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1. Accurate delineation of individual tree crowns in tropical forests from aerial RGB imagery using Mask R‐CNN

Author

James G. C. Ball, Sebastian H. M. Hickman, Tobias D. Jackson, Xian Jing Koay, James Hirst, William Jay, Matthew Archer, Mélaine Aubry‐Kientz, Grégoire Vincent, and David A. Coomes

Subjects
Convolutional neural networks, deep learning, Detectron2, forest monitoring, Mask R‐CNN, tree crown delineation, Technology, Ecology, QH540-549.5
Abstract

Abstract Tropical forests are a major component of the global carbon cycle and home to two‐thirds of terrestrial species. Upper‐canopy trees store the majority of forest carbon and can be vulnerable to drought events and storms. Monitoring their growth and mortality is essential to understanding forest resilience to climate change, but in the context of forest carbon storage, large trees are underrepresented in traditional field surveys, so estimates are poorly constrained. Aerial photographs provide spectral and textural information to discriminate between tree crowns in diverse, complex tropical canopies, potentially opening the door to landscape monitoring of large trees. Here we describe a new deep convolutional neural network method, Detectree2, which builds on the Mask R‐CNN computer vision framework to recognize the irregular edges of individual tree crowns from airborne RGB imagery. We trained and evaluated this model with 3797 manually delineated tree crowns at three sites in Malaysian Borneo and one site in French Guiana. As an example application, we combined the delineations with repeat lidar surveys (taken between 3 and 6 years apart) of the four sites to estimate the growth and mortality of upper‐canopy trees. Detectree2 delineated 65 000 upper‐canopy trees across 14 km2 of aerial images. The skill of the automatic method in delineating unseen test trees was good (F1 score = 0.64) and for the tallest category of trees was excellent (F1 score = 0.74). As predicted from previous field studies, we found that growth rate declined with tree height and tall trees had higher mortality rates than intermediate‐size trees. Our approach demonstrates that deep learning methods can automatically segment trees in widely accessible RGB imagery. This tool (provided as an open‐source Python package) has many potential applications in forest ecology and conservation, from estimating carbon stocks to monitoring forest phenology and restoration. Python package available to install at https://github.com/PatBall1/Detectree2.

Published
2023
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2. Corrigendum to 'Benchmarking 136Xe neutrinoless ββ decay matrix element calculations with the 138Ba(p,t) reaction' [Phys. Lett. B 809 (2020) 135702]

Author

B. Rebeiro, M. Kamil, B. A. Brown, Mihai Horoi, J. C. Nzobadila Ondze, P. Z. Mabika, P. E. Garrett, Dong-Liang Fang, S. Triambak, J. N. Orce, P. Adsley, C. Burbadge, Robert S. Lindsay, K. G. Leach, H.-F. Wirth, A. Diaz Varela, B. Jigmeddorj, T. Faestermann, Ralf Hertenberger, G. C. Ball, and V. Bildstein

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, QC1-999, Matrix element, Benchmarking
Published
2021

3. Benchmarking $^{136}$Xe Neutrinoless $\beta\beta$ Decay Matrix Element Calculations with the $^{138}{\rm Ba}(p,t)$ Reaction

Author

A. Diaz Varela, J. N. Orce, C. Burbadge, K. G. Leach, P. Z. Mabika, Mihai Horoi, V. Bildstein, B. Jigmeddorj, J. C. Nzobadila Ondze, M. Kamil, B. Rebeiro, B. A. Brown, Robert S. Lindsay, P. E. Garrett, Dong-Liang Fang, P. Adsley, T. Faestermann, S. Triambak, Ralf Hertenberger, G. C. Ball, and H.-F. Wirth

Subjects
Nuclear and High Energy Physics, Nuclear Theory, SHELL model, 01 natural sciences, Shell model, Matrix (mathematics), Transfer reactions, Double beta decay, Nuclear matrix elements, 0103 physical sciences, Neutron, Beta (velocity), Matrix element, Neutrinoless double beta decay, 010306 general physics, Nuclear Experiment, Nuclear theory, Physics, QRPA, 010308 nuclear & particles physics, Observable, lcsh:QC1-999, Atomic physics, lcsh:Physics
Abstract

We used a high-resolution magnetic spectrograph to study neutron pair-correlated 0 + states in 136Ba, produced via the Ba 138 ( p , t ) reaction. In conjunction with state-of-the-art shell model calculations, these data benchmark part of the dominant Gamow-Teller component of the nuclear matrix element (NME) for 136Xe neutrinoless double beta ( 0 ν β β ) decay. We demonstrate for the first time an evaluation of part of a 0 ν β β decay NME by use of an experimental observable, presenting a new avenue of approach for more accurate calculations of 0 ν β β decay matrix elements.

Published
2020

4. In-beam internal conversion electron spectroscopy with the SPICE detector

Author

Leonid Kurchaninov, L. J. Evitts, S. Georges, G. Hackman, J. L. Pore, R. Krücken, Corina Andreoiu, M. Constable, A. B. Garnsworthy, S. W. Yates, D. Southall, R. Caballero-Folch, D. Bishop, J. Berean-Dutcher, J. K. Smith, M. Moukaddam, P. Lu, M. Williams, S. Hallam, Joochun Park, Panu Ruotsalainen, T. Zidar, P. E. Garrett, Erin E. Peters, A. Kurkjian, E. O'Sullivan, E. T. Rand, R. Dunlop, B. Olaizola, James Smallcombe, C. Bolton, T.E. Drake, M. Wiens, R. Henderson, M. Spencer, D. S. Cross, G. C. Ball, C. E. Svensson, and Jack Henderson

Subjects
Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Spice, FOS: Physical sciences, Electron, 01 natural sciences, 7. Clean energy, Electron spectroscopy, Internal conversion, 0103 physical sciences, Magnetic lens, Nuclear Experiment, 010306 general physics, Instrumentation, Physics, Spectrometer, 010308 nuclear & particles physics, business.industry, Detector, Instrumentation and Detectors (physics.ins-det), Physics::Accelerator Physics, Optoelectronics, business, Beam (structure)
Abstract

The SPectrometer for Internal Conversion Electrons (SPICE) has been commissioned for use in conjunction with the TIGRESS $\gamma$-ray spectrometer at TRIUMF's ISAC-II facility. SPICE features a permanent rare-earth magnetic lens to collect and direct internal conversion electrons emitted from nuclear reactions to a thick, highly segmented, lithium-drifted silicon detector. This arrangement, combined with TIGRESS, enables in-beam $\gamma$-ray and internal conversion electron spectroscopy to be performed with stable and radioactive ion beams. Technical aspects of the device, capabilities, and initial performance are presented.

Published
2018

5. Reorientation-effect measurement of the first 2+ state in 12C : Confirmation of oblate deformation

Author

Chandana Sumithrarachchi, H. Al Falou, J. Wong, D.L. Mavela, E. T. Rand, T.E. Drake, C. E. Svensson, S. J. Williams, N. Erasmus, C. Ngwetsheni, S. Sjue, M. Kumar Raju, D.S. Cross, A. B. Garnsworthy, C. J. Pearson, S. Masango, J. N. Orce, K. Abrahams, P. E. Garrett, M. Djongolov, G. G. O'Neill, E. R. Tardiff, E.H. Akakpo, M.J. Mokgolobotho, S. Triambak, C. Mehl, P. Finlay, Ritesh Kshetri, G. C. Ball, D. G. Jenkins, K. G. Leach, G. Hackman, R. Churchman, and Petr Navrátil

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, State (functional analysis), 01 natural sciences, Coincidence, lcsh:QC1-999, Nuclear Theory (nucl-th), Ab initio quantum chemistry methods, Polarizability, Excited state, 0103 physical sciences, Quadrupole, Atomic physics, Nuclear Experiment (nucl-ex), 010306 general physics, Ground state, Nuclear Experiment, lcsh:Physics
Abstract

A Coulomb-excitation reorientation-effect measurement using the TIGRESS γ−ray spectrometer at the TRIUMF/ISAC II facility has permitted the determination of the 〈 2 1 + ‖ E 2 ˆ ‖ 2 1 + 〉 diagonal matrix element in 12C from particle−γ coincidence data and state-of-the-art no-core shell model calculations of the nuclear polarizability. The nuclear polarizability for the ground and first-excited (2 1 + ) states in 12C have been calculated using chiral NN N4LO500 and NN+3NF350 interactions, which show convergence and agreement with photo-absorption cross-section data. Predictions show a change in the nuclear polarizability with a substantial increase between the ground state and first excited 2 1 + state at 4.439 MeV. The polarizability of the 2 1 + state is introduced into the current and previous Coulomb-excitation reorientation-effect analyses of 12C. Spectroscopic quadrupole moments of Q S ( 2 1 + ) = + 0.053 ( 44 ) eb and Q S ( 2 1 + ) = + 0.08 ( 3 ) eb are determined, respectively, yielding a weighted average of Q S ( 2 1 + ) = + 0.071 ( 25 ) eb, in agreement with recent ab initio calculations. The present measurement confirms that the 2 1 + state of 12C is oblate and emphasizes the important role played by the nuclear polarizability in Coulomb-excitation studies of light nuclei.

Published
2018

6. New low-spin states of 122Xe observed via high-statistics β-decay of 122Cs

Author

Joochun Park, E. T. Rand, P. Voss, Corina Andreoiu, Baharak Hadinia, Z. M. Wang, J. L. Wood, A. B. Garnsworthy, M. Moukaddam, D. S. Cross, J. L. Pore, B. Jigmeddorj, T. Bruhn, M. M. Rajabali, G. C. Ball, U. Rizwan, S. W. Yates, A. J. Radich, C. E. Svensson, and P. E. Garrett

Subjects
Physics, Spin states, Spectrometer, 010308 nuclear & particles physics, QC1-999, 01 natural sciences, Beta decay, Nuclear physics, Angular correlation, Excited state, 0103 physical sciences, 010306 general physics, Hpge detector, Spin (physics)
Abstract

Excited states of 122Xe were studied via the β+/EC decay of 122Cs with the 8π γ-ray spectrometer at the TRIUMF-ISAC facility. Compton-suppressed HPGe detectors were used for measurements of γ-ray intensities, γγ coincidences, and γ-γ angular correlations. Two sets of data were collected to optimize the decays of the ground (21.2 s) and isomeric (3.7 min) states of 122Cs. The data collected have enabled the observation of about 505 new transitions and about 250 new levels, including 51 new low-spin states. Spin assignments have been made for 58 low-spin states based on the deduced β-decay feeding and γ-γ angular correlation analyses.

Published
2018

7. Investigation of excited 0+ states in 160Er populated via the (p, t) two-neutron transfer reaction

Author

T. Faesternann, A. Diaz Varela, M. R. Dunlop, Ralf Hertenberger, E. T. Rand, A. J. Radich, G. C. Ball, A. D. MacLean, C. Burbadge, V. Bildstein, D. S. Jamieson, P. E. Garrett, J. Loranger, H.-F. Wirth, R. Dunlop, K. G. Leach, D. Kisliuk, C. E. Svensson, and S. Triambak

Subjects
Rare earth nuclei, Physics, 010308 nuclear & particles physics, QC1-999, Nuclear structure, State (functional analysis), 01 natural sciences, medicine.anatomical_structure, Excited state, 0103 physical sciences, medicine, Neutron, Atomic physics, 010306 general physics, Ground state, Nucleus
Abstract

Many efforts have been made in nuclear structure physics to interpret the nature of low-lying excited 0+ states in well-deformed rare-earth nuclei. However, one of the difficulties in resolving the nature of these states is that there is a paucity of data. In this work, excited 0+ states in the N = 92 nucleus 160Er were studied via the 162Er(p, t)160Er two-neutron transfer reaction, which is ideal for probing 0+ → 0+ transitions, at the Maier-Leibnitz-Laboratorium in Garching, Germany. Reaction products were momentum-analyzed with a Quadrupole-3-Dipole magnetic spectrograph. The 0+2 state was observed to be strongly populated with 18% of the ground state strength.

Published
2018

8. First Results from Griffin Including The Half-lives Of $^{128-130}$Cd

Author

Joshua N. Smith, J. L. Pore, M. R. Dunlop, Ruohong Li, R. Caballero-Folch, I. Dillmann, E. Macconnachie, Ryan Dunlop, Elizabeth Padilla-Rodal, C. Burbadge, A. B. Garnsworthy, A. D. MacLean, Corina Andreoiu, B. Olaizola, James Smallcombe, P. E. Garrett, H. Bidaman, G. Hackman, A. J. Radich, O. Paetkau, R. Krücken, A. Teigelhöfer, Joochun Park, G. C. Ball, E. McGee, A. Jungclaus, N. Bernier, S. V. Ilyushkin, P. Boubel, M. Moukaddam, V. Bildstein, D. Kisliuk, Samuel Tabor, F. H. Garcia, L. J. Evitts, T. Zidar, Jack Henderson, J. Lassen, S. Hallam, C. E. Svensson, J. Turko, P. Ruotsalainen, C. M. Petrache, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Isotope, Spectrometer, Astrophysics::High Energy Astrophysical Phenomena, Nuclear structure, Electron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, Semiconductor detector, Nuclear physics, Internal conversion, Nuclear astrophysics, Neutron, Nuclear Experiment
Abstract

Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei (GRIFFIN) is a new high-efficiency $\gamma$-ray spectrometer for decay spectroscopy research with low-energy (20-60 keV) stopped radioactive beams from the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, Canada. GRIFFIN is comprised of 16 HPGe clover detectors and hosts a suite of auxiliary detection systems for tagging $\beta$ particles, neutrons, and internal conversion electrons in coincidence with $\gamma$ rays. GRIFFIN is a powerful new tool for studying the nuclear structure of exotic short-lived isotopes far from stability, and for measuring weak $\gamma$-ray branches that are important in tests of fundamental symmetries and nuclear astrophysics. In this work, first results from the GRIFFIN physics program will be discussed, including a recent measurement of the half-lives of the neutron-rich $^{128-130}$Cd and $^{131}$In isotopes.

Published
2016

9. High-precision Half-life And Branching Ratio Measurements For Superallowed $\beta^+$ Emitters At TRIUMF-ISAC

Author

Steffen Ketelhut, J. R. Leslie, C. E. Svensson, A. Diaz Varela, P. Voss, B. Blank, A. Valencik, P. C. Bender, A. J. Radich, J. P. Thomas, Joochun Park, J. Giovinazzo, Aaron Chester, S. Triambak, J. Wong, I. S. Towner, G. C. Ball, Corina Andreoiu, D. W. Miller, C. Unsworth, A. B. Garnsworthy, R. Dunlop, K. Starosta, D. S. Jamieson, B. Jigmeddorj, J. Grinyer, H. Bidaman, W. J. Mills, Mustafa Rajabali, E. R. Tardiff, E. F. Zganjar, G. Hackman, A. T. Laffoley, A. D. MacLean, P. Finlay, M. Moukaddam, E. T. Rand, D. S. Cross, S. Chagnon-Lessard, R. A. E. Austin, Z. M. Wang, S. W. Yates, G. F. Grinyer, J. Glister, K. G. Leach, J. Turko, D. Kisliuk, G. Deng, V. Bildstein, S. J. Williams, H. Bouzomita, Baharak Hadinia, Michelle Dunlop, P. E. Garrett, T. Ballast, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear physics, Physics, Spectrometer, Branching fraction, Electroweak interaction, Half-life, Weak interaction, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Fermi Gamma-ray Space Telescope
Abstract

High precision measurements of the $ft$ values for superallowed Fermi $\beta$ transitions between $J^\pi~=~0^+$ isobaric analogue states allow for stringent tests of the electroweak interaction described by the Standard Model. These transitions provide an experimental probe of the Conserved-Vector-Current hypothesis, enable the most precise determination of the up-down ($V_{ud}$) element of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix, and allow one to set stringent limits on the existence of scalar currents in the weak interaction. An extensive program of superallowed branching-ratio and half-life measurements at TRIUMF's Isotope Separator and Accelerator (ISAC) facility has covered the full range of superallowed emitters, from the lightest case, $^{10}$C, to the heaviest case for which precision data are currently available, $^{74}$Rb. These experiments have been performed using a 4$\pi$ continuous-flow gas proportional $\beta$ counter, the 8$\pi$ $\gamma$-ray spectrometer, and, most recently, the new high-efficiency GRIFFIN $\gamma$-ray spectrometer. In this paper, recent highlights from the superallowed Fermi $\beta$ decay program at TRIUMF will be summarized, including high-precision half-life measurements for all three of the lightest superallowed emitters, $^{10}$C, $^{14}$O, and $^{18}$Ne, with the greatest sensitivity to a potential weak scalar current contribution, as well as high-precision branching-ratio measurements for the heavy superallowed emitters $^{62}$Ga and $^{74}$Rb.

Published
2016

10. High-Precision Half-Life Measurements for the Superallowed β+ Emitter $^{10}$C: Implications for Weak Scalar Currents

Author

M R, Dunlop, C E, Svensson, G C, Ball, G F, Grinyer, J R, Leslie, C, Andreoiu, R A E, Austin, T, Ballast, P C, Bender, V, Bildstein, A, Diaz Varela, R, Dunlop, A B, Garnsworthy, P E, Garrett, G, Hackman, B, Hadinia, D S, Jamieson, A T, Laffoley, A D, MacLean, D M, Miller, W J, Mills, J, Park, A J, Radich, M M, Rajabali, E T, Rand, C, Unsworth, A, Valencik, Z M, Wang, E F, Zganjar, Grand Accélérateur National d'Ions Lourds (GANIL), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], ComputingMilieux_MISCELLANEOUS
Abstract

Precision measurements of superallowed Fermi β-decay transitions, particularly for the lightest superallowed emitters ^{10}C and ^{14}O, set stringent limits on possible scalar current contributions to the weak interaction. In the present work, a discrepancy between recent measurements of the ^{10}C half-life is addressed through two high-precision half-life measurements, via γ-ray photopeak and β counting, that yield consistent results for the ^{10}C half-life of T_{1/2}=19.2969±0.0074 s and T_{1/2}=19.3009±0.0017 s, respectively. The latter is the most precise superallowed β-decay half-life measurement reported to date and the first to achieve a relative precision below 10^{-4}. A fit to the world superallowed β-decay data including the ^{10}C half-life measurements reported here yields b_{F}=-0.0018±0.0021 (68% C.L.) for the Fierz interference term and C_{S}/C_{V}=+0.0009±0.0011 for the ratio of the weak scalar to vector couplings assuming left-handed neutrinos.

Published
2016

11. Direct reactions for nuclear structure required for fundamental symmetry tests

Author

E. T. Rand, D. S. Jamieson, H.-F. Wirth, Ralf Hertenberger, C. E. Svensson, G. C. Ball, K. G. Leach, A. Diaz Varela, V. Bildstein, Thomas Faestermann, P. E. Garrett, Baharak Hadinia, and B. Jigmeddorj

Subjects
Physics, 010308 nuclear & particles physics, QC1-999, Nuclear structure, Structure (category theory), Inelastic scattering, 7. Clean energy, 01 natural sciences, Symmetry (physics), Electric dipole moment, Distribution (mathematics), 0103 physical sciences, Direct reaction, Atomic physics, 010306 general physics, Nuclear Experiment, Excitation
Abstract

A program of nuclear structure studies to support fundamental symmetry tests has been initiated. Motivated by the search for an electric dipole moment in Hg-199, the structure in the vicinity has been explored via direct reaction studies. To date, these have included the Hg-198,Hg-200(d, d') inelastic scattering reactions, with the aim to obtain information on the E2 and E3 strength distributions, and the Hg-198(d, p) and Hg-200(d, t) reactions to obtain information on the single-particle states in 199Hg. The studies using the 200Hg targets have been fully analyzed using the FRESCO reaction code yielding the E2 and E3 strength distribution to 4 MeV in excitation energy, and the (d, t) single-particle strength to over 3 MeV in excitation energy.

Published
2016

12. Nuclear structure of 122Xe studied via high-statistics β+/EC-decay

Author

Corina Andreoiu, A. B. Garnsworthy, P. Voss, S. W. Yates, J. L. Pore, M. Moukaddam, C. E. Svensson, A. J. Radich, G. Hackman, P. E. Garrett, D. S. Cross, M. M. Rajabali, Z. Wang, G. C. Ball, U. Rizman, B. Jigmeddorj, Joochun Park, J. L. Wood, Baharak Hadinia, E. T. Rand, and T. Bruhn

Subjects
Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, QC1-999, Analytical chemistry, Nuclear structure, 01 natural sciences, Excited state, 0103 physical sciences, Isotopes of xenon, Biophysics, 010306 general physics, Radioactive decay
Abstract

The nuclear structure of 122 Xe has been investigated with measurements of the β + /EC decay of 122 Cs with the 8 π γ -ray spectrometer at the TRIUMF-ISAC facility. The data collected have enabled the determination of relative B(E2) values of some low-energy transitions, and the in-band transitions of the excited 0+ bands have been observed. As a result, the 2+ rotational band members for the 0+ 2 and 0+ 3 states have been firmly identified.

Published
2016

13. High-Precision Half-Life Measurements for the Superallowed Fermi $\beta$+ Emitters $^{14}$O and $^{18}$Ne

Author

B. Hadinia, A. J. Radich, G. Deng, K. G. Leach, Corina Andreoiu, J. C. Thomas, A. B. Garnsworthy, D. S. Jamieson, E. R. Tardiff, D.W. Miller, H. Bouzomita, G. F. Grinyer, G. C. Ball, A. D. MacLean, Bertram Blank, Steffen Ketelhut, P. C. Bender, D. S. Cross, Rae Austin, M. Moukaddam, P. Voss, Mustafa Rajabali, H. Bidaman, E. T. Rand, J. Giovinazzo, B. Mills, M. R. Dunlop, A. T. Laffoley, A. Diaz Varela, P. Finlay, V. Bildstein, R. Dunlop, C. Unsworth, D. Kisliuk, P. E. Garrett, B. Jigmeddorj, J. Turko, J Grinyer, J. R. Leslie, C. E. Svensson, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear physics, Physics, Oxygen-14, half-life, Neon-18, Half-life, Superallowed beta decay, Beta (velocity), Atomic physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], ComputingMilieux_MISCELLANEOUS, Fermi Gamma-ray Space Telescope
Abstract

International audience

Published
2014

14. Investigation of the E2 and E3 matrix elements in 200Hg using inelastic scattering

Author

Baharak Hadinia, Ralf Hertenberger, C. E. Svensson, G. C. Ball, P. E. Garrett, H.-F. Wirth, E. T. Rand, Thomas Faestermann, V. Bildstein, D. S. Jamieson, K. G. Leach, and B. Jigmeddorj

Subjects
Physics, Nuclear physics, Electric dipole moment, Scattering, Physics beyond the Standard Model, QC1-999, Nuclear structure, CP violation, Born approximation, Inelastic scattering, Charged particle
Abstract

A nuclear structure campaign has been initiated to investigate the isotopes of mercury near A = 199. Currently 199Hg provides the most stringent limit on an atomic electric dipole moment (EDM). The observation of a permanent EDM would represent a clear signal of CP violation from new physics beyond the Standard Model. Theoretical calculations for 199Hg are very difficult and give varied predictions for the excited-state spectrum. Understanding the E2 and E3 strengths in the neighbouring even-even isotopes of mercury will make it possible to develop a nuclear structure model for the Schiff strength based on these matrix elements, and thereby constrain present model predictions of the contribution of octupole collectivity to the Schiff moment of the nucleus.

Published
2014

15. High-Precision Half-life Measurements for the Superallowed $\beta$+ Emitter $^{14}$O

Author

Baharak Hadinia, P. E. Garrett, R. Dunlop, C. Unsworth, A. Diaz Varela, B. Blank, R. A. E. Austin, J. C. Thomas, A. B. Garnsworthy, J. Giovinazzo, G. C. Ball, G. Hackman, J. R. Leslie, D. S. Cross, Corina Andreoiu, C. E. Svensson, A. T. Laffoley, K. G. Leach, G. F. Grinyer, Steffen Ketelhut, H. Bouzomita, D. S. Jamieson, E. R. Tardiff, P. Finlay, Department of Physics [Guelph], University of Guelph, Department of Astronomy and Physics [Halifax], Saint Mary's University [Halifax], TRIUMF [Vancouver], Noyaux exotiques (NEX), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Instituut voor Kern-en Stralingsfysica (IKS), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Isotope, Spectrometer, QC1-999, Analytical chemistry, chemistry.chemical_element, Germanium, Scintillator, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Semiconductor detector, chemistry, Excited state, Statistical physics, Fermi Gamma-ray Space Telescope, Common emitter
Abstract

The half-life of 14 O, a superallowed Fermi β + emitter, has been determined via simultaneous γ and β counting experiments at TRIUMF’s Isotope Separator and Accelerator facility. Following the implantation of 14 O samples at the center of the 8 π spectrometer, a γ counting measurement was performed by detecting the 2313 keV γ -rays emitted from the first excited state of the daughter 14 N using 20 high-purity germanium (HPGe) detectors. A simultaneous β counting experiment was performed using a fast plastic scintillator positioned directly behind the implantation site. The results, T ½ ( γ ) = 70:632 ± 0:094 s and T ½ ( β ) = 70:610 ± 0:030 s, are consistent with one another and, together with eight previous measurements, establish a new average for the 14 O half-life of T ½ = 70:619 ± 0:011 s with a reduced χ 2 of 0.99.

Published
2013

16. High-precision half-life and branching-ratio measurements for superallowed Fermi + emitters at TRIUMF - ISAC

Author

S. Triambak, A. B. Garnsworthy, Chandana Sumithrarachchi, J. Giovinazzo, Steffen Ketelhut, B. Blank, S. Chagnon-Lessard, D. Bandyopadhyay, G. Hackman, J. Wong, A. A. Phillips, A. Diaz Varela, Corina Andreoiu, E. T. Rand, I. S. Towner, D. S. Jamieson, G. C. Ball, S. J. Williams, G. F. Grinyer, G. A. Demand, M. Djongolov, C. J. Pearson, K. G. Leach, J. R. Leslie, E. F. Zganjar, D. S. Cross, C. E. Svensson, R. Dunlop, A. T. Laffoley, H. Bouzomita, C. Unsworth, K. L. Green, R. A. E. Austin, J. C. Thomas, J. Glister, A. Chester, S. W. Yates, S. Ettenauer, Baharak Hadinia, P. E. Garrett, K. Starosta, E. R. Tardiff, P. Finlay, Department of Physics [Guelph], University of Guelph, Instituut voor Kern-en Stralingsfysica (IKS), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Department of Astronomy and Physics [Halifax], Saint Mary's University [Halifax], TRIUMF [Vancouver], Noyaux exotiques (NEX), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Ion beam, Isotope, half-life, Branching fraction, QC1-999, Half-life, Superallowed Fermi β decay, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, Standard Model, Nuclear physics, Isospin, Physics::Accelerator Physics, Symmetry breaking, branching ratio, Nuclear Experiment, 26Alm, Fermi Gamma-ray Space Telescope
Abstract

International audience; A program of high-precision half-life and branching-ratio measurements for superallowed Fermi emitters is being carried out at TRIUMF's Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. Recent half-life measurements for the superallowed decays of 14O, 18Ne, and 26Alm, as well as branching-ratio measurements for 26Alm and 74Rb are reported. These results provide demanding tests of the Standard Model and the theoretical isospin symmetry breaking (ISB) corrections in superallowed Fermi decays.

Published
2013

17. Towards Na-26 via (d,p) with SHARC and TIGRESS and a novel zero-degree detector

Author

M. Djongolov, M. Porter-Peden, H. J. Boston, S. M. Brown, C. Aa. Diget, Jun Chen, C. Unsworth, N. Galinski, U. Hager, N. A. Orr, D. S. Cross, R. Churchman, J. N. Orce, A. B. Garnsworthy, A. Chen, G. Hackman, S. Sjue, C. J. Pearson, C. E. Svensson, G. L. Wilson, R. Kanungo, J. Dech, W. N. Catford, S. J. Williams, B. R. Fulton, A. J. Boston, R. A. E. Austin, F. Sarazin, R. Ashley, P. Adsley, T.E. Drake, R. Wadsworth, S. P. Fox, D. S. Jamieson, J. P. Martin, G. C. Ball, H. Al-Falou, K. G. Leach, S. Triambak, J. C. Blackmon, C. Sumithrarachchi, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear reaction, History, Proton, 010308 nuclear & particles physics, Detector, Scintillator, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Particle detector, Computer Science Applications, Education, Semiconductor detector, Nuclear physics, 0103 physical sciences, Scintillation counter, 010306 general physics, Nucleon, Nuclear Experiment
Abstract

Nucleon transfer experiments have in recent years begun to be exploited in the study of nuclei far from stability, using radioactive beams in inverse kinematics. New techniques are still being developed in order to perform these experiments. The present experiment is designed to study the odd-odd nucleus Na which has a high density of states and therefore requires gamma-ray detection to distinguish between them. The experiment employed an intense beam of up to 3×10 pps of Na at 5.0 MeV/nucleon from the ISAC-II facility at triumf. The new silicon array SHARC was used for the first time and was coupled to the segmented clover gamma-ray array TIGRESS. A novel thin plastic scintillator detector was employed at zero degrees to identify and reject reactions occurring on the carbon component of the (CD) target. The efficiency of the background rejection using this detector is described with respect to the proton and gamma-ray spectra from the (d,p) reaction. © Published under licence by IOP Publishing Ltd.

Published
2011

18. TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS): a versatile tool for radioactive beam physics

Author

J. M. Wan, Rituparna Kanungo, O. Newman, A. J. Boston, J. P. Martin, Reynold J. Cooper, S. J. Williams, Fred Sarazin, C. J. Pearson, G. A. Demand, K. L. Green, Ching-Yen Wu, Matthew Richard Dimmock, Andrew Whitbeck, C. E. Svensson, A. N. Grint, H. C. Boston, D Dashdorj, H. Savajols, J J Ressler, G. Hackman, Elizabeth Padilla-Rodal, P. Finlay, M. A. Schumaker, René Roy, R. Maharaj, G. C. Ball, D.S. Cross, Andrei Andreyev, P. J. Nolan, J. A. Becker, A. A. Phillips, A. B. Hayes, T.E. Drake, D. Cline, R. A. E. Austin, A. Chen, L. Nelson, L. J. Harkness, M. Porter-Peden, Chris Ruiz, P. E. Garrett, F. Gagon-Moisan, A. T. Gallant, S. Mythili, D. Bandyopadhyay, A. C. Morton, J. C. Waddington, F. Cifarelli, D.P. Scraggs, R. Churchman, G. Lee, J. Wong, K. G. Leach, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, 010308 nuclear & particles physics, Physics::Instrumentation and Detectors, Detector, Gamma ray, Coulomb excitation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, 0103 physical sciences, Physics::Accelerator Physics, 010306 general physics, Nuclear Experiment, Radioactive beam
Abstract

International audience; TIGRESS is a new generation gamma-ray spectrometer designed for use with radioactive beams from ISAC. This paper gives an overwiew of the project and presents results from the first radioactive beam experiment with TIGRESS, the Coulomb excitation of 20,21Na.

Published
2006

19. Source size scaling of fragment production in projectile breakup

Author

M. Samri, A. Galindo-Uribarri, R. Roy, P. Lautesse, Y. Larochelle, D. Guinet, E. Hagberg, B. Djerroud, Dieter Fox, J. Pan, Luc Beaulieu, D. R. Bowman, D. Horn, C. St-Pierre, S. Das Gupta, Richard Laforest, D. Doré, G. C. Ball, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Flores, Sylvie

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Projectile, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Breakup, 01 natural sciences, Nuclear physics, 0103 physical sciences, Thermal, Production (computer science), Atomic physics, Nuclear Experiment (nucl-ex), 010306 general physics, Nucleon, Nuclear Experiment, Scaling, Excitation, Energy (signal processing)
Abstract

Fragment production has been studied as a function of the source mass and excitation energy in peripheral collisions of $^{35}$Cl+$^{197}$Au at 43 MeV/nucleon and $^{70}$Ge+$^{nat}$Ti at 35 MeV/nucleon. The results are compared to the Au+Au data at 600 MeV/nucleon obtained by the ALADIN collaboration. A mass scaling, by $A_{source} \sim$ 35 to 190, strongly correlated to excitation energy per nucleon, is presented, suggesting a thermal fragment production mechanism. Comparisons to a standard sequential decay model and the lattice-gas model are made. Fragment emission from a hot, rotating source is unable to reproduce the experimental source size scaling., Comment: 13 pages LaTeX file, including 3 postscript figures (in .tar.gz fornmat), accepted in Phys. Rev. C . Also available at http://thomson.phy.ulaval.ca/ions_lourds/gil-en.html

Published
1996

20. Structure of states in 12Be via the 11Be(d,p) reaction

Author

B. Pietras, L. Buchmann, K. G. Leach, P. E. Garrett, Camilo Ruiz, Henrik B. Jeppesen, R.A.E. Austin, A.C. Shotter, C. J. Pearson, F. Sarazin, C. E. Svensson, P. Finlay, A. A. Phillips, G. Hackman, D. S. Cross, D. C. Oxley, J. Wong, C. Unsworth, M. Uchida, D. Bandyopadhyay, D. Cline, S. Grist, S. Triambak, A.T. Gallant, S. J. Williams, K. L. Green, N. Galinski, A. M. Hurst, P.L. Walden, H. C. Boston, G. C. Ball, D. Howell, S.J. Colosimo, H. Dare, T.E. Drake, M. A. Schumaker, Götz Ruprecht, A. J. Boston, R. M. Clark, A. O. Macchiavelli, L. J. Harkness, M. Djongolov, C.S. Sumitharachchi, Ching-Yen Wu, J. A. Becker, A. B. Garnsworthy, Barry Davids, A. B. Hayes, Isao Tanihata, Rituparna Kanungo, Corina Andreoiu, B. A. Brown, and Susan Rigby

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, SHELL model, 01 natural sciences, Shell structure, Transfer reactions, Inverse kinematics, Excited state, 0103 physical sciences, Bound state, Neutron, Atomic physics, 010306 general physics, Ground state, Beam (structure), Radioactive beams
Abstract

The s-wave neutron fraction of the 0 + levels in 12Be has been investigated for the first time through the 11Be( d , p ) transfer reaction using a 5 A MeV 11Be beam at TRIUMF, Canada. The reaction populated all the known bound states of 12Be. The ground state s-wave spectroscopic factor was determined to be 0.28 − 0.07 + 0.03 while that for the long-lived 0 2 + excited state was 0.73 − 0.40 + 0.27 . This observation, together with the smaller effective separation energy indicates enhanced probability for an extended density tail beyond the 10Be core for the 0 2 + excited state compared to the ground state.

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21. New Opportunities in Decay Spectroscopy with the GRIFFIN and DESCANT Arrays

Author

E. T. Rand, J. P. Martin, V. Bildstein, G. C. Ball, M. M. Rajabali, Joochun Park, Y. Linn, R. Kokke, J. Wong, P. Voss, C. Unsworth, A. Cheeseman, U. Rizwan, G. A. Demand, D. Brennan, K. Starosta, P. C. Bender, P. E. Garrett, R. Krücken, Iris Dillmann, Corina Andreoiu, S. Ciccone, L.N. Morrison, N. Bernier, G. Hackman, S. Georges, J. L. Pore, C. Bartlett, C. J. Pearson, T. Ballast, Baharak Hadinia, Chandana Sumithrarachchi, Barry Davids, F. Sarazin, C. Lim, J. Williams, A. B. Garnsworthy, W. J. Mills, B. Shaw, L. Bianco, D. Bishop, T. Bruhn, C. E. Svensson, D. Miller, Z. Wang, C.A. Ohlmann, R. Churchman, and S. Wong

Subjects
Physics, Spectrometer, Physics::Instrumentation and Detectors, Detector, Beta decay, Scintillator, Physics and Astronomy(all), Beta-delayed neutron emission, HPGe clover detectors, Deuterated Benzene Neutron Detectors, Semiconductor detector, Nuclear physics, Neutron detection, Neutron, Gamma spectroscopy, Gamma-ray spectroscopy, Spectroscopy
Abstract

The GRIFFIN (Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei) project is a major upgrade of the decay spectroscopy capabilities at TRIUMF-ISAC. GRIFFIN will replace the 8π spectrometer with an array of up to 16 large-volume HPGe clover detectors and use a state-of-the-art digital data acquisition system. The existing ancillary detector systems that had been developed for 8π, such as the SCEPTAR array for β-tagging, PACES for high-resolution internal conversion electron spectroscopy, and the DANTE array of LaBr3/BaF2 scintillators for fast γ-ray timing, will be used with GRIFFIN. GRIFFIN can also accommodate the new neutron detector array DESCANT (Deuterated Scintillator Array for Neutron Tagging), enabling the study of β-delayed neutron emitters. DESCANT consists of up to 70 detectors, each filled with approximately 2 liters of deuterated benzene, a liquid scintillator that provides pulse-shape discrimination (PSD) capabilities to distinguish between neutrons and γ-rays interacting with the detector. In addition, the anisotropic nature of n-d scattering as compared to the isotropic n-p scattering allows for the determination of the neutron energy spectrum directly from the pulse-height spectrum, complementing the time-of-flight (TOF) information. The installation of GRIFFIN is under way and first experiments are planned for the fall of 2014. The array will be completed in 2015 with the full complement of 16 clovers. DESCANT will be tested coupled with GRIFFIN in spring of 2015.

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