Fusion Engineering and Design 88 (2013) 1253–1256 Contents lists available at ScienceDirect Fusion Engineering and Design journal h om epa ge: www.elsevier.com/locat e/fusengdes Design of a visible tomography diagnostic for negative ion RF source SPIDER R. Pasqualotto ∗ , M. Agostini, M. Brombin, R.S. Delogu, N. Fonnesu, L. Lotto, F. Molon, C. Piron, G. Serianni, C. Taliercio, M. Tollin, B. Zaniol Consorzio RFX – Associazione Euratom-Enea sulla Fusione, corso Stati Uniti 4, I-35127 Padova, Italy h i g h l i g h t s ◮ Prototype ITER neutral beam injector requires beam proﬁle diagnostics. ◮ Visible tomography of H  emission can measure 2D beam intensity pro- ﬁle. ◮ A system with 15 linear CCD cameras and 3000 lines of sight is proposed. ◮ Camera speciﬁcations are discussed against requirements and expected signal. ◮ Test of prototype CCD camera vali- dates selected sensor. g r a p h i c a l a b s t r a c t a r t i c l e i n f o Article history: Available online 7 March 2013 Keywords: Beam diagnostic Tomography Neutral beam injector Negative ion source Linear CCD camera a b s t r a c t The ITER heating neutral beam injector, based on 1 MV D - ions, will be tested and optimized in the SPIDER source and MITICA full injector prototypes, using a set of diagnostics not available on ITER. Beam inten- sity uniformity is required to stay within ±10%, thus beam proﬁle is measured with a complementary set of diagnostics. Among them, visible tomography measures the line of sight (LOS) integrated H  or D  radiation generated by the collisions between fast particles and neutral background molecules, and emitted on a plane perpendicular to the beam. A sufﬁcient number of well arranged LOSs allows a tomo- graphic reconstruction of the 2D beam emission proﬁle, which is proportional to the beam density. On SPIDER the system is equipped with about 3000 LOSs, grouped in 15 fans, and the tomographic algorithm is based on the pixel method. The design of the diagnostic is presented, with description of layout and main components and test of the prototype linear CCD camera. © 2013 Consorzio RFX Associazione Euratom ENEA sulla Fusione. Published by Elsevier B.V. All rights reserved. 1. Beam intensity proﬁle diagnostics on SPIDER The ITER heating neutral beam injector, based on a 40 A negative deuterium ion beam produced by an RF source and accelerated at 1 MV [1], will be tested and optimized in the SPIDER source [2] and MITICA full injector prototypes [3], using a comprehensive set of diagnostics [4]. The beam is composed of 1280 beamlets, corresponding to the holes of the acceleration grids, spanning an area of 1520 mm × 560 mm. SPIDER has to produce 100 kV accel- erated beam pulses, up to 1 h duration, with extracted D current ∗ Corresponding author. Tel.: +39 0498295849. E-mail address: roberto.pasqualotto@igi.cnr.it (R. Pasqualotto). density > 285 A/m 2 , co-extracted electron fraction (e - /D - ) < 1, beam uniformity within ±10% and beamlet divergence ≤7 mrad. These speciﬁcations have never been simultaneously achieved so far in a full scale, full performance device, thus source plasma and accelerated beam need to be thoroughly diagnosed. A set of diagnostics measures the characteristics of the beam. Visible tomography estimates the 2D beam intensity proﬁle with sufﬁcient spatial resolution and its evolution during the entire pulse duration. It measures the line of sight (LOS) integrated H  or D  radiation (656 nm) generated after the collisions between fast beam particles and neutral background molecules; a sufﬁcient number of well arranged LOSs allows a tomographic reconstruc- tion of the 2D beam emission proﬁle, which is proportional to the beam density. Tomography complements four other diagnostics. 0920-3796/$ – see front matter © 2013 Consorzio RFX Associazione Euratom ENEA sulla Fusione. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fusengdes.2013.02.009