Estimating the vulnerability is a key challenge for plasma diagnostics designed to operate in radiative background
associated with megajoule class laser facilities. Since DT shots at OMEGA laser facility reproduce the perturbing source
expected during the first 100 nanoseconds of a typical DT shot realized at National Ignition Facility (NIF) and Laser
MegaJoule facility (LMJ), vulnerability of diagnostic elements such as optical relays or optical analyzers were
experimentally studied and, if necessary, hardening approaches have been initiated to authorize their use at higher
radiative constraints. Other facilities such as nuclear reactor or accelerator have been also used to estimate vulnerability
issues as radiation induced emission of glasses or damage in multilayer coatings.
The Laser MegaJoule (LMJ) facility will host inertial confinement fusion experiments in order to achieve ignition by
imploding a Deuterium-Tritium filled microballoon . In this context an X-ray imaging system is necessary to diagnose
the core size and the shape of the target in the 10-100 keV band. Such a diagnostic will be composed of two parts: an X-ray
optical system and a detection assembly. The survivability of each element of this diagnostic has to be ensured within
the mixed pulse consisting of X-rays, gamma rays and 14 MeV neutrons created by fusion reactions.
The design of this diagnostic will take into account optics and detectors vulnerability to neutron yield of at least 1016. In
this work, we will present the main results of our vulnerability studies and of our hardening-by-system and hardening-by-
This paper presents a summary of the main results we observed after several years of study on irradiated custom
imagers manufactured using 0.18 μm CMOS processes dedicated to imaging. These results are compared
to irradiated commercial sensor test results provided by the Jet Propulsion Laboratory to enlighten the differences
between standard and pinned photodiode behaviors. Several types of energetic particles have been used
(gamma rays, X-rays, protons and neutrons) to irradiate the studied devices. Both total ionizing dose (TID)
and displacement damage effects are reported. The most sensitive parameter is still the dark current but some
quantum efficiency and MOSFET characteristics changes were also observed at higher dose than those of interest
for space applications. In all these degradations, the trench isolations play an important role. The consequences
on radiation testing for space applications and radiation-hardening-by-design techniques are also discussed.
We present here a study on both CMOS sensors and elementary structures (photodiodes and in-pixel MOSFETs) manufactured in a deep submicron process dedicated to imaging. We designed a test chip made of one 128×128-3T-pixel array with 10 μm pitch and more than 120 isolated test structures including photodiodes and MOSFETs with various implants and different sizes. All these devices were exposed to ionizing radiation up to 100 krad and their responses were correlated to identify the CMOS sensor weaknesses. Characterizations in darkness and under illumination demonstrated that dark current increase is the major sensor degradation. Shallow trench isolation was identified to be responsible for this degradation as it increases the number of generation centers in photodiode depletion regions. Consequences on hardness assurance and hardening-by-design are discussed.