PURPOSE: The purpose of our study was to retrospectively evaluate the feasibility, safety and effectiveness of microwave ablation (MWA) in nine patients with unresectable lung tumour. MATERIALS AND METHODS: Ten lesions were treated in ten ablation sessions in nine patients. The treatments were performed with a microwave generator with 45 W and 915 MHz connected to a 14.5-gauge antenna for 10 min. Antenna placement was performed with computed tomography (CT) fluoroscopy guidance or XperGuide. All patients underwent CT follow-up at 1, 3 and 6 months from the procedure. RESULTS: Technical success was obtained in all cases; mortality at 30 days was 0%. CONCLUSIONS: This study shows that in selected patients, MWA is a valid alternative to other ablative techniques. Further studies are required to demonstrate the short- and long-term effects of this technique and to make a comparison with other available ablation systems, especially with radiofrequency.


Subject(s)
Catheter Ablation/methods , Lung Neoplasms/diagnostic imaging , Lung Neoplasms/surgery , Microwaves/therapeutic use , Tomography, X-Ray Computed , Aged , Aged, 80 and over , Catheter Ablation/adverse effects , Feasibility Studies , Female , Humans , Lung Neoplasms/pathology , Lung Neoplasms/secondary , Male , Microwaves/adverse effects , Neoplasm Metastasis , Retrospective Studies , Treatment Outcome
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