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Surrogate neutron-capture studies with fission detection in inverse kinematics at the ESR storage ring
Authors:
Bogusław Włoch,
Camille Berthelot,
Guy Leckenby,
Beatriz Jurado,
Jerome Pibernat,
Manfred Grieser,
Jan Glorius,
Yuri A. Litvinov,
Laurent Audouin,
Bertram Blank,
Lucas Bégué--Guillou,
Alex Cobo Zarzuelo,
Sophia Florence Dellmann,
Marc Dupuis,
Oliver Forstner,
Alexis Francheteau,
David Freire Fernández,
Miki Fukutome,
Mathias Gerbaux,
Jérôme Giovinazzo,
Alexandre Gumberidze,
Andreas Heinz,
Ana Henriques,
Regina Hess,
Indu Jangid
, et al. (17 additional authors not shown)
Abstract:
The NECTAR (Nuclear rEaCTions At storage Rings) experiment at the ESR heavy-ion storage ring at GSI/FAIR Darmstadt is dedicated to surrogate reaction studies of neutron-induced reactions on heavy nuclei in inverse kinematics. In this work, we report on the implementation and performance of a newly developed fission-fragment detection system integrated into the NECTAR experimental setup. The upgrad…
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The NECTAR (Nuclear rEaCTions At storage Rings) experiment at the ESR heavy-ion storage ring at GSI/FAIR Darmstadt is dedicated to surrogate reaction studies of neutron-induced reactions on heavy nuclei in inverse kinematics. In this work, we report on the implementation and performance of a newly developed fission-fragment detection system integrated into the NECTAR experimental setup. The upgraded detector configuration enables, for the first time in a surrogate experiment, the simultaneous detection ofgamma-decay residues, multi-neutron-emission residues, and fission fragments. The full setup was used for the first time in an experiment where a stored beam of bare 238U92+ ions at 17.24 MeV/u interacted with a gas-jet deuterium target, populating excited 238U and 239U nuclei via the 238U(d,d') and 238U(d,p) reactions. We describe the geometry of the used fission fragment detectors, design constraints, and simulation-based efficiency determination. The target-like particle identification and beam-like residue spectra demonstrating the performance of the complete setup are also shown.
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Submitted 20 May, 2026; v1 submitted 23 February, 2026;
originally announced February 2026.
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Storage, Accumulation and Deceleration of Secondary Beams for Nuclear Astrophysics
Authors:
J. Glorius,
Yu. A. Litvinov,
M. Aliotta,
F. Amjad,
B. Brückner,
C. G. Bruno,
R. Chen,
T. Davinson,
S. F. Dellmann,
T. Dickel,
I. Dillmann,
P. Erbacher,
O. Forstner,
H. Geissel,
C. J. Griffin,
R. Grisenti,
A. Gumberidze,
E. Haettner,
R. Hess,
P. -M. Hillenbrand,
C. Hornung,
R. Joseph,
B. Jurado,
E. Kazanseva,
R. Knöbel
, et al. (39 additional authors not shown)
Abstract:
Low-energy investigations on rare ion beams are often limited by the available intensity and purity of the ion species in focus. Here, we present the first application of a technique that combines in-flight production at relativistic energies with subsequent secondary beam storage, accumulation and finally deceleration to the energy of interest. Using the FRS and ESR facilities at GSI, this scheme…
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Low-energy investigations on rare ion beams are often limited by the available intensity and purity of the ion species in focus. Here, we present the first application of a technique that combines in-flight production at relativistic energies with subsequent secondary beam storage, accumulation and finally deceleration to the energy of interest. Using the FRS and ESR facilities at GSI, this scheme was pioneered to provide a secondary beam of $^{118}$Te$^{52+}$ for the measurement of nuclear proton-capture at energies of 6 and 7 MeV/u. The technique provided stored beam intensities of about $10^6$ ions at high purity and brilliance, representing a major step towards low-energy nuclear physics studies using rare ion beams.
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Submitted 30 May, 2023; v1 submitted 25 May, 2023;
originally announced May 2023.
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Electron capture of Xe$^{54+}$ in collisions with H${_2}$ molecules in the energy range between 5.5 MeV/u and 30.9 MeV/u
Authors:
F. M. Kröger,
G. Weber,
M. O. Herdrich,
J. Glorius,
C. Langer,
Z. Slavkovská,
L. Bott,
C. Brandau,
B. Brückner,
K. Blaum,
X. Chen,
S. Dababneh,
T. Davinson,
P. Erbacher,
S. Fiebiger,
T. Gaßner,
K. Göbel,
M. Groothuis,
A. Gumberidze,
Gy. Gyürky,
S. Hagmann,
C. Hahn,
M. Heil,
R. Hess,
R. Hensch
, et al. (41 additional authors not shown)
Abstract:
The electron capture process was studied for Xe$^{54+}$ colliding with H$_2$ molecules at the internal gas target of the ESR storage ring at GSI, Darmstadt. Cross section values for electron capture into excited projectile states were deduced from the observed emission cross section of Lyman radiation, being emitted by the hydrogen-like ions subsequent to the capture of a target electron. The ion…
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The electron capture process was studied for Xe$^{54+}$ colliding with H$_2$ molecules at the internal gas target of the ESR storage ring at GSI, Darmstadt. Cross section values for electron capture into excited projectile states were deduced from the observed emission cross section of Lyman radiation, being emitted by the hydrogen-like ions subsequent to the capture of a target electron. The ion beam energy range was varied between 5.5 MeV/u and 30.9 MeV/u by applying the deceleration mode of the ESR. Thus, electron capture data was recorded at the intermediate and in particular the low collision energy regime, well below the beam energy necessary to produce bare xenon ions. The obtained data is found to be in reasonable qualitative agreement with theoretical approaches, while a commonly applied empirical formula significantly overestimates the experimental findings.
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Submitted 10 May, 2020; v1 submitted 5 May, 2020;
originally announced May 2020.
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First investigation of the response of solar cells to heavy ions above 1 AMeV
Authors:
A. Henriques,
B. Jurado,
J. Pibernat,
J. C. Thomas,
D. Denis-Petit,
T. Chiron,
L. Gaudefroy,
J. Glorius,
Yu. A. Litvinov,
L. Mathieu,
V. Méot,
R. Pérez-Sánchez,
O. Roig,
U. Spillmann,
B. Thomas,
B. A. Thomas,
I. Tsekhanovich,
L. Varga,
Y. Xing
Abstract:
Solar cells have been used since several decades for the detection of fission fragments at about 1 AMeV. The advantages of solar cells regarding their cost (few euros) and radiation damage resistance make them an interesting candidate for heavy ion detection and an appealing alternative to silicon detectors. A first exploratory measurement of the response of solar cells to heavy ions at energies a…
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Solar cells have been used since several decades for the detection of fission fragments at about 1 AMeV. The advantages of solar cells regarding their cost (few euros) and radiation damage resistance make them an interesting candidate for heavy ion detection and an appealing alternative to silicon detectors. A first exploratory measurement of the response of solar cells to heavy ions at energies above 1 AMeV has been performed at the GANIL facility, Caen, France. Such measurements were performed with 84Kr and 129Xe beams ranging from 7 to 13 AMeV. The energy and time response of several types of solar cells were studied. The best performance was observed for cells of 10x10 mm2, with an energy and time resolution of σ(E)/E=1.4% and 3.6 ns (FWHM), respectively. Irradiations at rates from a few hundred to 106 particles per second were also performed to investigate the behavior of the cells with increasing intensity.
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Submitted 1 April, 2020; v1 submitted 22 December, 2019;
originally announced December 2019.
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Revisiting fission-probability data using $\mathcal{R}$-matrix Monte-Carlo simulations : application to Pu fissile isotopes over the 4 to 8 MeV excitation energy range
Authors:
O. Bouland,
B. Jurado
Abstract:
This article describes an original approach to analyze simultaneously cross sections and surrogate data measurements using efficient Monte Carlo extended $\mathcal{R}$-matrix theory algorithm based on unique set of nuclear structure parameters. The alternative analytical path based on the manifold Hauser-Feshbach equation was intensively used in this work to gauge the errors carried by the surroga…
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This article describes an original approach to analyze simultaneously cross sections and surrogate data measurements using efficient Monte Carlo extended $\mathcal{R}$-matrix theory algorithm based on unique set of nuclear structure parameters. The alternative analytical path based on the manifold Hauser-Feshbach equation was intensively used in this work to gauge the errors carried by the surrogate-reaction method commonly taken to predict neutron-induced cross sections from observed partial decay probabilities. Present paper emphasizes in particular a dedicated way to treat direct reaction entrance and prior decay excited nucleus outgoing channels widths correlations. Present smart theoretical foundation brought the opportunity to apply successfully our method to both fission-probability data and directly measured neutron cross sections according to Pu fissile isotopes; namely the $^{237, 238, 240, 242~and~244}$Pu$^*$ nuclei. This new capability opens genuine perspectives in matter of 'evaluation process' from foreseen fission- and $γ$-decay probabilities simultaneously measured as derived data will become available.
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Submitted 28 February, 2019;
originally announced March 2019.
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A new gas-based proton-recoil telescope for quasi-absolute neutron flux measurements between 0.2 and 2 MeV neutron energy
Authors:
P. Marini,
L. Mathieu,
M. Aïche,
J. -L. Pedroza,
T. Chiron,
P. Baron,
S. Czajkowski,
F. Druillole,
P. Hellmuth,
B. Jurado,
A. Rebii,
I. Tsekhanovich
Abstract:
Absolute measurements of neutron flux are an essential prerequisite of neutron-induced cross section measurements, neutron beam lines characterization and dosimetric investigations. A new gaseous detector has been developed for measurements of 0.2 to 2 MeV neutron flux based on proton-recoil process. The detector, consisting of two segmented ionization chambers read by Micromegas technology, has b…
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Absolute measurements of neutron flux are an essential prerequisite of neutron-induced cross section measurements, neutron beam lines characterization and dosimetric investigations. A new gaseous detector has been developed for measurements of 0.2 to 2 MeV neutron flux based on proton-recoil process. The detector, consisting of two segmented ionization chambers read by Micromegas technology, has beed conceived to provide quasi-absolute neutron flux measurements with an accuracy of \simeq3%. The gas pressure flexibility makes the telescope non sensitive to γ and electrons background, and therefore advantageous over semi-conductor materials as a neutron flux instrument. The adjustable gas pressure and H-sample thickness, the use of Micromegas technology and the tracking capabilities allows the detection of neutrons on a large dynamical range and down to 200 keV with a good rejection of scattered neutron events and random background
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Submitted 18 January, 2019;
originally announced January 2019.
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Experimental set-up for the simultaneous measurement of fission and gamma-emission probabilities induced by transfer or inelastic-scattering reactions
Authors:
R. Pérez Sánchez,
B. Jurado,
P. Marini,
M. Aiche,
S. Czajkowski,
D. Denis-Petit,
Q. Ducasse,
L. Mathieu,
I. Tsekhanovich,
A. Henriques,
V. Méot,
O. Roig
Abstract:
Fission and gamma-emission probabilities induced by transfer or inelastic scattering reactions with light projectile nuclei are very valuable quantities for constraining the models that describe the de-excitation of heavy nuclei. We have developed an experimental set-up that allows us to simultaneously measure fission and gamma-emission probabilities. The measurement of the gamma-emission probabil…
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Fission and gamma-emission probabilities induced by transfer or inelastic scattering reactions with light projectile nuclei are very valuable quantities for constraining the models that describe the de-excitation of heavy nuclei. We have developed an experimental set-up that allows us to simultaneously measure fission and gamma-emission probabilities. The measurement of the gamma-emission probability at excitation energies where the fission channel is open is challenging due to the intense background of gamma rays emitted by the fission fragments. We discuss the procedure to subtract such a background and the constraints that this subtraction and other experimental conditions put on the set up. We show that our set-up complies with these constraints.
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Submitted 9 April, 2019; v1 submitted 11 January, 2019;
originally announced January 2019.
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Development of a gaseous proton-recoil detector for neutron flux measurements between 0.2 and 2 MeV neutron energy
Authors:
Paola Marini,
Ludovic Mathieu,
Mourad Aïche,
Serge Czajkowski,
Beatriz Jurado,
Igor Tsekhanovich
Abstract:
Absolute measurements of neutron fluence are an essential prerequisite of neutron-induced cross section measurements, neutron beam lines characterization and dosimetric investigations. The H(n,p) elastic scattering cross section is a very well known standard used to perform precise neutron flux measurements in high precision measurements. The use of this technique, with proton recoil detectors, is…
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Absolute measurements of neutron fluence are an essential prerequisite of neutron-induced cross section measurements, neutron beam lines characterization and dosimetric investigations. The H(n,p) elastic scattering cross section is a very well known standard used to perform precise neutron flux measurements in high precision measurements. The use of this technique, with proton recoil detectors, is not straightforward below incident neutron energy of 1 MeV, due to a high background in the detected proton spectrum. Experiments have been carried out at the AIFIRA facility to investigate such background and to determine its origin and components. Based on these investigations, a gaseous proton-recoil detector has been designed with a reduced low energy background. A first test of this detector has been carried out at the AIFIRA facility, and first results will be presented.
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Submitted 2 November, 2018;
originally announced November 2018.
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A spallation-based neutron target for direct studies of neutron-induced reactions in inverse kinematics
Authors:
René Reifarth,
Kathrin Göbel,
Tanja Heftrich,
Mario Weigand,
Beatriz Jurado,
Franz Käppeler,
Yuri A. Litvinov
Abstract:
We discuss the possibility to build a neutron target for nuclear reaction studies in inverse kinematics utilizing a storage ring and radioactive ion beams. The proposed neutron target is a specially designed spallation target surrounded by a large moderator of heavy water (D$_2$O). We present the resulting neutron spectra and their properties as a target. We discuss possible realizations at differ…
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We discuss the possibility to build a neutron target for nuclear reaction studies in inverse kinematics utilizing a storage ring and radioactive ion beams. The proposed neutron target is a specially designed spallation target surrounded by a large moderator of heavy water (D$_2$O). We present the resulting neutron spectra and their properties as a target. We discuss possible realizations at different experimental facilities.
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Submitted 27 April, 2017;
originally announced April 2017.
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Application of the EXtrapolated Efficiency Method (EXEM) to infer the gamma-cascade detection efficiency in the actinide region
Authors:
Q. Ducasse,
B. Jurado,
L. Mathieu,
P. Marini,
B. Morillon,
M. Aiche,
I. Tsekhanovich
Abstract:
The study of transfer-induced gamma-decay probabilities is very useful for understanding the surrogate-reaction method and, more generally, for constraining statistical-model calculations. One of the main difficulties in the measurement of gamma-decay probabilities is the determination of the gamma-cascade detection efficiency. In [Nucl. Instrum. Meth. A 700, 59 (2013)] we developed the Extrapolat…
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The study of transfer-induced gamma-decay probabilities is very useful for understanding the surrogate-reaction method and, more generally, for constraining statistical-model calculations. One of the main difficulties in the measurement of gamma-decay probabilities is the determination of the gamma-cascade detection efficiency. In [Nucl. Instrum. Meth. A 700, 59 (2013)] we developed the Extrapolated Efficiency Method (EXEM), a new method to measure this quantity. In this work, we have applied, for the first time, the EXEM to infer the gamma-cascade detection efficiency in the actinide region. In particular, we have considered the 238U(d,p)239U and 238U(3He,d)239Np reactions. We have performed Hauser-Feshbach calculations to interpret our results and to verify the hypothesis on which the EXEM is based. The determination of fission and gamma-decay probabilities of 239Np below the neutron separation energy allowed us to validate the EXEM.
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Submitted 19 January, 2016; v1 submitted 24 December, 2015;
originally announced December 2015.