The ATLAS facility has recently seen a number of upgrades, both in terms of the accelerator and the associated instrumentation. The Argonne Gas-Filled Separator, AGFA, represents a new design for such separators that consists of only two magnetic elements allowing for a short ion trajectory from target to focal plane. It can be operated in stand-alone mode or in conjunction with Gammasphere to...
The region of proton-rich nuclei around the N=Z offers a rich testing
ground for various nuclear models. Rapid shape changes have been
observed between from prolate deformation in 76Kr to an oblate ground
state in 72Kr. Based on the comparison with its mirror nucleus 70Se, an
oblate shape is expected for 70Kr. Breaking of isospin symmetry as well
as the proximity to the proton drip line...
The goal of ESSnuSB project is to discover and measure neutrino CP violation using a long-baseline oscillation experiment taking advantage of two recent opportunities. The first is the construction of the European Spallation Source, ESS, in Lund, which is planned to be the world’s most intense proton source.The second is the recently measured large value of the oscillation mixing angle θ13. A...
The region of $\alpha$ decaying nuclei close to $^{100}$Sn offers a unique opportunity to study $\alpha$ decays, where the valence nucleons occupy the same orbitals. This might give a rise to exceptionally high $\alpha$-particle preformation factor, leading to very fast $\alpha$ decay. This kind of enhanced $\alpha$ decay was suggested already in 1965 [1], however, to date there is no...
The recent upgrade to the ISOLDE radioactive beam facility, the HIE-ISOLDE project, opens new possibilities for studies of exotic nuclei. At the current stage HIE-ISOLDE can provide up to 8MeV/A post-accelerated radioactive beam, and will reach 10MeV/A in the summer of 2018. Combined with ISOLDE’s high purity and intensity beams, we can take on the challenge of studying light nuclei near the...
In this talk we will discuss Studies of the Atomic Nuclei performed by the Madrid-Arhus-Göteborg (MAGISOL)-collaboration at the CERN-ISOLDE facility.
The MAGISOL installations at the ISOLDE Decay station and at the XT03 beam line of HIE-ISOLDE are described. In continuation a discussion on resent experiments; IS633 on the Electron capture of 8B into highly excited states in 8Be, and IS561 on...
Despite a century of the finest theoretical and experimental efforts, we still lack a precise, accurate, and systematic description of the strong interaction between protons and neutrons. In this talk I will present some of the recent developments and future perspectives towards a predictive theory for atomic nuclei. I will focus on the effects of including the delta baryon in a chiral...
Exploring nuclei far away from the valley of stability on the drip lines is one of the main topics at the forefront of current nuclear physics research. Fundamental properties and structure of these so-called neutron-rich, exotic nuclei provide the necessary ingredients to the physics of the unknown “terra incognita” region. Both theoretical and experimental discoveries near the drip lines...
In this contribution we will discuss the observation of the previously unknown isotope $^{72}$Rb, with 14 observed events in BigRIPS and the ZeroDegree spectrometer during the EURICA campaign at RIKEN [1]. For context, the role of the neighbouring nuclei $^{72}$Kr and $^{73}$Rb will be discussed in their role as a waiting point in x-ray burst rp-process scenarios. The nonobservation of the...
Studies of close-to-magic nuclei are of fundamental importance for our understanding of nuclear structure. In addition, the properties of N=126 semi-magic nuclei are important in predicting the abundances of elements in the A~195 r-process peak [1].
Neutron-rich nuclei around $^{208}$Pb can be populated in fragmentation and deep-inelastic (multi-nucleon transfer) reactions, with dedicated...
JYFLTRAP is a double Penning trap setup in the accelerator laboratory of University of Jyväskylä dedicated primarily for atomic mass measurements of exotic ions and for providing clean samples of ions for decay spectroscopy studies. The setup has been operational for more than a decade utilizing time-of-flight ion-cyclotron resonance (TOF-ICR) technique for atomic mass measurements and various...
JYFLTRAP is a cylindrical double Penning trap mass spectrometer [1] located at the Ion Guide Isotope Separator On-Line (IGISOL) [2] facility in Jyväskylä. In total, over 330 atomic masses for nuclear structure, fundamental physics and nuclear astrophysics have been measured with JYFLTRAP. In this contribution, I will discuss our recent results for nuclear structure and astrophysics.
On the...
The double Penning-trap mass spectrometer JYFLTRAP [1] at IGISOL [2] has been recently used to measure the masses of neutron-rich Fe, Co, Ni, Cu, and Zn isotopes. The masses of these nuclei close to the Z=28 and N=50 closed shells are relevant for understanding the nuclear structure far from stability but also for the studies of core-collapse supernovae. Electron captures play a key role...
Measurements of proton decay from nuclei near or beyond the proton dripline have been widely used in recent works to shed light on otherwise inaccessible nuclear structure information, such as mother and daughter state spin assignments. There is a high sensitivity relationship between the proton decay energy (Q$_P$) and the partial proton decay half-life, and measurements of these quantities...
Improved independent fission yields will enhance our understandig of the fission process. The mass and charge distribution contain valuable information on the scission configuration and the nuclear potential-energy landscape.
To this end, a Be(p,xn)-neutron converter target and a dedicated ion guide for neutron induced fission reactions has been developed for the IGISOL-4 facility at the...
The response of the atomic nucleus to external stimulation provides crucial information about its structure and the complex forces acting between constituent nucleons. To access these excited modes, within the framework of superfluid nuclear density functional theory, linear response theory, that is, the quasiparticle random-phase-approximation, (QRPA) is one of the commonly used method....
One of the major issues in modern astrophysics concerns the analysis and understanding of the present composition of the Universe and its various constituting
objects. Nucleosynthesis models aim to explain the origin of the different nuclei observed in nature by identifying the possible processes able to synthesize them. Though the origin of most of the nuclides lighter than iron through the...
Photonuclear cross sections are important to both practical applications and astrophysics in addition to being interesting in their own right from a nuclear structure point of view. Despite this, existing data taken at different laboratories are discrepant and some important cross sections have not been studied at all or are considered unreliable. The Phoenix Collaboration aims at providing...
Over the last 7 years researchers from the University of Oslo and iThemba LABS have continued to increase collaboration to advance scientific knowledge and student education through cooperation in nuclear physics research. The institutes have effectively utilized the experimental facilities and associated equipment on both sides and have co-ordinated research efforts in experimental nuclear...
High-resolution optical measurements of the atomic level structure readily yield fundamental and model-independent data on nuclear ground and isomeric states, namely changes in the size and shape of the nucleus, as well as the nuclear spin and electromagnetic moments [1]. Laser spectroscopy combined with on-line isotope separators and novel ion manipulation techniques provides the only...
Transition strengths in the Ni isotopes between N=40 and N=50 have been recently subject of
extensive experimental and theoretical investigations [1-6], aiming to understand whether the
tensor force acts to reduce the Z=28 shell closure as the neutron g 9/2 orbit is filled towards 78 Ni.
The effect of the Z=28 shell gap quenching and its evolution from 68 Ni towards 78 Ni would be
reflected as...
Over the last few years, a programme of research performed at the University of Jyvaskyla, Finland has established the first measurements of the nuclear state lifetimes built above proton emitting states [1-5]. Lifetimes have been deduced in several nuclei; 109I [1], 151Lu [2,3] and 113Cs [4] for the first time using a specially constructed Differential Plunger for Unbound Nuclear States...
In a collabortation between Centre de Sciences Nucléaires et de
Sciences de la Matière (CSNSM) and Institut de physique nucléaire
d'orsay (IPNO) a so-called Plunger device used for Recoil Distance
Doppler Shift measurements and Time Differential Recoil-in-Vacuum
measurements for g-factor measurements has been developed.
I will present the device, in the forefront of the transition from...
In-beam $\gamma$-ray measurement of Pb-184
Joonas Ojala
University of Jyväskylä
joonas.k.ojala@jyu.fi
The excited states in Pb-184 were first observed at Accelerator Laboratory of the University of Jyväskylä in in-beam gamma-ray experiment using the recoil-decay tagging technique by Cocks et al. [1]. They assigned transitions belonging to a...
The Super-FRS separator-spectrometer to be built at FAIR will be able to unambiguously separate and identify all beams from p to U. The identification will be dome using the $\Delta E-B\rho-TOF$ method. Finland will provide detectors that will be used to provide data for beam identification in event-by-event mode. The tracking detectors will be constructed to provide the $B\rho$ information...
Studies of nuclear orbitals migration in exotic isotopes far from stability is a great challenge for modern nuclear physics. Commonly a few experiments are needed to get the necessary information about single-particle states which later can be used for the nuclear orbitals mapping. However, the same information can be collected by performing one experiment where identification of spins and...
Prompt fission neutrons carry valuable information on how excitation energy is shared between fragments in nuclear fission. Precise measurements on the neutron multiplicity are needed both as a function of fragment mass and excitation energy, as data are rather scarce. In this work we present two complementary experimental setups to measure prompt fission-neutrons, at different excitation...
Despite long efforts on experimental and theoretical studies of nuclear reactions, it is still not possible to predict the cross sections of most reactions from the first principles, and therefore accurate measurements are still necessary in order to improve evaluated nuclear data files and to benchmark nuclear model codes. In particular, studies of neutron-induced reactions in medium-energy...
The interplay between single-particle and collective degrees of freedom in $^{251}$Fm was investigated using combined internal conversion electron (ICE) and $\gamma$-ray spectroscopy. Excited states in $^{251}$Fm were populated via the $\alpha$-decay of $^{255}$No produced in the fusion-evaporation reactions: $^{208}$Pb($^{48}$Ca, 1n)$^{255}$No and $^{209}$Bi($^{48}$Ca, 2n)$^{255}$Lr. The...
The future of nuclear medicine would appear to be the paradigm of personalized medicine — targeted radionuclide therapy to spare healthy tissue, and theranostic medicine, which pairs an imaging isotope with a therapeutic isotope to provide simultaneous, real-time dose delivery and verification, leading to drastic reductions in prescribed patient dose. Candidate isotopes to meet these needs...
The study of targeted porous nanoparticles as drug carriers is a growing field in cancer-therapy research. The porosity of the particle enables anticancer drugs to be loaded inside the particle and its surface can be modified to include tumour targeting properties. The nanoparticles are then injected into the blood stream and through the properties of the carrier nanoparticles the anticancer...
Particle therapy uses proton or $^{12}\mathrm{C}$ beams for the treatment of deep-seated solid tumours. Due to the features of energy deposition of charged particles a small amount of dose is released to the healthy tissue in the beam entrance region, while the maximum of the dose is released to the tumour at the end of the beam range, in the Bragg peak region. Dose deposition is dominated by...
In order to carry out work in the nuclear sector in a cost effective way, while keeping risks ALARA, it is necessary to perform calculations of dose rates in areas where workers will be present, and it is important to choose the right tool for each job. The dependence of this choice upon the type of radiation, material, and geometry is obvious. Of at least equal importance, however, are...
We report the first detection of the second-forbidden, non-unique,
$2^+\rightarrow 0^+$, ground-state transition in the beta decay of $^{20}$F.
A low-energy, mass-separated $^{20}$F beam produced at the IGISOL
facility in Jyväskylä, Finland, was implanted in a thin carbon foil and the
beta spectrum measured using a magnetic transporter and a plastic-scintillator
detector. The log-ft value...
Light nuclei has received new interest with the advent of ab-initio calculations.
In order to test these calculations we need detailed experimental knowledge for comparison.
A prime test candidate is 8Be as it has both a-cluster and single particle states that interfere.
The 8Be system can be populated using the 7Li(p,g)8Be reaction which has a resonance with a branching ration of ~1‰ at...
The recent measurement of the Neutron Star Merger event by LIGO [1] and subsequent optical measurements have revealed that Neutron star mergers are probably one of the primary sites for the r-process of nucleosynthesis [2]. An important source of uncertainty in the r-process models is the nuclear data input [3], especially important is the neutron capture cross-section which is directly...
The MONSTER (MOdular Neutron SpectromeTER) is a time-of-flight (TOF) spectrometer based on scintillation detectors [1,2]. It is originally intended as a research instrument for DESPEC, in the Low Energy Branch of the Super-FRS recoil separator in FAIR, to be utilized in the beta-delayed neutron emission studies far from the beta stability line. The modularity of the detector array...
One of the many open questions regarding fission is the origin of the angular momentum of the primary fission fragments. Although it is well established that they carry considerable amount of angular momentum, there are competing theories on how this is generated. It is thus desirable to obtain information on the angular momenta of the fragments as it can provide insights on the properties of...
The steady progress over the past twenty years in the development of beams of radioactive isotopes has allowed to vastly expand the objectives of experimental nuclear research. It is becoming possible to study in the laboratory a range of nuclear reactions that take place in exploding stars providing crucial information to understand how the chemical elements that we find on Earth were formed....
Neutron-capture reactions on very neutron-rich nuclei are essential for heavy-element nucleosynthesis through the rapid neutron-capture process, now shown to take place in neutron-star merger events. For these exotic nuclei, radiative neutron capture is sensitive to their $\gamma$-emission probability at low $\gamma$ energies.
In this talk, we present measurements of the $\gamma$-decay...
Accurate predictive models of neutron capture cross sections are key to understanding cosmogenic nucleosynthesis, fundamental nuclear physics, and nuclear stockpile security. For several decades, the "Oslo Method" has been used to determine gamma-ray strength functions and nuclear level densities, important input parameters to such models. This method has traditionally been limited to the...
A project to increase the γ-ray detection efficiency of the iThemba LABS setup was recently funded by the South African National Research Foundation (NRF). This project will result in the acquisition and installation of the γ-ray detector array ALBA (African LaBr Array), composed of 23 large volume LaBr3:Ce. The array could be used as a stand-alone gamma-ray spectrometer as well as coupled to...
Photonuclear reaction cross sections are well described by the Brink-Axel hypothesis and are widely used to describe the E1 "photon strength" above the neutron separation energy. The Oslo Method has been developed to unfold total "photon strength" below the neutron separation energy. Although both methods are commonly assumed to derive "photon strengths", they actually derive the product of...
John L. Wood,
School of Physics, Georgia Institute of Technology, Atlanta, Ga 30332-0430, USA
Particle-core coupling is an essential concept in the organization of nuclear data.
All odd and odd-odd nuclei demand such a concept, and broken-pair states in all nuclei require it. Models such as the particle-vibrator (weak-coupling) model and the particle-rotor (strong-coupling) model have been...
Several recent forums have highlighted the need for a new fission product yield (FPY) evaluation for a wide variety of applied nuclear science and engineering applications. However, since most measurements of FPYs are made through the observation of decay radiations, any new FPY evaluation requires an integral validation which convolves both FPY and the relevant decay data. FIER is a software...
An significant the upgrade of the Dubna Radiactive Ion Beams facility is the replacement of the ACCULINNA fragment separator with a new high acceptance device - the ACCULINNA-2. The project of a new in-flight facility for low energy $30-60$ AMeV primary beams with $3 ≤ Z ≤ 36$ has been started in 2011. The new device is destined to add considerably to the studies of drip-line nuclei performed...
In this experiment we use the stacked foil activation technique to measure cross sections for the $^{nat}$La(p,x) reaction, with proton energies in the 35-60 MeV range. The primary motivation for this measurement is to quantify the production of $^{134}$Ce, a positron-emitting analogue of the medical isotope $^{225}$Ac, which has applications for kinetic bio-distribution assays of new...
This talk will present a number of high precision results on matrix
elements of quark bilinear operators between nucleon states using
lattice QCD. From these, we extract a number of exciting quantities,
at the intersection of nuclear and particle physics. We show that the
axial charge $g_A$, a fundamental parameter encapsulating the weak
interaction of nucleons, is calculated with a few...
The influence of relativistic effects on the stability of three-body systems is of great interest.
From a general point of view, understanding the interaction in terms of the fundamental degrees of freedom is very important for nuclear and particle non-perturbative physics. Since that is a very difficult problem, simple models are of great value for understanding the crucial qualitative...
Abstract—Gamma-ray astronomy is the study of astronomical objects using the most energetic form of electromagnetic radiation, gamma-rays. Some of the most violent phenomena in the cosmos emit gamma-rays. This study deals with the detection of high-energy gamma-ray showers using ground-based telescopes. These gamma-rays, upon reaching the Earth’s atmosphere create a cascade of particles,...
