ISOLDE Workshop and Users meeting 2014 "50th Anniversary Edition"

15 Dec 2014, 09:00 → 17 Dec 2014, 14:00 Europe/Zurich

503/1-001 - Council Chamber (CERN)

Maria Jose Garcia Borge (CERN)

This workshop aims to bring together the present and prospective ISOLDE user community to review the status of the ISOLDE experimental programme and to discuss future plans and ideas. This year the event will include a special session to celebrate the 50th anniversary of the approval of ISOLDE. This event is partially supported by the EU funded project ENSAR.

Slides Welcome_ISOLDE_Workshop.pdf Welcome_ISOLDE_Workshop.pptx

Monday 15 December

Facilities

Convener: Lutz Schweikhard

1 Welcome

Speaker: Maria Jose Garcia Borge (CERN)

Slides Welcome_ISOLDE_Workshop.pdf Welcome_ISOLDE_Workshop.pptx

2 Mass spectrometry and decay spectroscopy at CARIBU

A new facility for the production of short-lived neutron-rich isotopes, CARIBU, is now operational at Argonne National Laboratory. CARIBU, the Californium Rare Ion Breeder Upgrade (CARIBU) of the ATLAS superconducting linac facility, provides low energy and reaccelerated neutron-rich radioactive beams to address key nuclear physics and astrophysics questions. These beams are obtained from fission fragments of a 252Cf source, thermalized and collected into a low-energy particle beam by a large helium gas catcher, mass analyzed by an isobar separator, and charge bred to higher charge states for acceleration in ATLAS. The approach employed at CARIBU is fast and universal and short-lived isotopes are extracted with a yield essentially following the Californium fission distribution. Over 110 neutron-rich species have been extracted and used for experiments so far. The facility will be described and results from measurements at low energy and with reaccelerated beams will be given. This work was supported by the US DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357.

Speaker: Prof. Guy Savard (Argonne National Laboratory and University of Chicago)

3 Laser and mass spectroscopy at SLOWRI of RIKEN RIBF

A universal stopped and low-energy RI-beam facility (SLOWRI) [1] is finally being installed at RIKEN RIBF. It will convert relativistic RI-beams from the inflight separator BigRIPS to low-energy, low-emittance, high-purity RI beams using two different gas catcher cells: RF-carpet gas cell and PALIS gas cell [2, 3]. The former is a 1.5-m long cell filled with 100 mbar He gas and operated at 77 K cryogenic temperature. It will be placed at the exit of D4 magnet of BigRIPS to accept main beams from BigRIPS. The thermal ions in the large cell can be transported quickly toward the exit by a large RF-carpet [4, 5] with the ion-surfing method [6, 7, 8]. The latter cell will be placed in the vicinity of F2 focal plane of BigRIPS where unused RI-beams were simply abandoned. The cell is 30 cm long and filled with 1 bar Ar gas in which most thermal ions quickly become neutral. The neutral RI atoms can be transported by a gas flow toward the exit where resonant laser radiations re-ionize the atoms selectively. This gas cell will be used concurrently with the other BigRIPS experiments so that parasitic low-energy experiments can be carried out everyday. The extracted RI-beams from the gas cells will be mass separated by dipole magnets at 30 keV and the beams will be merged into a single beam line leading to the experimental room where various precision spectrometers such as a multi-reflection time-of-flight mass spectrograph [9, 10, 11], ion traps [12, 13] and a collinear laser spectroscopy apparatus will be placed and users can access the room without any restrictions. Many experiments and tuning the spectrometers can be conducted daily using the parasitic beam; the main beam will be required only when very rare isotopes are studied. At SLOWRI, various precision spectroscopy experiments will be performed. One is laser spectroscopy for the electromagnetic ground state properties of exotic nuclei, especially for so called ‘difficult’ elements which are not available at originally ISOL facilities. The other is precision mass measurements with the MRTOF mass spectrograph. It will be able to determine multiple nuclei simultaneously when directly coupled with gas catcher at BigRIPS. [1] M. Wada et al., Hyp. Int. 199 (2011) 269. [2] T. Sonoda et al. APS Conf. Proc. 1104 (2009) 132. [3] T. Sonoda et al., Nucl. Instr. Meth. B295 (2013) 1. [4] M. Wada et al., Nucl. Instr. Meth. B204 (2003) 570. [5] A. Takamine et al., Rev. Sci. Inst. 76 (2005) 103503. [6] G. Bollen, Int. J. Mass Spectrom. 299 (2011) 131. [7] M. Brodeur et al., Int. J. Mass Spectrom. 336 (2013) 53. [8] F. Arai et al., Int. J. Mass. Spectrom. 362 (2014) 56. [9] Y. Ito et al., Phys. Rev. C 88 (2013) 011306(R). [10] P. Schury et al., Int. J. Mass. Spectrom. (2013) DOI:10.1016/j.ijms.2013.11.005. [11] P. Schury et al., Nucl. Instr. Meth. B335 (2014) 39.

Speaker: Michiharu Wada (RIKEN)

Slides Michiharu_Wada.pdf

4 Facility for Rare Isotope Beams under Construction

FRIB, the US’s “Facility for Rare Isotope Beams” at Michigan State University (MSU), will be based on a 400 kW, 200 MeV/u heavy ion linear accelerator. Once realized, FRIB will be a world-leading rare isotope beam facility, providing a wide variety of high-quality beams of unstable isotopes at unprecedented intensities, opening exciting research perspectives with fast, stopped, and reaccelerated beams. NSCL, the present premier rare isotope beam user facility in the US, enables pre-FRIB science and will eventually be integrated into FRIB. This talk will review present the FRIB facility and its science opportunities, and summarize the status of the project for which construction has started.

Speaker: Georg Bollen (Michigan State University)

Slides _Bollen_ISOLDE_WS14_FRIB-3b.pdf _Bollen_ISOLDE_WS14_FRIB-3b.pptx

5 Status and highlights from ISAC/TRIUMF

The ISAC facility at TRIUMF with its ISOL-based radioactive beam operation with up to 50kW production targets offers some unique research capabilities to its 18 permanently installed (and 3 general purpose experimental stations) experiments. ISAC has been operational for over 15 years and its experimental program includes nuclear structure studies, electroweak-precision studies, nuclear astrophysics, and material science. It has a low-energy (60keV) medium-energy (up to 1.8 MeV/u) and high energy (up to 16 MeV/u) experimental area. In addition, TRIUMF is building a new electron-accelerator-based photo—fission ISOL facility, called ARIEL (Advanced Rare IsotopE Laboratory) which will provide two radioactive beams to the experimental areas. A first milestone for ARIEL has recently been reached with the acceleration of electrons to over 20 MeV. In this presentation I will give an overview and show highlights of the ISAC experimental program as well as the ARIEL project.

Speaker: Jens Dilling (triumf/UBC)

10:50 Coffee Break

Applications

Convener: Prof. Klaus Wendt (University of Mainz)

6 Medical Isotope Production and Use, with a special view on the need for ISOLDE and other big science facilities

Medical use of radioactive isotopes for diagnosis and therapy is a widespread and commonly accepted application of radioactivity. It has historical roots back to Curie, Hevesy and Lawrence, and while the principles are the same as a 100 years ago, the number of applications, their sophistication and precision, and not least the clinical benefits are growing each day. Although “new” isotopes are being introduced to medicine each year, by far the most procedures are carried out using just a dozen of well known and trivial radioisotopes, either derived from fission of uranium in reactors or from simple compound nuclear reactions in small to medium energy accelerators. As the talk will explain some of the large scale infrastructure necessary for continuous growth of nuclear medicine is now under attack, as is the case with the aging research reactors used for Mo-99 and I-131 production. New facilities and new technologies can fill in the gap, if conceived, funded and build in time, but decisions and foresight is needed now. Big Science facilities do not easily fit into such demanding routine production commitments, but they may very well help demonstrate and develop the technology needed. Production of neutrons by spallation and extraction of isotopes from spallation targets are good examples. There are also cases of some isotopes with special imaging or therapy applications, where spallation and isotope separation is the only road to get them, and these examples will be discussed. However, big science involvement is not the ultimate answer to the needs of nuclear medicine. A recent and very interesting development is the global dissemination of hundreds of small medical cyclotrons, initially intended only for PET, but each also capable of making other isotopes than F-18 and C-11. Even therapeutic applications are conceivable with this “cottage industry“ platform. It has the benefit of flexibility, multiplicity, quick reaction time and very simple distribution logistics,- and in this way much more failure-resistant. Perhaps it can even be characterised as “sustainable”. With further development of chemistry and automation, it may well change and improve the future use of nuclear medicine imaging. The talk will try to use past and present experience to predict the future role and the future gaps in medical use of radioactive isotopes.

Speaker: Prof. Mikael Jensen (DTU-NUTECH, Technical University of Denmark)

Slides Medical_Isotopes_Isolde_Jensen.pdf Medical_Isotopes_Isolde_Jensen.pptx

7 Development of a networked and modular personal dosimetry system

We will describe the development of a personal radiation level monitoring system based on an autonomous, advanced dosimeter, which takes advantage of a scintillator-SiPM combination and integrates isotope identification capabilities. The measurements are time and position stamped, including indoor locations. The device implements Wireless Sensor Networks access in such a way that several networked personal dosimeters can be addressed as mobile sensors providing a high sampling rate over an extended area. The dosimetry system is modular, including three main elements: the Personal Dosimeters themselves, a Wireless Gateway deployment and a Central System, which is a web-based remote storage, monitoring and management system.

Speaker: Luis Mario Fraile (Universidad Complutense de Madrid)

Slides fraile_dosimeter_ISOLDE_WS.pdf

8 Beta-delayed particle emission from $^{21}$Mg

The beta-decay of the proton rich nuclei $^{21}$Mg was used as a calibration source for the IS507 experiment. The aim of the experiment was to study the beta-decay of $^{20}$Mg with a dedicated charged particle detection setup consisting of two opposing $\Delta$E-E telescopes. As $^{21}$Mg is close in mass to $^{20}$Mg and is a known beta-delayed proton emitter, with intense proton branches, it is suitable for energy calibrations. A closer look at the data reveals new decay channels not previously seen in the decay of $^{21}$Mg. Clear signs of beta-delayed alpha emission and new beta-delayed proton channels were evident. A detailed investigation of the alpha spectrum has led to the conclusion that four beta-delayed alpha branches are measured, $^{21}$Mg($\beta$)$^{21}$Na($\alpha$)$^{17}$F, going through high-lying resonances in $^{21}$Na. Coincidences between the two opposing $\Delta$E-E telescopes have led to the conclusion that a weak decay channel via the decay chain $^{21}$Mg($\beta$)$^{21}$Na(p)$^{20}$Ne($\alpha$)$^{16}$O is also seen for the first time. The proton spectrum measured gives rise to a new interpretation of the decay scheme. Due to the use of a DSSSD detector beta summing is reduced to a negligible level. Together with recent measurements of elastic scattering of protons on $^{20}$Ne this has led to a new tentative interpretation of the decay scheme. Confirmation of this new interpretation would be possible in the remaining beam time at the new ISOLDE Decay Station, where detection of coincident gamma rays is possible.

Speaker: Morten Vinther Lund (Aarhus University (DK))

Slides ISOLDE_workshop_MortenLund.pdf

9 In Gas Laser Ionization and Spectroscopy of neutron deficient 212-215Ac isotopes

The In-Gas Laser Ionization and Spectroscopy (IGLIS) technique was employed at the LISOL facility to produce radioactive beams of high purity and obtain important information on the nuclear ground- and excited-state properties of, e.g., neutron deficient copper [1] and silver [2]isotopes. Recent experiments on the actinide region have allowed us to efficiently produce beams of neutron deficient actinium isotopes from $^{212}$Ac to $^{215}$Ac, in the N=126 shell closure, and perform detailed in-gas-cell laser spectroscopy of the $^2$D$_{3/2}\rightarrow ^4$P$_{5/2}$transition at 438 nm with a relative spectral resolution $\delta\nu/\nu$=1$\cdot$10$^{-5}$. Unlike in-gas cell laser spectroscopy studies, laser ionization in the low-temperature and low-density gas jet allows eliminating the pressure broadening thus improving the spectral resolution by, at least, one order of magnitude ($\delta\nu/\nu$=5$\cdot$10$^{-7}$), as recently demonstrated in off-line experiments on the stable copper isotopes [3]. In the HELIOS laboratory, being commissioned at KU Leuven, the formation of supersonic gas jets using a de Laval nozzle will be investigated in off-line experiments in parallel to tests of a new gas cell design and the characterization of a new high-power high-repetition pulse rate laser system. Visualization of the jets by planar laser induced fluorescence will be carried out to determine the best experimental conditions to perform laser spectroscopy with an enhanced resolution in the new radioactive beam facility S$^3$ at SPIRAL2 [4]. Results on the isotope shifts and the magnetic moments of the actinium isotopes will be reported in this talk and a summary on the experimental activities to optimize the IGLIS technique at the offline HELIOS laboratory will be presented. [1] T. E. Cocolios et al., Phys. Rev. Lett. 103 (2009) 102501., [2] R. Ferrer et al. Phys. Lett. B 728 (2014) 191., [3] Yu. Kudryavtsev et al., Nucl. Instr. Methods B 297 (2013) 7., [4] R. Ferrer et al. Nucl. Instr. Meth. B 317 (2013) 570.

Speaker: Rafael Ferrer Garcia (KU Leuven (BE))

Slides ISOLDE2014_RFerrer.pptx

12:45 Lunch Break

Technical Session

Convener: Mats Lindroos

10 Developments for the ISOLDE resonance ionization laser ion source RILIS

The long shutdown (LS1) provided an opportunity for ionization scheme and ion source development for the ISOLDE resonance ionization laser ion source (RILIS), in addition to several upgrades to the general RILIS set up. Several of these results will be presented along with a summary of the current RILIS status. New RILIS ionization schemes have been successfully developed and tested for Ba, Li, Ge, Hg, and Cr. What is believed to be the world’s first resonance ion-ionization in a hot cavity was demonstrated, creating Ba2+ to meet a specific need to eliminate the problem of a surface ionized isobaric background from beams of 112-118Ba. The first demonstration of resonance laser ionization inside the VADIS, ISOLDE’s FEBIAD type ion source, was demonstrated off-line with gallium. This RILIS Mode operation of the VADIS cavity was then successfully applied on-line, coupling a molten Pb target with RILIS for the first time, to produce laser-ionized beams of neutron-deficient mercury isotopes[1]. [1] Gaffney (2014) https://cds.cern.ch/record/1953719

Speaker: Thomas Day Goodacre (CERN)

Slides ISOLDE_workshop_2014_EN_TDG.pdf ISOLDE_workshop_2014_EN_TDG.pptx

11 The ISOLDE robot upgrade

During the LS1 a major safety upgrade was held at ISOLDE, the complete robotic system for the target exchange has been replaced. This upgrade was done in order to improve the operation and the safety of the facility. This presentation will explain the different phases of the project from the idea of upgrading the system to it final operation and although the future evolution of the system.

Speaker: Jean-Louis Grenard (CERN)

Slides

• CERN_60ans_movie.mp4
• The_ISOLDE_robots_upgrade_ISOLDE_WS_15-12-2014.pdf
• The_ISOLDE_robots_upgrade_ISOLDE_WS_15-12-2014.pptx

12 The TWINEBIS test bench

For more than a decennium REX-ISOLDE has been a key element at the ISOLDE radioactive beam facility. The post-accelerator consists of a Penning trap for bunching and cooling of the 1+ ions delivered from ISOLDE, an EBIS for charge breeding and a LINAC for the actual acceleration. It has delivered over 100 different radioactive radionuclides with an energy of a few MeV/u. While successful, the high beam demand has not allowed for intrusive machine studies to be carried out at the REX facility. In the case of the EBIS, several issues could not be investigated with the required thoroughness, for instance cathode poisoning and electron current limitations. Neither could time-modulation of the extracted ion pulse in order to match the very short injection time of the suggested TSR@ISOLDE setup, or long uniform extraction time for fixed target experiments that are presently affected by dead-time effects in detectors and/or data-acquisition systems be explored properly. Furthermore we would like to test a different type of cathode material, IrCe, which is used at other laboratories. Here the interest lies in the extractable electron current and the cathode lifetime as compared to the routinely used LaB6. Therefore, during the last few years a dedicated offline EBIS test bench, TwinEBIS, has been setup at CERN. The EBIS is a copy of the REXEBIS, although with minor modifications in the drift-tube structure, a more versatile control system and with no injection presently available. The TWINEBIS setup has been commissioned and several investigations have begun. In this contribution an overview of the setup and the first results will be given. By end of October we will embark on TWINEBIS - phase 2. It includes the move of the system to a more spacious laboratory area, which allows adding an injection ion-source and an analysis magnet to investigate charge breeding times for different elements as function of different settings of the EBIS, for example electron current and density, magnetic field etc. The layout of the new test facility will also be presented.

Speaker: Martin Breitenfeldt (Universidad Complutense (ES))

Slides 2014-12-15_ISOLDE_WS_Breitenfeldt.pdf 2014-12-15_ISOLDE_WS_Breitenfeldt.pptx

13 Development progress of a charge breeder for HIE-ISOLDE and TSR@ISOLDE

As part of the HIE-ISOLDE design study options for a new high-performance successor to the REXEBIS charge breeder have been investigated. In a parametric study based on the HIE-ISOLDE linac upgrade, and a possible future extension of HIE-ISOLDE by TSR@ISOLDE, a set of design requirements for the new breeder was elaborated. In collaboration with the Advanced Ion Sources group at Brookhaven National Lab a research program was initiated. Based on a BNL design a high-compression electron gun was built at CERN and shipped to BNL, commissioned, tested and brought to operation on the full scale TestEBIS. The electron beam was extracted from the gun, guided to the full compression region, transported through the ionization region, which has a comparable length to a HIE-ISOLDE breeder, and efficiently absorbed in the collector. The beam was transmitted in a magnetic field strength up to 3.3 T over about 4 meters distance. In these experiments we achieved electron currents up to 1.7 A and the electron energy was approximately 35 keV. This is a significant step towards the full HIE-ISOLDE charge breeder specifications of 3.5 A and 60 keV (up to 150 keV for TSR@ISOLDE). We have identified potential sources of a 20 mA loss current limiting the transmitted current to 1.7 A. At the moment, a series of design modifications is on the way to address and mitigate the limiting loss. In a series of preliminary experiments the electron beam was used to ionize residual gas in the unbaked EBIS vacuum chamber. During the autumn of 2014 the experimental research is continued. At BNL an upgraded electron gun with enhanced optics is under preparation. At CERN we are building diagnostics tools to analyze the charge-state distribution, energy distribution and emittance of the charge bred ions during the commissioning. Furthermore we continue the design studies by addressing the required modifications in order to allow changing the electron collector optics from immersed flow electron-beams with 20-25% duty cycle to high compression beams of near 100% duty cycle. In this presentation we would like to give a summary of the R&D on the upgrade of the HIE-ISOLDE charge breeder. We will present a revised parametric study, recent experimental results, experimental plans for the nearest future and the longer development perspective.

Speaker: Andrey Shornikov (CERN)

Slides Shornikov_IW_2014_3.pdf Shornikov_IW_2014_3.pptx

14 LIEBE: Design of a molten metal target based on a Pb-Bi loop at CERN-ISOLDE

Future perspective for physics measurements at CERN-ISOLDE call for the use of molten metal targets to improve the yield of radioactive isotopes delivered to the experiments and better handle the high power density from the beam. CERN launched in 2012 an R&D project called LIEBE to investigate the feasibility of testing on line a Pb/Bi loop target compatible with the present installations at ISOLDE. While ISOLDE will be able to deliver a maximum of 10 kW of beam power, the power density on target is comparable to those available in existing or future facilities as EURISOL. The design of the loop has been performed in collaboration with SCK-CEN, CEA, PSI, IPOOL and the prototyping phase has now started. The design of this target includes key components that never been integrated in an Isolde target before such as a heat exchanger to evacuate the high power deposited by the beam and an electromagnetic pump to ensure the circulation of the liquid metal. In the same time, the designs proposed for the irradiation and diffusion chambers have been optimized to allow a faster release of the produced isotopes. All these elements need to be extensively tested before the on-line installation of the target and the prototyping phase has now started. This talk focuses on the development of the element of the liquid metal loop target, presenting the challenges due to the different constraints involved and developing the proposed target design. Finally, an overview of the results of preliminary tests will be presented while future prototypes and tests will be introduced.

Speaker: Melanie Delonca (Universite de Technologie de Belfort-Montbeliard (FR))

Slides IsoldeWS-Deloncav02.pdf IsoldeWS-Deloncav02.pptx

15 CATHI and the HIE-ISOLDE Design Study

Financed by the European Commission within the Marie Curie Actions-ITN program, the CATHI (Cryogenics, Accelerators and Targets for Hie-ISOLDE) was launched in 2010 with the recruitment of 20 researchers; 11 of whom completed their training while working on different aspects of the HIE-ISOLDE Design Study. As the project terminates in 2014, their work will be collected in a final report that will provide a baseline for the upgrade of both the ISOLDE facility in order to accommodate a potential increase in proton-beam power and an improvement of beam quality through a new layout of the High Resolution Mass Spectrometer. This presentation will highlight the achievements of the CATHI Fellows and will attempt to project future changes of the facility necessary to implement improvements identified in the HIE-Design Study.

Speaker: Richard Catherall (CERN)

Slides CATHI_and_the_Design_Study.pptx

15:30 Coffee Break

Ground-State Properties

Convener: Andreyev Andreev (University of York (GB))

16 Nuclear Structure Theory: today and tomorrow

The long-term vision of nuclear theory is to arrive at a comprehensive and unified description of nuclei and their reactions, grounded in the interactions between the constituent nucleons. Theorists seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. A new and exciting focus in this endeavor lies in the description of exotic and short-lived nuclei at the limits of proton-to-neutron asymmetry, mass, and charge. In this talk, theoretical advances in rare isotope research will be reviewed in the context of the main scientific questions. Particular attention will bo given to the progress in theoretical studies of nuclei due to the advent of extreme-scale computing platforms.

Speaker: Witold Nazarewicz (Michigan State University)

Slides Nazarewicz.pdf Nazarewicz.pptx

17 Structure of Potassium and Calcium isotopes studied by Collinear Laser Spectroscopy

We have investigated the ground state structure of K and Ca over a wide range of isotopes, from below N=20 across the N=28 shell gap using the bunched-beam collinear laser spectroscopy technique. Thanks to the background reduction using the bunched-beam correlation method and the improved optical detection using a newly-designed detection set-up, experiments could be extended for both K and Ca up to N=32 (51K and 52Ca respectively). From the magnetic moments and spins of the K isotopes, the evolution of the proton single particle levels can be studies as the neutron p3/2 level is being filled [1,2]. The isotope shifts provide information on the change in mean square charge radii across the N=28 shell gap, showing a strong increase towards N=32, both for K and Ca [3,4]. The isomer shift in the N=Z mirror nucleus 38K reveals the importance of proton-neutron pairing correlations in the 0+ isomeric state [5]. The magnetic and quadrupole moments of the 47,49,51Ca ground states provide a stringent test to recent calculations including 3N interactions [6]. Highlights from these experiments will be presented. [1] J. Papuga et al., Phys. Rev. Lett. 110, 172503 (2013) [2] J. Papuga et al., Phys. Rev. C 90, 034321 (2014) [3] K. Kreim et al., Phys. Lett. B 731, 97 (2014) [4] M.L. Bissell et al, to be published [5] M.L. Bissell et al., Phys. Rev. Lett. 113, 052502 (2014) [6] R.F. Garcia Ruiz et al., in preparation.

Speaker: Prof. Gerda Neyens (K.U. Leuven)

Slides Neyens_new.pdf Neyens_new.pptx

18 The CRYRING@ESR project - status and prospects

The CRYRING@ESR project is the early installation of the low-energy storage ring LSR, the Swedish in kind contribution to FAIR, which was proposed as the central decelerator ring for antiprotons at the FLAIR facility. Since the modularized start version of FAIR does not include the erection of the FLAIR building, it was proposed to install the CRYRING storage ring behind the existing experimental storage ring ESR already now. This opens the opportunity to endeavor part of the low energy atomic physics with heavy, highly charged ions as proposed by the SPARC collaboration but also experiments of nuclear physics background in the NUSTAR collaboration much sooner than foreseen in the FAIR general schedule. Furthermore, since the installation of the ring will be handled mostly by FAIR standards, it will be used to test major parts of the FAIR control system for the first time and well ahead of time before it is needed to run SIS100. Rare ions for storage in CRYRING@ESR are produced and separated in the FRS and then stored, cooled and decelerated in the ESR. This imposes a lower life time limit of several ten seconds for ions available for experiments in the storage ring at energies between several 100 keV/nucleon and about 10 MeV/nucleon. A future connection to the Super FRS at FAIR would increase the available yields of rare, heavy and highly charged ions considerably and hence also extend the physics oportunities.

Speaker: Frank HERFURTH (GSI Darmstadt)

Slides Herfurth.pdf Herfurth.pptx

19 High-precision mass measurements of 129-131Cd and their impact on nuclear astrophysics

The high-precision mass spectrometer ISOTLRAP has been pioneering Penning-trap mass measurements of exotic nuclei already since 1987, when it was installed at the ISOLDE 1 facility, connected to CERN’s Synchrocyclotron (SC). After the move of ISOLDE to the Proton Synchrotron Booster (PSB) in 1990, the ISOLTRAP experiment reassumed its successful mass-measurement campaign on short-lived nuclei, which continues until today [1]. During the recent first long shutdown of CERN (LS1), ISOLTRAP has undergone a prolonged maintenance operation, including a full refurbishment of its superconducting magnets. With the restart of physics at ISOLDE in the summer of 2014, ISOLTRAP contributed to a number of experiments. The contribution will briefly report on the work that was performed during LS1 and describe the current status of the setup. The results of the first successful beam times of 2014 will be discussed. One of the highlights is the mass measurement of the r-process waiting-point nuclide 130Cd and of its neighbors 129,131Cd. In addition, ISOLTRAP contributed to the study of the hyperfine structure of astatine isotopes by in-source laser spectroscopy and allowed yield studies of different ISOLDE beams in support of on-going target and ion source developments. References: [1] H.J. Kluge, Int. J. Mass. Spectrom. 349-350 (2013) 26-37

Speaker: Mr Frank Wienholtz (Ernst-Moritz-Arndt-Universitaet (DE))

Slides 2014-12-15_ISOLDE_WS_Wienholtz_1.pptx

Poster Session

Tuesday 16 December

Solid State Physics

Convener: Anthony Peaker

20 Recent highlights and future possibilities in ferromagnetic semiconductors

The epitaxial diluted magnetic semiconductor (Ga,Mn)As is a model system for investigating spin and spin-orbit phenomena in magnetic and semiconducting systems. Studies of this compound have led to the elucidation of new functionalities in experimental spintronic devices, including optical and electrical control of the magnetic order, with general applicability to a wide range of material systems. This talk will review the basic material properties of (Ga,Mn)As and recent progress in understanding its electronic, magnetic and structural properties, including the mechanisms limiting its Curie temperature. Future prospects for new materials, with functionality at elevated temperatures, will be discussed.

Speaker: Kevin Edmonds (urn:Facebook)

Slides Edmonds.pdf Edmonds.pptx

21 Carrier Mobility and Magnetic Interactions in TiO2

Thin films and powder samples of intrinsic and transition metal doped titanium dioxide were investigated by an atomic resolution hyperfine nuclear technique in order to study the relation between defects and ferromagnetism. Complementarily, the crystalline structure, morphology and composition of the samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) characterization techniques. Magnetic properties were further investigated by magnetization measurements using a vibrating sample magnetometer (VSM). Hyperfine parameters were studied as a function of temperature by means of perturbed gamma-gamma angular correlation (PAC) spectroscopy using different probe nuclei 111In/111Cd, 181Hf/181Ta and 111mCd/111Cd. Thin films of 88-100 nm thickness were deposited by magnetic sputtering on Si (100) substrates, inducing the formation of the rutile phase. Doping of the films with Fe and Co was achieved by ion implantation and the powder samples were prepared by the Sol Gel Method. PAC measurements were carried out after implantation of 111In or 181Hf at the BONIS implanter in Bonn University, with and without magnetic field applied and after 111mCd at ISOLDE laboratory. After the initial measurements carried out as implanted, the samples were annealed at 600°C in vacuum or air, which allowed the permanence of defects caused by the implantation process and voluntarily lead to the formation of the Magnéli phases. PAC results show the presence of up to three site fractions for the probe nuclei depending on the heat treatment. One is assigned to the probe nuclei at the substitutional Ti sites and the other two can be assigned to defect sites, either near the doping ions or near shear planes, which gives rise to the observed magnetic interaction on the atomic scale PAC data and on a macroscopic scale magnetometry data. However, the most important result of this work was the correlation between the magnetic interactions and the observed rearrangement of the charges as a function of the temperature for all the three different probe elements nuclei. This means that the recombination of local charge carriers can be associated with the macroscopic observation of the hysteresis curves obtained by magnetometry, an effect that is enhanced with the decrease of the temperature.

Speaker: Mrs Juliana Marques ramos (Instituto de Pesquisas Energéticas e Nucleares / Helmholtz-Institut für Strahlen- und Kernphysik)

Slides ISOLDE2014.pptx

22 Fighting f-factors and implantation damage in emission Mössbauer spectroscopy

The Mössbauer collaboration at ISOLDE/CERN applies short lived isotopes for emission Mössbauer spectroscopy (eMS) within material sciences. Mössbauer spectroscopy (MS) gives various detailed information on the probe atoms, through the hyperfine interactions. There are several benefits of eMS in particular we can perform measurements in the extremely dilute regime (~10$^{-4}$ at. %) and make use of the chemical nature of the parent (implanted) atom. In cases, where we want to study defect physics, the implantation damage is beneficial. In other cases it can impede investigations. Conventionally, we implant/measure at elevated temperatures to monitor the annealing of radiation damage, however, this can hamper the measurement due to the Debye Waller factor (probability of MS transition). In some cases, the interesting material physics are at low temperature, such as magnetic interactions. For the first time since the 1980’s we have applied so-called quenching experiments with short lived isotopes (~minutes), i.e. implantation at elevated temperatures (>300 K), while the measurement is performed at low temperature (77 K). In my presentation I will discuss some of the physics involved in connection with our new proposals. In addition, the data obtained from quenching experiments in the 1980’s will be revisited. Finally some of the new data acquired at the 2014 beam-time will be presented followed by a discussion of future possibilities.

Speaker: Haraldur Gunnlaugsson (Aarhus University)

Slides Gunnlaugsson.pdf Gunnlaugsson.pptx

23 Lattice location and thermal stability of Mn in ferromagnetic (Ga,Mn)As

Mn-doped GaAs, or (Ga,Mn)As, has become the model system in which to explore the physics of carrier-mediated ferromagnetism in semiconductors and the associated spintronic phenomena [1]. In particular, as the most widely studied dilute magnetic semiconductors (DMS), (Ga,Mn)As is an ideal example of how the magnetic behavior of DMS materials is strongly influenced by the lattice sites occupied by the magnetic dopants [1]. We present emission channeling experiments performed at the EC-SLI setup on the lattice location of radioactive ⁵⁶Mn (t_1/2 = 2.56 h) implanted into (Ga,Mn)As thin films. We show that the tetrahedral interstitial site with four As nearest neighbors (T_As) is the energetically favorable site regardless of the interstitial Mn atom being isolated or forming complexes with substitutional Mn. Furthermore, we show that the thermal stability of both substitutional and interstitial Mn, with respect to diffusion and segregation, strongly decreases with increasing Mn concentration (within the several % Mn regime). We discuss the implications of these findings on the understanding of Mn self-compensation in (Ga,Mn)As, and introduce the ongoing emission channeling experiments on the wider class of Mn-doped III-V DMS systems. [1] T. Dietl and H. Ohno, *Rev. Mod. Phys.* **86**, 187 (2014).

Speaker: Mr Tiago Lima (KU Leuven, Instituut voor Kern en Stralingsfysica, 3001 Leuven, Belgium)

Slides Lima.pdf Lima.pptx

10:15 Coffee Break

Coulomb Excitation and Reactions

Convener: silvia leoni (University of Milano and INFN)

24 Direct reactions with exotic nuclei and projects at HIE-ISOLDE

Direct reactions in inverse kinematics at low energies are essential tools to study the shell structure of unstable nuclei. Transfer reactions allow to determine the distribution of the spectroscopic strength, necessary to investigate the shell evolution across the nuclear landscape. Proton-induced elastic and inelastic scattering give access to unique information about collectivity and matter radius. A brief overview of current direct reaction programs with exotic nuclei worldwide will be given as well as the related technical developments. Possible new developments and studies in this field at ISOLDE and HIE-ISOLDE will discussed.

Speaker: Dr Alexandre Obertelli (CEA Saclay)

Slides Obertelli.pdf Obertelli.pptx

25 Shape Coexistence in $^{100}$Zr Studied by Low-energy Coulomb Excitation

The region surrounding the neutron number N = 60 for the Sr and Zr isotopic chains is an interesting example of shape evolution. Starting from the N = 50 closed spherical shell, and removing a few neutrons, the Sr and Zr isotopes become well deformed. On the neutron-rich side of these isotopic chains, N = 56 is observed to become an effective sub-shell closure with $^{96}$Zr exhibiting the properties of a doubly-magic nucleus. However, with the addition of only four more neutrons, $^{100}$Zr is observed to become strongly deformed. This sudden change from a spherical shape to one with large deformation, which is also observed for neighbouring N = 60 isotones such as $^{98}$Sr, has attracted many theoretical and experimental investigations over several decades and is probably the most sudden change from a spherical shape to one with large deformation of known nuclei. A stringent analysis of the nuclear structure and intrinsic shape of the nucleus $^{100}$Zr is, therefore, imperative. In order to shed new light on this phenomenon a Coulomb excitation experiment was performed with the aim of measuring reduced transition probabilities between low-lying excited states and quadrupole moments in order to determine the states’ intrinsic shapes. The $^{100}$Zr beam was provided by the Californium Rare Isotope Breeder Upgrade (CARIBU) system, the only facility able to deliver intense beams of refractory elements such as zirconium. De-excitation $\gamma$-rays were detected with GRETINA detector array with the CHICO2 particle detector array employed for the detection of $^{100}$Zr projectiles and recoiling target nuclei. In this presentation, an overview of the recently performed experiment will be given and initial results presented.

Speaker: Dr Daniel Doherty (CEA Saclay)

Slides ISOLDE_DTD1.pdf

26 Nuclear structure studies of neutron-rich Rb isotopes using Coulomb excitation

The neutron-rich A=100 mass region has recently risen up a high interest of the nuclear structure community. When going from N=58 to N=60, a rapid shape transition occurs from spherical to well deformed ground state shape, similar to what is observed in the rare earths region. This region firstly accessible by fission [1] has been later studied by mass and laser spectroscopy (e.g. [2]), which highlighted the presence of deformation at N~60. According to recent mass [3] and Coulomb excitation [4] measurements, the Kr isotopic chain presents a more gradual evolution of deformation. Since the Rb isotopic chain is placed at the low-Z border of deformation region, it constitutes a good candidate to identify and characterize the mechanisms involved in the development of deformation. Excited states in $^{93,95,97,99}$Rb were populated via low-energy Coulomb excitation. The nuclei of interest were produced at ISOLDE (CERN) using a UCx target. The beam is post-accelerated up to 2.83 MeV/u using REX-ISOLDE and then impinges on a secondary target of $^{60}Ni$ positioned in the centre of the MiniBall array used for particle and gamma-ray detection. Excited states in $^{97,99}$Rb were observed for the first time in this study. Level schemes have been constructed by analysing gamma-gamma matrices, which show a clear rotational character in contrast to what is observed for the spherical-like $^{93,95}$Rb isotopes. It validates the scenario of a rapid shape transition at N=60, which is also confirmed by the transition probabilities extracted from this dataset using the GOSIA code (see abstract of M. Zielinska *et al.*). The particle-rotor model constitutes an appropriated tool to interpret the level scheme as rotational bands. By comparing experimental and theoretical values from a quasi-particle model of the B(M1)/B(E2) ratios and g-factor, a firmed assignment of the $3/2^{+}[431]$ Nilsson orbital as the ground state configuration of the $^{97}$Rb has been determined. [1] S.A.E Johansson *et al.*, Nuclear Physics 64, p. 147-160 (1965) [2] C. Thibault *et al.*, Phys. Rev. C 23, 2720 (1981). [3] S. Naimi *et al.*, Phys. Rev. Lett. 105, 032502, (2010). [4] M. Albers *et al.*, Phys. Rev. Lett. 108, 062701 (2012).

Speaker: Christophe Sotty (KU Leuven (BE))

Slides ISOLDE_Workshop_2014_Christophe_SOTTY_v2.pdf ISOLDE_Workshop_2014_Christophe_SOTTY_v2.pptx

27 In trap polarization of radioactive ion beams

In this contribution we discuss the potentials of a new technique of optical orientation of radioactive ions trapped in an open Paul trap, permitting to reach a very high degree of polarization, for beta decay experiments. More precisely, laser polarization of the alkali-earth ions 23Mg+ and 39Ca+ in a Paul trap and detection of the emitted electron and recoil ion shall enable the measurement of the so-called D correlation. D is a triple correlation of the form <**J**> (**pe** x **pnu**) with pe and pnu being the momenta of the electron and the neutrino, and J the nuclear spin. The D correlation violates Time reversal. While such violation is predicted to occur in the Standard Model via the quark mixing mechanism, experimental constraints are 5 to 10 orders of magnitude lower [1].There is a large window in which D, R correlations and neutron EDM searches can contribute to the search for other sources of CP violation at a much higher level, which could explain for example the large matter-antimatter asymmetry observed in the universe. The best constraints so far on D arise from the neutron decay and are of the order of 2×10-4 on coupling constants of interactions violating T [2]. Lower constraints have been obtained from hyperon, Kaon, and nuclear decays. The latter were derived from the decay of 19Ne yielding a constraint of 6×10-4, limited by statistics [3]. With the expected rates from the upgraded SPIRAL facility at GANIL, an experiment aiming at D-correlation measurement with an unprecedented sensitivity of the order of 10-4 can be conceived. It is envisaged to perform a proof-of-principle of the laser polarization method at ISOLDE, using the COLLAPS laser setup, together with an optimized trapping setup inspired by the one of LPCTrap [4]. [1]: G. Ban et al., Nucl. Phys. A 827, 422c (2009) [2]: J. Beringer et al, (Particle Data Group) Phys. Rev. D 86 (2012) 010001 [3]: F. P. Calaprice, Hyp. Interact. 22 (1985) 83 [4]: G. Ban et al, Ann. Phys. (Berlin) 525(2013)576

Speaker: Pierre Delahaye (Grand Accelerateur National d'Ions Lourds (FR))

Slides Delahaye.pdf Delahaye.pptx

12:00 Lunch Break

Ground States and Decays

Convener: Olof Tengblad (Consejo Superior de Investigaciones Cientificas (CSIC) (ES))

28 Study of Gamow Teller transitions using beta decay and charge exchange reactions

The study of the properties of nuclei far from stability is one of the main frontiers of modern nuclear physics. Among many possible observables for nuclear structure, the $\beta$ decay strengths provide important testing grounds for nuclear structure theories far from stability. The mechanism of $\beta$ decay is well understood and dominated by allowed Fermi (F) and Gamow-Teller (GT) transitions. A successful description of the nuclear structure of the states involved should provide good predictions for the corresponding transition strengths $B$(F) and $B$(GT). Gamow-Teller and Fermi transitions can be studied in two different ways, namely in $\beta$ decay mediated by the weak interaction and in charge exchange(CE) reactions where the strong interaction is involved. The $\beta$ decay has an advantage in that it provides absolute $B$(GT) values, the GT transition strengths, but is limited by the energy window available. In contrast, CE reactions provide only relative $B$(GT) values, but there are no restrictions on the accessible excitation energy in the final nucleus. An alternative approach is to assume isospin symmetry and to compare $\beta$ decay and CE reactions in mirror nuclei. % Assuming the same GT response in mirror transitions, one can combine $\beta$ and CE to produce a complete picture of the GT strengths in both mirror nuclei. This is possible when the proton-rich nucleus $\beta$ decays and the neutron-rich nucleus provides a stable target. In this talk I will concentrate on two $\beta$ studies carried out at fragmentation facilities, the first one was carried out at GSI on $T_{z}= -1$ nuclei and the second beta-decay at GANIL on the $T_{z}= -2$ nucleus $^{56}$Zn. In both cases the results will be compared with the mirror CE reactions performed at RCNP. In the case of $^{56}$Zn a very exotic decay mode at the proton drip-line, $\beta$-delayed $\gamma$-proton decay, has been observed. This result will be discussed in detail.

Speaker: Prof. Berta Rubio (IFIC)

Slides 1_isolde_rubio.pdf 1_isolde_rubio.pptx

29 Hyperfine structure studies of At isotopes using in-source laser spectroscopy at ISOLDE

J. G. Cubiss* University of York (UK) The competition between spherical and deformed configurations at low energy gives rise to shape coexistence in the neutron-deficient isotopes around the Z=82 shell closure [1], while on the neutron-rich side effects due to octupole deformation could be important. In order to determine the extent to which the ground and isomeric states of these nuclides are affected by these phenomena, an extended campaign of investigation of changes in the mean-square charge radii is being conducted at ISOLDE by the Windmill Collaboration. The measurements rely on the high sensitivity provided by a combination of the in-source laser spectroscopy with RILIS, ISOLDE mass separation and Windmill spectroscopy setup [2]. During the September 2014 IS534-III experiment, a collaborative effort was made by the RILIS [3], ISOLTRAP [4] and Windmill teams to investigate HFS/IS in a long chain of isotopes ranging from 194At to 219At (Z=85, N=109-134) [5]. These isotopes span from the region of expected deformation near the neutron mid-shell at N=104, across the spherical region at N=126, before reaching an area of predicted octupole deformation at N=132. In this contribution, we will present the systematics of the charge radii obtained from this isotopic chain. [1] K. Heyde and J. Wood, Rev. Mod. Phys., 83, 1467 (2011) [2] A.N. Andreyev et al., Phys. Rev. Lett. 105, 252502 (2010) [3] B.A. Marsh et al., Nucl. Instr. and Meth. B 317, 550-556 (2013) [4] R.N. Wolf et al., Nucl. Instr. and Meth. A 686, 82-90 (2012) [5] A.N. Andreyev, A. E. Barzakh, V. N. Fedosseev, P. Van Duppen et al., IS534-III experiment at ISOLDE (Sep 2014) *On behalf of ISOLTRAP – RILIS – Windmill – Bratislava-Leuven-Gatchina-ISOLDE-Mainz-Manchester-York Collaboration

Speaker: James Gerald Cubiss (University of York (GB))

Slides JGC_ISOLDE_2014.pptx

30 Study of multi-neutron emission in the beta-decay of 11Li

Beta-decay spectroscopy is one of the most important tools for the study of nuclear structure. In exotic nuclei beta-decay can often be followed by the emission of delayed particles, a process which becomes the dominant decay channel when approaching the driplines. In the most exotic species, the emission of two or more delayed particles can also occur with a significant probability. Whereas two delayed proton spectroscopy has been performed in a number of cases, no spectroscopic study of two delayed neutron emission, with measurement of the neutron energies and angles, has been undertaken. We performed an experiment at ISOLDE in October 2014 to detect for the first time in coincidence two delayed neutrons from the decay of 11Li and measure their energies and angles, in order to study the sequential or direct character of the emission and the possible correlations between the neutrons. This experiment used an array of liquid scintillator modules coupled to a digital electronics and signal processing system for the detection of neutrons. The use of liquid scintillator allows to perform neutron-gamma discrimination to suppress random coincidences involving background. This talk will present the aim of this experiment, the analysis techniques and the status of the data analysis.

Speaker: Dr Franck Delaunay (LPC Caen, France)

Slides FDelaunay_ISOLDE_WS_2014.pdf FDelaunay_ISOLDE_WS_2014.ppt

31 Study of the $^{129}$Sn structure by beta decay: On the nature of the $3/2^+$ ground state and $1/2^+$ $315.3$-keV level

We have investigated levels in $^{129}$Sn populated from the $\beta^-$ decay of $^{129}$In isomers at the ISOLDE facility. The $^{129}$Sn nucleus is a three-neutron hole system next to the doubly magic $^{132}$Sn. The involved states of spin $1/2^+$ and $3/2^+$ are expected to have a configuration determined by the neutron $s_{1/2}$ and $d_{3/2}$ single particle states, respectively. Consequently, these states should be connected by a rather slow $l$-forbidden M1 transition. Using the fast timing technique we have measured the lifetime of the $1/2^+$ 315.3-keV level and determined the transition rate for the 315.3-keV $\gamma$-ray feeding the $3/2^+$ ground state. Our measurement shows a moderately fast M1 transition with a very weak, if any, E2 component. The previously reported level schemes in $^{129}$Sn were mostly confirmed by the $\gamma - \gamma$ coincidences. This study represents the first test of the ISOLDE Decay Station (IDS).

Speaker: Razvan Lica (IFIN-HH Bucharest (RO))

Slides RazvanLica_129In_ISOLDE-Workshop-2014_v4.pdf

32 Estimation of production rates and secondary beam intensities

Summary of the work, performed as a part of the project Eurisol Design Study, will be presented and possibilities for further activities at the HIE-ISOLDE will be discussed. As a part of the Eurisol Design Study, dedicated task Beam Intensity Calculation focused on possibilities to predict achievable secondary beam intensities at the ISOL facility using the spallation reaction. Model calculations were performed and the results were compared to available data. Successful calculations allow to estimate production of exotic nuclei in the target and thus offer possibilities for study of the mechanism of the transport of such nuclei out of the target. Possibilities to continue this work in systematic way at ISOLDE will be discussed.

Speaker: Martin Veselsky (Slovak Academy of Sciences (SK))

Slides Veselsky.pdf Veselsky.ppt

33 Results from the recent 207Tl experiment using the ISOLDE Decay Station with triggerless data acquisition.

Results from the recent 207Tl experiment using the ISOLDE Decay Station with triggerless data acquisition. R. J. Carroll1, Zs. Podolyák1, E. Rapisarda2, T. Alexander1, A. Algora3, A. Andreyev4, S. Ansari5, F. Browne6, A. Bruce6, B. Cheal7, T. E. Cocolios8, J. Cubriss4, Zs. Dombrádi9, P. Van Duppen10, K. Flanagan8, L. M. Fraile11, C. Fahlander12, W. Gelletly1, R.-B. Gerst5, M. Gorska13, H. Grawe13, A. Gredley7, P. Greenlees14, M. Huyse10, L. Harkness-Brennan7, D. Jenkins4, D. T. Joss7, S. Judge15, U. Koester16, J. Konki14, M. Kowalska2, I. Kuti9, S. Lalkovski1, I. Lazarus17, R. Lică18, G. Lotay1, M. V. Lund, M. Madurga2, N. Marginean18, R. Marginean18, C. Mihai18, R. E. Mihai18, A. Negret18, C. Nobs6, S. Noe18, C. Nita6,18, R. D. Page7, S. Pascu18, Z. Patel1, V. Pucknell17, P. H. Regan1,15, R. Raabe10, C. M. Shand1, D. Sohler9, T. Storra2, H. Stroke19, S. Stegmann5, Ch. Sotty10, V. Vedia11, R. Wadsworth4, P. M. Walker1, F. Wearing7, E. Wilson1, G. Wilson4, H. De Witte10. 1Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom 2CERN, Physics Department, 1211 Geneva 23, Switzerland 3IFIC, CSIC-Universidad de Valencia, 46071, Spain 4Department of Physics, University of York, Heslington, York YO10 5DD, UK 5Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany 6University of Brighton, Brighton BN2 4GJ, United Kingdom 7Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK 8Department of Physics and Astronomy, The University of Manchester, M13 9PL Manchester, United Kingdom 9Institute of Nuclear Research of the Hungarian Academy of Sciences, 4026 Debrecen, Hungary 10KU Leuven, Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200D, 3001 Leuven, Belgium 11Grupo de Física Nuclear, FAMN, Universidad Complutense, CEI Moncloa, 28040 Madrid, Spain 12Department of Physics, Lund University, S-22100, Lund, Sweden 13GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany 14Department of Physics, PO Box 35 (YFL), FI-40014 University of Jyväskylä, Finland 15National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK 16Institut Laue-Langevin, 6 rue J. Horowitz, F-38042 Grenoble, France 17STFC, Daresbury Laboratory, Warrington, WA4 4AD, United Kingdom 18H. Hulubei National Institute for Physics and Nuclear Engineering, Bucharest, Romania 19Department of Physics, New York University, New York, New York 10003, USA A recent experiment was performed using the ISOLDE Decay Station to measure low-lying states in 207Tl populated via the β decay of 207Hg, produced using a molten lead target. The 207Tl nucleus has one proton less than 208Pb, which is a classic shell model core. Above the lowest-lying states, structure is likely based on the coupling of the proton hole to either a broken proton or neutron pair, which would require excitation across a shell closure, or to a collective octupole excitation. The observation of these states will reveal information on the single-particle orbitals near the shell closures at Z = 82 and N = 126, which will be valuable for the improvement of the predictive power of nuclear models. An additional objective of the experiment was to test the feasibility of producing a 208Hg beam from a molten lead target with the intention of studying states in 208Tl populated via the β decay of 208Hg. Such a study is crucial for the understanding of the proton-hole neutron-particle interactions in this region as information is scarce. The ISOLDE Decay Station consisted of a four HPGe Clover detectors and a MINIBALL cluster for high-resolution γ-ray spectroscopy, in addition to three plastic scintillator detectors for observing radioactive β-decay events. Beams of 207Hg and 208Hg were implanted onto a tape from which subsequent radioactive decays could be observed. Data were recording using a triggerless data acquisition system in which every signal was recorded with a time stamp, enabling coincident signals to be correlated in software. Preliminary results from the early analysis of this experiment, showing many promising new γ rays associated with 207Tl, will be presented for both the 207Tl and 208Tl objectives.

Speaker: Robert John Carroll (University of Surrey (GB))

Slides Carroll.pdf

14:55 Coffee break

Facilities and Instruments

Convener: Claes Harry Fahlander (Lund University (SE))

34 The iThemba LABS Facility: Coulomb excitation studies and future plans at HIE-ISOLDE

HIE-ISOLDE will revolutionize the scientific outcome of muti-step Coulomb excitation and reorientation effect measurements. Particularly, in reorientation effect measurements, the magnitude and sign of the diagonal matrix element for the first 2+ excitation in even-even nuclei will be determined with a higher degree of precision, which will improve our current understanding of phenomena such as shape coexistence, prolate vs oblate shapes, surface vibrations or how nuclei rotate. Nonetheless, RIB facilities are generally deficient delivering high-intensity beams and higher-lying states may be difficult to populate using Coulomb-excitation reactions. This is the case, for example, of establishing shape coexistence by determining the spectroscopic quadrupole moment of the second 2+ state in many nuclei (e.g., CERN-INTC-2012-067, INTC-P-368). Additional reorientation-effect measurements with stable ion beams have been carried out at iThemba LABS. A flexible chamber for particle-gamma coincidence measurements has been constructed and the pipe-line for Coulomb-excitation measurements (S3 detectors, electronics, feedthroughs, etc) finalized. The first experiments ran successfully last November-December 2013. Moreover, a new funding application for an array of 16 clover HPGe detectors (GAMKA) has been submitted to the National Research Foundation, which would allow angular distribution measurements. New exotic stable beams are also being developed at iThemba LABS using organometallic chemistry, which will allow the study of novel reorientation-effect measurements. These measurements with stable beams at iThemba LABS will prepare our students with hands-on and data-analysis skills for similar RIB measurements as well as complementing the physics case at HIE-ISOLDE. Coulomb excitation studies and supportive measurements at iThemba LABS, that will support the HIE-ISOLDE program, will be presented. Moreover, the prospect of a RIB facility at iThemba LABS is a strong motivation to strengthen our research program at HIE-ISOLDE.

Speaker: Nico Orce (University of the Western Cape)

Slides ISOLDE_Dec2014_2.pdf

35 The ALTO Facility

The ALTO facility consists in two accelerators within the same installation. A Tandem accelerator dedicated to stable (ions and cluster) beam and a linear electron accelerator dedicated to the production of radioactive beams. The ALTO facility can deliver radioactive beams, stable beams and cluster beams having a large physics case from nuclear structure to atomic physics, cluster physics, biology and nano-technology. A brief description of the facility will be given as well as of the on-going research program and future developments.

Speaker: Georgi Georgiev (CSNSM)

Slides ISOLDE_workshop2014_Georgiev_1.pdf ISOLDE_workshop2014_Georgiev_1.pptx

36 The AGATA Array and Recent Results

The Advanced GAmma Tracking Array is a next generation high-resolution gamma-ray spectrometer for nuclear structure studies based on the novel principle of gamma-ray tracking. It will be built from a novel type of high-fold segmented germanium detectors which will operate in position-sensitive mode by employing digital electronics and pulse-shape decomposition algorithms. AGATA is and will be employed at the leading infrastructures for nuclear structure studies in Europe. The first implementation of the array consisted of 5 AGATA modules; it was operated at INFN Legnaro. A larger array of AGATA modules was employed at the FRS focal plane at GSI for experiments with unstable ion beams at relativistic energies. The presentation will describe the novel gamma-ray tracking method. Examples of physics cases from the two different sites and the new spectrometer will be presented.

Speaker: Prof. Peter Reiter (University Cologne, Nuclear Physics Institut)

Slides AGATA_Reiter.pdf AGATA_Reiter.pptx

37 Status of the HIE-ISOLDE Project

After 20 years of successful ISOLDE operation at the PS-Booster, a major upgrade of the facility, the HIE-ISOLDE (High Intensity and Energy ISOLDE) project was launched in 2010. It is divided into three parts; a staged upgrade of the REX post-accelerator to increase the beam energy from 3.3 MeV/u to 10 MeV/u using a super-conducting Linac, an evaluation of the critical issues associated with an increase in proton-beam intensity and energy (increase from 1.4 GeV to 2 GeV) and a machine design for an improvement in RIB quality. The latter two will be addressed within the HIE-ISOLDE Design Study. This presentation aims to provide an overview of the present status of the overall project by providing; an insight to the infrastructure modifications, progress on the high beta Quarter Wave Resonant (QWR) cavities and cryomodule production as well as the installation of the HEBT lines.

Speaker: Yacine Kadi (CERN)

Slides ISWU-YKadi-status.pdf ISWU-YKadi-status.pptx

38 Results from the first tests with the SPEDE spectrometer

The SPEDE spectrometer [1, 2] aims to combine a silicon detector, for the detection of electrons, with the MINIBALL $\gamma$-ray detection array for in-beam studies employing radioactive ion beams at the HIE-ISOLDE facility at CERN. SPEDE is one of the first attempts to combine in-beam $\gamma$-ray and conversion electron spectroscopy with radioactive ion beams. The setup will be primarily used for octupole collectivity [3] and shape coexistence studies [4, 5] in Coulomb excitation experiments. In the shape coexistence cases the transitions between states of the same spin and parity have enhanced E0 strength [6]. Additionally the 0$^+$→0$^+$ transitions, typically present in nuclei exhibiting shape coexistence [7], can only occur via E0 transitions, i.e. via internal conversion electron emission. The simultaneous observation of both electrons and $\gamma$-rays is especially important for the analysis of multi-step Coulex data. The concept of the SPEDE spectrometer was introduced for the ISOLDE community in the previous users meeting. In this presentation the finalized design of the spectrometer will be described together with results from the first tests. [1] J. Pakarinen et al., Letter of Intent to the INTC for HIE-ISOLDE (2010). [2] J. Konki et al., EPJ Web of Conferences 63, 01019 (2013). [3] P.A Butler et al., Proposal to the INTC for HIE-ISOLDE (2012). [4] K. Wrzosek-Lipska et al., Proposal to the INTC for HIE-ISOLDE (2012). [5] J. Pakarinen et al., Proposal to the INTC for HIE-ISOLDE (2013). [6] C.Y. Wu et al., Phys. Lett. B 541, 59 (2002). [7] K. Heyde and J.L. Wood, Rev. Mod. Phys. 83, 1467 (2011).

Speaker: Pilippos Papadakis (University of Jyvaskyla (FI))

Slides papadakis-spede.pdf papadakis-spede.pptx

Special Topic

Convener: Claes Harry Fahlander (Lund University (SE))

39 Results from the LHC

The LHC is the highest energy collider in the world, and has run successfully over recent years. The experiments at the LHC will be briefly reviewed, along with some of their key results from the first run. Particular focus will be made on the dedicated flavour-physics experiment LHCb, and prospects for the future run.

Speaker: Roger Forty (CERN)

Slides Isolde-LHC.pdf Isolde-LHC.pptx

19:30 Workshop Dinner

Wednesday 17 December

Golden Jubilee

Convener: Helge Ravn

40 From pre-ISOLDE to ISOLDE: some personal recollections

A constellation of special circumstances made the approval of ISOLDE possible, in spite of the main priority of CERN as an elementary particle physics laboratory. I have personally experienced some of these as a post-doc at CERN as will be briefly discussed.

Speaker: Prof. Torleif Ericson (CERN (retired))

Slides

• Ericson.docx
• Ericson.pdf
• Ericson.pptx

Video in CDS Video in CDS

41 From ISOLDE to ISOLDE 2

On December 17, 1964 the CERN DG, Victor Weisskopf, sent a letter to the ISOLDE Collaboration giving green light to perform experiments at CERN. An underground hall was built close to the SC, which accelerated protons to 600MeV energy. The first experiment at ISOLDE was preformed on September 17, 1967. In my talk I shall cover the first years of experiments at ISOLDE at CERN, the SC Improvement Programme and the building of ISOLDE 2.

Speaker: Bjorn Jonson (Institute of Theoretical Physics)

Slides ISOLDE50BJonson.pdf ISOLDE50BJonson.pptx

Video in CDS Video in CDS

42 ISOLDE 1985-1987: In the shadow of LEP construction

This report describes my time at CERN from 1985 to 1987. Only very briefly before, ISOLDE was recognized by the CERN Management as a CERN facility and not only as a collaboration performing experiments at the synchrocyclotron (SC). Due to LEP construction the human resources were extremely restricted and I acted in one person as ISOLDE Group Leader, as Coordinator of the Synchrocyclotron, and as person responsible for the ISOLDE Technical Group. In addition, I was responsible for the students of my research groups from Mainz University which were active in laser spectroscopy of neutron-deficient nuclides in the mercury region and in getting ISOLTRAP on the floor and into operation. Due to LEP construction also the financial resources were extremely limited and my requests to the EP Division Leader B. Hyams and to the Director General H. Schopper for financial support for installation of a laser ion source and ISOLTRAP were turned down. Still, I and my students had a lot of fun at ISOLDE and I am very happy that there are still some remains of my time at CERN: first of all ISOLTRAP, but also RILIS (which came into full swing only when ISOLDE was relocated at the PS Booster), or some traces back to the ISOLDE Users’ Guide of 1986, or the weekly meetings of the ISOLDE Technical Group.

Speaker: H.-Jürgen Kluge (GSI)

Slides 14-12-17_Kluge_50y_ISOLDE_final_corr.pdf 14-12-17_Kluge_50y_ISOLDE_final_corr.pptx

Video in CDS Video in CDS

43 Last 3 years of the SC-ISOLDE and move to PS-Booster

In 1987 the very successful operation of ISOLDE-2 could be continued with an ever increasing number of users. The ISOLDE-3 facility was finished in 1988 and made available too, even in high-resolution mode. As it was evident that post-acceleration of the radioactive beams would be needed in the future, a first project with a series of linacs was forwarded. It had been clear, however, that CERN could not support the SC operation in the long term. An envisaged transfer to the Rutherford-Appleton Lab did not materialize, primarily for financial reasons. Fortunately the CERN management agreed to support a move to the PS-Booster and preparations started immediately following this decision. Thus in the years 1989 and 1990 a special effort was made to supply beam to as many research projects as possible, resulting in a record number of beam shifts from the ISOLDE separators. The collaboration even had to partially support the last year of SC running before the final shutdown in December 1990.

Speaker: Heinz Haas (CERN-ISOLDE)

Slides ISOLDE-WS_Haas.pdf ISOLDE-WS_Haas.ppt

Video in CDS Video in CDS

44 1993-1995: the Pre REX-ISOLDE Era

Soon after the commissioning of ISOLDE at the PS-Booster facility, first experiments took place. This contribution will discuss highlights from the 1993-1995 period with a special focus on the preparatory work for the proposal to post-accelerate the ISOLDE beams. This lead eventually to the approval of the "Radioactive beam EXperiments at ISOLDE: Coulomb excitation and neutron transfer reactions of exotic nuclei" proposal under IS347.

Speaker: Prof. Piet Van Duppen (KU Leuven (BE))

Slides 2014_12_17_ISOLDE_50_Piet_Van_Duppen.pdf 2014_12_17_ISOLDE_50_Piet_Van_Duppen.pptx

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10:45 Coffee break

Golden Jubilee

Convener: Maria Jose Garcia Borge (CERN)

45 ISOLDE 1996-1999: Preparing for new science opportunities

1996-1999 was a time in which ISOLDE saw important changes. In order to make space for REX-ISOLDE the experimental hall saw its first extension and first equipment for REX-ISOLDE was installed and commissioned.

Speaker: Georg Bollen (Michigan State University)

Slides Bollen_ISOLDE_WS14_50_years.pdf Bollen_ISOLDE_WS14_50_years.pptx

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46 ISOLDE at the turn of the millennium

At the transition to the twenty first century ISOLDE was undergoing a major upgrade from a very successful low-energy radioactive ion beam facility towards a new era of nuclear structure studies employing accelerated radioactive beams [1]. The first accelerated beam was obtained in November 2001 when REX-ISOLDE produced a 2.2 MeV/u beam of 26Na ions. Additionally, the ISOLDE complex was made particularly attractive facility due to other break-through developments in the fields of laser ion sources and ion traps. Some highlights from the years 1999 to 2002 during my time as a group leader will be presented. 1. Juha Äystö, CERN’s longest serving experimental facility, in Physics Reports 403 (2004) 459

Speaker: Prof. Juha Äystö (Helsinki Institute of Physics)

Slides ISOLDE50_Äystö.pdf ISOLDE50_Äystö.ppt

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47 ISOLDE: the Anglo-Saxon Era 2002-2005

This presentation summarises the highlights at ISOLDE during my time as group leader 2002-2005

Speaker: Prof. Peter Butler (University of Liverpool (GB))

Slides Butler.pptx

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48 The ISOLDE group 2005-2008

In the years leading up to the first beams in LHC in the autumn 2008 most CERN efforts were focussed on finishing the LHC. Still, ISOLDE managed to evolve and broaden its physics scope. I shall give a brief overview of the main events taking place at ISOLDE in the period 2005-2008, including the consolidation of the existing infrastructure and the preparations for the HIE-ISOLDE project, and remind about some of the physics results coming out. I shall also mention the developments in and around the ISOLDE Collaboration.

Speaker: Dr Karsten Riisager (Aarhus University (DK))

Slides ISOLDE05_08.pdf ISOLDE05_08.ppt

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49 My time as Group Leader 2008-2012

I will give some highlights about my time as ISOLDE Physics Group Leader from 2008 to 2012.

Speaker: Yorick Blumenfeld (Institut de Physique Nucléaire Orsay)

Slides Yorick-GL.pdf Yorick-GL.pptx

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50 Concluding Remarks

Speaker: Rolf Heuer (CERN)

51 Workshop Closing Comments

Speaker: Maria Jose Garcia Borge (CERN)

Slides Concluding_Remarks.pdf Concluding_Remarks.pptx

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Golden Jubilee Aperitif