Speaker
Description
SPARC is a compact, high-field Deuterium-Tritium (DT) tokamak currently under construction by Commonwealth Fusion Systems (CFS). The device aims to achieve net fusion energy, targeting a plasma gain (QP) greater than 5 and producing up to 140 MW of fusion power (PFUS). It will feature a poloidal neutron camera (NCAM) designed to provide energy, time, and space-resolved measurements of neutron emission. The system consists of multiple detectors located at the endpoints of collimated lines of sight (LOS). For high-power DT operations, the NCAM adopts Chemical Vapor Deposition diamond detectors as its baseline technology, selected for their radiation hardness, ~1% intrinsic energy resolution at 14 MeV, high count-rate capability (up to 1 MHz), and compact size (~10 mm³).
This work focuses on optimizing the layout of the NCAM diamond detectors to support ion temperature profile reconstruction over a broad range of neutron fluxes expected during DT plasmas. Specifically, it investigates the optimal number and size of diamond pixels at the LOS endpoints to support both inter-shot analysis and potential real-time applications. Synthetic data and an inversion algorithm are developed and applied to the reference SPARC plasma scenario. To assess the reconstruction capability of different NCAM configurations with the developed algorithm, the reference scenario is perturbed using heuristic variations, designed to test robustness against plasma shape and position changes, as well as Poisson noise.
The results demonstrate that multiple design configurations satisfy the required time and energy resolution for ion temperature profile reconstruction, specifically, a time resolution below 100 ms and an Ion Temperature profile accuracy better than 10%. A minimum viable setup for DT operations is identified, capable of supporting both early-phase experiments (1 MW < Pfus < 20 MW) and later high-power campaigns (Pfus < 140 MW).
This work was supported by Commonwealth Fusion Systems and ENI SpA.
