SPIDER, the negative ion source prototype for the ITER HNB, is hosted at Consorzio RFX and it aims at accelerating up to 285–355 A/m2 of d-/H- ions at 100 keV. The beam is composed by 1280 beamlets, divided into 16 groups arranged in a 4 × 4 matrix. Each group is made of 16 × 5 = 80 beamlets. Beam optics is a fundamental requirement for the ITER heating neutral beam (HNB) so that, besides optimizing the single beamlet divergence by proper electrode shaping, it is also important to compensate for any additional source of optics distortion. The most relevant causes of beam deterioration are given by the deflections induced by the magnetic fields inside the accelerator and by the Coulombic repulsion among the beamlets. First beam campaigns were performed at SPIDER by accelerating a reduced subset of beamlets; these experiments permitted to investigate the quality of the implemented solutions by means of a high resolution calorimeter made of 1D carbon- fiber carbon composite (CFC). A modified shape for the extraction grid aperture has been designed and realised to improve the beam performance at the restart of the operation.
Experimental validation of the SPIDER accelerator design and grid developments
Pimazzoni, Antonio;Sartori, Emanuele;Veltri, Pierluigi
2025
Abstract
SPIDER, the negative ion source prototype for the ITER HNB, is hosted at Consorzio RFX and it aims at accelerating up to 285–355 A/m2 of d-/H- ions at 100 keV. The beam is composed by 1280 beamlets, divided into 16 groups arranged in a 4 × 4 matrix. Each group is made of 16 × 5 = 80 beamlets. Beam optics is a fundamental requirement for the ITER heating neutral beam (HNB) so that, besides optimizing the single beamlet divergence by proper electrode shaping, it is also important to compensate for any additional source of optics distortion. The most relevant causes of beam deterioration are given by the deflections induced by the magnetic fields inside the accelerator and by the Coulombic repulsion among the beamlets. First beam campaigns were performed at SPIDER by accelerating a reduced subset of beamlets; these experiments permitted to investigate the quality of the implemented solutions by means of a high resolution calorimeter made of 1D carbon- fiber carbon composite (CFC). A modified shape for the extraction grid aperture has been designed and realised to improve the beam performance at the restart of the operation.
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
