Mr. Philippe Legou Profile

Philippe Legou

at CEA-DRF-IRFU

SPIE Involvement:

Author

Publications (2)

Proceedings Article | 9 September 2019 Presentation

A generic modular neutron diagnostic for inertial confinement fusion experiments, magnetic fusion facilities, and for particle physics accelerators safety system (Conference Presentation)

Philippe Legou, Michel Combet, François Nizery

Proceedings Volume 11114, 1111419 (2019) https://doi.org/10.1117/12.2529255

KEYWORDS: Diagnostics, Sensors, Particle physics, Magnetism, Safety, Spectroscopy, National Ignition Facility, Particles, Fusion energy, Electromagnetism

Read Abstract +

We present the construction and the test of a generic neutrons detector for fusion experiment : OMEGA and NIF(USA) LMJ and APPOLON (France), usable also on particle physics accelerators such as ESS(Sweden), SPIRAL2(France), Berkley (USA) and for magnetic fusion facilities WEST, ITER (France), DIIID(USA). This detector is based on the MICROMEGAS technology detector. This diagnostic has been designed to achieve neutron spectroscopy in large γ background. Tests have been performed on the 60 beams, 30 kJ OMEGA laser system at the University of Rochester(LLE), and on LINAC4 accelerator at CERN (Switzerland), and AMANDE(CEA). In Inertial Confinement Fusion experiment on facilities such as Laser MegaJoule (LMJ) in France and the National Ignition Facility (NIF) in the U.S.we plan to achieve the ignition of capsules by compression deuterium-tritium (DT) or a deuteriumdeuterium (DD) filled target, and thus initiate a thermonuclear burn wave. In these experiments <ρ.R> may be measured using neutrons output from the imploded capsule, like secondary and tertiary neutrons produced respectively in DD and DT targets. Measurement of these neutrons remains a challenge as the γ-rays and scattered neutrons induced by primary neutronsinteractions on the experimental hardware can blind detectors. The concept is based on the association of a Micromegas detector with a neutron-to-charged particle converter associated to a fast low noise electronics (<800ps). A dedicated study has been performed for the neutron to converter particle (ncp) in order to be efficient of few hundred KeV energy neutrons to 14 MeV neutrons. Electrons produced by γ-rays go through the Micromegas with a low ionization probability, making the detector γ-rays insensitive. This low γ sensitivity makes this concept appealing for inertial confinement fusion experiments. The good time resolution of the apparatus allows the reconstruction of neutron energy spectra with the time-of-flight technique. A time-of-flight spectrometer must satisfy a numberof requirements to perform hr:Ri measurement. Main characteristics are the time resolution, the detection efficiency, the dynamic range (The dynamic range is an important characteristic sincethe primary neutron yield can vary from several decades (nowadays on OMEGA Facility to future experiments on LMJ andNIF), but also transparency to different types of background. We present the main characteristics of the detector and the Front-end and Digitizer boards. The data acquisition system is a digitization system. It allows more flexibility foronline or offline treatments and is particularly useful in the prototyping or early phases of the experiments. A special attention has been given to electromagnetic compatibility(EMC) during the design to sustend the huge electromagnetic pulse caused by the shot, shieldings and connectors are described. This diagnostic can also be usefull for particle physics accelerator as safety diagnostic.

Proceedings Article | 9 September 2019 Presentation

A fast neutron detector for neutron spectroscopy or particle accelerator safety (Conference Presentation)

Philippe Legou, Michel Combet, François Nizery

Proceedings Volume 11114, 111140P (2019) https://doi.org/10.1117/12.2531479

KEYWORDS: Sensors, Safety, Particle accelerators, Spectroscopes, Spectroscopy, National Ignition Facility, Electronics, Particle physics, Diagnostics, Laser systems engineering

Read Abstract +

We present the construction and the test of a generic neutrons detector for fusion experiments : OMEGA and NIF(USA), LMJ and APPOLON (FRANCE). The detector can be also used as a safety device on particle physics accelerator (ESS, Sweeden), Spiral2(France) etc.. . This detector is based on the technology CEA / IRFU MICROMEGAS detector. This diagnostic has been designed to achieve neutron spectroscopy in large γ background. Tests have been performed on the 60 beams, 30 kJ OMEGA laser system at the University of Rochester(LLE), and on LINAC4 accelerator at CERN during last november (Switzerland), and AMANDE(CEA). In Inertial Confinement Fusion experiment on facilities such as Laser MegaJoule (LMJ) in France and the National Ignition Facility (NIF) and OMEGA, LLE Rochester, USA we plan to achieve the ignition of capsules by compression deuterium-tritium (DT) or a deuteriumdeuterium (DD) filled target, and thus initiate a thermonuclear burn wave. In these experiments <ρ.R> may be measured using neutrons output from the imploded capsule, like secondary and tertiary neutrons produced respectively in DD and DT targets. Measurement of these neutrons remains a challenge as the γ-rays and scattered neutrons induced by primary neutronsinteractions on the experimental hardware can blind detectors. The concept is based on the association of a Micromegas detector with a neutron-to-charged particle converter associated to a fast low noise electronics (<800ps). Electrons produced by γ-rays go through the Micromegas with a low ionization probability, making the detector γ-rays insensitive. This low γ sensitivity makes this concept appealing for inertial confinement fusion experiments. The good time resolution of the apparatus allows the reconstruction of neutron energy spectra with the time-of-flight technics. In this Inertial Confinement Fusion experiments, we have to deal with huge flux of neutrons. We present here the fast-front end electronics (rise time<800 ps, gain 40dB, noise<450µVrms) which is able to deals with high flux without saturates, with a good dynamic range (to see neutrons from hundred of KeV to14 MeV and above). The data acquisition system is a digitization system. A digitization system offers more flexibility for on-line or off-line treatments than a TOT device (Time Over Threshold) for example. We present the whole electronic-chain (front-end and digitizers). Cable and connectors are described, as a matter of fact, a special care has been given for EMC effects during the study, in order to be able to deals with the huge electromagnetic pulses caused by the shot. The design and the construction of the Micromegas detector are presented.

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years