MoDSS - a compact Mobile Decay Spectroscopy Set-up for the investigation of heavy and superheavy nuclei after separation

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Development of the (d,n) proton-transfer reaction in inverse kinematics for structure studies

Transfer reactions have provided exciting opportunities to study the structure of exotic nuclei and are often used to inform studies relating to nucleosynthesis and applications. In order to benefit from these reactions and their application to rare ion beams (RIBs) it is necessary to develop the tools and techniques to perform and analyze the data from reactions performed in inverse kinematics, that is with targets of light nuclei and heavier beams. We are continuing to expand the transfer reaction toolbox in preparation for the next generation of facilities, such as the Facility for Rare Ion Beams (FRIB), which is scheduled for completion in 2022. An important step in this process is to perform the (d,n) reaction in inverse kinematics, with analyses that include Q-value spectra and differential cross sections. In this way, proton-transfer reactions can be placed on the same level as the more commonly used neutron-transfer reactions, such as (d,p), (9Be,8Be), and (13C,12C). Here we present an overview of the techniques used in (d,p) and (d,n), and some recent data from (d,n) reactions in inverse kinematics using stable beams of 12C and 16O.Comment: 9 pages, 4 figures, presented at the XXXV Mazurian Lakes Conference on Physics, Piaski, Polan

Structure Studies of 13Be^{13}\text{Be} from the 12^{12}Be(d,p) reaction in inverse kinematics on a solid deuteron target

The low-lying structure of $^{13}$Be has remained an enigma for decades. Despite numerous experimental and theoretical studies, large inconsistencies remain. Being both unbound, and one neutron away from $^{14}$Be, the heaviest bound beryllium nucleus, $^{13}$Be is difficult to study through simple reactions with weak radioactive ion beams or more complex reactions with stable-ion beams. Here, we present the results of a study using the $^{12}$Be(d,p)$^{13}$Be reaction in inverse kinematics using a 9.5~MeV per nucleon $^{12}$Be beam from the ISAC-II facility. The solid deuteron target of IRIS was used to achieve an increased areal thickness compared to conventional deuterated polyethylene targets. The Q-value spectrum below -4.4~MeV was analyzed using a Bayesian method with GEANT4 simulations. A three-point angular distribution with the same Q-value gate was fit with a mixture of $s$- and $p$-wave, $s$- and $d$-wave, or pure $p$-wave transfer. The Q-value spectrum was also compared with GEANT simulations obtained using the energies and widths of states reported in four previous works. It was found that our results are incompatible with works that revealed a wide $5/2^+$ resonance but shows better agreement with ones that reported a narrower width.Comment: 10 pages, 5 figure

Decay spectroscopy of 257,258Db isotopes

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Decay spectroscopy studies of 257;258Db

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Beam tracking with micromegas and wire chambers in secondary electron detection configuration

S3 (Super Separator Spectrometer) is a device designed for experiments with the very high intensity stable beams of LINAC, the superconducting linear accelerator of GANIL, which will be built in the framework of SPIRAL2. The aim of this project is to open new opportunities in several physics domains like: very-heavy, and super-heavy nuclei, spectroscopy at and beyond the drip line, isomers and ground state properties, multi-nucleon transfer and deep inelastic reactions. For nuclei identification purposes at the focal plane of S3it is necessary to reconstruct their trajectories. Considering that classical tracking detectors in beam would generate a lot of angular and energy straggling, due to their thickness, it was decided that SeD (Secondary electron Detector) system will be used. It consists from a thin emissive foil in beam with a low pressure gaseous detector off-beam to detect the secondary electrons ejected from the foil. Since 2008, several low pressure gaseous detectors (wire chambers and micromegas) were constructed and tested. Results obtained in the tests with the small prototype detectors convinced us that building a real size 2D prototype wire chamber and a small prototype bulk 2D micromegas is a right decision. Different tests for spatial and time characterization of the new prototype detectors were preformed. The obtained results, among which the results from the first spatial characterization of the micromegas, will be presented

Spectroscopie des isotopes 257,258^{257,258}Db autour de la fermeture de couche déformée N=152

Investigations on the nuclear structure in the region around N = 152 deformed shell gap provide anunderstanding of the existence of superheavy elements (Z > 104). Recent experimental studies havelead to the determination of the size and the strength of this gap. Its influence was studied for nucleilike $^{255}_{103}$Lr$_{152}$ and $^{256}_{104}$Rf$_{152}$. Valuable information can be obtained by studying further the evolution of theN = 152 deformed shell gap. To this purpose, the isotopes of $^{257}_{105}$Db and $^{258}_{105}$Db were produced and arethe subject of this work. Even though these two isotopes were previously studied, the currently availabledata are limited and the level schemes are still not fully determined.The $^{257}$Db was produced through the fusion-evaporation reaction $^{209}$Bi($^{50}$Ti,2n)$^{257}$Db at GANIL. Thetwo previously observed long lived states of $^{257}$Db were confirmed in this experiment, as well as the twoisomeric states of $^{253}$Lr. The $^{258}$Db was produced through the fusion-evaporation reaction $^{209}$Bi($^{50}$Ti,1n)$^{258}$Db at GSI. A strongindication of the existence of two states in $^{258}$Db with different half lives was observed. A new $\gamma$-ray transition of $^{250}$Md was identified and its placement in the partial level scheme is proposed. The $\alpha$ decayof $^{258}$Rf was also observed, suggesting a smaller branching ratio than previously reported.L’étude de la structure des noyaux autour de la fermeture de couche déformée N = 152 offre des donnéescapitales pour la compréhension de l’existence des éléments super lourds (Z > 104). Des expériencesrécentes ont conduit à la détermination de l’amplitude et de la constance de cette fermeture de couche.Son influence sur des noyaux tels que le $^{255}$Lr et $^{256}$Rf a été étudiée. L’étude plus poussée sur l’évolutionde la fermeture de couche déformée N = 152 fournirait des informations précieuses quant à la formationdes noyaux super lourds. A cette fin, les isotopes de $^{257}$Db et $^{258}$Db ont été produits et font l’objet del’étude présentée dans ce manuscrit. Bien que ces deux noyaux aient déjà été étudiés précédemment, lesdonnées disponibles à l’heure actuelle sont limitées et ne permettent pas l’établissement d’un schéma deniveau complet. Le $^{257}$Db a été produit au GANIL par la réaction de fusion-évaporation $^{209}$Bi($^{50}$Ti,2n)$^{257}$Db. Les deuxétats de longue durée de vie observés précédemment ont pu être confirmés, ainsi que les deux étatsisomériques du $^{253}$Lr. Le $^{258}$Db a été produit à GSI par la réaction de fusion-évaporation $^{209}$Bi($^{50}$Ti,1n)$^{258}$Db. Une forteindication de l’existence de deux états dans le $^{258}$Db de durées de vie différentes a été observée. Unenouvelle transition $\gamma$ dans le $^{250}$Md a été identifiée et son placement dans le schéma de niveau partielproposé. La décroissance $\alpha$ du $^{258}$Rf a également été observée, suggérant un rapport de branchementplus faible que ce qui avait été mesurée auparavant

Spectroscopy of 257Db at LISE

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