Speaker
Description
The main goal of ITER operation is demonstration of fusion power reaching values up to 10 times greater than the supplied plasma heating power. This demonstration relies on the set of neutron diagnostics capable of measuring the neutron yield with 10% accuracy and of providing reliable data stream for regulatory purposes. The specified accuracy is planned to be achieved through in situ neutron calibration with a powerful sealed tube D-T neutron generator (NG) with the yield of up to 1e11 n/s as a source. For operation without tritium, a similar calibration is provisioned with a D-D NG (yield ~1e9 n/s). Source definition for neutron transport analysis of these campaigns is crucial and can only be done in conjunction with model validation in experiments with fusion neutrons.
We demonstrate the results of neutron flux and spectrum anisotropy measurements using sets of diamond detectors, fast scintillators, fission chambers, boron counters and activation samples. Some of the proposed detectors are shown to be suitable as a part of the NG monitoring system. The use of high sensitivity neutron counters allows to characterize the source from directions in the shadow of the irradiation unit. The model of the neutron source demonstrates good accuracy in the frontal sphere of the NG, while the discrepancies arising from NG inner contents constitute a systematic impact on the neutron flux and spectrum in the back part of the NG. We quantitatively discuss the shadow cone approach to better characterize the scattered neutron flux component during the measurements.
Current work is supported under the Task Agreement IO/25/TA/4500000251 as of 12.12.2025 between ITER Organization and Institution “Project Center “ITER”. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.
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