27 results match your criteria: "Institute for Nuclear Research of Russian Academy of Sciences[Affiliation]"

The projected sensitivity of the effective electron neutrino-mass measurement with the KATRIN experiment is below 0.3 eV (90 % CL) after 5 years of data acquisition. The sensitivity is affected by the increased rate of the background electrons from KATRIN's main spectrometer.

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Background: Bi is a short-lived radionuclide currently trialed for alpha therapy of various oncological diseases. A serious obstacle to the wide medical use is decay losses of Bi during a conventional synthesis of radiopharmaceuticals. In this work, we aimed to develop a two-column Aс/Bi generator providing the accumulation of Bi separately from the parent Ac via continuous circular separation and decay of intermediate Fr.

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The article presents a novel gas-chemical approach for Ac/Bi generators, which provides effective separation of Bi from parent Ac. The main problem with the generators of high activity is the radiation stability of sorbents, which is not substantial in this gas-chemical method of separation, where only radiationally stable inorganic materials are used. The approach includes heating at high temperature (about 900-1000 °C) Ac sample deposited on a backing material (Nb, quartz glass, stainless steel) in hydrogen-containing inert gas flow.

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Stringent Tests of Lorentz Invariance Violation from LHAASO Observations of GRB 221009A.

Phys Rev Lett

August 2024

Key Laboratory of Particle Astrophysics and Experimental Physics Division and Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.

Article Synopsis
  • - On October 9, 2022, LHAASO detected a significant afterglow from the gamma-ray burst 221009A, achieving record photon statistics in the TeV energy range.
  • - This observation allowed researchers to test the idea of Lorentz invariance violation (LIV), which is related to faster-than-light travel predictions in some quantum gravity theories.
  • - The study established that the energy scales for LIV effects are significantly higher than previously thought, with new lower limits being 10 times the Planck energy for linear effects and 6×10^{-8} times the Planck energy for quadratic effects, improving earlier constraints by 5-7 times.
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Constraints on Ultraheavy Dark Matter Properties from Dwarf Spheroidal Galaxies with LHAASO Observations.

Phys Rev Lett

August 2024

Key Laboratory of Particle Astrophysics and Experimental Physics Division and Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.

In this Letter we try to search for signals generated by ultraheavy dark matter at the Large High Altitude Air Shower Observatory (LHAASO) data. We look for possible γ rays by dark matter annihilation or decay from 16 dwarf spheroidal galaxies in the field of view of the LHAASO. Dwarf spheroidal galaxies are among the most promising targets for indirect detection of dark matter that have low fluxes of astrophysical γ-ray background while having large amount of dark matter.

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The γ-ray emission from the W51 complex is widely acknowledged to be attributed to the interaction between the cosmic rays (CRs) accelerated by the shock of supernova remnant (SNR) W51C and the dense molecular clouds in the adjacent star-forming region, W51B. However, the maximum acceleration capability of W51C for CRs remains elusive. Based on observations conducted with the Large High Altitude Air Shower Observatory (LHAASO), we report a significant detection of γ rays emanating from the W51 complex, with energies from 2 to 200 TeV.

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Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A.

Phys Rev Lett

March 2024

Key Laboratory of Particle Astrophysics and Experimental Physics Division and Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.

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Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A.

Phys Rev Lett

October 2023

Key Laboratory of Particle Astrophyics & Experimental Physics Division & Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15° View Article and Find Full Text PDF

In the current research, we conducted a comparative study of the Ac complex with HDOTA and HBATA. The stability constants of the [AcBATA] and [AcDOTA] complexes were studied directly by extraction methods. We discovered that the thermodynamic properties of the [AcBATA] complex are superior to those of [AcDOTA].

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A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst.

Science

June 2023

Key Laboratory of Particle Astrophysics & Experimental Physics Division & Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory (LHAASO) of the bright GRB 221009A, which serendipitously occurred within the instrument's field of view. More than 64,000 photons >0.

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A radionuclide generator of the short-lived alpha emitter Th was proposed. An original scheme consisting of two in-series chromatographic columns was developed for rapidly producing a neutral citric-buffered eluate of high purity Th. The first column filled with TEVA resin retained the parent U, while Th was eluted with 7 M HCl solution to be immediately adsorbed on the second column containing DGA resin or UTEVA resin.

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Introduction: The feasibility of preparing the "in-house" generators and the Th- DTPA(DOTA)-Nimotuzumab radioimmunoconjugate was evaluated. Th is perspective for TAT, however, due to short half-life it is preferable to apply this radionuclide for readily available epithelial malignancies. Nimotuzumab being specific for EGFR expressing cells as a targeting moiety is considered to be suitable for thorium delivery.

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The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g.

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New Constraint on the Local Relic Neutrino Background Overdensity with the First KATRIN Data Runs.

Phys Rev Lett

July 2022

Tritium Laboratory Karlsruhe (TLK), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.

We report on the direct search for cosmic relic neutrinos using data acquired during the first two science campaigns of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by a high-resolution MAC-E filter around the end point at 18.57 keV.

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Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO.

Phys Rev Lett

February 2022

Key Laboratory of Particle Astrophysics and Experimental Physics Division and Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum.

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Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A.

Phys Rev Lett

June 2021

Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, 210023 Nanjing, Jiangsu, China.

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.

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A new two-column Ac/Bi generator was developed specifically for using Ac containing an impurity of long lived Ac. The parent Ac was retained on the first Actinide Resin column, while Bi was accumulated on the second column filled with AG MP-50 resin via continuous elution and decay of intermediate Fr. The Bi accumulation was realized in circulation mode which allowed a compact generator design.

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Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources.

Nature

June 2021

Key Laboratory of Particle Astrophysics & Experimental Physics Division & Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China.

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation.

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Bound on 3+1 Active-Sterile Neutrino Mixing from the First Four-Week Science Run of KATRIN.

Phys Rev Lett

March 2021

Tritium Laboratory Karlsruhe (TLK), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.

We report on the light sterile neutrino search from the first four-week science run of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are analyzed by a high-resolution MAC-E filter down to 40 eV below the endpoint at 18.57 keV.

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We numerically study interaction of a very intense (I∼10^{17} to 5×10^{19}W/cm^{2}) femtosecond obliquely incident p-polarized laser pulse with a steep-gradient (L∼λ) plasma, i.e., within the conditions typical for modern experiments.

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Some unexpected sporadic increases of an environmental radioactive background have been recorded at mountain level at Baksan Neutrino Observatory (BNO, 1700 m above sea level) using electron-neutron detectors (en-detectors), which could be explained by radioactive aerosol enhancements. The large area inorganic scintillator en-detectors developed for cosmic ray study are continuously monitoring environmental thermal neutron fluxes at various geophysical conditions. Application of the pulse shape discrimination method allows us to select and separately measure both thermal neutrons and radioactive beta-decay nuclides being products of radon decays in air (mostly Rn-222 and Rn-220).

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Article Synopsis
  • * Data collection began in early 2019, and initial analyses revealed that KATRIN doubled the known limit on neutrino mass thanks to the excellent performance of its system components.
  • * The laser Raman monitoring system (LARA) continuously tracks the gas composition in the experiment, providing precise measurements of tritium isotopic purity, essential for accurate neutrino mass calculations, achieving greater precision than required.
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Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN.

Phys Rev Lett

November 2019

Institute for Nuclear Physics (IKP), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.

We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.

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Introduction: The applicability of "Rubidium Chloride, Rb from Generator" radiopharmaceutical for brain tumors (BT) diagnostics is demonstrated on the basis of the application experience of the radiopharmaceutical in neurooncology.

Experimental: A total of 21 patients with various brain tumors and nonneoplastic abnormal brain masses were investigated.

Results And Discussions: The results of the imaging and differential diagnostics of malignant and benign tumors, nonneoplastic abnormal brain masses and lesions revealed the prevalence of high uptake of the radiopharmaceutical in the malignant tumors in comparison with benign glioma and arteriovenous malformations in which Rb-chloride accumulates in the vascular phase but does not linger further.

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First Measurement of Electron Neutrino Appearance in NOvA.

Phys Rev Lett

April 2016

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA.

We report results from the first search for ν_{μ}→ν_{e} transitions by the NOvA experiment. In an exposure equivalent to 2.74×10^{20} protons on target in the upgraded NuMI beam at Fermilab, we observe 6 events in the Far Detector, compared to a background expectation of 0.

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