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Abstract

A new LabVIEW-based control system for the ISOLTRAP facility at ISOLDE/CERN has been implemented by using the Control System (CS) framework which has been developed by DVEE/GSI during the last two years. CS is an object-oriented, multi-threaded, event-driven framework with Supervisory Control and Data Acquisition (SCADA) functionality. It allows one to implement distributed control systems by adding experiment specific add-ons. This paper gives an overview on the CS framework, describes the requirements for ISOLTRAP and reports on the implementation of the new control system.

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... The computer is communicating with the trap by a control software called CS, which was developed at GSI [Bec04]. In order to register ambient pressure and temperature, a LabVIEW c -based program is monitoring several temperature and pressure probes observing the room temperature, the bore temperature between magnet and vacuum tube, the pressure on the helium recovery line and the buffer-gas line. ...
... The PC that controls the ISEG high-voltage modules communicates via CAN bus with the ISEG crate. The MLLTRAP facility is controlled by a program called CS [Bec04], based on the programming language LabVIEW. It has been specially developed to match the demands of ion trap facilities such as SHIPTRAP [Bec04], ISOLTRAP or MLLTRAP. ...
... The MLLTRAP facility is controlled by a program called CS [Bec04], based on the programming language LabVIEW. It has been specially developed to match the demands of ion trap facilities such as SHIPTRAP [Bec04], ISOLTRAP or MLLTRAP. As mentioned in Sec. ...
... In the past years, the CS framework has been developed at GSI [1]. The typical applications of CS have a couple of thousands process variables and require a large flexibility. ...
... However, the first version of CS was based on ObjectVIEW, but it turned out that this toolkit did not meet the performance requirements. As a consequence, a new object oriented approach was implemented within the CS framework [1]. This approach allows creating and destroying objects on the fly; tools for inheritance and a class browser have been implemented as well. ...
... Implementation details are described in the appendix of [1]. ...
Article
Since a few years, the CS (Control System) framework is in use at a couple of experiments at various laboratories. The main idea behind CS is to provide a common basis which can be used to develop dedicated control systems by adding experiment specific add-ons. The key features of CS are an object oriented approach, event driven communication, the lack of intrinsic bottle necks like a central event manager, its ability to be distributed over many nodes, and the usage of LabVIEW which guarantees a fast learning curve as well as an excellent connectivity to hardware. The aim of this paper is to present the status of CS as well as to highlight recent achievements.
... 61 % at the longer filter rods only, the shorter parts are operated at 50 % to aid the ion transition across field boundaries. To control experimental timings and data acquisition, an in-house control software based on LabVIEW [30] and a Field-Programmable-Gate-Array (FPGA) card (National Instruments, PCI-7811R) is used. The FPGA card generates transistor-transistor logic (TTL) pulses which can be processed by all devices of the setup parts attached to the module. ...
... The results are compared to previous simulations [13]. The present work shows that the module is capable of filtering ions with a mass resolving power up to = 230 (30), which is comparable to the simulation and capable of selecting cluster sizes or biomolecule charge states. The digital ion trap is able to accumulate incoming ions and thermalize them within a few milliseconds. ...
Article
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The combination of a linear quadrupole ion-filter and linear Paul trap operated with a rectangular guiding field for the filtering and accumulation of ions within the M ass S pectrometry for S ingle P article I maging of D ipole O riented protein C omplexes (MS SPIDOC) prototype [T. Kierspel et al., Anal. Bioanal. Chem. , published online] is characterized. Using cationic caesium-iodide clusters, the ion-separation performance, ion accumulation, cooling, and ejection via in-trap pin electrodes is evaluated. Furthermore, proof-of-principle measurements are performed with 64 kDa multiply-charged non-covalent protein complexes of human hemoglobin and 804 kDa non-covalent complex of GroEL, to demonstrate that the module meets the criteria to handle high-mass ions which are the main objective of the MS SPIDOC project. The setup's performance is found to be in line with previous results from ion-trajectory simulations [F. Simke et al., Int. J. Mass Spectrom. 473 (2022) 116779].
... Since the requirements were not really known at the beginning of the PENTATRAP project, it was decided to implement "CS -A Control System Framework for Experiments" (CS-framework or simply CS in the following) already developed by D. Beck and H. Brand at GSI [181,182] using the LabVIEW System Design Software from National Instruments (NI) [183] as a control system for the SHIPTRAP mass spectrometer. In this context, CS was a promising tool by many reasons given in the following list of requirements imposed to the ISOLTRAP control system [184]: ...
... The first measurements on the Q-values of 112 Sn → 112 Cd, 136 Ce → 136 Ba and 74 Se → 74 Ge transitions were performed at JYFLTRAP[136][137][138] and 74 Se → 74 Ge was also measured at the FSU-TRAP[139]. The Q -value of184 Os → 184 W was obtained at TRIGATRAP[140] and the majority of the transitions were investigated at SHIPTRAP[108,133,134,141,142]. Within a set of the recently renewed Q -values several remarkable candidates have to be mentioned. ...
Article
In neutrino physics, a variety of experiments aim for the determination of the neutrino mass by means of the beta-decay and electron-capture spectra, while a detection of the neutrinoless double-electron capture would reveal the Majorana nature of neutrinos. However, a lack of knowledge on the total decay energy (Q-value) of these processes constrains present neutrino experiments. To this end, high-precision measurements of the Q-values are obligatory. In order to find suitable nuclides for neutrinoless double-electron capture experiments, a determination of the Q-values by direct Penning-trap mass-ratio measurements on 106Pd/102Ru, 106Cd/106Pd, 144Sm/144Nd and 156Dy/156Gd with a relative precision of a few 10E−9 were performed for the first time at SHIPTRAP using the Time-of-Flight Ion-Cyclotron-Resonance (ToF-ICR) detection technique and the multiresonance phenomenon in 156Dy was discovered. A novel Phase Imaging Ion-Cyclotron-Resonance detection technique was developed being substantially faster and providing ca. 40-fold gain in resolving power in comparison with the presently used ToF-ICR technique. The novel Penning-trap mass spectrometer PENTATRAP aims for direct mass-ratio measurements with a relative precision better than 10E−11, which is required for the beta-decay and electron-capture experiments. In this context, the PENTATRAP Control System was developed in order to maximize the efficiency of the measurement process.
... To allow for standardized operation by the laser crew, the components of PHELIX are monitored and controlled remotely by the PHELIX control system (PCS). The PCS is based on the CS-framework, an in-house development at GSI [41] , which uses an object-oriented approach, is scalable, distributed, event driven and freely available under the terms of the GNU Public License [42] . The PCS is realized in the programming language LabVIEW. ...
Article
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The high-energy/high-intensity laser facility PHELIX of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany, has been in operation since 2008. Here, we review the current system performance, which is the result of continuous development and further improvement. Through its versatile frontend architecture, PHELIX can be operated in both long- and short-pulse modes, corresponding to ns-pulses with up to 1 kJ pulse energy and sub-ps, 200 J pulses, respectively. In the short-pulse mode, the excellent temporal contrast and the control over the wavefront make PHELIX an ideal driver for secondary sources of high-energy ions, neutrons, electrons and X-rays. The long-pulse mode is mainly used for plasma heating, which can then be probed by the heavy-ion beam of the linear accelerator of GSI. In addition, PHELIX can now be used to generate X-rays for studying exotic states of matter created by heavy-ion heating using the ion beam of the heavy-ion synchrotron of GSI.
... The specialized components implement various subsets of the SCADA functionality and communicate with each other using these events. This concept has seen previous use, Beck et al., for instance, provide an overview of a LabVIEWbased control system that is event-driven and has SCADA capabilities [11]. Approaches that implement SCADA as a distributed event-driven system are also known. ...
Article
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This paper analyzes Hat, an open-source framework for developing event-driven component-based SCADA applications, and discusses possibilities to add various analytical tools to such platforms. As a part of the contribution, an open-source component called Artificial Intelligence Model Manager (AIMM) has been developed and integrated into a Hat-based SCADA platform. AIMM is extensible through various plugins, allowing the addition of various models for advanced analytics e.g., machine learning tools, statistical tools, etc. The paper describes AIMM architecture and provides a use case in which state estimation was performed in a medium-voltage distribution grid. This case study demonstrates that it is possible to extend component-based SCADA systems with components for advanced analytics with minimal fundamental system changes.
... 37 Ion detection is performed with an off-axis Channeltron detector, a fast preamplifier (ORTEC, VT120a), and a fast multiscaler/TDC (Fast ComTec, MCS6A). The control of the experimental timing pattern and switching operations is performed with a LabVIEW-based control software 38 and a field-programmable-gatearray card (National Instruments, PCI-7811R). ...
Article
Repeated switching of electric potentials within a single experimental cycle is introduced for a multi-reflection time-of-flight mass spectrometer (also known as an electrostatic ion beam trap) in order to eject different ion species after different storage times. The method is demonstrated with two cluster ions with considerably different mass-to-charge ratios (the A = 624 and 832 isotopologues of Pb3+ and Pb4+, respectively) for the specific case where the sequential ejections result in an identical number of revolution periods. Thus, the ions’ flight lengths are identical, and the resulting time-of-flight values allow single-reference mass determination. The requirements for the switching time window are studied in detail. For the present system and ion pair, the relative mass uncertainty is found to be 3 · 10⁻⁷ for short measurements (≈10 min) and 6 · 10⁻⁸ for longer ones (≈2 h).
... Its signals are amplified (Becker & Hickl GmbH, and digitalized by a computer-mounted multiscaler card (Becker & Hickl GmbH, MSA-300). The experimental timing pattern is provided by a control system based on LabVIEW (Beck et al., 2004 andBeck et al., 2009) and a Field-Programmable-Gate-Array (FPGA) card (National Instruments, PCI-7811R). ...
Article
The recently introduced method of ion separation by transversal ejection of unwanted species in electrostatic ion-beam traps and multi-reflection time-of-flight devices has been further studied in detail. As this separation is performed during the ion storage itself, there is no need for additional external devices such as ion gates or traps for either pre- or postselection of the ions of interest. The ejection of unwanted contaminant ions is performed by appropriate pulses of the potentials of deflector electrodes. These segmented ring electrodes are located off-center in the trap, i.e., between one of the two ion mirrors and the central drift tube, which also serves as a potential lift for capturing incoming ions and axially ejecting ions of interest after their selection. The various parameters affecting the selection effectivity and resolving power are illustrated with tin-cluster measurements, where isotopologue ion species provide mass differences down to a single atomic mass unit at ion masses of several hundred. Symmetric deflection voltages of only 10 V were found sufficient for the transversal ejection of ion species with as few as three deflection pulses. The duty cycle, i.e., the pulse duration with respect to the period of ion revolution, has been varied, resulting in resolving powers of up to several tens of thousands for this selection technique.
... Finally, the measurement data have to be acquired and stored. The Isoltrap control system is based on the CS framework (see Section 5.1) [107], which has been developed and maintained by the Experiment Elektronik (EE) group at the Gsi Helmholtzzentrum für Schwerionenforschung GmbH in Darmstadt, Germany. ...
Article
The mass is a unique fingerprint of each nucleus as it reflects the sum of all interactions within it. Comparing experimental mass values with theoretical calculations provides an important benchmark of how well the role of these interactions is already understood. By investigating differences of experimental binding energies, such as two-neutron separation energies (S2n), valuable indications for nuclear-structure studies are provided. The present thesis contributes to these studies providing new high-precision mass measurements especially in the heavy-mass region. Here, nuclear theory is heavily challenged due to the large number of nucleons. The data have been obtained at the Penning-trap mass spectrometer ISOLTRAP located at the radioactive-ion-beam facility Isolde at CERN. For the determination of the masses, the time-of-flight ion-cyclotron-resonance technique has been applied. While the new mass data for 122−124Ag continue existing trends in the S2n energies, the new mass values for 207,208Fr render them more precisely. In the case of the mass values for 184,186,190,193−195Tl a new interesting odd-even effect has been revealed. The comparison of the measured mass values with theoretical models furthermore demonstrates significant problems in reproducing the strength of the pairing correctly. This is of special interest for the discussion about shape coexistence in the region around the doubly-magic 208Pb.
... At Pentatrap, a control system (CS) based on the CS-framework (GSI, Darmstadt) will be used. This framework is built in the Lab View development system (National Instruments) and was originally developed for time-of-flight detection experiments [178]. The CS offers a high stability and a control of all hardware units in use within one frame. ...
Article
The novel Penning-trap mass spectrometer Pentatrap aims for mass-ratio measure- ments of highly-charged ions with a relative precision of a few parts in 10^12. As the key part, an innovative trap assembly was designed. It consists of five cylindrical traps allowing for simultaneous measurements of two ion species and for continuous moni- toring of the trapping conditions. This promises a substantial reduction of systematic errors. Moreover, in the course of this thesis a detection system was developed and characterized, which will enable fast and accurate measurements through its single-ion sensitivity and high signal-to-noise ratio. In neutrino physics, the detection of neutrinoless double-electron capture would un- ambiguously prove the Majorana nature of neutrinos. In search for a suitable nuclide for the observation of this process, precise information about the total decay energy (Q-value) is needed in order to find a transition with a resonant enhancement of the decay rate. The mass ratios of 152Sm/152Gd and 164Dy/164Er were measured to a relative uncertainty of ∼ 10^−9 at Shiptrap. This presents the first directly determined Q-values for the corresponding transitions.
... The HITRAP control system (CS) is being developed to meet all these requirements: new hardware modules are being included, scans and cycles capabilities are being expanded, user interface is being improved. The system design is based on the CS used in the Isoltrap experiment [Bec04]. The HI-TRAP CS will manage and monitor HITRAP operations starting from the LEBT and up to high-precision experiments. ...
Article
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The HITRAP (Highly charged Ions TRAP)facility is being set up and commissioned at GSI, Darmstadt. It will provide heavy, highly charged ions at low velocities to high-precision atomic physics experiments. Within this work the Cooler trap- the key element of the HITRAP facility was tested. The Cooler trap was assembled, aligned, and commissioned in trapping experiments with ions from off-line sources.The work performed within the scope of this thesis provided the baseline for further operation and maintenance of the Cooler trap.
... These and other devices are controlled (and in some cases read out) with the PENTA-TRAP control system (CS), which is based on the CS-framework that was developed at GSI [179]. The framework is based on National Instruments LabVIEW. ...
Article
The novel Penning-trap mass spectrometer PENTATRAP aims at mass-ratio determinations of medium-heavy to heavy ions with relative uncertainties below 10^−11. From the mass ratios of certain ion species, the corresponding mass differences will be determined with sub-eV/c^2 uncertainties. These mass differences are relevant for neutrino-mass experiments, a test of special relativity and tests of bound-state QED. Means to obtain the required precision are very stable trapping fields, the use of highly-charged ions produced by EBITs, a non-destructive cyclotron-frequency determination scheme employing detectors with single-ion sensitivity and a five-trap tower, that allows for measurement schemes being insensitive to magnetic field drifts. Within this thesis, part of the detection electronics was set up and tested under experimental conditions. A single-trap setup was realized. A Faraday cup in the trap tower enabled the proper adjustment of the settings of the beamline connecting the EBIT and the Penning-trap system, resulting in the first trapping of ions at PENTATRAP. A stabilization of switched voltages in the beamline and detailed studies of ion bunch characteristics allowed for reproducible loading of only a few ions. Detection of the axial oscillation of the trapped ions gave hints that in some cases, even single ions had been trapped. Furthermore, valuable conclusions about necessary modifications of the setup could be drawn.
... Although this design study demonstrates the usefulness of LVOOP successfully, this approach must be confirmed by application to a real control system like, as an example, the CS-framework [5]. ...
Article
In 2006, LabVIEW Object Oriented Programming (LVOOP) became available as a new feature with LabVIEW version 8.20. This work accomplishes a design study in order to investigate the use of LVOOP to control system development. With LVOOP, the way of object-oriented programming must be reconsidered, since this approach reveals quite a few differences compared to conventional object-oriented programming.
... The LabVIEW-based control and data taking system for the different measurement sequences is based on the GSI Control System (CS) framework [150,151]. Whereas the original framework is developed to maintain the Time-of-Flight Cyclotron Resonance detection technique [152], the further development for Pentatrap maintains the FT-ICR detection technique within our specific setup. Thus, it is possible to control the ion sources (see Chap. 8), the ion optics and the diagnostics. ...
Thesis
The five-Penning-trap mass spectrometer PENTATRAP is a novel high-precision experiment located at the Max-Planck-Institut für Kernphysik, Heidelberg. PENTATRAP aims for an accuracy of up to a few parts in 10^12 for mass ratios of long-lived highly charged nuclides up to uranium. A physics program for PENTATRAP includes, e.g., measurements of Q-values of relevant beta-transitions for neutrino physics, stringent tests of quantum electrodynamics in extreme electromagnetic fields, and a test of special relativity. Thanks to a multi-trap configuration various fast measurement schemes comprising simultaneous frequency measurements can be applied. Further main features of PENTATRAP are highly sensitive cryogenic non-destructive detection systems and the access to highly charged ions via the small PENTATRAP-EBIT and the Heidelberg-EBIT. In the context of the present thesis, the assembly of this world-wide unique facility was started and was considerably put forward. The ion transport and capture in the Penning-traps was simulated and a multitude of operational test, e.g., the investigation of the magnetic field of the superconducting magnet were performed. A magnetic field compensation system and the instrumentally challenging cryogenic translation and tilt system were built up and characterized. Furthermore, the highly tolerated Penning traps were designed, built and assembled. The first installation of the cryogenic assembly including the first cabling of the Penning traps finally allowed the first cool down of the experiment. Moreover, the successful installation of the PENTATRAP-EBIT was performed and the first production of highly charged rhenium and osmium ions which are required for Q-value measurements was demonstrated and optimized.
... The other PC is connected via GPIB bus to the frequency generators and the multi-channel scaler. The LabVIEW-based control software CS[BEC04] and the C++-based measurement software MM6, which was developed at the ISOLTRAP (CERN) facility run on this PC. The control software CS, developed at GSI to meet the requirements of ion trap facilities such as SHIPTRAP, ISOLTRAP or MLLTRAP, provides communication to the attached devices and the timing card. ...
... The system is in daily operation and has proven its reliability. The PCS is based on a framework which is in-house developed by the ECOS group [5]. Parts of the PCS have been implemented and tested until now while others are under commissioning. ...
Article
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1 Gesellschaft für Schwerionenforschung mbH; 2 TU Darmstadt; 3 Lawrence Livermore National Laboratory, USA; 4 Fachhochschule Münster; 5 Julius-Maximilians Universität Würzburg; 6 Max-Born-Institut Berlin We report the major achievements of the phys-ics/engineering design effort and the construction of the PHELIX laser, which will be capable of producing pulses up to a peak power of one PW (10 15 W) in 500 fs and 400 GW in 10 ns. One of the main technological challenges in the produc-tion of high-energy petawatt (HEPW) pulses is the reduction of the peak power on today's highest damage threshold laser components (some GW/cm 2). The enabling technological advancement which reduces the intensity in the high-energy laser amplifier of PHELIX by a factor of 30,000 and thus avoids catastrophic damage as well as deleterious nonlinear effects is chirped pulse amplification (CPA) [1, 2]. In the front-end section of PHELIX, a low-energy (~nJ), 15 nm bandwidth seed-pulse is passed through a positive-dispersion delay line (grating stretcher). This produces out of the 110 fs oscillator pulse a three ns duration chirped pulse which is then amplified at an irradiance well below the self-focusing threshold. After amplification in the main am-plifier to ~650 J, the high-energy chirped pulse will be re-compressed by a pair of parallel diffraction gratings to ~500 fs. The emerging technology of multi-layer dielectric (MLD) gratings is believed to offer a substantial improvement of the laser induced damage threshold (LDT) compared to the traditional meter size gold coated gratings [3, 4]. In coopera-tion with LLE Rochester in the US and LULI in France, we spent significant effort for the investigation of the LDT of MLD gratings produced by Horiba Jobin Yvon, Lawrence Livermore National Laboratory, and General Atomics. We designed and built a vacuum test bed for 500 fs LDT meas-urements. The set-up used 45 mJ pulses from the PHELIX fs-front-end which were compressed in our 10 joule terawatt compressor and then focused to a 300 micron diameter spot onto the test sample. With this set-up a large number of measurements were conducted during the course of the year with grating samples ranging from 2 inch to 480 x 330 mm 2 in size. Uniquely so far, the measurements are fully con-ducted in vacuum. This avoids nonlinear pulse distortion as well as providing the actual environment in which the grat-ings will finally be operated. In 2004 the physics design of the PW compressor was completed. We developed a ray tracing and beam propaga-tion model that allowed us to evaluate the performance of different geometries. Our model predicts that a single pass is the optimum solution for our requirements. This geometry offers the highest possible throughput and the most effi-cient/economic use of the available grating surface. How-ever, the output beam exhibits a considerable amount of uncompensated spatial chirp. Our beam propagation calcula-tions model the impact of the chirp onto the focused inten-sity as well as the effect of spectral clipping on the limited size gratings. In addition we studied the near-field propaga-tion effects that could potentially lead to damage of the final optics behind the compressor. The simulations show a shear of the pulse front in the focus (Fig. 1) which results in an increase in the duration of the energy deposition across the focus by 5% (~20 fs). However, the pulse stays locally short and the peak intensity remains unchanged. The code should be extendable to also simulate the alignment and wave front tolerances for a tiled grating compressor which should allow to go beyond one PW in the future.
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The FRS Ion Catcher setup at GSI is used for high precision measurements of slowed down exotic nuclei. The current setup consists of a gas-filled stopping cell, working at cryogenic temperatures for improved gas purity, coupled to a radio-frequency quadrupole beamline for bunching and pre-selection and a multiple-reflection time-of-flight mass spectrometer for precise mass measurements. The setup with all its components is controlled by various control systems. The development of a new slow control system for monitoring, control, and logging of all components of this setup is presented. The slow control is based on the LabVIEW Actor Framework enhanced by the Control System++ libraries, a highly scalable and extendable platform which is a powerful tool to create complex messaging schemes from custom events. The implementation and testing of the control system at the FRS Ion Catcher setup is discussed.
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A multi-reflection time-of-flight (MR-ToF) device has been set up for the development and test of new MR-ToF techniques and for future applications in atomic cluster research. The instrument, consisting of a laser-ablation ion source, a quadrupole bender, the MR-ToF analyzer (with ion mirrors and in-trap lift), and a channeltron detector, is described in detail and characterized with respect to preliminary results of its performance parameters. In addition, cluster ions were mass selected in the MR-ToF device and photodissociated. The charged fragments were stored and mass analyzed in a proof-of-principle MS/MS experiment where both MS steps were performed in the MR-ToF operation mode.
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Photofragmentation spectra for small bismuth-cluster cat- and anions are recorded for the investigation of their fragmentation pathways as a function of cluster size. To this end, the ions of interest are stored and size-selected in an electrostatic ion beam trap/a multi-reflection time-of-flight mass spectrometer with high resolving power. The subsequent photoexcitation is timed to their turn-around point in the trap’s mirror potential. In this novel approach, charged fragment clusters exhibit the same energy as the precursor ions and, thus, can be further stored and investigated with identical trap configurations. The results suggest a high stability of the neutral bismuth tetramer in accordance with previous reports, which is attributed to bismuth clusters exhibiting semimetal properties. Additionally, there is evidence for the loss of larger neutral fragments. Graphical abstract Open image in new window
Chapter
The high-energy high-power laser system PHELIX (Petawatt High Energy Laser for heavy Ion eXperiments) [1] is currently under construction at the Gesellschaft fuer Schwerionenforschung mbH (GSI) Darmstadt. With PHELIX GSI will offer the unique combination of a high-current, high-energy (GeV/u) heavy-ion beam with an intense laser beam. This will open the door to a variety of fundamental science issues in the field of atomic physics, plasma physics and nuclear physics. The project will gain further interest in the near future by the dramatic increase of the accelerator performance with the starting FAIR project at GSI [2]. This paper reports the current status of the project as well as the laser architecture. The proposed physics program and a first experiment carried out with PHELIX, the realization of a transient collisionally excited x-ray laser [3], will also be reviewed briefly.
Article
The CS framework is used in production runs at various experiments. Results that were obtained using CS as control and data acquisition systems have been published. In general, the experimentalists are satisfied with the CS framework. CS is also envisaged as a candidate for control systems at FLAIR and HITRAP. Technically, CS has concentrated on the device layer. For larger control systems, the application layer is becoming more important. As an example, future developments will deal with security/locking mechanisms as well as object nets.
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Most of the Penning trap spectrometers for precision measurements at radioactive ion beam facilities make use of another Penning trap, located upstream in the experimental set up, to perform isobaric separation and deliver cooled and pure ion samples to be measured. The preparation trap for the project TRAPSENSOR at the University of Granada has been built to prepare ions, produced off-line with a laser-desorption ion source, using firstly the buffer-gas cooling technique. The system has been built following the geometrical specifications given in the Technical Design Report for the MATS Penning-trap system to be built at the future Facility for Antiprotons and Ion Research (FAIR) in Darmstadt. So far, cooling resonances have been obtained for stable nuclides, with mass-to-charge ratios ranging from 40 to about 200, with a performance similar to those systems already in operation at radioactive ion beam facilities. In this contribution, the preparation trap, built and commissioned at the University of Granada, will be briefly described. First results on buffer-gas cooling will be presented.
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Investigation of short-lived nuclei is a challenging task that MATS and LaSpec will handle at the low energy branch of Super-FRS at FAIR. The groundwork for those experiments is laid-out already today at the TRIGA-SPEC facility as a powerful development platform located at the research reactor TRIGA Mainz. The latest status, new developments and first results of commissioning runs are presented here.
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Trapping and cooling techniques play an increasingly important role in many areas of science. This publication focuses on high-accuracy mass spectrometry of radionuclides by use of Penning traps where storing and cooling is also essential. The pioneering set-up, the very first Penning trap installed at a radioactive-beam facility was ISOLTRAP, still in operation after almost thirty years at the on-line isotope separator ISOLDE at CERN. This publication describes how ISOLTRAP was developed over the years as a high-performance mass spectrometer. In the meantime, the application of Penning traps to mass spectrometry of short-lived nuclei became very popular so that such systems are operated or planned at nearly all radioactivebeam facilities worldwide. (c) 2013 Elsevier B.V. All rights reserved.
Conference Paper
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A multi-reflection time-of-flight mass spectrometer has been set up for systematic studies of Coulomb effects of stored ion bunches. We report preliminary experimental results and simulations of peak coalescence of time-of-flight signals as a function of the number of simultaneously trapped ions.
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The Paul trap with a rectangular driving field, known as digital ion trap (DIT) has been investigated by mapping the stability diagram, i.e., measuring the relative storage efficiency with respect to the trapping parameters, and comparison to the conventional Paul trap with harmonic guiding field. The results show that the performance of the DIT can be described in terms of the conventional trap, when the trapping parameters are redefined according to the zeroth and first order Fourier component of the driving field. The higher harmonics seem to have only little influence.
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The Penning trap is one of the most important experimental devices in the field of nuclear physics, and measures atomic masses with the highest precision in the world. Many such devices are currently in operation, with more being designed and constructed. To start the experimental study of atomic masses with very high precision in China, the Lanzhou Penning Trap (LPT) is being constructed at the Institute of Modern Physics, Chinese Academy of Sciences. In this paper the progress and status of the LPT will be reported.
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. A radial dipolar excitation has been applied to a hyperbolic Paul trap with a segmented ring electrode. In addition, this configuration allowed the generation of an elliptical Paul trap by superimposing the RF trapping field with an electrostatic azimuthally quadrupolar field. The changes in the radial ion motions with respect to the conventional Paul trap are discussed and investigated experimentally. As expected, the formerly degenerated radial eigenfrequencies of the standard Paul trap split into two separate resonances at and , while the axial eigenfrequency remains unaffected. The new trap design adds flexibility and extends the range of applications of Paul traps.
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A cylindrical double Penning trap system has been installed and commissioned at the Maier-Leibnitz-Laboratory (MLL) in Garching. This trap system has been designed to isobarically purify low-energy ion beams and perform highly accurate mass measurements. Technical details of the device and the first results of the commissioning measurements will be presented. The mass resolving power achieved in the first trap for 85Rb ions is R=139(2)×103, while a relative mass uncertainty of δm/m=2.9×10−8 was reached with the second trap (no analysis of systematic uncertainties included) when using 87Rb as a reference ion for 85Rb.
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The Petawatt High Energy Laser for Ion eXperiments (1,2), will offer the unique combination of a high current, high energy (GeV/u) heavy-ion beam with a powerful laser beam thus providing the opportunity to investigate a variety of fundamental science issues in the field of atomic physics, nuclear physics, and plasma physics. The PHELIX Control System (PCS) is based on the CS framework (3,4). About 40 additional classes were developed for the PCS and about 250 objects are distributed on 13 PC's publishing about 10000 process variables. The PCS has been upgraded to CS version 3.0 recently. In CS 3.0 the entire communication layer has been changed to DIM (5) (Distributed Information Management), which is a light weight protocol for inter- process communication based on TCP/IP. The PCS was redesigned to make use and profit from the concept of named services. Clients may receive information from a service (observer pattern) or may send a command to a server (command pattern). By these means the implementation of the PCS behaviour with hierarchical state machines was eased. CS FRAMEWORK 3.0 CS is a framework that can be used by many experiments. It is a multi-threaded, event driven, object oriented and distributed framework with SCADA functionality based on LabVIEW (6,7) from National Instruments and DIM. An experiment control system can be developed by combining the CS framework with experiment specific add-ons. CS is supported on MS- Windows, Linux and the real-time OS Pharlab (LabVIEW RT). The CS framework provides an object oriented approach for standard LabVIEW by using template-VI's to create unique object references and threads and Functional Global Variables (uninitialized Shift-Registers) to maintain the object attribute values protected by semaphores. DIM is used for the local and network communication layer. The CS framework provides base classes for GUI's, State Machines or active processes that can react on events (see Fig. 1). As an example, objects of BaseProcess class can subscribe to DIM services and declare commands to ensure a common event data structure. Objects are instances of such classes and are created at runtime. Due to the common event mechanism, objects of BaseProcess or inherited classes can be dynamically combined to a dedicated distributed control
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LPT (Lanzhou Penning Trap) is an ion-trap facility in Lanzhou, China. As ions can be cooled to an extremely small phase space and can be stored for a very long time, ion traps are a perfect instrument for high precision mass measurements. A system with specialized electronics for LPT is under construction now. This system could be used for voltage and timing control to make ions moving in a special mode, and the data acquisition and analysis online/offline could be achieved in the mean time. The requirements of control system, the distribution of hardware, the overview of software, and the latest progress of LPTCtrlSys (Lanzhou Penning Trap Control System) are presented.
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For the control of experimental sequences composed of triggers, gates and delays a Pulse-Pattern Generator (PPG) has been developed based on a Field Programmable Gate Array (FPGA) addressed in a LabVIEW environment. It allows a highly reproducible timing of measurement procedures by up to 64 individual channels with pulse and delay periods from the nanoseconds to the minutes range. The PPG has been implemented in the context of the development of a new control system for the ClusterTrap setup, an ion storage device for atomic-cluster research, in close contact with the SHIPTRAP and ISOLTRAP collaborations at GSI and CERN, respectively. As the new PPG is not ion-trap specific it can be employed in any experiment based on sequences of triggers, pulses and delays.
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A multi-reflection time-of-flight (MR-ToF) mass analyzer has been integrated into ISOLTRAP, the precision mass spectrometer for on-line mass determinations of short-lived nuclides at ISOLDE/CERN. The new instrument improves ISOLTRAP by providing a fast separation of isobaric contaminant species as well as subsequent ion selection using the fast Bradbury–Nielsen gate. Suppression ratios of up to 10^4 and mass-resolving powers of over 10^5 have been reached in off-line experiments. Preliminary data from on-line applications illustrate the benefit and performance of the device and its potential in the context of the ISOLTRAP setup.
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The mass of radionuclides contribute to a variety of fundamental studies including tests of the weak interaction and the standard model. The limits of mass measurements on exotic nuclides have been extended considerably by the Penning-trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN. Recent ISOLTRAP measurements are summarized and current technical improvements are outlined.
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At the Helmholtz center GSI, PHELIX (Petawatt High Energy Laser for heavy Ion eXperiments) has been commissioned for operation in stand-alone mode and, in combination with ions accelerated up to an energy of 13 MeV/u by the heavy ion accelerator UNILAC. The combination of PHELIX with the heavy-ion beams available at GSI enables a large variety of unique experiments. Novel research opportunities are spanning from the study of ion–matter interaction, through challenging new experiments in atomic physics, nuclear physics, and astrophysics, into the field of relativistic plasma physics. Abstract At the Helmholtz center GSI, PHELIX (Petawatt High Energy Laser for heavy Ion eXperiments) has been commissioned for operation in stand-alone mode and, in combination with ions accelerated up to an energy of 13 MeV/u by the heavy ion accelerator UNILAC. The com-bination of PHELIX with the heavy-ion beams available at GSI enables a large variety of unique experiments. Novel research opportunities are spanning from the study of ion– matter interaction, through challenging new experiments in atomic physics, nuclear physics, and astrophysics, into the field of relativistic plasma physics.
Article
The WITCH experiment will for the first time use a dedicated Penning trap as a radioactive source. By combining this with a retardation spectrometer, general access is opened to the b-recoil energy observable, which allows, e.g. to test the validity of the V-A form of the weak interaction. A system of specialized electronics with accompanying networked software control system has been developed for WITCH. Herein is given a short overview of the general control system and details about the electronic as well as software components special for the fast control of this Penning-trap-plus-spectrometer set-up. r 2004 Elsevier B.V. All rights reserved.
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ClusterTrap has been designed to investigate properties of atomic clusters in the gas phase with particular emphasis on the dependence on the cluster size and charge state. The combination of cluster source, Penning trap and time-of-flight mass spectrometry allows a variety of experimental schemes including collision-induced dissociation, photo-dissociation, further ionization by electron impact, and electron attachment. Due to the storage capability of the trap extended-delay reaction experiments can be performed. Several recent modifications have resulted in an improved setup. In particular, an electrostatic quadrupole deflector allows the coupling of several sources or detectors to the Penning trap. Furthermore, a linear radio-frequency quadrupole trap has been added for accumulation and ion bunching and by switching the potential of a drift tube the kinetic energy of the cluster ions can be adjusted on their way towards or from the Penning trap. Recently, experiments on multiply negatively charged clusters have been resumed.
Chapter
A new versatile LabVIEW® based control system has been developed and implemented at the ISOLTRAP experiment. This enhances the ease of use as well as the flexibility and reliability for ISOLTRAP and is flexible enough to be used for other trap experiments as well.
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The WITCH experiment is a medium-scale experimental set-up located at ISOLDE/CERN. It combines a double Penning trap system with a retardation spectrometer for energy measurements of recoil ions from β decay. For a correct operation of such a set-up a whole range of different devices is required. Along with the installation and optimization of the set-up a computer control system was developed to control these devices. The CS-Framework that is developed and maintained at GSI, was chosen as a basis for this control system as it is perfectly suited to handle the distributed nature of a control system.We report here on the required hardware for WITCH, along with the basis of this CS-Framework and the add-ons that were implemented for WITCH.
Article
The research reactor TRIGA Mainz is an ideal facility to provide neutron-rich nuclides with production rates sufficiently large for mass spectrometric and laser spectroscopic studies. Within the TRIGA-SPEC project, a Penning trap as well as a beamline for collinear laser spectroscopy are being installed. Several new developments will ensure high sensitivity of the trap setup enabling mass measurements even on a single ion. Besides neutron-rich fission products produced in the reactor, also heavy nuclides such as 235U or 252Cf can be investigated for the first time with an off-line ion source. The data provided by the mass measurements will be of interest for astrophysical calculations on the rapid neutron-capture process as well as for tests of mass models in the heavy-mass region. The laser spectroscopic measurements will yield model-independent information on nuclear ground-state properties such as nuclear moments and charge radii of neutron-rich nuclei of refractory elements far from stability. TRIGA-SPEC also serves as a test facility for mass and laser spectroscopic experiments at SHIPTRAP and the low-energy branch of the future GSI facility FAIR. This publication describes the experimental setup as well as its present status.
Article
This paper reports on the status of the PHELIX petawatt laser which is built at the Gesellschaft fuer Schwerionenforschung (GSI) in close collaboration with the Lawrence Livermore National Laboratory (LLNL), and the Commissariat à l'Energie Atomique (CEA) in France. First experiments carried out with the chirped pulse amplification (CPA) front-end will also be briefly reviewed.
Article
The high-energy high-power laser system PHELIX (Petawatt High Energy Laser for heavy ton eXperiments) [1] is currently under construction at the Gesellschaft fuer Schwerionenforschung mbH (GSI) Darmstadt. With PHELIX GSI will offer the unique combination of a high-current, high-energy (GeV/u) heavy-ion beam with an intense laser beam. This will open the door to a variety of fundamental science issues in the field of atomic physics, plasma physics and nuclear physics. The project will gain further interest in the near future by the dramatic increase of the accelerator performance with the starting FAIR project at GSI [2]. This paper reports the current status of the project as well as the laser architecture. The proposed physics program and a first experiment carried out with PHELIX, the realization of a transient collisionally excited x-ray laser [3], will also be reviewed briefly.
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The novel five-Penning trap mass spectrometer PENTATRAP is developed at the Max-Planck-Institut f\"ur Kernphysik (MPIK), Heidelberg. Ions of interest are long-lived highly charged nuclides up to bare uranium. PENTATRAP aims for an accuracy of a few parts in 10^12 for mass ratios of mass doublets. A physics program for PENTATRAP includes Q-values measurements of \beta-transitions relevant for neutrino physics, stringent tests of quantum electrodynamics in the regime of extreme electric fields, and a test of special relativity. Main features of PENTATRAP are an access to a source of highly charged ions, a multi-trap configuration, simultaneous measurements of frequencies, a continuous precise monitoring of magnetic field fluctuations, a fast exchange between different ions, and a highly sensitive cryogenic non-destructive detection system. This paper gives a motivation for the new mass spectrometer PENTATRAP, presents its experimental setup, and describes the present status.
Article
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Mass measurements provide important information concerning nuclear structure. This work presents results from the pioneering Penning trap spectrometer Isoltrap at CERN-ISOLDE. High-precision mass measurements of neutron-rich manganese (58−66Mn) and krypton isotopes (96,97Kr) are presented, of which the 66Mn and 96,97Kr masses are measured for the first time. In particular, the mass of 97Kr was measured using the preparation trap and required the definition of a new fit function. In the case of the manganese isotopes, the N = 40 shell closure is addressed. The two-neutron-separation energies calculated from the new masses show no shell closure at N = 40 but give an estimation of the proton-neutron interaction (around 0.5 MeV) responsible for the increase of collectivity and nuclear deformation in this mass region. The new krypton masses show behavior in sharp contrast with heavier neighbors where sudden and intense deformation is present, interpreted as the establishment of a nuclear quantum shape/phase transition critical-point boundary. The new masses confirm findings from nuclear mean-square charge-radius measurements up to N = 60 but are at variance with conclusions from recent gamma-ray spectroscopy. Another part of this work was the design of new decay spectroscopy system behind the Isoltrap mass spectrometer. The beam purity achievable with Isoltrap will allow decay studies with and detection coupled to a tape-station. This system has been mounted and commissioned with the radioactive beam 80Rb.
Article
Nuclear masses are an important quantity to study nuclear structure since they reflect the sum of all nucleonic interactions. Many experimental possibilities exist to precisely measure masses, out of which the Penning trap is the tool to reach the highest precision. Moreover, absolute mass measurements can be performed using carbon, the atomic-mass standard, as a reference. The new double-Penning trap mass spectrometer Triga-Trap has been installed and commissioned within this thesis work, which is the very first experimental setup of this kind located at a nuclear reactor. New technical developments have been carried out such as a reliable non-resonant laser ablation ion source for the production of carbon cluster ions and are still continued, like a non-destructive ion detection technique for single-ion measurements. Neutron-rich fi ssion products will be available by the reactor that are important for nuclear astrophysics, especially the r-process. Prior to the on-line coupling to the reactor, Triga-Trap already performed o -line mass measurements on stable and long-lived isotopes and will continue this program. The main focus within this thesis was on certain rare-earth nuclides in the well-established region of deformation around N ~ 90. Another fi eld of interest are mass measurements on actinoids to test mass models and to provide direct links to the mass standard. Within this thesis, the mass of 241Am could be measured directly for the fi rst time.
Article
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Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique “fingerprint”. Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10−5 to below 10−8 for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an A_dvanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10−9 can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. This accuracy limit is important for fundamental interaction tests, but also allows for the study of the fine structure of the nuclear mass surface with unprecedented accuracy, whenever required. The use of the FT-ICR technique provides true single ion sensitivity. This is essential to access isotopes that are produced with minimum rates which are very often the most interesting ones. Instead of pushing for highest accuracy, the high charge state of the ions can also be used to reduce the storage time of the ions, hence making measurements on even shorter-lived isotopes possible. Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools for in-trap high-resolution conversion-electron and charged-particle spectroscopy from carrier-free sources will be developed, aiming e.g. at the measurements of quadrupole moments and E0 strengths. With the possibility of both high-accuracy mass measurements of the shortest-lived isotopes and decay studies, the high sensitivity and accuracy potential of MATS is ideally suited for the study of very exotic nuclides that will only be produced at the FAIR facility. Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear deformation is achieved. Laser spectroscopy provides the only mechanism for such studies in exotic systems and uniquely facilitates these studies in a model-independent manner. The accuracy of laser-spectroscopic-determined nuclear properties is very high. Requirements concerning production rates are moderate; collinear spectroscopy has been performed with production rates as few as 100 ions per second and laser-desorption resonance ionization mass spectroscopy (combined with β-delayed neutron detection) has been achieved with rates of only a few atoms per second. This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy, which will provide a complete system with respect to the physics and isotopes that can be studied. Since MATS and LaSpec require high-quality low-energy beams, the two collaborations have a common beamline to stop the radioactive beam of in-flight produced isotopes and prepare them in a suitable way for transfer to the MATS and LaSpec setups, respectively.
Article
Full-text available
Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique “fingerprint”. Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10−5 to below 10−8 for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an A_dvanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10−9 can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. This accuracy limit is important for fundamental interaction tests, but also allows for the study of the fine structure of the nuclear mass surface with unprecedented accuracy, whenever required. The use of the FT-ICR technique provides true single ion sensitivity. This is essential to access isotopes that are produced with minimum rates which are very often the most interesting ones. Instead of pushing for highest accuracy, the high charge state of the ions can also be used to reduce the storage time of the ions, hence making measurements on even shorter-lived isotopes possible. Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools for in-trap high-resolution conversion-electron and charged-particle spectroscopy from carrier-free sources will be developed, aiming e.g. at the measurements of quadrupole moments and E0 strengths. With the possibility of both high-accuracy mass measurements of the shortest-lived isotopes and decay studies, the high sensitivity and accuracy potential of MATS is ideally suited for the study of very exotic nuclides that will only be produced at the FAIR facility.Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear deformation is achieved. Laser spectroscopy provides the only mechanism for such studies in exotic systems and uniquely facilitates these studies in a model-independent manner.The accuracy of laser-spectroscopic-determined nuclear properties is very high. Requirements concerning production rates are moderate; collinear spectroscopy has been performed with production rates as few as 100 ions per second and laser-desorption resonance ionization mass spectroscopy (combined with β-delayed neutron detection) has been achieved with rates of only a few atoms per second.This Technical Design Report describes a new Penning trap mass spectrometry setup as well as a number of complementary experimental devices for laser spectroscopy, which will provide a complete system with respect to the physics and isotopes that can be studied. Since MATS and LaSpec require high-quality low-energy beams, the two collaborations have a common beamline to stop the radioactive beam of in-flight produced isotopes and prepare them in a suitable way for transfer to the MATS and LaSpec setups, respectively.
Article
Full-text available
ISOLTRAP is a Penning trap mass spectrometer for high-precision mass measurements on short-lived nuclides installed at the on-line isotope separator ISOLDE at CERN. The masses of close to 300 radionuclides have been determined up to now. The applicability of Penning trap mass spectrometry to mass measurements of exotic nuclei has been extended considerably at ISOLTRAP by improving and developing this double Penning trap mass spectrometer over the past two decades. The accurate determination of nuclear binding energies far from stability includes nuclei that are produced at rates less than 100 ions/s and with half-lives well below 100ms. The mass-resolving power reaches 107 corresponding to 10keV for medium heavy nuclei and the uncertainty of the resulting mass values has been pushed down to below 10-8. The article describes technical developments achieved since 1996 and the present performance of ISOLTRAP.
Article
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The goal of the low-energy-beam and ion-trap (LEBIT) project is to convert the high-energy exotic beams produced at NSCL/MSU into low-energy low-emittance beams. This beam manipulation will be done by a combination of a high-pressure gas stopping cell and a radio-frequency quadrupole ion accumulator and buncher. The first experimental program to profit from the low-energy beams produced will be high-accuracy mass measurements on very short-lived isotopes with a 9.4 T Penning trap system. The status of the project is presented with an emphasis on recent stopping tests range of 100 MeV/A 40Ar18+ ions in a gas cell.
Article
Full-text available
Mass measurements of 34Ar, 73-78Kr, and 74,76Rb were performed with the Penning-trap mass spectrometer ISOLTRAP. Very accurate Q EC-values are needed for the investigations of the t-value of 0+ → 0+ nuclear β-decays used to test the standard model predictions for weak interactions. The necessary accuracy on the Q EC-value requires the mass of mother and daughter nuclei to be measured with δm/m ⩽ 3 . 10-8. For most of the measured nuclides presented here this has been reached. The 34Ar mass has been measured with a relative accuracy of 1.1 . 10-8. The Q EC-value of the 34Ar 0+ → 0+ decay can now be determined with an uncertainty of about 0.01%. Furthermore, 74Rb is the shortest-lived nuclide ever investigated in a Penning trap.
Article
Full-text available
Direct mass measurements of short-lived Cs and Ba isotopes have been performed with the tandem Penning trap mass spectrometer ISOLTRAP installed at the on-line isotope separator ISOLDE at CERN. Typically, a mass resolving power of 600 000 and an accuracy of δm ≈ 13 keV have been obtained. The masses of 123,124,126Ba and 122mCs were measured for the first time. A least-squares adjustment has been performed and the experimental masses are compared with theoretical ones, particularly in the frame of a macroscopic-microscopic model.
Article
Full-text available
Mass measurements on (33,34,42,43)Ar were performed using the Penning trap mass spectrometer ISOLTRAP and a newly constructed linear Paul trap. This arrangement allowed us, for the first time, to extend Penning trap mass measurements to nuclides with half-lives below one second ( 33Ar: T(1/2) = 174 ms). A mass accuracy of about 10(-7) (deltam approximately 4 keV) was achieved for all investigated nuclides. The isobaric multiplet mass equation was checked for the A = 33, T = 3/2 quartet and found to be inconsistent with the generally accepted quadratic form.
Article
A single charged particle in a Penning trap is a bound system that rivals the hydrogen atom in its simplicity and provides similar opportunities to calculate and measure physical quantities at very high precision. We review the theory of this bound system, beginning with the simple first-order orbits and progressively dealing with small corrections which must be considered owing to the experimental precision that is being achieved. Much of the discussion will also be useful for experiments with more particles in the trap, and several of the mathematical techniques have a wider applicability.
Article
The motion of an ion in a Penning trap has been investigated in the presence of an azimuthal quadrupole radio frequency field and a damping force provided by buffer gas collisions. Analytical expressions are derived which describe the line shape of the cyclotron resonance as well as the properties of the mass-selective cooling mechanism for heavy ions. Excellent agreement is observed between theoretical results and experimental data obtained with the tandem Penning trap mass spectromer ISOLTRAP at ISOLDE (CERN).
Article
The Penning trap mass spectrometer ISOLTRAP is a facility for high-precision mass measurements of short-lived radioactive nuclei installed at ISOLDE/CERN in Geneva. More than 200 masses have been measured with relative uncertainties of 1 × 10−7 or even close to 1 × 10−8 in special cases. This publication gives an overview of the measurements performed with ISOLTRAP and discusses some results.
Article
GSI proposes to build a next-generation facility for research with relativistic beams of ions and antiprotons. This facility allows a broad range of topics in nuclear and astrophysics, plasma and atomic physics to be addressed. The topic most interesting in the context of this conference is physics with high-intensity beams of exotic nuclei. In addition, a short overview of the opportunities in the other fields of nuclear physics is given.
Article
SHIPTRAP is an ion trap facility which is being set up to deliver very clean and cool beams of singly-charged recoil ions produced at the SHIP velocity filter at GSI Darmstadt. SHIPTRAP consists of a gas cell for stopping and thermalizing high-energy recoil ions from SHIP, a rf ion guide for extraction of the ions from the gas cell, a linear rf trap for accumulation and bunching of the ions, and a Penning trap for isobaric purification. The physics programme of the SHIPTRAP facility comprises mass spectrometry, nuclear spectroscopy, laser spectroscopy and chemistry of transeinsteinium elements.
Article
The Penning trap mass spectrometer ISOLTRAP plays a leading role in mass spectrometry of short-lived nuclides. The recent installation of a radio-frequency quadrupole trap and a carbon cluster ion source allowed for the first time mass measurements on exotic nuclei with a relative uncertainty of δm/m≈1×10−8. The status of ISOLTRAP mass spectrometry and recent highlights are presented.
Article
The tandem Penning trap mass spectrometer ISOLTRAP has been set up at the on-line mass separator ISOLDE at CERN/Geneva for accurate mass measurements of short-lived nuclei with . The mass measurement is performed via the determination of the cyclotron frequency of an ion in a magnetic field. The design of the spectrometer matches the particular requirements for on-line mass measurements on short-lived isotopes. With the ISOLTRAP spectrometer masses of more than 70 radioactive nuclei have so far been determined with resolving powers exceeding one million and an accuracy of typically 10−7.
Article
An ion beam cooler and buncher has been developed for the manipulation of radioactive ion beams. The gas-filled linear radiofrequency ion trap system is installed at the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. Its purpose is to accumulate the 60-keV continuous ISOLDE ion beam with high efficiency and to convert it into low-energy low-emittance ion pulses. The efficiency was found to exceed 10% in agreement with simulations. A more than 10-fold reduction of the ISOLDE beam emittance can be achieved. The system has been used successfully for first on-line experiments. Its principle, setup and performance will be discussed.
Article
In the past three years, the sensitivity and the performance of the Penning trap mass spectrometer ISOLTRAP have been enhanced significantly. These improvements, which range from technical developments to systematic studies of the various factors contributing to the uncertainty of the final mass result, now allow mass measurements of short-lived radionuclides with half-lives of less than 100 ms and with a precision of better than 10−8. Using a newly developed carbon cluster ion source, ISOLTRAP can perform absolute mass measurements relative to the microscopic mass standard 12C. These developments are reviewed as pertaining to the extension of ISOLTRAP mass measurements to higher precision and shorter half-lives and to molecular mass measurements.
Article
The Penning trap mass spectrometer ISOL\-TRAP, installed at the on-line isotope separator ISOLDE at CERN, has been used to measure atomic masses of $^{88,89,90m,91,92,93,94}$Rb and $^{91,92,93,94, 95}$Sr. Using a resolving power of $R \approx 1$ million a mass accuracy of typically 10 keV was achieved for all nuclides. Discrepancies with older data are analyzed and discussed, leading to corrections to those data. Together with the present ISOLTRAP data these corrected data have been used in the general mass adjustment.
Article
Mass measurements with the Penning trap mass spectrometer ISOLTRAP at ISOL\-DE/CERN are extended to non-surface ionizable species using newly developed ion beam bunching devices. % Masses of $^{179-197}$Hg, $^{196,198}$Pb, $^{197}$Bi, $^{198}$Po and $^{203}$At were determined with an accuracy of 1$\cdot$10$^{-7}$ corresponding to $\delta m$\,$\approx$\, 20\,keV. Applying a resolving power of up to 3.7$\cdot$10$^6$ ground and isomeric states of $^{185,187,191,193,197}$Hg were separated. First experimental values for the isomeric excitation energy of $^{187,191}$Hg are obtained. A least-squares adjustment has been performed and theoretical approaches are discussed to model the observed fine structure in the binding energy.
Article
The ISOLDE on-line isotope separators have been operated since 1967 at the CERN-SC. This 600 MeV proton synchro-cyclotron had to be shut down in December 1990 after 33 years of service and it was decided to move ISOLDE to a new experimental area. The new on-line mass-separator facility is now under construction at the CERN PS-Booster. This accelerator provides an average current of about 2 μA of 1 GeV protons in very short high intensity pulses at low repetition rate. The beam can hit either one of the two target stations, the general purpose separator (GPS), a reconstructed ISOLDE-2 type machine (which can deliver beams simultaneously into three beam lines), and the high resolution separator (HRS), which is essentially the slightly modified ISOLDE-3 separator. The central GPS beam line and the HRS feed a common beam transport system to which most of the experiments will be connected. The new facility will be taken into operation in spring 1992.
Article
Masses of the short-lived radionuclides 32Ar (T(1/2)=98 ms) and 33Ar (T(1/2)=173 ms) have been determined with the Penning trap mass spectrometer ISOLTRAP. Relative uncertainties of 6.0x10(-8) (deltam=1.8 keV) and 1.4x10(-8) (deltam=0.44 keV), respectively, have been achieved. At present, these new mass data serve as the most stringent test of the quadratic form of the isobaric-multiplet mass equation. Furthermore, the improved accuracy for the mass of 32Ar will allow for a better constraint on scalar contributions to the weak interaction. New mass values have also been measured for 44Ar and 45Ar, and a 20sigma deviation for 44Ar from the literature value was found and interpreted.
Article
We tabulate the atomic mass excesses and nuclear ground-state deformations of 8979 nuclei ranging from $^{16}$O to $A=339$. The calculations are based on the finite-range droplet macroscopic model and the folded-Yukawa single-particle microscopic model. Relative to our 1981 mass table the current results are obtained with an improved macroscopic model, an improved pairing model with a new form for the effective-interaction pairing gap, and minimization of the ground-state energy with respect to additional shape degrees of freedom. The values of only 9 constants are determined directly from a least-squares adjustment to the ground-state masses of 1654 nuclei ranging from $^{16}$O to $^{263}$106 and to 28 fission-barrier heights. The error of the mass model is 0.669~MeV for the entire region of nuclei considered, but is only 0.448~MeV for the region above $N=65$. Comment: 50 pages plus 20 PostScript figures and 160-page table obtainable by anonymous ftp from t2.lanl.gov in directory masses, LA-UR-93-3083
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