At present, the only method for assessing the fusion power throughput of a reactor relies on the absolute measurement of 14 MeV neutrons produced in the D-T nuclear reaction. [1] For ITER and DEMO, however, at least another independent measurement of the fusion power is required. The 5Henucleus produced in the D-T fusion reaction has two de-excitation channels. The most likely is its disintegration in a particle and a neutron, D+T->5He->?+n, by means of the nuclear force. There is however also an electromagnetic channel, with a branching ratio ~10-5, which leads to the emission of a 17 MeV gamma-ray, i.e. D+T->5He*-> 5He+?. [2] The detection of this gamma-ray emission could serve as an independent method to determine the fusion power. In order to enable 17 MeV gamma-ray measurements, there is need for a detector with some coarse energy discrimination and, most importantly, capable to work in a neutron rich environment. Conventional inorganic scintillators, such as LaBr3(Ce), have comparable efficiencies to neutrons and gamma rays and they cannot be used for 17 MeV gamma-ray measurements without significant neutron shielding. In order to overcome this limitation, we here propose the conceptual design of a gamma ray counter with a variable energy threshold based on the Cherenkov effect and designed to operate in intense neutron fields. The detector geometry has been optimized using Geant4 so to achieve a gamma-ray to neutron efficiency ratio better than 105. The design is based on a gas Cherenkov detector and uses a CsI coated scintillating GEM (Gas Electron Multiplier) as photon pre-amplifier, together with a wavelength shifter to minimize the sensitivity to neutrons. Photons produced in the GEM are collected by an optical window and a bundle of optical fibers, which guides them towards an array of silicon photomultipliers (SiPMs) located further away from the plasma, in a region at low nuclear radiation.<\/p>\n","protected":false},"excerpt":{"rendered":"
Putignano O.; Croci G.; Muraro A.; Cancelli S.; Giacomelli L.; Gorini G.; Grosso G.; Kushoro M.H.; Marcer G.; Nocente M.; Perelli Cippo E.; Rebai M.; Tardocchi M.<\/p>\n","protected":false},"featured_media":1294,"comment_status":"closed","ping_status":"open","template":"","meta":[],"product_cat":[709],"product_tag":[835,2265,2331,3336],"class_list":["post-9336","product","type-product","status-publish","has-post-thumbnail","hentry","product_cat-proceedings-papers","product_tag-magnetic-confinement","product_tag-gamma-ray-diagnostic","product_tag-fusion-plasmas","product_tag-gas-cherenkov-detector","prodpage-style2"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product\/9336","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/comments?post=9336"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/media\/1294"}],"wp:attachment":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/media?parent=9336"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product_cat?post=9336"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product_tag?post=9336"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}