The “Particle beams” research platform of CEMHTI includes three accelerators: one Pelletron electrostatic accelerator and two positron accelerators*. 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.

TOPICS @ SPECIFITIES

• Generate disorder in materials, study the irradiation effects, modify (aging or adaptation) the properties of materials, microstructural changes under irradiation : Irradiation in temperature (100-1600K) at controlled dpa rate (Up to 1dpa/day) and in situ monitoring by Raman
• Study the hydrogen and helium behavior (diffusion, migration) in materials : Implantation in temperature (120-1600K) – Desorption rate and depth profiling vs temperature by EBS and NRA techniques
• Study solid/gas interfaces under temperature and controlled atmosphere (D2,O2…), up to 10-3 mbar : In situ or operando sorption and/or desorption rate and depth profiling measurements by IBA techniques
• Ex situ, in situ and operando characterization of materials by nuclear techniques : Chemistry and microstructure of thin layers or bulks near surface using PIXE, PIGE, NRA, EBS and RBS techniques and Channeling IBA

* The positron accelerators (not included in the EMIR&A network) produces monokinetic positrons beams with energy varying from 0.1 to 30 keV to analyze the nature, concentration and chemical environment of native or irradiation-induced defects in materials by Doppler Broadening Spectroscopy (DBS) in temperature (30 to 900K).

PELLETRON PERFORMANCES

IRRADIATION AND IMPLANTATION SETUPS

The Pelletron accelerator of CEMHTI is equipped with three experimental setups for irradiation and hydrogen or helium implantation (from 120K to RT and up to 1600K).

Irradiation 24/24h, He and H implantation, high dpa rate, temperature from 120 to 1600K, irradiated area from 1 to 60 cm2, on line Raman spectroscopy, metals, ceramics, glasses, semi-conductors, …

ECLAIR (Experiment Chamber for Large Area Irradiation or Implantation at Room temperature)

The ECLAIR device is dedicated to perform irradiation or implantation at room temperature on large surfaces, up to 60 cm2. The sample-holder is water-coole

d at a regulated temperature of 18°C and the maximum mean flux is about 1012cm-2.s-1. The irradiation or implantation homogeneity of the surface sample is made by using Lissajous beam scanning (frequency up to 120 Hz). 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 60 cm2.

Luana Cognini, thesis Politenico di Milano, Investigation of helium behaviour in oxide nuclear fuel (2021) http://hdl.handle.net/10589/174327

DIHF (Dispositif d’Irradiation à Haut Flux)

DIHF is devoted to implantation or irradiation in temperature (120 – 1600K) 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 120 to 380K, the jaws are in contact with the sample holder and the respective heating and cooling powers are adjusted to obtain a temperature regulated to few degrees. The temperature is measured by two thermocouples fixed on the jaws.

At high temperature (580-1600K), the temperature is measured directly on the sample or on the SiC sample holder by pyrometry, depending on the optical properties of the irradiated material. The scanning is a lissajous-type at a maximum frequency of 10 Hz. The sample holder is extracted from set-up through a transfer chamber.

For very high dpa rate (max 1 dpa/24h), the beam participates to the sample heating. The beam power is remote controlled and modulated to obtain a regulated temperature of the sample.

M. Boisson, L. Legras, E. Andrieu, L. Laffont, Corrosion Science (2019) 108194 10.1016/j.corsci.2019.108194

RAMSESS (RAMan SpEctroscopy for in Situ Studies)

A Raman spectrometry probe was developed and implemented on the irradiation chamber to monitor in situ the structural changes of the irradiated material. The micro-Raman probe provides high spectral and spatial resolutions to perform Raman mapping. Due to the ionoluminescence induced by the particle beam, Raman measurements and irradiation run are sequential. The sample holder (X and Y translation) is water or LN2 cooled to avoid any thermal effects.

A. Canizarès, F. Foucher, M. Baqué, J-P de Vera, T. Sauvage, O. Wendling, A. Bellamy, P. Sigot, T. Georgelin, P. Simon and F. Westall, Applied Spectroscopy 76(6) (2022) 723-729, 10.1177/00037028211062943

CHARACTERIZATION using IBA TECHNIQUES

Ion Beam Analysis (IBA) uses light MeV ions beam to probe elemental composition vs depth with a depth resolution of 5-20 nn. The analysis is fast, nondestructive and standardless for RBS to quantify the stoichiometry of elements in compounds, the thin layer thickness or porosity as well as structural disorder in single crystals or epitaxial films by ion channeling, but is insensitive to their chemical environments. Ion Beam Analysis is a broad term that involves several specific techniques, Rutherford backscattering spectrometry (RBS), Elastic Recoil Detection Analysis (ERDA), Nuclear reaction analysis (NRA), Particle induced X-ray or gamma-ray emission (PIXE and PIGE) and ion channeling analysis.

The major assets of the CEMHTI are a great expertise of all these techniques and the ability to design experimental devices allowing to couple several techniques on a case-by-case basis for a more relevant analysis. Investigations are carried out thanks to a state-of-the-art equipment, a philosophy of constant development and a highly qualified team.

IBA analysis are commonly performed ex-situ, with the specimen exposed to ambient conditions during its transfer to the experimental chamber. For interface solid/gas studies, eventual near-surface physico-chemical modifications while exposing sample to atmosphere can induce some misinterpretations about its own surface reactivity against the studied gaseous medium. For these reasons, CEMHTI designed with different approaches setups for in-situ investigation of materials modifications under temperature and controlled atmosphere with the potential use of isotopic gas.

Low-Z elements characterization (H, D, He, C, N, O, ..), thin layer stoichiometry, impurities localization in a crystal lattice, damage characterization, situ or operando measurement (sorption, desorption, diffusion, migration, interdiffusion under irradiation, temperature, controlled atmosphere and illumination, solid/gas interface, isotopic gas, IBA techniques coupling, characterization in metals, ceramics, glasses, semi-conductors, …

DIADDHEM (DIspositif d’Analyse de la Diffusion du Deutérium et de l’HElium dans les Matériaux)

The originality of the DIADDHEM setup 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 temper

ature (120 – 1600K) in nuclear materials and depth profiles after annealing. Diffusion coefficients and activation energy are extracted from depth profile evolution.
The last upgrade of DIADDHEM concerns the implementation of a gas distribution and the control by mass spectrometer of the differential pressures (D2, O2, CO2 up to 10-3 mbar) to investigate in situ or operando by IBA technique the surface reactivity of specimens, exposed to a gaseous medium under temperature. The NRA technique ability to provide quantitative and non-destructive depth profiling allows the characterization of species sorption at interface solid/gas, migration and/or diffusion, elemental interdiffusion at interfaces in cases of multilayers.

V. Motte, D. Gosset, T. Sauvage b, H. Lecoq, N. Moncoffre, Journal of Nuclear Materials 517 (2019) 165-174 10.1016/j.jnucmat.2019.02.012

Mini-Beam Setup

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 500×500µm2 sample surface. The implementation of 3 detectors (PIPS, SDD and HPGe) allows the coupling of the RBS, PIXE et PIGE nuclear techniques.

D. Strivay, C. Ramboz, J.-P. Gallien, D. Grambole, T. Sauvage, K. Kouzmanov, Nuclear Instruments and Methods in Physics Research B 266 (2008) 2375–2378 10.1016/j.nimb.2008.03.068

IBIC (Ion Beam Implantation and Channeling)

This device is a vacuum chamber to analyze chemical composition of materials b

y 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.

T. Belhabib, P. Desgardin, T. Sauvage, H. Erramli, M.F. Barthe, F. Garrido, G. Carlot, L. Nowicki, P. Garcia, Journal of Nuclear Materials 467 (2015) 1-8 10.1016/j.jnucmat.2015.09.001