scholarly journals APAPES - Atomic Physics with Accelerators: Projectile Electron Spectroscopy

2019 ◽  
Vol 21 ◽  
pp. 153
Author(s):  
I. Madesis ◽  
A. Lagoyannis ◽  
M. Axiotis ◽  
T. J. Mertzimekis ◽  
M. Andrianis ◽  
...  
Keyword(s):  
Atomic Physics ◽  
Nuclear Physics ◽  
Strong Field ◽  
Ion Beam ◽  
Strong Support ◽  
Heavy Ion ◽  
Collision Dynamics ◽  
Atomic Collisions ◽  
Zero Degree ◽  
Gas Targets

The only existing heavy-ion accelerator in Greece, the 5.5 MV TANDEM at the National Research Center “Demokritos” in Athens has been used to date primarily for investigations centering around nuclear physics. Here, we propose to establish the new (for Greece) discipline of Atomic Physics with Accelerators, a strong field in the EU with important contributions to fusion, hot plasmas, astrophysics, accelerator technology and basic atomic physics of ion-atom collision dynamics, structure and technology. This will be accomplished by combining the existing interdisciplinary atomic collisions expertise from three Greek universities, the strong support of distinguished foreign researchers and the high technical ion-beam know-how of the TANDEM group into a cohesive initiative.Using the technique of Zero-degree Auger Projectile Spectroscopy (ZAPS), we shall complete a much needed systematic isoelectronic investigation of K-Auger spectra emitted from collisions of pre-excited ions with gas targets using novel techniques. Our results are expected to lead to a deeper understanding of the neglected importance of cascade feeding of metastable states [1] in collisions of ions with gas targets and further elucidate their role in the non-statistical production of excited three-electron states by electron capture, recently a field of conflicting interpretations awaiting further resolution.

scholarly journals Atomic Physics at the 5 MV Tandem at Demokritos: the UoC APAPES project

2019 ◽  
Vol 23 ◽  
pp. 65
Author(s):  
I. Madesis ◽  
A. Dimitriou ◽  
S. Doukas ◽  
A. Laoutaris ◽  
C. Nounis ◽  
...  
Keyword(s):  
Atomic Physics ◽  
Mixed State ◽  
Ground State ◽  
Ion Beam ◽  
Tandem Accelerator ◽  
Angle Correction ◽  
Research Initiative ◽  
Zero Degree ◽  
Gas Targets ◽  
Set Up

University of Crete (UoC) has initiated the research initiative APAPES funded by THALES‡ that has already set up a new experimental station with a beam line dedicated solely on basic atomic physics research. This new experiment utilizing Zero-degree Auger Projectile Spectroscopy (ΖΑPS) is located at the 5 MV TANDEM accelerator of the National Center for Scientific Research (NCSR) “Demokritos” in Athens, and has been put together to perform high resolution studies of electrons emitted during ion-atom collisions. The apparatus consists of a Hemispherical Deflector Analyzer (HDA) combined with a 2-dimensional Position Sensitive Detector (PSD) and a doubly-differentially pumped gas cell containing the gas-target. The goal is to perform a systematic isoelectronic investigation of K-Auger spectra emitted from pre-excited and ground state He-like ions in collisions with gas targets using novel techniques. So far, various Auger electron spectra produced through collisions of mixed state (1s2, 1s2s3S) C4+ ion beam with various gas targets have been recorded. In addition, detailed simulations using SIMION have also explored the optimal lens voltages and the solid angle correction factors for long-lived metastable states. A terminal gas stripper system is scheduled to be installed in the accelerator, extending its range of available charge states and enabling the production of pure ground state as well as mixed state beams with different metastable fractions, a measurement vital to APAPES. Here, we report on the progress made up to date on the APAPES project, the description of the apparatus, updated results and plans for the near future.

scholarly journals Heavy-ion beam-pumped lasers: Optical gain on the 476.5-nm Ar II transition

1993 ◽  
Vol 11 (3) ◽  
pp. 529-535 ◽  
Author(s):  
J. Wieser ◽  
A. Ulrich ◽  
B. Busch ◽  
R. Gernhäuser ◽  
W. Krötz ◽  
...  
Keyword(s):  
Ion Beam ◽  
Optical Gain ◽  
Heavy Ion ◽  
Spectroscopic Studies ◽  
Particle Energy ◽  
Probe Laser ◽  
Rare Gas ◽  
Ion Probe ◽  
Heavy Ion Beam ◽  
Gas Targets

The possibility of heavy-ion beam-pumped ion lasers is demonstrated by observation of optical gain on the 476.5-nm Ar II 4p–4s ion laser transition in argon gas excited by 2.5–ns pulses of 110–MeV 32S ions with repetition rates up to 156 kHz. The particle energy per pulse was about 20 μJ. The projectiles were stopped in the target at pressures between 5 and 35 kPa. The beam from an argon ion probe laser operated at 476.5 nm was used to determine gain amplitude and time structure from a measured transient increase of the probe laser intensity when target excitation by the ion beam was present. The maximum gain observed was (0.5 ± 0.1) x 10-3 at a target gas pressure of 5 kPa. The optical gain observed in argon is consistent with calculations based upon an analysis of spectroscopic studies of rare gas targets excited by heavy-ion beams.

scholarly journals Investigation of the C3+ Auger KLL spectrum obtained in collisions of 6-15 MeV C4+ (1s2, 1s2s 3S) with gas targets

2019 ◽  
Vol 26 ◽  
pp. 125
Author(s):  
I. Madesis ◽  
A. Laoutaris ◽  
E. P. Benis ◽  
T. J. M. Zouros
Keyword(s):  
Cross Sections ◽  
Collision Energy ◽  
Ion Beam ◽  
Tandem Accelerator ◽  
Naturally Occurring ◽  
Zero Degree ◽  
Gas Targets ◽  
A New Technique ◽  
Beam Component

Single electron transfer to the 1s2s 3S long-lived component of the naturally occurring mixed-state(1s2, 1s2s 3S) C4+ion beam in collisions with gas targets was investigated using zero-degree Auger projectile spectroscopy at the Demokritos 5.5 MV tandem accelerator. The observed KLL Auger spectrum contains 1s2s2p 2P and 4P states resulting from direct 2p transfer to the 1s2s 3S. Higher lying (1s2s 3S)nl2,4L states produced by nl transfer (n>2) were also observed and can in principle feed the lower lying 1s2s2p2Pand 4Pstates. However, due to spin selection rules only the quartets have large enough radiative branching ratios resulting in a proposed selective feeding of only the 1s2s2p 4P state by E1 cascades, while minimally affecting the 1s2s2p 2P states. In the absence of cascades, the ratio of cross sections for 2p transfer to the 1s2s 3S state, Rm≡ σm(4P)/σm(2P), is 2 according to spin statistics. However, the 1s2ground state beam component also contributes to the production of the 1s2s2p 2P doublet states by transfer-excitation. To isolate just the 1s2s 3S transfer contribution and compute Rm, a new technique was employed requiring the recording of two KLL spectra, with the same collision energy, but each with appreciably different 1s2s 3S content, varied by stripping techniques. Our determination of Rmshows this to be >2, in agreement with spin statistics, but contrary to the expected 4P enhancement due to cascade feeding. Details of the analysis and results are discussed.

scholarly journals Zero-degree Auger Projectile Electron Spectroscopy of Li-like Ions obtained in Collisions of 1s2s 3S He-like Ions with Gaseous Targets

2019 ◽  
Vol 24 ◽  
pp. 1
Author(s):  
I. Madesis ◽  
A. Laoutaris ◽  
E. P. Benis ◽  
A. Lagoyannis ◽  
M. Axiotis ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
Particle Physics ◽  
Ion Beam ◽  
Tandem Accelerator ◽  
Dilute Gas ◽  
Zero Degree ◽  
Gas Targets ◽  
Set Up

An experimental station has recently been completed with a beam line dedicated to atomic collision physics at the 5.5 MV TANDEM accelerator laboratory of the Institute of Nuclear and Particle Physics (INPP) at the National Center for Scientific Research (NCSR) “Demokritos” in Athens. A Zero-degree Auger Projectile Spectroscopy (ZAPS) apparatus composed of a single-stage Hemispherical Deflector Analyser (HDA) and a 2-dimensional Position Sensitive Detector (PSD), combined with a doubly differentially pumped gas target has been set up for high resolution studies of electrons emitted from projectile ions at θ = 0◦ with respect to the beam direction in collisions with dilute gas targets. A terminal gas stripper, as well as both a foil and a gas post-stripper, have also been newly installed, enhancing the capabilities of the TANDEM by allowing for the production of more intense, highly charged ion beams, thus complementing and expanding the range of the available energies and charge states of the TANDEM. Using this setup, a systematic isoelectronic investigation of high resolution K-Auger electron spectra emitted from pre-excited ions in collisions with gas targets has been commenced within the APAPES initiative. Here, we present some highlights of this program together with recent results. This investigation is expected to lead to a better understanding of electron capture to excited states of the ion beam and in particular the overlooked role of cascade feeding of metastable states contributing to the capture cross sections, recently a field of contested interpretations awaiting further resolution.

Strong-field atomic physics meets $^{229}$Th nuclear physics

2021 ◽  
Author(s):  
Wu Wang ◽  
Hanxu Zhang ◽  
Xu Wang
Keyword(s):  
Excited State ◽  
Simple Model ◽  
Atomic Physics ◽  
Ground State ◽  
Nuclear Physics ◽  
Strong Field ◽  
Nuclear Excitation ◽  
The Core ◽  
Research Areas ◽  
Nuclear Ground State

Abstract We show how two apparently unrelated research areas, namely, strong-field atomic physics and $^{229}$Th nuclear physics, are connected. The connection is possible due to the existence of a very low-lying excited state of the $^{229}$Th nucleus, which is only about 8 eV above the nuclear ground state. The connection is physically achieved through an electron recollision process, which is the core process of strong-field atomic physics. The laser-driven recolliding electron is able to excite the nucleus, and a simple model is presented to explain this recollision-induced nuclear excitation (RINE) process. The connection of these two research areas provides novel opportunities for each area and intriguing possibilities from the direct three-partite interplay between atomic physics, nuclear physics, and laser physics.

scholarly journals Energy loss dynamics of intense heavy ion beams interacting with solid targets

2002 ◽  
Vol 20 (3) ◽  
pp. 485-491 ◽  
Author(s):  
D. VARENTSOV ◽  
P. SPILLER ◽  
N.A. TAHIR ◽  
D.H.H. HOFFMANN ◽  
C. CONSTANTIN ◽  
...  
Keyword(s):  
Energy Loss ◽  
Ion Beam ◽  
Theoretical Models ◽  
Heavy Ion ◽  
High Energy ◽  
Ion Beams ◽  
High Energy Density ◽  
Back Surface ◽  
Hydrodynamic Simulations ◽  
Gas Targets

At the Gesellschaft für Schwerionenforschung (GSI, Darmstadt) intense beams of energetic heavy ions have been used to generate high-energy-density (HED) state in matter by impact on solid targets. Recently, we have developed a new method by which we use the same heavy ion beam that heats the target to provide information about the physical state of the interior of the target (Varentsov et al., 2001). This is accomplished by measuring the energy loss dynamics (ELD) of the beam emerging from the back surface of the target. For this purpose, a new time-resolving energy loss spectrometer (scintillating Bragg-peak (SBP) spectrometer) has been developed. In our experiments we have measured energy loss dynamics of intense beams of 238U, 86Kr, 40Ar, and 18O ions during the interaction with solid rare-gas targets, such as solid Ne and solid Xe. We observed continuous reduction in the energy loss during the interaction time due to rapid hydrodynamic response of the ion-beam-heated target matter. These are the first measurements of this kind. Two-dimensional hydrodynamic simulations were carried out using the beam and target parameters of the experiments. The conducted research has established that the ELD measurement technique is an excellent diagnostic method for HED matter. It specifically allows for direct and quantitative comparison with the results of hydrodynamic simulations, providing experimental data for verification of computer codes and underlying theoretical models. The ELD measurements will be used as a standard diagnostics in the future experiments on investigation of the HED matter induced by intense heavy ion beams, such as the HI-HEX (Heavy Ion Heating and EXpansion) EOS studies (Hoffmann et al., 2002).

Nondestructive surface analysis by nuclear scattering techniques

1987 ◽  
Vol 65 (8) ◽  
pp. 950-955 ◽  
Author(s):  
S. C. Gujrathi ◽  
P. Aubry ◽  
L. Lemay ◽  
J. -P. Martin
Keyword(s):  
Surface Analysis ◽  
Nuclear Physics ◽  
Ion Beam ◽  
Heavy Ion ◽  
Rutherford Backscattering ◽  
Nuclear Scattering ◽  
Elastic Recoil ◽  
Accelerator Facility ◽  
Elastic Recoil Detection ◽  
The Masses

An elastic-recoil detection (ERD) technique is developed and successfully applied in the simultaneous, nondestructive multielement depth-profile studies of thin films with thicknesses up to 2 μm, used in various material technologies. In this technique, the light elements are knocked out of the target by using an energetic heavy-ion beam obtained from the Tandom Accelerator Facility of the Nuclear Physics Laboratory. A time-of-flight method is used to separate the masses and the energies of the recoiled elements as well as the Rutherford backscattering incident ions. Using 30 MeV35Cl as the beam probe, we get an observed surface resolution of better than 100 Å at a 30° detection angle. Typical mass resolutions for energies >5 MeV are 0.2 amu in the C region and 0.7 amu in the Si region. The factors related to the mass and depth resolutions, probing depth, and approximate detection limit are systematically studied using 19F, 35Cl, and 79Br as incident beams. This newly developed ERD method, along with the already existing Rutherford backscattering (RBS) technique, makes the Nuclear Scattering Facility at the Université de Montréal unique for surface analysis.

scholarly journals Appied Nuclear Physics-Advanced Ion Beam Materials Analysis at small Accelerators

2020 ◽  
Vol 13 ◽  
pp. 43
Author(s):  
R. Grötzschel ◽  
U. Kreissig ◽  
Ch. Neelmeijer
Keyword(s):  
Thin Film ◽  
Nuclear Physics ◽  
Large Scale ◽  
Ion Beam ◽  
Depth Resolution ◽  
Heavy Ion ◽  
Thin Layers ◽  
Wide Energy Range ◽  
Elastic Recoil ◽  
Novel Technologies

The ossendorf Ion Beam Laboratory has been developed to an international large scale user facility in the field of ion beam physics and ion beam materials research. The laboratory operates a large number of modern experimental equipment at three MeV accelerators, three implanters, an ECR source and a FIB which together pro- vide almost all ions species in a wide energy range from a few hundred eV to a few ten MeV. Also IBAD and PHI devices were installed for various purposes. The re- search stations at the accelerators are supplemented by complementary techniques like TEM, SEM, AUGER, AFM etc., all contributing useful information to thin film investigations. In this paper a short overview of the laboratory is given and a few recent experiments and their results are shown. Rutherford Backscattering Spec- trometry ( RBS) and Elastic Recoil Detection Analysis (ERDA) are well established techniques for quantitative thin film. The advantage of these methods consists in the simple physics they are basing on, namely the stopping of energetic ions in matter and the binary scattering of at the Coulomb potential of atomic nuclei. The increasing importance of ultra-thin layers for novel technologies demands quantita- tive analysis techniques with a depth resolution of atomic monolayers, which can be obtained for RBS and ERDA by magnetic spectrometers only. The magnetic spec- trometers we have installed at the 3 MV Tandetron and at the 5 MV tandem are described , recent applications are shown and a few problems to achieve high depth resolution will be discussed. Heavy ion detectors as Bragg IC, dE-Erest-telescopes and ToF spectrometers, developed for nuclear physics experiments, are now applied for ERDA, providing an efficient analysis of thin films containing light elements. The lateral position resolution of such detectors enables kinematic corrections and allows large solid angles. Thus by ERDA in situ studies during surface modification processes are possible like in the case of the nitridation of aluminum and stainless steel. At the external beam mainly objects of fine arts or of historical value are analysed. It will be shown, how the complementary application of PIXE, RBS and PIGE can help to detect the beginning corrosion of mediaeval glass objects.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

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