skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Beta Environmental Fine Structure (BEFS): The XAFS Nuclear Analogue

Abstract

The Beta Environmental Fine Structure (BEFS) effect is an oscillatory modulation on the otherwise smooth spectrum of electrons emitted by beta-decaying nuclei. The existence of this effect was theoretically proposed in 1991, for condensed emitters, in analogy with XAFS. In BEFS the electron, playing the role of the XAFS photoelectron, originates directly from the nucleus and an anti-neutrino is emitted at the same time. We present evidence for BEFS oscillations observed in Silver Perrhenate (AgReO4) low-temperature (0.1K) microbolometers, together with a XAFS-like analysis that allowed for the first time a direct measurement of the anti-neutrino angular momentum. We discuss the physical analogies and differences between BEFS and XAFS and the implications for the next generation experiments aimed at measuring the neutrino mass on purely kinematic grounds. Moreover, we briefly discuss the potential and the limits of BEFS-based techniques with respect to the classical XAFS.

Authors:
 [1];  [2];  [3]; ; ;  [4];  [5];  [6]
  1. ITC-IRST and INFN sez. Padova, Via Sommarive, 18 I-38050 Povo (Italy)
  2. Dipartimento di Scienza dei Materiali dell'Universita di Milano-Bicocca, Via Cozzi 53, I-20125 Milan (Italy)
  3. (INFN) sez. Milano-Bicocca, Piazza delle Scienze 3, I-20126 Milan (Italy)
  4. Istituto Nazionale di Fisica Nucleare (INFN) sez. Milano-Bicocca, Piazza delle Scienze 3, I-20126 Milan (Italy)
  5. (Italy)
  6. Dipartimento di Fisica dell'Universita dell'Aquila, Via Vetoio, I-67010 Coppito di L'Aquila (Italy)
Publication Date:
OSTI Identifier:
21054577
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 882; Journal Issue: 1; Conference: XAFS13: 13. international conference on X-ray absorption fine structure, Stanford, CA (United States), 9-14 Jul 2006; Other Information: DOI: 10.1063/1.2644456; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ABSORPTION SPECTROSCOPY; ANGULAR MOMENTUM; BETA DECAY; ELECTRONS; EMISSION; FINE STRUCTURE; MODULATION; NEUTRINO OSCILLATION; NEUTRINOS; PERRHENATES; SILVER; SILVER COMPOUNDS; X-RAY SPECTRA; X-RAY SPECTROSCOPY

Citation Formats

Monfardini, A., Benedek, G., Istituto Nazionale di Fisica Nucleare, Cremonesi, O., Nucciotti, A., Sisti, M., Dipartimento di Fisica dell'Universita di Milano-Bicocca, Piazza delle Scienze 3, I-20126 Milan, and Filipponi, A. The Beta Environmental Fine Structure (BEFS): The XAFS Nuclear Analogue. United States: N. p., 2007. Web. doi:10.1063/1.2644456.
Monfardini, A., Benedek, G., Istituto Nazionale di Fisica Nucleare, Cremonesi, O., Nucciotti, A., Sisti, M., Dipartimento di Fisica dell'Universita di Milano-Bicocca, Piazza delle Scienze 3, I-20126 Milan, & Filipponi, A. The Beta Environmental Fine Structure (BEFS): The XAFS Nuclear Analogue. United States. doi:10.1063/1.2644456.
Monfardini, A., Benedek, G., Istituto Nazionale di Fisica Nucleare, Cremonesi, O., Nucciotti, A., Sisti, M., Dipartimento di Fisica dell'Universita di Milano-Bicocca, Piazza delle Scienze 3, I-20126 Milan, and Filipponi, A. Fri . "The Beta Environmental Fine Structure (BEFS): The XAFS Nuclear Analogue". United States. doi:10.1063/1.2644456.
@article{osti_21054577,
title = {The Beta Environmental Fine Structure (BEFS): The XAFS Nuclear Analogue},
author = {Monfardini, A. and Benedek, G. and Istituto Nazionale di Fisica Nucleare and Cremonesi, O. and Nucciotti, A. and Sisti, M. and Dipartimento di Fisica dell'Universita di Milano-Bicocca, Piazza delle Scienze 3, I-20126 Milan and Filipponi, A.},
abstractNote = {The Beta Environmental Fine Structure (BEFS) effect is an oscillatory modulation on the otherwise smooth spectrum of electrons emitted by beta-decaying nuclei. The existence of this effect was theoretically proposed in 1991, for condensed emitters, in analogy with XAFS. In BEFS the electron, playing the role of the XAFS photoelectron, originates directly from the nucleus and an anti-neutrino is emitted at the same time. We present evidence for BEFS oscillations observed in Silver Perrhenate (AgReO4) low-temperature (0.1K) microbolometers, together with a XAFS-like analysis that allowed for the first time a direct measurement of the anti-neutrino angular momentum. We discuss the physical analogies and differences between BEFS and XAFS and the implications for the next generation experiments aimed at measuring the neutrino mass on purely kinematic grounds. Moreover, we briefly discuss the potential and the limits of BEFS-based techniques with respect to the classical XAFS.},
doi = {10.1063/1.2644456},
journal = {AIP Conference Proceedings},
number = 1,
volume = 882,
place = {United States},
year = {Fri Feb 02 00:00:00 EST 2007},
month = {Fri Feb 02 00:00:00 EST 2007}
}
  • Digermene, the germanium analogue of ethylene, has a multiple bonding motif that differs greatly from that of alkenes and exhibits no pure σ or π type bonds. The electronic structure of digermenes is difficult to study experimentally due to their reactivity, and is computationally challenging because of their shallow potential energy surfaces. Using X-ray absorption near edge structures at both the germanium K and L edges we have been able to directly probe the unoccupied electronic states, or the lowest unoccupied molecular orbital (LUMO), and LUMO+ etc. in the Ge=Ge bond of tetramesityldigermene. We have demonstrated that the LUMO, LUMO+,more » etc. are composed of hybrid Ge 4s and 4p orbitals. Additionally, our data suggest that the LUMO exhibits relatively more Ge 4s character, whereas the LUMO+ and LUMO+2 exhibit relatively more Ge 4p character. An X-ray excited optical luminescence study of Ge 2Mes 4 revealed one broad optical emission band at 620 nm, which is significantly red shifted compared to the known energy gap of this molecular germanium compound.« less
  • The mixed occurrence of s-wave and p-wave contributions in a first forbidden unique Gamow-Teller {beta} decay has been investigated for the first time by measuring the beta environmental fine structure (BEFS) in a {sup 187}Re crystalline compound. The experiment has been carried out with an array of eight AgReO{sub 4} thermal detectors operating at a temperature of {approx}100 mK. A fit of the observed BEFS spectrum indicates the p-wave electron emission as the dominant channel. The complete understanding of the BEFS distortion of the {sup 187}Re {beta} decay spectrum is crucial for future experiments aiming at the precise calorimetric measurementmore » of the antineutrino mass.« less
  • Combined {mu}-XRF, {mu}-XAFS, and {mu}-XRD investigations of a uranium-rich tertiary sediment, from a nuclear repository natural analogue site, and a fractured granite bore core section after a column tracer experiment using a Np(V) containing cocktail have been performed. Most {mu}-XRF/{mu}-XAFS measurements are recorded in a confocal geometry to provide added depth information. The U-rich sediment results show uranium to be present as a tetravalent phosphate and that U(IV) is associated with As(V). Arsenic present is either As(V) or As(0). The As(0) forms thin coatings on the surface of pyrite nodules. A hypothesis for the mechanism of uranium immobilization is proposed,more » where arsenopyrite acted as reductant of ground water dissolved U(VI) leading to precipitation of less soluble U(IV) and thereby forming As(V). Results for the granite sample show the immobilized Np to be tetravalent and associated with facture material.« less
  • The x-ray excited optical luminescence (XEOL) from a variety of rare-earth ions was used as a detection mode for the collection of {ital L}-edge x-ray absorption fine-structure (XAFS) data. In order to understand the source of the observed optical signal, advantage is taken of the known luminescent response of {ital f} ions in a variety of transparent host materials. Whereas some samples exhibit an optical response that is indistinguishable from the transmission XAFS data, other samples show marked differences between the data obtained with the two different detection schemes. The unexpected optical luminescence of a Gd{sub 2}O{sub 3} sample ismore » traced to a Eu impurity. An optical spectrum of 0.4{percent} Tb in Gd{sub 2}O{sub 2}S, excited by x-ray photons at the Gd edge, is used to demonstrate that the optical signal may arise from an ion different from the absorbing ion. The implications of this energy transfer are discussed in terms of the suitability of XEOL as a detection scheme for XAFS spectroscopy. {copyright} {ital 1998 American Institute of Physics.}« less
  • The initial kinetics of Cr(III) oxidation on mineral surfaces is poorly understood, yet a significant portion of the oxidation process occurs during the first seconds of reaction. In this study, the initial rates of Cr(III) oxidation on hydrous manganese oxide (HMO) were measured at three different pH values (pH 2.5, 3, and 3.5), using a quick X-ray absorption fine structure spectroscopy (Q-XAFS) batch method. The calculated rate constants were 0.201, 0.242, and 0.322 s{sup -1} at pH 2.5, 3, and 3.5, respectively. These values were independent of both [Cr(III)] and [Mn(II)] and mixing speed, suggesting that the reaction was 'chemically'more » controlled and not dependent upon diffusion at the time period the rate parameters were measured. A second-order overall rate was found at three pH values. This represents the first study to determine the chemical kinetics of Cr(III) oxidation on Mn-oxides. The results have important implications for the determination of rapid, environmentally important reactions that cannot be measured with traditional batch and flow techniques. An understanding of these reactions is critical to predicting the fate of contaminants in aquatic and terrestrial environments.« less