Yves Serruys

Combined effects of nuclear and electronic energy losses in solids irradiated with a dual-ion beam

Single and dual-beam irradiations of oxide (c-ZrO2, MgO, Gd2Ti2O7) and carbide (SiC) single crystals were performed to study combined effects of nuclear (Sn) and electronic (Se) energy losses. Rutherford backscattering experiments in channeling conditions show that the Sn/Se cooperation induces a strong decrease of the irradiation-induced damage in SiC and MgO and almost no effects in c-ZrO2 and Gd2Ti2O7. The healing process is ascribed to electronic excitations arising from the electronic energy loss of swift ions. These results present a strong interest for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where expected cooperative Sn/Se effects may lead to the preservation of the integrity of nuclear devices.

Application of nuclear reaction geometry for 3He depth profiling in nuclear ceramics

Abstract Direct observation of nuclear reactions leading to the emission of charged particles (p or α) allows to determine specifically the spatial distribution of isotopes of light elements from 1H to 23Na and despite low cross section values some heavier isotopes from 24Mg to 68Zn. After a brief overview of the analytical capabilities offered by μNRA, this contribution is focussed on the measurement of the thermal diffusion coefficient of 3He in crystalline ceramics. The experimental method is based on the observation of the 3He(d, p)α reaction. Due to the severe energy loss along the outgoing path, the choice of the detection of the high energy proton or recoil α nucleus depends on the average depth of the 3He distribution. For near surface distributions (

3He thermal diffusion coefficient measurement in crystalline ceramics by μnra depth profiling

Abstract This contribution is devoted to the measurement of the thermal diffusion coefficient of 3He in crystalline nuclear ceramics. The experimental method is based on the observation of the 3He(d,p)α reaction. The detection of the high energy proton (12–14 MeV) is convenient for large implantation depths (5 μm

Recovery effects due to the interaction between nuclear and electronic energy losses in SiC irradiated with a dual-ion beam

Single and dual-beam ion irradiations of silicon carbide (SiC) were performed to study possible Synergetic effects between Nuclear (Sn) and Electronic (Se) Energy Losses. Results obtained combining Rutherford backscattering in channeling conditions, Raman spectroscopy, and transmission electron microscopy techniques show that dual-beam irradiation of SiC induces a dramatic change in the final sample microstructure with a substantial decrease of radiation damage as compared to single-beam irradiation. Actually, a defective layer containing dislocations is formed upon dual-beam irradiation (Sn&Se), whereas single low-energy irradiation (Sn alone) or even sequential (Sn + Se) irradiations lead to full amorphization. The healing process is ascribed to the electronic excitation arising from the electronic energy loss of swift ions. These results shed new light on the long-standing puzzling problem of the existence of a possible synergy between Sn and Se in ion-irradiation experiments. This work is interesting ...

Limits in point to point resolution of MOS based pixels detector arrays

In high energy physics point-to-point resolution is a key prerequisite for particle detector pixel arrays. Current and future experiments require the development of inner-detectors able to resolve the tracks of particles down to the micron range. Present-day technologies, although not fully implemented in actual detectors, can reach a 5-μm limit, this limit being based on statistical measurements, with a pixel-pitch in the 10 μm range. This paper is devoted to the evaluation of the building blocks for use in pixel arrays enabling accurate tracking of charged particles. Basing us on simulations we will make here a quantitative evaluation of the physical and technological limits in pixel size. Attempts to design small pixels based on SOI technology will be briefly recalled here. A design based on CMOS compatible technologies that allow a reduction of the pixel size below the micrometer is introduced here. Its physical principle relies on a buried carrier-localizing collecting gate. The fabrication process needed by this pixel design can be based on existing process steps used in silicon microelectronics. The pixel characteristics will be discussed as well as the design of pixel arrays. The existing bottlenecks and how to overcome them will be discussed in the light of recent ion implantation and material characterization experiments.

The TRAMOS pixel as a photo-detection device: Design, architecture and building blocks

Abstract The deep trapping gate device concept for charged particle detection was recently introduced in Saclay/IRFU. It is based on an n-MOS structure in which a buried gate, located below the n-channel, collects carriers which are generated by ionizing particles. They deposit their energy in a volume which extends in the bulk, below the buried gate. The n-channel device is based on holes in-buried gate localization. Source–drain current modulation occurs, measurable during readout. The buried gate (Deep Trapping Gate or DTG) contains deep level centers which can be introduced during process or may be made with a Quantum Well. The device can be scaled down providing a micron range resolution. The proof of principle for such a device was verified using 2D device and process simulations. Work under way focusses on the study of building blocks. In this contribution, the pixel proof of design, using existing fabrication techniques will be discussed first. The use of this pixel for photon imaging will be discussed.

Radiation-induced cavities in aluminium alloy imaged by in line electron holography

Abstract In irradiated material, cavities result from the condensation of vacancies induced by collision cascades. The study of their formation is a relevant topic since a high density of cavities may alter significantly the material performance. In this work, a simplified version of in line holography was successfully applied for imaging cavities in ion-irradiated 6061 aluminium alloy. In transmission electron microscopy, the incoming electrons experience a phase shift owing to the potential variation induced by the cavities. The retrieval of this phase shift provides a convenient map to observe and highlight the cavities. Information on density of cavities can be easily obtained. In addition, interstitial clusters may also be detected.

How to Simulate the Microstructure Induced by a Nuclear Reactor with an Ion Beam Facility : DART

Even if the Binary Collision Approximation does not take into account relaxation processes at the end of the displacement cascade, the amount of displaced atoms calculated within this framework can be used to compare damages induced by different facilities like pressurized water reactors (PWR), fast breeder reactors (FBR), high temperature reactors (HTR) and ion beam facilities on a defined material. In this paper, a formalism is presented to evaluate the displacement cross-sections pointing out the effect of the anisotropy of nuclear reactions. From this formalism, the impact of fast neutrons (with a kinetic energy En superior to 1 MeV) is accurately described. This point allows calculating accurately the displacement per atom rates as well as primary and weighted recoil spectra. Such spectra provide useful information to select masses and energies of ions to perform realistic experiments in ion beam facilities.

Recoil Spectrometry with a ΔE-E Telescope

In ERDA spectrometry an absorber limits the method to determining target elements lighter than the incident ions, as for example determining hydrogen isotopes when applying MeV helium-4 ions. In both MeV 4He+-induced elastic recoil spectrometry and in HI-ERDA analysis, mass separation between scattered ions and recoiled nuclei can be improved by measuring their difference in stopping power. This can be done in either a gas-filled ionization chamber(1) or a solid-state transmission detector(2); the residual energy in this case is measured by a thick silicon surface barrier detector.

Hydrogen Determination by Nuclear Resonance

Hydrogen determination in solids can be carried out by a large number of analytic techniques from nuclear magnetic resonance to infrared absorption spectroscopy, from electron paramagnetic resonance to neutron scattering, from ion-induced photon spectroscopy or secondary ion mass spectrometry to MeV IBA. Most of these techniques are not considered further, because in Chapter 15 we focus on hydrogen depth profiling in the framework of ion beam techniques. Chapter 15 discusses and compares the respective capabilities and limitations of both nuclear resonant reaction analysis and ERDA for hydrogen determination. Thus we compare hydrogen (1H) depth-profiling approaches using either ERDA or nuclear resonance.