Artículos (Centro Nacional de Aceleradores)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/10939

Examinar

Mostrando 1 - 20 de 46

New data for the definition of neutron beams for Boron Neutron capture therapy
(Elsevier, 2021-08) Macías Martínez, Miguel; Fernández Martínez, Begoña; Praena, J.; Física Atómica, Molecular y Nuclear; Ministerio de Economía y Competitividad (MINECO). España; Junta de Andalucía; Asociación Española contra el Cárcer (AECC)
Boron Neutron Capture Therapy (BNCT) is neutron radiotherapy used to treat tumours cells previously doped with Boron-10. This therapy requires an epithermal neutron beam for the treatment of deep tumours and a thermal beam for shallow ones. Thanks to recent high-current commercial accelerators, Accelerator-Based Neutron Sources (ABNS) are a competitive option for providing therapeutic neutron beams in hospitals. In this work, the neutron field generated by the 7Li (p,n)7Be reaction at 1950 keV is studied as a neutron source in ABNS, being measured by the Time-Of-Flight (TOF) technique at HiSPANoS facility (Spain). Moreover, two Beam Shaping Assemblies (BSA) for deep and shallow tumour treatment, which are specially designed for the 1950 keV neutron field, are evaluated for BNCT via Monte Carlo simulations (MCNP). Results in agreement with the International Atomic Energy Agency (IAEA) figures of merit endorse the use of this neutron field for BNCT.
The first neutron time-of-flight line in Spain: Commissioning and new data for the definition of a neutron standard field
(Elsevier, 2020-03) Macías Martínez, Miguel; Fernández Martínez, Begoña; Praena, Javier; Física Atómica, Molecular y Nuclear; Ministerio de Economía y Competitividad (MINECO). España; Asociación Española contra el Cáncer (AECC); Junta de Andalucía
The National Accelerator Laboratory (CNA) has developed the first accelerator line in Spain devoted to the measurement of cross sections involving neutrons by means of the time-of-flight technique. For neutron generation, pulsed proton beams with 1 nsec pulse width and with variable repetition rates are delivered. The data acquisition has been built using a CAEN Digitizer. The aim of this work is to demonstrate the good performance of the time-of-flight system. The commissioning of the line has consisted of the measurement of the neutron field generated by protons at 1912 keV impinging on a thick lithium target. Such a field has been extensively used in nuclear astrophysics since 1988. Recently, there have been experimental works with the goal to support it as a standard neutron field. The results show the good performance of the time-of-flight system and also support its possible definition as a standard.
Soft error rate comparison of 6T and 8T SRAM ICs using mono-energetic proton and neutron irradiation sources
(Elsevier, 2017-11) Malagón, D.; Bota, S. A.; Torrens, G.; Praena, J.; Fernández Martínez, Begoña; Macías Martínez, Miguel; Quesada Molina, José Manuel; Guerrero Sánchez, Carlos; Jiménez Ramos, María del Carmen; García López, Francisco Javier; Merino, J. L.; Segura, J.; Física Atómica, Molecular y Nuclear; Física Aplicada II; Ministerio de Economía y Competitividad (MINECO). España
We present experimental results of soft errors produced by proton and neutron irradiation of minimum-size six-transistors (6T) and eight-transistors (8T) bit-cells SRAM memories produced with 65 nm CMOS technology using an 18 MeV proton beam and a neutron beam of 4.3–8.5 MeV. All experiments have been carried out at the National Center of Accelerators (CNA) in Seville, Spain. Similar soft error rate levels have been observed for both cell designs despite the larger area occupied by the 8T cells, although the trend for multiple events has been higher in 6T.
Trace americium contamination sources in the environment can be detected using 243Am/241Am
(Springer Nature, 2026) Chamizo, Elena; López Lora, Mercedes; López Fuentes, Antonio Jesús; Física Atómica, Molecular y Nuclear; Física Aplicada II; Centro Nacional de Aceleradores (CNA); Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España
Despite the widespread presence of americium in the environment since the 1950s from nuclear activities, the use of americium isotopic composition to trace contamination sources has not been investigated. Here we report the detection of 243 Am in environmental samples and demonstrate that the ratio of 243 Am to 241 Am can serve as a distinctive fingerprint of radioactive emissions, with characteristic values of 0.05 for thermonuclear explosions, 0.023 for global fallout, below 0.0015 for low-yield nuclear tests, and 0.0013 for releases from a nuclear reprocessing facility. In nuclear detonations, 243 Am is produced as the decay product of 243 Pu. The ratio of 243 Am to 239 Pu in global fallout is about 3.2 × 10⁻⁴, supporting the predicted formation of neutron-rich heavy plutonium isotopes during nuclear detonations.
Calibration and Performance Tests of Detectors for Laser-Accelerated Protons
(Institute of Electrical and Electronics Engineers (IEEE), 2015-11-09) Seimetz, M.; Bellido, P.; Soriano, A.; García López, Francisco Javier; Jiménez Ramos, María del Carmen; Fernández Martínez, Begoña; Conde, P.; Crespo, E.; González, A. J.; Benlloch, J. M.; Física Atómica, Molecular y Nuclear; Física Aplicada II; Ministerio de Economía y Competitividad (MINECO). España; Agencia Estatal de Investigación. España; Generalitat Valenciana
We present the calibration and performance tests carried out with two detectors for intense proton pulses accelerated by lasers. Most of the procedures were realized with proton beams of 0.46-5.60 MeV from a tandem accelerator. One approach made use of radiochromic films, for which we calibrated the relation between optical density and energy deposition over more than three orders of magnitude. The validity of these results and of our analysis algorithms has been confirmed by controlled irradiation of film stacks and reconstruction of the total beam charge for strongly non-uniform beam profiles. For the spectral analysis of protons from repeated laser shots, we have designed an online monitor based on a plastic scintillator. The resulting signal from a photomultiplier directly measured on a fast oscilloscope is especially useful for time-of-flight applications. Variable optical filters allow for suppression of saturation and an extension of the dynamic range. With pulsed proton beams we have tested the detector response to a wide range of beam intensities from single particles to 3 ×105 protons per 100 ns time interval.
Structure and Nonlinear Optical Properties of TeO2–WO3–PbO Thin Film Glasses
(Elsevier, 2025) Gorni, G.; Muñoz Martín, D.; Ruiz de la Cruz, A.; Martin Diaconescu, V.; Simonelli, L.; García López, Francisco Javier; Fernández Navarro, J. M.; Solís, J.; Gonzalo, J.; Física Atómica, Molecular y Nuclear; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Consejo Superior de Investigaciones Científicas (CSIC); Ministerio de Ciencia e Innovación (MICIN). España
Lead tungsten tellurite thin film glasses have been produced by pulsed laser deposition in a broad TeO2 compositional range (50–85 mol%). Films present high transparency with an optical band gap Eg =3.3–3.4 eV, large refractive index (n >2) and reduced absorption (k <10 4) in the visible and near infrared ranges, whereas their nonlinear optical response (∣χ(3)∣) is found to be ≥10 12 esu at 1.3 μm. The dependence of n, Eg and ∣χ(3)∣ with film composition is analyzed and compared with the values determined for the parent bulk glasses. ∣χ(3)∣ increases as the TeO2 content in the film glasses decreases, while it remains constant for bulk glasses. This behaviour is analyzed in the frame of Line’s model and correlated to the structural differences between bulk and film glasses. In the case of bulk glasses, X-ray absorption spectroscopy results at the W L3 and L1-edges clearly indicate the presence of W6+ions in a distorted octahedral coordination, with the coordination environment and W–O bond distance remaining unchanged regardless of the WO3 content. Raman analysis suggests that films have a structure close to that of bulk glasses, with a moderate WO3 and PbO enrichment, and a relative increase of the non-bridging oxygen fraction that are proposed to be responsible for the observed increase of ∣χ(3)∣ in the films.
Microstructure and composition evolution of He Charged solid-gas Nanocomposite Films of Different Matrix Elements During Thermal Annealing in Vacuum
(Nature Publishing Group, 2025) Fernández, Asunción; Jiménez de Haro, María del Carmen; Hufschmidt, Dirk; Montes, Olga; Sauvage, Thierry; Ferrer Fernández, Francisco Javier; Caillard, Amaël; Brault, Pascal; Thomann, Anne Lise; Física Atómica, Molecular y Nuclear
Sputtering of cobalt, silicon and zirconium in a helium magnetron discharge (MS) is reported as a bottom-up procedure to obtain He-charged films (i.e. 4He and 3He filled nanopores encapsulated in the matrix material). Composition and microstructural analyses are presented from ion beam analysis (IBA) and scanning and transmission electron microscopies (SEM and TEM). Helium desorption was investigated by IBA in a dedicated chamber for “in situ” thermal evolution in vacuum. The simultaneous recording of the helium and matrix-element signals shows different behaviors of the different matrix elements (i.e. Co, Si and Zr) and deposition conditions (i.e., DC or RF discharge modes and dynamic or quasistatic vacuum). Effusion, blistering, delamination and flaking have been observed for the different samples leading to the formation of nano-porous/nanostructured thin films. The methodology is being envisaged as a process for nanostructured thin-films fabrication with potential applications.
The Lyon Mint in the Roman Tomares Hoard (Seville): Some Considerations on Its Metallic Composition Determined by XRF
(Willey, 2025-06-15) Pliego Vázquez, Ruth; Gómez-Tubio, Blanca María; Alcaide Ramírez, María; Scrivano, Simona; Respaldiza Galisteo, Miguel Ángel; Física Atómica, Molecular y Nuclear; Prehistoria y Arqueología; Física Aplicada III; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Universidad de Sevilla
COSMONAUT: A COmpact Spectrometer for Measurements of Neutrons at the ASDEX Upgrade Tokamak
(American Institute of Physics, 2024) Nocente, M.; Molin, A. D.; D Rigamonti, D.; Rosa, M. D.; Fernández Martínez, Begoña; Fugazza, S.; Guerrero Sánchez, Carlos; Gorini, G.; Kazakov, Y. O.; Tardini, G.; Tardocchi, M.; ASDEX Upgrade Team; Eurofus Tokamak Exploitat Team; Física Atómica, Molecular y Nuclear; European Union (UE); European Union (UE). H2020
A COmpact Spectrometer for Measurements Of Neutrons at the ASDEX Upgrade Tokamak (COSMONAUT) has been developed for spectroscopy measurements of the 2.45 MeV neutron emission from deuterium plasmas at the ASDEX Upgrade. The instrument is based on a CLYC-7 inorganic scintillator, whereby the detection of fusion neutrons occurs via their interaction with 35Cl nuclei in the detector crystal, leading to a peak in the detector response function and providing excellent neutron/gamma-ray discrimination capabilities. The diagnostics is installed along a radial line of sight and makes use of a digital system to record time resolved data for the whole duration of the discharge. Measurements in ASDEX Upgrade plasmas with neutral beam injection have been carried out and are successfully interpreted using state-of-the-art modeling codes. Next step applications of the diagnostics are in experiments aimed at generating energetic particles by ion cyclotron resonance heating schemes. In these scenarios, COSMONAUT will provide unique information on the acceleration of deuterons beyond the beam injection energy and on their confinement, for comparison with modeling.
Experimental study of 6He Coulomb breakup as an indirect measurement of 4He(2n,γ)6He reaction rate for the astrophysical r-process
(EDP Sciences, 2024-10-08) Godos, D.; Acosta, L.; Fernández García, Juan Pablo; O'Malley, P.; Sánchez Benítez, A. M.; Casal Berbel, Jesús; Gómez Camacho, Joaquín José; Arias Carrasco, José Miguel; Rodríguez Gallardo, Manuela; von Seeger, W.; Física Atómica, Molecular y Nuclear; National Science Foundation (NSF). United States; Universidad Autónoma de México (UNAM); Consejo Nacional de Ciencia y Tecnología (CONACYT). México
In this work, we report the measurement of elastic and Coulomb break-up channels in 6He+208Pb collisions at Elab = 19.3 MeV, close to the Coulomb barrier of this system ∼ 19 MeV. In the context of the astrophysical r-process, the reaction 4He(2n,γ)6He has been proposed to be a key reaction in the path of synthesizing seed nuclei for the r-process, as 12C, in an environment composed mainly of alpha particles and neutrons. Based on a theoretical approach for treating three body reactions by means of which its reaction rate can be inferred, our experimental approach aims to obtain an indirect measurement of the reaction rate of 4He(2n,γ)6He by measuring the Coulomb breakup of 6He under the intense electric field produced by a 208Pb target nucleus. The experiment was carried out at the TriSol facility operated in the Nuclear Science Laboratory of the University of Notre Dame, USA, which delivered a 6He beam together with other contaminants. Particular care must be taken for the alpha particles produced in the production reaction.
Tuning the Er3+ Sensitization by Si Nanoparticles in Nanostructured as-grown Al2 O3 Films
(American Institute of Physics, 2009) Núez Sánchez, S.; Serna, R.; García López, Francisco Javier; Petford Long, A. K.; Tanase, M.; Kabius, B.; Física Atómica, Molecular y Nuclear; Comisión Interministerial de Ciencia y Tecnología (CICYT). España; European Union (UE); Electron Microscopy Center. Chicago
Nanostructured films consisting of single Si nanoparticles (NPs) and Er3+ ions layers separated by nanometer-scale Al2 O 3 layers of controlled thickness have been prepared in order to tune the energy transfer between Si NPs and Er3+ ions. The amorphous Si NPs with an effective diameter of ∼4.5 nm are formed during growth and are able to sensitize the Er3+ ions efficiently with no postannealing treatments. The characteristic distance for energy transfer from Si NPs to Er3+ ions in Al2 O3 is found to be in the 1 nm range. It is shown that in the nanostructured films, it is possible to achieve an optimized configuration in which almost all the Er3+ ions have the potential to be excited by the Si NPs. This result stresses the importance of controlling the dopant distribution at the nanoscale to achieve improved device performance.
Modular Apparatus for Nuclear Reactions Spectroscopy (MARS): Characterization and First Application to Determine 12C(6Li,4He)14Ng.s Nuclear Reaction Cross Sections
(Springer, 2025) Garrido Gómez, Laura; Vegas Díaz, Alejandro; González Álvarez, Marcos Aurelio; Fernández García, Juan Pablo; Fernández Martínez, Begoña; Ferrer Fernández, Francisco Javier; Lopez Aires, D.; Física Atómica, Molecular y Nuclear; Gobierno de España; Ministerio de Economía y Competitividad (MINECO). España; Junta de Andalucía; Ministerio de Ciencia e Innovación (MICIN). España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; National Science Foundation (NSF). United States
This work presents MARS (Modular apparatus for nuclear reactions spectroscopy) and its characterization prior to its first application to measure 6Li+12C nuclear reactions. Measurements were performed at the 3 MV tandem accelerator of the CNA (National Accelerator Center), in Seville, Spain. The 6Li projectiles were accelerated at energies around the 6Li+12C Coulomb barrier (Vcm B ∼ 3.0 MeV - center of mass and V lab B ∼ 4.5 MeV - laboratory frame). Using a 6Li2+ beam, we measured at 13 laboratory energies from 4.00 to 7.75 MeV. Thus, we present the excitation function of 12C(6Li,4He)14Ng.s. reaction, at 2 backward angles (110.0◦ and 140.0◦). The projectile dissociation, leading to this reaction, increases with the bombarding energies around the Coulomb barrier. This dissociation is favored at an optimum energy Eop b ≥ VB + |Qbu|, where VB is the Coulomb barrier of the system, and |Qbu| is the module of Q-value for the 6Li dissociation into 4He+2H. This result corroborates a systematic analysis of weakly bound projectiles reacting on several targets
Production and measurement of a stellar neutron spectrum at 30 keV
(Springer, 2024-10-06) Praena, Javier; Verdera, Antònia; García López, Javier; Martín Hernández, Guido; Física Atómica, Molecular y Nuclear; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Commission (EC)
A few years ago, we theoretically studied the production of a stellar neutron spectrum at kT = 30 keV using a shaped proton beam impinging on a thick lithium target. Here, we first measure the proton distribution to better control the produced neutron spectrum. Then, we measure the forward-emitted angle-integrated neutron spectrum of the 7Li(p,n)7Be reaction via time-of-flight neutron spectrometry with such proton distribution. The result resembles a stellar neutron spectrum at kT = 30 keV. This method avoids in activation experiments the need for spectrum correction. In the case of spherical samples, no knowledge of the cross-section of the isotope being measured by activation would be necessary. Therefore, the present method is of interest for isotopes with unknown or poorly known cross-sections, such as branching points in astrophysics. The key point of our method is the experimental control of the proton distribution that impinges on the lithium target.
Tuning light emission in Bi and V codoped MgAl2O4 nanostructured films
(Elsevier, 2025-02-24) Gorni, G.; Serna, R.; García López, Francisco Javier; Gonzalo, J.; Física Atómica, Molecular y Nuclear; Agencia Estatal de Investigación. España; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Consejo Superior de Investigaciones Científicas (CSIC); Ministerio de Ciencia e Innovación (MICIN). España; NextGeneration. U. E.
This study investigates the synthesis of novel Bi and V-codoped MgAl2O4 nanostructured thin films for near-white-light emission upon UV excitation. Sequential pulsed laser deposition (PLD) from Bi, V, and MgAl2O4 targets was employed to prepare nanostructured films with different compositions. The films have been thoroughly analyzed using Rutherford backscattering spectrometry (RBS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and photoluminescence spectroscopy (PL). Upon heat treatments at 500 °C and 800 °C, the films exhibit a broad blue emission in Bi-doped films and a broad yellow emission in V-doped films, respectively. We demonstrate that a strategic combination of Bi and V codoping in MgAl2O4 nanostructures results in near-white light emission. This study highlights the ability to finely control the nanostructure and emission properties of thin films using PLD, and the use of abundant and non-toxic elements to produce white light emission, with significant implications for advanced and sustainable photonic applications.
Characterization of New Silicon Carbide Neutron Detectors with Thermal and Fast Neutrons
(Elsevier, 2024) Pérez, Martín; Zamorano, Felipe; Fleta, Celeste; Fernández Martínez, Begoña; Guerrero Sánchez, Carlos; Godignon, Philippe; Pellegrini, Giulio; Pérez Maroto, Pablo; Guardiola, Consuelo; Física Atómica, Molecular y Nuclear; European Union (UE). H2022; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)
The aim of this work is to present a characterization of a new silicon carbide (SiC) neutron detector fabricated at the Institute of Microelectronics of Barcelona (IMB-CNM-CSIC). The device is based on a 50μm thick p-n diode built in a 4H-SiC wafer. Performance studies were carried out under different neutron energy spectra, including thermal and quasi-monoenergetic fast neutrons at the CNA HiSPANoS facility. We implemented a method for the fabrication of enriched LiF conversion layers to use for the detection of thermal neutrons. The detector was proven to be capable of being used for thermal neutron detection with conversion layers of 10B and LiF. A detection efficiency of 6 ± 1% was achieved with a 25μm thick LiF conversion layer. It was also confirmed that the device can be employed for the detection of recoil nuclei and protons produced by fast neutrons. The spectra obtained experimentally were compared with PHITS simulations. This work represents the first step towards the design and fabrication of new SiC neutron detectors in the IMB-CNM-CSIC clean room with potential applications in various scientific and technological fields.
Ultra-Thin Plastic Scintillator-Based Proton Detector for Timing Applications
(Multidisciplinary Digital Publishing Institute (MDPI), 2025-02-06) Rodríguez Ramos, Mauricio; García López, Francisco Javier; Seimetz, Michael; Juan Morales, Jessica; Torres Muñoz, Carmen; Jiménez Ramos, María del Carmen; Física Atómica, Molecular y Nuclear; Física Aplicada II; Junta de Andalucía; Generalitat Valenciana; Consejo Superior de Investigaciones Científicas (CSIC)
The development of advanced detection systems for charged particles in laser-based accelerators and the need for precise time of flight measurements have led to the creation of detectors using ultra-thin plastic scintillators, indicating their use as transmission detectors with low energy loss and minimal dispersion for protons around a few MeV. This study introduces a new detection system designed by the Institute for Instrumentation in Molecular Imaging for time of flight and timing applications at the National Accelerator Center in Seville. The system includes an ultra-thin EJ-214 plastic scintillator coupled with a photomultiplier tube and shielded by aluminized mylar sheets. The prototype installation as an external trigger system at the ion beam nuclear microprobe of the aforementioned facility, along with its temporal performance and ion transmission, was thoroughly characterized. Additionally, the scintillator thickness and uniformity were analyzed using Rutherford backscattering spectrometry. Results showed that the experimental thickness of the EJ-214 sheet differs by approximately 46% from the supplier specifications. The detector response to MeV protons demonstrates a strong dependence on the impact position but remains mostly linear with the applied working bias. Finally, single ion detection was successfully achieved, demonstrating the applicability of this new system as a diagnostic tool.
Experiments and Gyrokinetic Simulations of TCV Plasmas with Negative Triangularity in View of DTT Operations
(Institute of Physics Publishing, 2024) Balestri, A.; Mantica, P.; Mariani, A.; Bagnato, F.; Bolzonella, T.; Ball, J.; Coda, S.; Dunne, M.; Faitsch, M.; Innocente, P.; Viezzer, Eleonora; EUROfusion MST1 Team; Física Atómica, Molecular y Nuclear; EUROfusion Consortium
Negative triangularity (NT) scenarios in TCV have been compared to positive triangularity (PT) scenarios using the same plasma shapes foreseen for divertor tokamak test tokamak operations. The experiments provided a NT/PT L-mode pair and a PT H-mode with different heating mixes. Regardless of the heating mix, NT L-modes always reached higher values of plasma pressure with respect to PT L-modes with the same power and recovered the central pressure of PT H-mode scenarios heated with up to twice the injected power. The experimental analysis shows that this enhanced performance in NT is due to larger temperature and density gradients close to the edge ( ρ t o r = [ 0.8 − 1.0 ] ) and higher values of pressure at the separatrix. Local gyrokinetic simulations agree with the experimental results and are able to catch the effect of shaping alone. Integrated modeling performed with ASTRA-TGLF reproduces reasonably well the PT shot but is not able to fully capture the improvements in the NT shot.
8B Reaction Dynamics Researched at HIE-ISOLDE
(Editrice Compositori s.r.l., 2024) Spartà, R.; DiPietro, A.; Figuera, P.; Tengblad, O.; Moro Muñoz, Antonio Matías; Lei, J.; Martel, I.; Fernández García, Juan Pablo; Acosta, L.; Borge, M. J.G.; Onses, S. Viñal; Física Atómica, Molecular y Nuclear; European Union (UE). H2020
For the first time a measurement of 8B + 64Zn reaction has been performed at HIE-ISOLDE at CERN at energies around the Coulomb barrier, to understand how the debated halo structure of the light nucleus can affect reaction dynamics.
Conceptual Design of a Scintillator-Based Fast-Ion Loss Detector for the Wendelstein 7-X Stellarator
(IEEE, 2022) Van Vuuren, Anton Jansen; Lazerson, S. A.; Leviness, A.; García Muñoz, Manuel; Gates, D.; Galdón Quiroga, Joaquín; Hidalgo Salaverri, Javier; Rueda Rueda, José; García Domínguez, Javier; Ayllón Guerola, Juan Manuel; Física Atómica, Molecular y Nuclear; Ingeniería Mecánica y Fabricación; European Union (UE); Ministerio de Ciencia e Innovación (MICIN). España
A conceptual design of a scintillator-based fast-ion loss detector (FILD) has been developed for the Wendelstein 7-X stellarator (W7-X). Simulations using the Monte Carlo codes ASCOT5 and BEAMS3D have been performed to calculate the expected flux of neutral beam injection (NBI)-generated fast hydrogen ions onto the conceptual detector probe head. These fast-ion loss fluxes have been calculated for several magnetic field configurations as well as probe insertion positions. At the maximum insertion position, both co- and counter-going losses with high incident pitch angles are observed; however, at retracted positions, only co-going fast ions reach the probe head. The FILDSIM code has been used to optimize the geometry of the detector entrance and collimating elements to achieve a wide velocity space coverage as well as a high velocity–space resolution. A synthetic FILD signal is calculated for the expected loss distribution via forward modeling using the instrument response function. The synthetic signal is found to largely retain the velocity space features of the loss distribution.
Plutonium Signatures in a Dated Sediment Core as a Tool to Reveal Nuclear Sources in the Baltic Sea
(American Chemical Society, 2023) López Lora, Mercedes; Olszewski, G.; Chamizo, E.; Tornquist, P.; Pettersson, H.; Eriksson, Mats; Física Atómica, Molecular y Nuclear; Swedish Radiation Safety Authority (SSM); Ministerio de Ciencia, Innovación y Universidades (MICINN). España
Plutonium distribution was studied in an undisturbed sediment core sampled from the Tvären bay in the vicinity of the Studsvik nuclear facility in Sweden. The complete analysis, including minor isotopes, of the Pu isotope composition (238Pu, 239Pu, 240Pu, 241Pu, 242Pu, and 244Pu) allowed us to establish the Pu origin in this area of the Baltic Sea and to reconstruct the Studsvik aquatic release history. The results show highly enriched 239Pu, probably originating from the Swedish nuclear program in the 1960s and 1970s and the handling of high burn-up nuclear fuel in the later years. In addition, the 244Pu/239Pu atomic ratio for the global fallout period between 1958 and 1965 is suggested to be (7.94 ± 0.31)·10-5. In the bottom layer of the sediment, dated 1953-1957, we detected a higher average 244Pu/239Pu ratio of (1.51 ± 0.11)·10-4, indicating the possible impact of the first US thermonuclear tests (1952-1958).

Examinar

Envíos recientes