Search results for "Accelerator"
showing 10 items of 1507 documents
Aperture edge scattering in focused MeV ion beam lithography and nuclear microscopy: An application for the GEANT4 toolkit
2009
Collimators are widely used to define MeV ion beams. Recent studies have shown the capability of combinations of collimators and lenses to define beams of MeV ions with sub-100 nanometre dimensions. Such nanometre beams have potential applications in MeV ion beam lithography, which is the only maskless technique capable of producing extremely high aspect ratio micro- and nano-structrures, as well as in high resolution MeV ion beam based imaging. The ion scattering from the collimator-edges can be a resolution restricting factor in these applications. Scattering processes at edges are difficult to study using conventional simulation codes because of the complicated geometry. In this work we …
Status and perspectives of atomic physics research at GSI
2003
A short overview on the results of atomic physics research at the storage ring ESR is given followed by a presentation of the envisioned atomic physics program at the planned new GSI facility. The proposed new GSI facility will provide highest intensities of relativistic beams of both stable and unstable heavy nuclei - up to a Lorentz factor of 24. At those relativistic velocities, the energies of optical transitions, such as for lasers.. are boosted into the X-ray region and the high-charge state ions generate electric and magnetic fields of exceptional strength. Together with high beam intensities a range of important experiments can be anticipated, for example electronic transitions in r…
Quadrupole interaction of $^{8}$Li and $^{9}$Li in LiNbO$_{3}$ and the quadrupole moment of $^{9}$Li
1988
The quadrupole interaction of nuclear spin polarized8Li (I=2) and9Li (I=3/2) in LiNbO3 has been studied at room temperature. The polarization was achieved by optical pumping of a fast atomic beam with circularly polarized laser light. The atoms were implanted into a hexagonal LiNbO3 single crystal and the quadrupole splitting ofβ-NMR spectra was measured. A ratio of ¦Q(9Li)/Q(8Li)¦=0.88(4) for the nuclear quadrupole moments was deduced, yielding a new value of ¦Q(9Li)¦=25.3 (9) mb for the quadrupole moment of9Li.
First radioactive ions charge bred in REXEBIS at the REX-ISOLDE accelerator
2003
REXEBIS is the charge breeder of the REX-ISOLDE post accelerator. The radioactive 1$^{+}$ ions produced at ISOLDE are accumulated, phase-space cooled and bunched in the REXTRAP, and thereafter injected into the EBIS with an energy up to 60 keV. The REXEBIS produced the first charge bred ions in August 2001 and has been running nearly non-stop during September to December 2001. It has delivered stable $^{39}$K$^{10+}$ and $^{23}$Na$^{6+}$ beams generated in the ion source in front of REXTRAP with a Na$^{7+}$ current exceeding 70 pA (6x10$^{7}$ p/s). Stable $^{27}$Al$^{7+}$ and $^{23}$Na$^{6+}$ from ISOLDE and also the first radioactive $^{26}$Na$^{7+}$ and $^{24}$Na$^{7+}$ beams (just 5x10$^…
Status report of the Jyvaskyla ion guide isotope separator on-line facility
1997
The ion guide isotope separator facility IGISOL of the University of Jyvaskyla has been moved to the new K-130 heavy ion cyclotron laboratory. The totally reconstructed facility is described in detail. The primary beams and targets, helium pumping, separator beam line construction and separator beam diagnostics are discussed. The spectroscopy stations are introduced with illustrative examples from the research program, including beta-delayed proton and neutron spectroscopy, gamma-ray spectroscopy with and without arrays, conversion electron spectroscopy, collinear laser spectroscopy and nuclear level lifetime spectroscopy.
Dosimetry for electron Intra-Operative RadioTherapy: Comparison of output factors obtained through alanine/EPR pellets, ionization chamber and Monte …
2015
Abstract In this work a comparison between the response of alanine and Markus ionization chamber was carried out for measurements of the output factors (OF) of electron beams produced by a linear accelerator used for Intra-Operative Radiation Therapy (IORT). Output factors (OF) for conventional high-energy electron beams are normally measured using ionization chamber according to international dosimetry protocols. However, the electron beams used in IORT have characteristics of dose per pulse, energy spectrum and angular distribution quite different from beams usually used in external radiotherapy, so the direct application of international dosimetry protocols may introduce additional uncer…
A pulsed high-voltage decelerator system to deliver low-energy antiprotons
2021
International audience; The GBAR (Gravitational Behavior of Antihydrogen at Rest) experiment at CERN requires efficient deceleration of 100 keV antiprotons provided by the new ELENA synchrotron ring to synthesize antihydrogen. This is accomplished using electrostatic deceleration optics and a drift tube that is designed to switch from -99 kV to ground when the antiproton bunch is inside – essentially a charged particle “elevator” – producing a 1 keV pulse. We describe the simulation, design, construction and successful testing of the decelerator device at -92 kV on-line with antiprotons from ELENA.
A Time Projection Chamber with GEM-Based Readout
2016
For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1 T solenoidal field and read out with three independent GEM-based readout modules, are reported. The TPC was exposed to a 6 GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.
Production of radioactive Ag ion beams with a chemically selective laser ion source
1997
Abstract We have developed a chemically selective laser ion source at the CERN-ISOLDE facility in order to study neutron-rich Ag nuclides. A pulsed laser system with high repetition rate has been used based on high-power coppe-vapour pump lasers and dye lasers. With this source significant reductions of the isobaric background has been achieved.
Laser preparation of bunched ion beams
1997
Abstract Laser ionization at ISOLDE is performed with high repetition laser beams in the ion source unit and for daughter elements with low repetition lasers synchronized with laser desorption from a secondary target. We are preparing an implementation of thermal adsorption followed by laser desorption and laser ionization in the target ion source unit of ISOLDE. The combination of resonance ionization with thermal bunching allows the preparation of bunched and chemically pure ion beams. Bunched ion beams of Mg or Ca are prepared for post-acceleration at REX-ISOLDE. In order to investigate the process of adsorption and pulsed laser desorption, experiments are performed with Ba vapour. In a …