Search

The very proton-rich 71Kr isotope was produced through the in-flight fragmentation of 78Kr on a beryllium target at RIKEN ¿ Nishina Center in order to study its ß-decay properties. A stack of double-sided silicon strip detectors, called WAS3ABi, was used as the decay station, where the detection of ion implants, ß-decays and ß-delayed protons took place. Beta-delayed ¿-rays were measured using a system of 84 HPGe detectors, called EURICA, surrounding the decay station. The main goal of the present study was the precise measurement of the half-life of 71Kr, as in the literature there is an almost 10 ¿ difference between the most precise independent results. Implant¿ß time correlations, implant¿proton time correlations and implant¿ß¿¿ time correlations were all used to derive the half-life value, followed by a thorough investigation of systematic uncertainties for each method. As these values were found to be consistent, the weighted average t1/2 = 94.40+19ms is reported as a new half-life value in this work. Furthermore a total of 26 previously unreported ¿ following the ß-decay of 71Kr were also identified in the analysis.

We report results on the long-term variation of the neutron counting rate at the Canfranc Underground Laboratory, of importance for several low-background experiments installed there, including rare-event searches. The measurement campaign was performed employing the High Efficiency Neutron Spectrometry Array (HENSA) mounted in Hall A and lasted 412 live days. The present study is the first long-term measurement of the neutron rate with sensitivity over a wide range of neutron energies (from thermal up to 0.1 GeV and beyond) performed in any underground laboratory so far. Data on the environmental variables inside the experimental hall (radon concentration, air temperature, air pressure and humidity) were also acquired during all the measurement campaign. We have investigated for the first time the evolution of the neutron rate for different energies of the neutrons and its correlation with the ambient variables.

The DEcay SPECtroscopy (DESPEC) setup for nuclear structure investigations was developed and commissioned at GSI, Germany in preparation for a full campaign of experiments at the FRS and Super-FRS. In this paper, we report on the first employment of the setup in the hybrid configuration with the AIDA implanter coupled to the FATIMA LaBr(Ce) fast-timing array, and high-purity germanium detectors. Initial results are shown from the first experiments carried out with the setup. An overview of the setup and function is discussed, including technical advancements along the path.

The present invention relates to a system (10) and method for the volumetric and isotopic identification of the spatial distribution of ionizing radiation from point or extensive radioactive sources (3) in radioactive surroundings. More specifically, this system (10) comprises a gamma radiation detector (2) and an optical transducer (1) joined to each other and linked to a control unit to detect the absolute position of radioactive sources (3) relative to a visual reference located in the radioactive surroundings, and to determine the radioactive activity of the sources, that is to say it detects the isotope composition of the radioactive sources (3).

The present invention relates to a system (10) and method for the volumetric and isotopic identification of the spatial distribution of ionizing radiation from point or extensive radioactive sources (3) in radioactive surroundings. More specifically, this system (10) comprises a gamma radiation detector (2) and an optical transducer (1) joined to each other and linked to a control unit to detect the absolute position of radioactive sources (3) relative to a visual reference located in the radioactive surroundings, and to determine the radioactive activity of the sources, that is to say it detects the isotope composition of the radioactive sources (3)

Ambient neutrons may cause significant background for underground experiments. Therefore, it is necessary to investigate their flux and energy spectrum in order to devise a proper shielding. Here, two sets of altogether ten moderated He3 neutron counters are used for a detailed study of the ambient neutron background in tunnel IV of the Felsenkeller facility, underground below 45 m of rock in Dresden/Germany. One of the moderators is lined with lead and thus sensitive to neutrons of energies higher than 10 MeV. For each He3 counter moderator assembly, the energy-dependent neutron sensitivity was calculated with the FLUKA code. The count rates of the ten detectors were then fitted with the MAXED and GRAVEL packages. As a result, both the neutron energy spectrum from 10-9 to 300 MeV and the flux integrated over the same energy range were determined experimentally. The data show that at a given depth, both the flux and the spectrum vary significantly depending on local conditions. Energy-integrated fluxes of (0.61±0.05), (1.96±0.15), and (4.6±0.4)×10-4 cm-2 s-1, respectively, are measured for three sites within Felsenkeller tunnel IV which have similar muon flux but different shielding wall configurations. The integrated neutron flux data and the obtained spectra for the three sites are matched reasonably well by FLUKA Monte Carlo calculations that are based on the known muon flux and composition of the measurement room walls.

The present invention relates to a system (10) and method for the volumetric and isotopic identification of the spatial distribution of ionizing radiation from point or extensive radioactive sources (3) in radioactive surroundings. More specifically, this system (10) comprises a gamma radiation detector (2) and an optical transducer (1) joined to each other and linked to a control unit to detect the absolute position of radioactive sources (3) relative to a visual reference located in the radioactive surroundings, and to determine the radioactive activity of the sources, that is to say it detects the isotope composition of the radioactive sources (3).

We report on the observation of a microsecond isomeric state in the single-proton-hole, three-neutron-particle nucleus In-134. The nuclei of interest were produced by in-flight fission of a U-238 beam at the Radioactive Isotope Beam Factory at RIKEN. The isomer depopulates through a gamma ray of energy 56.7(1) keV and with a half-life of T-1/2 = 3.5(4) mu s. Based on the comparison with shell-model calculations, we interpret the isomer as the I-pi = 5(-) member of the pi 0g(9/2)(-1) circle times nu 1f(7/2)(3) multiplet, decaying to the I-pi = 7(-) ground state with a reduced-transition probability of B(E2; 5(-) -> 7(-)) = 0.53(6) W.u. Observation of this isomer, and lack of evidence in the current work for a I-pi = 5(-) isomer decay in In-132, provides a benchmark of the proton-neutron interaction in the region of the nuclear chart >southeast> of Sn-132, where experimental information on excited states is sparse.

La presente invención es un sistema (10) y método para la identificación volumétrica e isotópica de la distribución espacial de una radiación ionizante procedente de fuentes radioactivas (3) puntuales, o extensas, en escenas radioactivas. Más concretamente, este sistema (10) comprende: un detector de radiación gamma (2) y un transductor óptico (1) solidarios entre si y vinculados con una unidad de control para detectar la posición absoluta, con respecto a una referencia visual que se encuentra en la escena radioactiva, de las fuentes radioactivas (3) y determina su actividad radioactiva, es decir detecta la composición de isótopos de las fuentes radioactivas (3)

Sistema y método para la identificación volumétrica e isotópica de distribuciones de escenas radioactivas. La presente invención es un sistema (10) y método para la identificación volumétrica e isotópica de la distribución espacial de una radiación ionizante procedente de fuentes radioactivas (3) puntuales, o extensas, en escenas radioactivas. Más concretamente, este sistema (10) comprende: un detector de radiación gamma (2) y un transductor óptico (1) solidarios entre si y vinculados con una unidad de control para detectar la posición absoluta, con respecto a una referencia visual que se encuentra en la escena radioactiva, de las fuentes radioactivas (3) y determina su actividad radioactiva, es decir detecta la composición de isótopos de las fuentes radioactivas (3).

The present invention relates to a system (10) and method for the volumetric and isotopic identification of the spatial distribution of ionising radiation from point or extensive radioactive sources (3) in radioactive surroundings. More specifically, this system (10) comprises a gamma radiation detector (2) and an optical transducer (1) joined to each other and linked to a control unit to detect the absolute position of radioactive sources (3) relative to a visual reference located in the radioactive surroundings, and to determine the radioactive activity of the sources, that is to say it detects the isotope composition of the radioactive sources (3). [EN], La presente invención es un sistema (10) y método para la identificación volumétrica e isotópica de la distribución espacial de una radiación ionizante procedente de fuentes radioactivas (3) puntuales, o extensas, en escenas radioactivas. Más concretamente, este sistema (10) comprende: un detector de radiación gamma (2) y un transductor óptico (1) solidarios entre si y vinculados con una unidad de control para detectar la posición absoluta, con respecto a una referencia visual que se encuentra en la escena radioactiva, de las fuentes radioactivas (3) y determina su actividad radioactiva, es decir detecta la composición de isótopos de las fuentes radioactivas (3). [ES]

[EN] The invention relates to a focusable Compton camera comprising: a Compton dispersion detector (1); at least one absorption detector (2, 2'), the planes of which are separate from the plane of the dispersion detector (1); and a mechanical system (3) for separating the dispersion (1) and absorption detectors (2, 2') so as to vary said distance (d) between said detectors (1, 2, 2'). The invention allows the improvement of the information associated with the formation of images by means of gamma radiation, by calculating the distance of the evaluated objects, and identifying the distribution of the radioisotopes present in said objects, thereby overcoming the limitations of other equipment and cameras of prior art., [ES] Cámara Compton focalizable equipada con detectores de separación variable. La presente invención se refiere a una cámara Compton focalizable que comprende: un detector de dispersión Compton (1); uno o más detectores de absorción (2, 2'), cuyos planos se encuentran separados del plano del detector de dispersión (1); y un sistema mecánico (3) de separación de los detectores de dispersión (1) y de absorción (2, 2') para variar la citada distancia (d) comprendida entre dichos detectores (1, 2, 2'). La invención permite mejorar la información asociada a la formación de imágenes por medio de radiación gamma, mediante el cálculo de la distancia de los objetos evaluados, así como identificar la distribución de los radioisótopos presentes en dichos objetos, superando así las limitaciones de otros equipos y cámaras del estado de la técnica.

[ES] Cámara Compton focalizable equipada con detectores de separación variable. La presente invención se refiere a una cámara Compton focalizable que comprende: un detector de dispersión Compton (1); uno o más detectores de absorción (2, 2'), cuyos planos se encuentran separados del plano del detector de dispersión (1); y un sistema mecánico (3) de separación de los detectores de dispersión (1) y de absorción (2, 2') para variar la citada distancia (d) comprendida entre dichos detectores (1, 2, 2'). La invención permite mejorar la información asociada a la formación de imágenes por medio de radiación gamma, mediante el cálculo de la distancia de los objetos evaluados, así como identificar la distribución de los radioisótopos presentes en dichos objetos, superando así las limitaciones de otros equipos y cámaras del estado de la técnica., [EN] The invention relates to a focusable Compton camera comprising: a Compton dispersion detector (1); at least one absorption detector (2, 2'), the planes of which are separate from the plane of the dispersion detector (1); and a mechanical system (3) for separating the dispersion (1) and absorption detectors (2, 2') so as to vary said distance (d) between said detectors (1, 2, 2'). The invention allows the improvement of the information associated with the formation of images by means of gamma radiation, by calculating the distance of the evaluated objects, and identifying the distribution of the radioisotopes present in said objects, thereby overcoming the limitations of other equipment and cameras of prior art.

[ES] Cámara Compton focalizable equipada con detectores de separación variable. La presente invención se refiere a una cámara Compton focalizable que comprende: un detector de dispersión Compton (1); uno o más detectores de absorción (2, 2'), cuyos planos se encuentran separados del plano del detector de dispersión (1); y un sistema mecánico (3) de separación de los detectores de dispersión (1) y de absorción (2, 2') para variar la citada distancia (d) comprendida entre dichos detectores (1, 2, 2'). La invención permite mejorar la información asociada a la formación de imágenes por medio de radiación gamma, mediante el cálculo de la distancia de los objetos evaluados, así como identificar la distribución de los radioisótopos presentes en dichos objetos, superando así las limitaciones de otros equipos y cámaras del estado de la técnica., [EN] The invention relates to a focusable Compton camera comprising: a Compton dispersion detector (1); at least one absorption detector (2, 2'), the planes of which are separate from the plane of the dispersion detector (1); and a mechanical system (3) for separating the dispersion (1) and absorption detectors (2, 2') so as to vary said distance (d) between said detectors (1, 2, 2'). The invention allows the improvement of the information associated with the formation of images by means of gamma radiation, by calculating the distance of the evaluated objects, and identifying the distribution of the radioisotopes present in said objects, thereby overcoming the limitations of other equipment and cameras of prior art.

Total absorption gamma-ray spectroscopy is used to measure accurately the intensity of ¿ emission from neutron-unbound states populated in the ß-decay of delayed-neutron emitters. From the comparison of this intensity with the intensity of neutron emission one can deduce information on the (n,¿) cross section for unstable neutron-rich nuclei of interest in r process abundance calculations. A surprisingly large ¿ branching was observed for a number of isotopes. The results are compared with Hauser-Feshbach calculations and discussed.

In this work we report on total absorption ¿-ray spectroscopy measurements of the ß decay of fission products that are important contributors to the antineutrino spectrum. The experiment was performed at IGISOL as a part of a campaign of measurements with the new DTAS spectrometer. Preliminary results of the analysis of the ß decay of 100Nb,100mNb and 140Cs are presented.

The contribution of each fission fragment to the reactor antineutrino spectra was determined using the summation method based on the existing information on fission yields and decay data contained in nuclear databases and the reactor evolution code MURE. The beta decay of some of the main contributors has been studied using the Total Absorption Spectroscopy (TAS) technique during two experimental campaigns at the IGISOL facility, in Jyväskylä (Finland). Results on the decay of 92Rb, the most important contributor in the 4–8 MeV energy region are reported. The status of the analysis of the second experiment is presented as well.

The beta decay of Pb-192,Pb-190 has been studied using the total absorption technique at the ISOLDE (CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the Pb-192,Pb-190 isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects. Published by the American Physical Society

A new Total Absorption Gamma-Ray Spectrometer for beta-decay studies (DTAS) has been developed within the DESPEC experiment of the NUSTAR collaboration [1]. The instrument has been designed [2] to determine accurately the beta-decay intensity distribution for exotic nuclei produced in high-energy reactions, which will be separated and identified by means of the Super Fragment Separator at the future FAIR facility. DTAS has a modular construction with up to 18 large NaI(Tl) detector modules (module dimension: 25cmx15cmx15cm) which can be assembled in a 4pi geometry with little dead material around the AIDA implantation detector, a stack of double sided Si strip-detectors [2]. We have recently performed the first experiment with this setup at the upgraded IGISOL IV (Jyväskylä, Finland) facility. The low energy radioactive beams have been further purified with the JYFLTRAP Penning trap [3]. The experiment aimed to study fission products of relevance in neutrino physics and reactor decay heat time evolution. The measurements allowed us to perform a careful characterization of the detector and to study the overall performance of the setup. The results of this work will be presented, including the performance of the gain stabilization system, the correction of electronic pulse pileup, the sensitivity to neutrons and the calibration of the response of the spectrometer to decay radiation by means of Geant4 Monte Carlo simulations.

The gamma rays and conversion electrons emitted in the beta decay of (78)Sr to levels in (78)Rb have been studied using Ge detectors and a mini-orange spectrometer. A reliable level scheme based on the results of these experiments has been established. The properties of the levels in (78)Rb have been compared with calculations based on deformed Hartree-Fock with Skyrme interactions and pairing correlations in the BCS approximation. This has allowed an interpretation of the nature of the observed sets of levels in the odd-odd nucleus (78)Rb.

The beta feeding probability of Tc-102,Tc- 104,Tc- 105,Tc- 106,Tc- 107, Mo-105, and Nb-101 nuclei, which are important contributors to the decay heat in nuclear reactors, has been measured using the total absorption technique. We have coupled for the first time a total absorption spectrometer to a Penning trap in order to obtain sources of very high isobaric purity. Our results solve a significant part of a long-standing discrepancy in the gamma component of the decay heat for Pu-239 in the 4-3000 s range.