GET-ART project: an alternative novel method to measure DT fusion power in magnetic confinement fusion based on detection of 17 MeV gamma rays

Marco Tardocchi

Instituto per la Scienza e Tecnologia dei Plasmi (ISTP)

Tuesday, March 28, 2023

1:00pm

NW17-218 Virtual

PSFC Seminars

Abstract: The GET-ART (Gamma ray Emission in Tokamaks: Assessment of Reaction rate Throughput)  project aims to demonstrate the use of a novel method based on gamma ray detection from the reaction D+T -> ⁵He+γ for the absolute measurements of DT fusion power in tokamaks. The method in use today is based on absolute 14 MeV neutron counting and requires long and time consuming in vessel calibration to benchmark neutron transport simulations from the extended plasma source to the flux monitor detectors (typically  fission chambers and activation foils) placed at selected positions around the tokamak. The GET-ART project is studying an alternative method that is based on absolute detection of the weak (~10^-5 with respect to neutrons) DT gamma ray emission along a well characterized line of view combined to a neutron camera reconstruction of the neutron/gamma emissivity profiles. This is particular relevant for future DT reactors such as ITER and DEMO where at least two independent methods are required for the licencing of reactors.

The presentation will describe the main challenges and solutions identified and the results achieved in the recent DT experiment at JET, where the absolute gamma-ray flux has been measured with a LaBr₃ spectrometer installed along an oblique line of sight. JET has an absolute calibration of the 14 MeV neutron emissions which gives the opportunity to assess the neutron to gamma ray DT branching ratio. Finally, the concept and a preliminary design of a new Cerenkov detector optimized for 17 MeV gamma-ray measurements for DT fusion power determination on the next generation tokamak will be presented.

Biography: Marco Tardocchi has a Master degree in Physics and a PhD obtained in 2000 at the Neutron Physics Department of Uppsala University (Sweden) where he worked on the development of the innovative MPR spectrometer for 14 MeV neutrons generated by DT fusion plasmas. He is responsible of the Neutron and Gamma ray group of the Institute for Plasma Science and Technology (ISTP) of CNR in Milan and a lecturer at University of Milano Bicocca.  Marco coordinates a research group in the field of nuclear measurements (neutrons, gamma rays, hard and soft X-rays) of thermonuclear plasmas and in the development of innovative instrumentation for spallation neutron sources.  The main results have been obtained at the tokamak JET where new diagnostics were specifically developed for high resolution/high count rate measurements in high performance DT plasmas. The gamma ray spectrometers based on LaBr3 crystals and 14 MeV neutron spectrometers based on artificial diamonds are worth mentioning. In 2020 Marco was promoter and coordinator of the CNR contribution to the Milano Ventilatore Meccanico project which created a FDA and CE certified pulmonary mechanical ventilator composed of few components, low costs and optimized for the treatment of COVID-19 patients.