Articolo in rivista, 2020, ENG, 10.1063/5.0023310
Agostini M.; Scarin P.; Milazzo R.; Cervaro V.; Ghiraldelli R.
Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), C.so Stati Uniti 4, 35127 Padova, Italy.
Thermal Helium Beam (THB) diagnostic is widely used for measuring the electron density and temperature in the boundary region of fusion plasmas, edges, and scrape-off layers. In its standard configuration, it measures three HeI lines (667.8 nm, 706.5 nm, and 728.1 nm) and, by using a collisional-radiative model, evaluates ne and Te from the ratios of their intensities. At large neutral He density (n0 ? 1017 m -3 ), radiation re-absorption is not negligible and it has to be taken into account; it can be estimated by measuring the intensity of the fourth HeI line, ? = 501.6 nm. The original THB diagnostic of the RFX-mod experiment has been upgraded, setting up the fourth line intensity acquisition. A Czerny-Turner spectrograph separates the lines, and the old multichannel photomultiplier (PMT) detectors are replaced with the new Multi-Pixel Photon Counter (MPPC). Two 16-channel MPPC array modules allow the observation of 32 signals (4 lines × 8 spatial points). Since the MPPCs are not sensitive to the magnetic field, the whole system can be installed near the experimental device, allowing a large reduction in the optical fibers' length with a gain in the collected signal intensity. This new THB will be installed in the new experiment RFX-mod2, the upgrade of the RFX-mod device. The RFX-mod2 will operate as both reversed field pinch and tokamak, and the goal of the THB is the evaluation of the edge electron density and temperature profiles in the two magnetic configurations, in D or H plasmas. This paper describes the system, the performance of the MPPC compared with the PMTs, the alignment, and the calibration.
Review of scientific instruments 91 , pp. 113503-1–113503-11
RFX-Mod2, thermal helium beam diagnostic
Cervaro Vannino, Ghiraldelli Raffaele, Agostini Matteo
ID: 436782
Year: 2020
Type: Articolo in rivista
Creation: 2020-11-20 15:18:07.000
Last update: 2021-04-27 15:06:51.000
CNR institutes
External IDs
CNR OAI-PMH: oai:it.cnr:prodotti:436782
DOI: 10.1063/5.0023310
Scopus: 2-s2.0-85096243766
ISI Web of Science (WOS): 000593972100001
PubMed: 33261442