Ivan Podadera

Bio: Ivan Podadera is an academic researcher from Complutense University of Madrid. The author has contributed to research in topics: Beam (structure) & Linear particle accelerator. The author has an hindex of 9, co-authored 62 publications receiving 452 citations. Previous affiliations of Ivan Podadera include CERN & Polytechnic University of Catalonia.

An ion cooler-buncher for high-sensitivity collinear laser spectroscopy at ISOLDE

Abstract: A gas-filled segmented linear Paul trap has been installed at the focal plane of the high-resolution separator (HRS) at CERN-ISOLDE. As well as providing beams with a reduced transverse emittance, this device is also able to accumulate the ions and release the sample in bunches with a well-defined time structure. This has recently permitted collinear laser spectroscopy with stable and radioactive bunched beams to be demonstrated at ISOLDE. Surface-ionized 39, 44, 46K and 85Rb beams were accelerated to 30keV, mass separated and injected into the trap for subsequent extraction and delivery to the laser setup. The ions were neutralized in a charge exchange cell and excited with a co-propagating laser. The small ion beam emittance allowed focussing in the ion-laser overlap region, which is essential to achieve the best experimental sensitivity. Fluorescent photons were detected by a photomultiplier tube as a frequency scan was taken. A gate (typically 7-12μs wide) was set on the photomultiplier signal to accept the fluorescent photons within the time window defined by the bunch. Thus, using accumulation times of 100ms, the dominant contribution to background due to continuous laser scattering could be reduced by a factor of up to 4×104 .

The accomplishment of the Engineering Design Activities of IFMIF/EVEDA: The European - Japanese project towards a Li(d,xn) fusion relevant neutron source

Abstract: The International Fusion Materials Irradiation Facility (IFMIF), presently in its Engineering Validation and Engineering Design Activities (EVEDA) phase under the frame of the Broader Approach Agreement between Europe and Japan, accomplished in summer 2013, on schedule, its EDA phase with the release of the engineering design report of the IFMIF plant, which is here described. Many improvements of the design from former phases are implemented, particularly a reduction of beam losses and operational costs thanks to the superconducting accelerator concept, the re-location of the quench tank outside the test cell (TC) with a reduction of tritium inventory and a simplification on its replacement in case of failure, the separation of the irradiation modules from the shielding block gaining irradiation flexibility and enhancement of the remote handling equipment reliability and cost reduction, and the water cooling of the liner and biological shielding of the TC, enhancing the efficiency and economy of the related sub-systems. In addition, the maintenance strategy has been modified to allow a shorter yearly stop of the irradiation operations and a more careful management of the irradiated samples. The design of the IFMIF plant is intimately linked with the EVA phase carried out since the entry into force of IFMIF/EVEDA in June 2007. These last activities and their on-going accomplishment have been thoroughly described elsewhere (Knaster J et al [19]), which, combined with the present paper, allows a clear understanding of the maturity of the European–Japanese international efforts. This released IFMIF Intermediate Engineering Design Report (IIEDR), which could be complemented if required concurrently with the outcome of the on-going EVA, will allow decision making on its construction and/or serve as the basis for the definition of the next step, aligned with the evolving needs of our fusion community.

Off-line commissioning of the ISOLDE cooler

Abstract: Among the multiple progresses in radioactive ion beam (RIB) manipulation for physics experiments, the beam cooling and bunching in gas-filled RF traps has become a widely used technique. It is particularly well adapted to precision experiments, such as Penning trap mass spectrometry or collinear laser spectroscopy. At ISOLDE, an rf quadrupole cooler and ion buncher (RFQCB) has been designed and developed to deliver radioactive beams of improved quality among most of the on-line experiments. The results of the first off-line tests have shown that high transmission efficiencies could be achieved with different RIBs of alkali metals, as it was expected. During the later tests that are presented here a special care was dedicated to the reproduction of the on-line experimental conditions of ISOLDE, with a wide range of different RIBs. This contribution will present the latest off-line tests.

The Linear IFMIF Prototype Accelerator (LIPAC) Design Development under the European-Japanese Collaboration

Abstract: The IFMIF aims to provide an accelerator-based, D-Li neutron source to produce high energy neutrons at sufficient intensity. Part of the BA agreement (Japan-EURATOM), the goal of the IFMIF/EVEDA project is to work on the engineering design of IFMIF and to validate the main technological challenges which includes a 125mA CW D⁺ accelerator up to 9 MeV mainly designed and manufactured in Europe. The components are in an advanced stage of manufacturing. The first components which allow the production of a 140 mA-100 keV deuteron beam have been delivered, installed and under commissioning at Rokkasho. The second phase (100 keV to 5 MeV) will end by March 2017. The third phase (short pulse) and forth phase (cw) will be the integrated commissioning of the LIPAc up to 9 MeV. The duration of the project has been recently extended up to end 2019 to allow the commissioning and operation of the whole accelerator (1MW). The aim of this paper is to give an overview of the LIPAc, currently under commissioning in Japan, to outline the engineering design and the development of the key components, as well as the expected outcomes of the engineering work, associated with the experimental program.

The medium energy beam transport line (mebt) of ifmif/eveda lipac ∗

Abstract: The IFMIF-EVEDA [1] Linear IFMIF Prototype Accelerator (LIPAc)will be a 9 MeV, 125 mA CW deuteron accelerator which aims to validate the technology that will be used in the future IFMIF accelerator. The acceleration of the beam will be carried out in two stages. An RFQ will increase the energy up to 5 MeV before a Superconducting RF (SRF) linac made of a chain of eight Half Wave Resonators bring the particles to the final energy. Between both stages, a Medium Energy Beam Transport line (MEBT) is in charge of transporting and matching the beam between the RFQ and the SRF. The transverse focusing of the beam is controlled by five quadrupole magnets with integrated steerers, grouped in one triplet and one doublet. Two buncher cavities surrounding the doublet handle the longitudinal dynamics. Two movable collimators are also included to purify the beam optics coming out the RFQ and avoid losses in the SRF. From the inputs of the beam dynamics group, CIEMAT is in charge of designing, manufacturing and integrating all the components of the beamline. In this contribution, the MEBT subsystem will be described and the main objectives and issues for each component will be discussed.

Materials research for fusion

Abstract: Fusion materials research started in the early 1970s following the observation of the degradation of irradiated materials used in the first commercial fission reactors. The technological challenges of fusion energy are intimately linked with the availability of suitable materials capable of reliably withstanding the extremely severe operational conditions of fusion reactors. Although fission and fusion materials exhibit common features, fusion materials research is broader. The harder mono-energetic spectrum associated with the deuterium–tritium fusion neutrons (14.1 MeV compared to <2 MeV on average for fission neutrons) releases significant amounts of hydrogen and helium as transmutation products that might lead to a (at present undetermined) degradation of structural materials after a few years of operation. Overcoming the historical lack of a fusion-relevant neutron source for materials testing is an essential pending step in fusion roadmaps. Structural materials development, together with research on functional materials capable of sustaining unprecedented power densities during plasma operation in a fusion reactor, have been the subject of decades of worldwide research efforts underpinning the present maturity of the fusion materials research programme. For achieving proper safety and efficiency of future fusion power plants, low-activation materials able to withstand the extreme fusion conditions are needed. Here, the irradiation physics at play and fusion materials research is reviewed.

Precision Atomic Physics Techniques for Nuclear Physics with Radioactive Beams

Abstract: Atomic physics techniques for the determination of ground-state properties of radioactive isotopes are very sensitive and provide accurate masses, binding energies, Q-values, charge radii, spins and electromagnetic moments. Many fields in nuclear physics benefit from these highly accurate numbers. They give insight into details of the nuclear structure for a better understanding of the underlying effective interactions, provide important input for studies of fundamental symmetries in physics, and help to understand the nucleosynthesis processes that are responsible for the observed chemical abundances in the Universe. Penning-trap and storage-ring mass spectrometry as well as laser spectroscopy of radioactive nuclei have now been used for a long time but significant progress has been achieved in these fields within the last decade. The basic principles of laser spectroscopic investigations, Penning-trap and storage-ring mass measurements of short-lived nuclei are summarized and selected physics results are discussed.

The ISOLDE facility

Abstract: The ISOLDE facility has undergone numerous changes over the last 17 years driven by both the physics and technical community with a common goal to improve on beam variety, beam quality and safety. Improvements have been made in civil engineering and operational equipment while continuing developments aim to ensure operations following a potential increase in primary beam intensity and energy. This paper outlines the principal technical changes incurred at ISOLDE by building on a similar publication of the facility upgrades by Kugler (2000 Hyperfine Interact. 129 23–42). It also provides an insight into future perspectives through a brief summary issues addressed in the HIE-ISOLDE design study Catherall et al (2013 Nucl. Instrum. Methods Phys. Res. B 317 204–207).