F. Issa

First tests of silicon-carbide semiconductors as candidate neutron detector for the ITER Test Blanket Modules

The tritium breeding blanket is an essential part of a future DT fusion power reactor. Test Blanket Modules (TBM) will be installed in the experimental reactor ITER with the aim to investigate the nuclear performance of different designs. Currently there is no qualified neutronics instrumentation for the TBMs which is able to withstand the harsh environment conditions such as high temperature and, depending on the operation scenario, intense radiation.

Radiation silicon carbide detectors based on ion implantation of boron

Radiation detectors based on radiation-hardened semiconductor such as silicon carbide (SiC), have received considerable attention in many applications such as in outer space, high energy physics experiments, gas and oil prospection, and nuclear reactors. For the first time it was demonstrated the reliability of thermal neutron detectors realized by standard ion implantation of boron layer as a neutron converter layer. Moreover, these detectors respond to thermal neutrons and gamma rays showing different counting rates at different voltages and under different types of shielding.

Detection of 14 MeV neutrons in high temperature environment up to 500 °C using 4H-SiC based diode detector

In reactor technology and industrial applications, detection of fast and thermal neutrons plays a crucial role in getting relevant information about the reactor environment and neutron yield. The inevitable elevated temperatures make neutron yield measurements problematic. Out of the currently available semiconductors 4H-SiC seems to be the most suitable neutron detector material under extreme conditions due to its high heat and radiation resistance, large band-gap and lower production cost than the competing diamond detectors. Some of future using and interesting applications of such SiC detector devices-for non-charged particles (photons and/or neutrons) are expected in the frame of non-destructive assays, nuclear reactor monitoring, safeguards, oil and gas prospections [1,2,3]. 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 × 1010-5.25 × 1010 n/s at Neutron Laboratory of the Technical University of Dresden in Germany. In the present work, we interpret the first measurement of SiC detector irradited with fast neutrons from room temperature up to 500 degrees Celsius. 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.

Nuclear radiation detector based on ion implanted p-n junction in 4H-SiC

In this paper, we propose a new device detector based on ion implanted p-n junction in 4H-SiC for nuclear instrumentation. We showed the interest to use 10Boron as a Neutron Converter Layer in order to detect thermal neutrons. We present the main results obtained during irradiation tests performed in the Belgian Reactor 1. We show the capability of our detector by means of first results of the detector response at different reverse voltage biases and at different reactor power.

4H-SiC Neutron Sensors Based on Ion Implanted 10 B Neutron Converter Layer

In the framework of the I_SMART project the main aim is to develop an innovative radiation detection system based on silicon carbide technology in view to detect neutrons (thermal and fast) and photons for harsh environments. In the present work two geometries have been realized based on ion implantation of boron. In the first geometry, 10B ions have been implanted into the Al metallic contact of a p-n diode to create the neutron converter layer. In the second geometry one single process has been used to realize both the p+-layer and the neutron converter layer. The technological processes followed to fabricate these detectors, with a study of their electrical behavior and their responses under thermal neutron irradiations are addressed in this paper.

Nuclear radiation detectors based on 4H-SiC p+-n junction

Silicon carbide (SiC) radiation detectors were realized by 10B implantation into the metal contact in order to avoid implantation-related defects within the sensitive area of the 4H-SiC pn junction. No post implantation annealing was performed. Such detectors respond to thermal neutrons showing consistent counting rates as function of external reverse bias voltages and radiation intensity.

SiC-based neutron detector in quasi-realistic working conditions: Efficiency and stability at room and high temperature under fast neutron irradiations

In the framework of the European I_SMART project, we have designed and made new SiC-based nuclear radiation detectors able to operate in harsh environments and to detect both fast and thermal neutrons. In this paper, we report experimental results of fast neutron irradiation campaign at high temperature (106 °C) in quasi-realistic working conditions. Our device does not suffer from high temperature, and spectra do show strong stability, preserving features. These experiments, as well as others in progress, show the I_SMART SiC-based device skills to operate in harsh environments, whereas other materials would strongly suffer from degradation. Work is still demanded to test our device at higher temperatures and to enhance efficiency in order to make our device fully exploitable from an industrial point of view.

Study of the Stability of 4H-SiC Detectors by Thermal Neutron Irradiation

Two types of 4H-SiC semiconductor detectors (D1 and D2) are realized based on ion implantation of 10B inside the aluminum metallic contact. The first detector shows a high leakage current after 10B implantation and low signal to noise ratio. However, improvements concerning the implantation parameters led to lower leakage current and thus to higher signal to noise ratio. Moreover such detectors show their stability under different thermal neutron fluxes showing the reproducible features of the pulse height spectra and same electrical behaviour before and after irradiation.