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A particle detection chain based on a CMOS SOI VCO circuit associated to a matrix of detection is presented. The solution is optimized for the recognition and tracking of various particles. Two ions are considered: an alpha and an aluminum. These two ions were chosen because there are very different in terms of energy and LET variations.

Neutron detection is a relevant topic in the field of nuclear instrumentation. It is at the heart of the concerns for fusion applications (neutron diagnostics, measurements inside the Test Blanket Modules TBM) as well as for fission applications (in-core and ex-core monitoring, neutron mapping or safety applications in research reactors). Moreover, due to the even more harsh conditions of the future experimental reactors such as the Jules Horowitz Reactor (JHR) or International Thermonuclear Experimental Reactor (ITER), neutron detectors need to be adapted to high neutron and γ fluxes, high nuclear heating rates and high temperatures. Consequently, radiation and temperature hardened sensors with fast response, high energy resolution and stability in a mixed neutron and γ environment are required. All these requirements make wide-bandgap semiconductors and, more precisely, Silicon Carbide (SiC) serious candidates due to their intrinsic characteristics in such extreme environments. Thus, since the last decades, SiC-based detectors are developed and studied for neutron detection in various nuclear facilities. In this paper, a SiC-based neutron detector is 3-D designed and studied through thermal and radiation-matter interaction numerical simulations for a future irradiation campaign at the Jožef Stefan Institute TRIGA Mark II research reactor in Slovenia. Firstly, this paper presents the scientific background and issues of our SiC-based detectors. In a second part the 3-D geometry is shown. Thereafter, the 3-D numerical thermal simulation results are reported. Finally, the 3-D numerical radiation/matter interaction simulations results are presented.

Neutron radiation detector for nuclear reactor applications plays an important role in getting information about the actual neutron yield and reactor environment. Such detector must be able to operate at high temperature (up to 600° C) and high neutron flux levels. It is worth nothing that a detector for industrial environment applications must have fast and stable response over considerable long period of use as well as high energy resolution. Silicon Carbide is one of the most attractive materials for neutron detection. Thanks to its outstanding properties, such as high displacement threshold energy (20-35 eV), wide band gap energy (3.27 eV) and high thermal conductivity (4.9 W/cm·K), SiC can operate in harsh environment (high temperature, high pressure and high radiation level) without additional cooling system. Our previous analyses reveal that SiC detectors, under irradiation and at elevated temperature, respond to neutrons showing consistent counting rates as function of external reverse bias voltages and radiation intensity. The counting-rate of the thermal neutron-induced peak increases with the area of the detector, and appears to be linear with respect to the reactor power. Diamond is another semi-conductor considered as one of most promising materials for radiation detection. Diamond possesses several advantages in comparison to other semiconductors such as a wider band gap (5.5 eV), higher threshold displacement energy (40-50 eV) and thermal conductivity (22 W/cm·K), which leads to low leakage current values and make it more radiation resistant that its competitors. A comparison is proposed between these two semiconductors for the ability and efficiency to detect fast neutrons. For this purpose the deuterium-tritium neutron generator of Technical University of Dresden with 14 MeV neutron output of 1010 n·s-1 is used. In the present work, we interpret the first measurements and results with both 4H-SiC and chemical vapor deposition (CVD) diamond detectors irradiated with 14 MeV neutrons at room temperature.

In this work we presented two types of 4H-SiC semiconductor detectors (D1 and D2) both based on ion implantation of 10B inside the aluminum metallic contact. The first detector shows a high leakage current after the implantation and low signal to noise ratio. However, improvements concerning the implantation parameters and the distance between the implanted 10B thermal neutron converter layer and the active pn-junction have led to low leakage current and thus to higher signal to noise ratio. This proves the strength of this new method of realizing sensitive SiC-based thermal neutron detectors.

Neutron radiation detector for nuclear reactor applications plays an important role in getting information about the actual neutron flux. Such a detector must be able to operate at high neutron flux levels (>109 cm−2 s−1) and discriminate the neutron and gamma responses in the nuclear reactor’s mixed neutron–gamma environment. Silicon carbide and diamond are the most attractive semiconductor materials for neutron detection, thanks to their outstanding properties, such as high displacement threshold energy and wide bandgap energy, which allow them to operate in high radiation levels and high temperature. The aim of this article is to compare the ability to detect thermal neutrons of these two semiconductors at the same irradiation conditions. For this purpose, the neutron irradiation tests of detectors were implemented at MINERVE research reactor at CEA Cadarache. The 4H-silicon carbide (SiC) p+n diode has demonstrated better neutron–gamma discrimination at 0-V bias voltage than at −200 V which is explained by its increased sensitivity to gamma photons at −200 V caused by a wider charge collection region than at 0 V. Therefore, it is preferable to use the 4H-SiC p+n diode without an external electric field for applications in the mixed neutron–gamma environment such as nuclear reactor environment. The results show that the single-crystal chemical vapor-deposited (sCVD) diamond-based detector has better neutron to gamma discrimination, thanks to the use of 6Li as a neutron converter instead of 10B. However, the study of the radiation stability of detectors showed that the sCVD diamond-based detector suffers from the “polarization effect” when it operates at a high neutron flux (~109 cm−2 ⋅ s−1). [ABSTRACT FROM AUTHOR]

We report on the application of introducing gettering sites by helium implantation prior to an annealing and subsequent gold diffusion as an approach to control the thermal conductivity and the charge carrier concentration in n-type 4H-SiC. Rutherford backscattering spectroscopy showed high diffusion of gold impurities to the introduced gettering sites which implied a success in introducing gettering sites. Data obtained from the measurements of the specific heat, thermal diffusivity, and room temperature density were used to deduce the thermal conductivity of the samples investigated. The thermal conductivity modeling showed that introducing gettering sites can increase the thermal conductivity in n-type 4H-SiC due to the reduction of phonon-impurity scattering. Raman measurements showed the presence of the desired defects introduted by ion implantation at 20 °C. The analysis of the Fourier transform infrared reflectivity showed that the gettering sites can act as majority carrier traps and reduce the recombination process. [ABSTRACT FROM AUTHOR]

Epilayers of 6H and 4H–SiC were Al implanted with various doses to form p-type layers after a postimplantation annealing performed at 1700 °C/30 min. Rutherford backscattering spectrometry in the channeling mode analyses carried out before and after annealing show virgin nonimplanted equivalent spectra if the implanted layers are not amorphized. The amorphous layers are recrystallized after annealing with a residual damage level of the lattice relative to the quantity of the dopant implanted. Secondary ion mass spectrometry measurements performed on the implanted samples before and after annealing illustrate a good superposition of the profiles obtained before and after the annealing on nonamorphized samples. Dopant redistribution occurs after annealing, only on amorphized layers, with an intensity that increases with the implanted dose. Deduced from sheet resistance measurements, the dopant activation increases with the implanted dose. Activation of 80%–90% is obtained from capacitance–voltage measurements on samples implanted with a 10[sup 13] cm[sup -2] total dose. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Radiation detectors based on wide-bandgap semi- conductors have received considerable attention in many applications such as the experiments in material testing reactors, high energy particle physics experiments, or fusion facilities for plasma diagnostics. In this paper, we compared a 4H-silicon-carbide (SiC)-based detector with a single crystal chemical vapor deposited (sCVD) diamond-based detector for 14-MeV neutron detection. For this purpose, the deuterium–tritium neutron generator of Technical University of Dresden with 14-MeV neutron output up to 1011 n/sin $4\pi $ has been used. In this paper, we interpret the results of our first measurements with both 4H-SiC and sCVD diamond detectors at low neutron flux of $9.4 \times 10^{6}\text {n}/(\mathrm {cm}^{2}\cdot \text {s})$ and at room temperature. [ABSTRACT FROM AUTHOR]

In the framework of the European I-Smart project, optimal 4H-SiC based diode geometries were developed for high temperature neutron detection. Irradiation tests were conducted with 14 MeV fast neutrons supplied by a deuterium-tritium neutron generator with an average neutron yield of 4.04 \times 10^10 - 5.25 \times 10^10\;\n/s at Neutron Laboratory of the Technical University of Dresden in Germany. In this paper, we interpret the first measurements and results with 4H-SiC detector irradiated with fast neutrons from room temperature up to 500 °C. These experiments are serving also the first simulation of the harsh environmental condition measurements in the tritium breeding blanket of the ITER fusion reactor, which is one of the most prominent planned location of high temperature neutron flux characterization studies in the near future. [ABSTRACT FROM PUBLISHER]

Ultraviolet (UV) photodetectors based on Schottky barriers to 4 H-SiC are formed on lightly doped n-type epitaxial layers grown by the chemical vapor deposition method on commercial substrates. The diode structures are irradiated at 25°C by 167-MeV Xe ions with a mass of 131 amu at a fluence of 6 × 10 cm. Comparative studies of the optical and electrical properties of as-grown and irradiated structures with Schottky barriers are carried out in the temperature range 23-180°C. The specific features of changes in the photosensitivity and electrical characteristics of the detector structures are accounted for by the capture of photogenerated carriers into traps formed due to fluctuations of the conduction-band bottom and valence-band top, with subsequent thermal dissociation. [ABSTRACT FROM AUTHOR]