Beam facility for irradiation/implantation and Characterization using IBA techniques
The "Particle beams" research platform of CEMHTI includes two ion accelerators : a CGR MeV cyclotron and a Pelletron electrostatic accelerator. This platform offers state-of-the-art scientific equipment for irradiation/implantation and characterization using IBA to the EMIR&A community.
The 3U-2 Pelletron of CEMHTI laboratory is a 3MV single-ended electrostatic accelerator from National Electrostatic Corporation company (NEC). Around this accelerator, CEMHTI develops experimental prototype set-ups for irradiation or light elements implantation in materials and ion beam analysis in wide diversity of scientific fields such as materials for energy, microelectronics, nanotechnology, biology or geology.
The CEMHTI cyclotron is an isochronous accelerator with variable energy. Its versatility and the very high degree of competences of associated technicians and scientists make it a multidisciplinary machine and an efficient instrument with applications in various fields such as the production of innovative radionuclides for preclinical imaging, archeometry or studies of material properties under irradiation. The experimental setups are made available to European networks (CYCLEUR, H2020 EURATOM projects) and to the national community in the EMIR&A network.
Key words : Ion-irradiation-induced damage in temperature, Hydrogen and Helium behavior in materials, Irradiation creep under stress and temperature, In situ Raman monitoring of materials under Irradiation, Solid / Liquid or Gas interfaces under irradiation, Neutron beam, Characterization using IBA techniques.
The characteristics of available ion beams are reported in the following tables.
|* Beam power regulation on the sample temperature for high irradiation damage (1 dpa / 24 h)
* High amplitude and frequency beam scanning for large area irradiation or implantation
* Multi-energy irradiation
|* Pulsed beam and synchronized optical techniques|
* Multi-energy irradiation
* Very low current irradiation (a few pA)
Irradiations with neutrons are available at CEMHTI cyclotron. Neutrons flux are produced by nuclear reaction of deuteron beams on a water-cooled beryllium target.
The maximum neutron flux is 1012 n.cm-2.s-1 and the mean energy of emitted neutrons can be selected from 5 to 10 MeV. The actual applications are in the fields of material studies for nuclear energy and of archeometry as well as geochronology with the use of the Neutron Activation Analysis technique.
IRRADIATION AND IMPLANTATION SETUPS
The roadmap for technical developments around CEMHTI accelerator facilities is focused on the investigation of physical properties evolution of materials under irradiation and their intentional modifications.
The Pelletron accelerator of CEMHTI is equipped with three experimental setups for irradiation or Hydrogen or Helium implantation (from -150°C to RT and up to 1400°C).
IBIC (Ion Beam Implantation and Channeling)
IBIC is dedicated to perform Implantation or Irradiation without or with channeling effects of single crystals. The sample-holder is set on a motorized goniometer which can be remote-controlled to ensure a random position of the single crystal in regard with the beam axis. The sample holder isn’t cooled and this limits the maximum fluence to 1015 at.cm-2 with a maximum flux around 1011 at.cm-2.s-1. The sample holder is extracted from IBIC set-up by a transfer chamber.
The implantation homogeneity of the surface (maximum 7 cm2) is ensured by using Lissajous beam scanning (frequency of 10 Hz).
ECLAIR (Experiment Chamber for Large Area Irradiation or Implantation at Room temperature)
The ECLAIR device is installed on a beam line to realize Irradiation or Implantation at Room temperature on large surfaces up to 80 cm2. The high scanning amplitude is obtained by special magnetic scanning coils with maximum frequency of 100 Hz. The sample-holder being water-cooled at a regulated temperature of 18°C, the maximum mean flux can be increased to a value of about 5.1012 at.cm-2.s-1.
The small volume of the ECLAIR setup allows to reach a good vacuum in few minutes and the collimator size of the incident beam is adjustable from a few cm2 to 80 cm2.
DIADDHEM (Dispositif d’Analyse de la diffusion du deutérium et de l’Hélium dans les Matériaux)
DIADDHEM is devoted to implantation or irradiation in temperature (from -150 to 1400°C) on one inch-diameter surface. The goniometer (X-Y translations and Y rotation) is equipped with an electronic bombardment furnace heating the rear side of the sample holder and a cooling system includes two retractable jaws cooled by cold nitrogen gas. For temperature from -150 to 100°C, the jaws are in contact with the sample holder and the respective heating and cooling powers are controlled to obtain a temperature regulated to few degrees. The temperature is measured by two thermocouples fixed on the jaws.
At high temperature (300°C-1400°C), the temperature is measured directly on the sample or on the SiC sample holder by pyrometry, depending on the optical properties of the implanted material. The scanning is a lissajous-type at a maximum frequency of 10 Hz. The sample holder is extracted from DIADDHEM set-up by a transfer chamber.
Regulation of sample temperature by beam power modulationFor high dpa rate, the beam participates to the sample heating. The beam power is modulated to obtain a regulated temperature of the sample.
The research activities of CEMHTI in the field of materials for nuclear energy led to equipping beam lines of cyclotron with dedicated set-ups for materials irradiation. The rare or unique features of the CNRS-CEMHTI cyclotron are : one vertical beam line, beryllium target for fast or moderate neutron beam production (1012 n.cm-2.s-1), beam line (high frequency pulsed ion and low flux) for alpha radiolysis, irradiation set-up for high damage rate under mechanical constraints, in situ characterization by optical techniques (Raman, Photoluminescence)and radioactive heavy ions implantation set-up.
ABC (Alphas Beam Controller) device and Pulsed beam system associated to ABC
The ABC device contains all components for beam diagnostic (alumina, faraday cup, ionization chamber, etc…) to perform reliable and reproducible experiments at ambient temperature. This device is devoted to radiolysis experiments at the liquid/solid interface with in situ Raman studies. The sample is located in a cell mounted on the back of the alphas (or other ions such as protons) beam controller device and the current can be fixed between a few pA to 400 nA.
For experiments which require ions bunches and time-synchronization instead of a continuous beam, an electrostatic deflector is installed upstream to the beam line to select one or several bunches. This system provides ions bunches with a minimal time-spread around 1 ns at a maximum frequency of 1 kHz.
This devise is dedicated to Solid/Liquid interface (Uranium dioxide / water for example) or Solid/Gas interface studies
under irradiation (Graphite/ CO2)
- Formation of radiolytic products in liquid or gas and of damages in the solid by He irradiation of the solid/liquid or gas interface
- Microstructural changes and damage creation studied by in situ RAMAN.
- RAMAN spectroscopy synchronized or not with the pulsed beam cyclotronic pulsation
- Max pressure of 2 bars and Max temperature of 700°C for Solid/Gas interface
Solid/Liquid interface Set-up
CH3ILDS (Chamber for Hydrogen or Helium Homogeneous Implantation at Large Depth in Sample) setup
This setup is devoted to the studies of mechanical properties of materials under stress and irradiation. Temperature, dpa yield and loading rate (Tensile) can be monitored, regulated and independently adjusted. To study the irradiation creep properties of materials, the damage profile is uniform in volume by using an energy degrader.
This setup is implemented within the collaboration with Paul Scherrer Institute (Villigen, Switzerland) for applications to core and primary components of advanced reactors (metallic alloys or ceramics).
DIAMANT (Dispositif d’Irradiation en Alphas de MAtériaux Nucléaires en Température) set-up
The core of DIAMANT is composed of different sample holders including one cooled with cold nitrogen gas for irradiation or hydrogen or helium implantation at low temperature (min -100°C) and an electronic bombardment furnace for irradiation or H/He implantation in temperature (max 1300°C) as well as of two Faraday cups and one alumina for beam diagnostic. All these components are mounted on a goniometer (X-Y translations and Y rotation). The sample temperature is measured using pyrometry for temperature higher than 100°C and using a thermocouple at low temperature. The sample holder is extracted from DIAMANT set-up by a transfer chamber.
DIAMANT is equipped with an energy degrader (up to 36 energies) based on a wheel supporting titanium foils with various thicknesses to obtain a homogeneous plateau of hydrogen or helium concentration. This option enables to reproduce the incorporation of helium or hydrogen impurities in the fission and fusion nuclear materials and to study as a function of temperature the H and He behavior and their interaction with defects.
One of DIAMANT assets is to enable in situ analysis using RAMAN and photoluminescence techniques of irradiated samples. This set allows observations of the combined effect of irradiation and temperature on the structure of solids (defects, colored centers ...).
CHARACTERIZATION using IBA TECHNIQUES
CEMHTI performs fundamental research in materials sciences, surfaces, interfaces and ion/matter interaction. Different kinds of materials and/or samples, coming from material sciences (thin layer engineering, semiconductor, nanomaterial…), life sciences, earth sciences can be thoroughly analyzed. One of CEMHTI major assets is a high expertise in nuclear techniques, which can be coupled together for higher relevant analysis. Investigations are performed thanks to a state-of-the-art equipment, a philosophy of constant development and a highly qualified team.
DIADDHEM setup (DIspositif d’Analyse de la Diffusion du Deutérium et de l’HElium dans les Matériaux)
The originality of the DIADDHEM facility resides in the coupling of the NRA coincidence technique with sample heating and cooling systems. DIADDHEM provides in situ measurements of helium or deuterium desorption as a function of temperature and depth profiles after annealing. Diffusion coefficients and activation energy are extracted from depth profile evolution. Investigation of thin films interfaces and surfaces.
Analysis : Behavior of helium or deuterium in nuclear materials, Interface diffusion between thin films …
Materials : Ceramics, semiconductors, metals, glasses, …
The ionic optics on this beam line has been optimized to obtain a beam size around 30-50 µm. This setup is equipped by a five positions sample-holder which can be moved by X and Y translation motors and by an endoscope to visualize the beam on a 500x500µm2 sample surface. X-rays detector and a gamma-rays detector allow performing PIXE et PIGE nuclear techniques.
Analysis : Low and high Z element characterization in the materials volume (a few tens of µm)
Materials : Geomaterials, biomaterials, industrial materials, …
IBIC (Ion Beam Implantation and Channeling) experimental device
This device is a vacuum chamber to analyze chemical composition of materials by nuclear techniques (RBS, NRA, PIXE). The 5 axis-goniometer allows to align on the beam axis a single crystal in axial or planar channeling position for damage characterization and impurities localization in lattice. The versatility of the set-up offers the possibility to couple several IBA techniques.
Analysis : Low-Z elements characterization (C, N, O..), thin layer stoichiometry, impurities localization in a crystal lattice, damage characterization…
Materials : Metals, semi-conductors, …
1D, Avenue de la Recherche Scientifique
45071 Orléans Cedex 2
33 2 38 25 54 29
How to come at CEMHTI
There are no specific formalities for a short duration experiment at the CEMHTI.