{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T18:56:08Z","timestamp":1790794568581,"version":"4.1.0"},"reference-count":43,"publisher":"AIP Publishing","issue":"9","license":[{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"vor","delay-in-days":29,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100006132","name":"Office of Science","doi-asserted-by":"publisher","award":["DE-AC02-09CH11466"],"award-info":[{"award-number":["DE-AC02-09CH11466"]}],"id":[{"id":"10.13039\/100006132","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,9,1]]},"abstract":"<jats:p>We present a compact photodiode-based diagnostic array developed to study low-energy neutral beam injection in the Lithium Tokamak Experiment spherical tokamak. The in-vacuum diagnostic combines filtered soft-x-ray (SXR), narrowband Lyman-\u03b1, and unfiltered absolute extreme ultraviolet (AXUV) photodiode rows with partly overlapping, nearly coincident tangential views of the plasma, including the neutral beam path. This geometry provides simultaneous sensitivity to beam-induced SXR emission; neutral-hydrogen line radiation associated with recycling, fast neutrals, and fueling; and broadband emission that can include direct neutral impacts from fast-ion charge-exchange losses. Initial measurements from 12 to 20\u00a0keV hydrogen beam operation show beam-synchronous detector responses in all three modalities. The unfiltered AXUV signals exhibit millisecond-scale rise and fall times that vary across sightlines and depend on lithium-conditioning history. Comparison with classical slowing-down time estimates indicates that charge exchange with background neutrals contributes appreciably to the measured decay. The diagnostic can potentially be used to constrain a forward model to estimate the time-resolved balance of beam heating and fueling for small tokamaks.<\/jats:p>","DOI":"10.1063\/5.0344755","type":"journal-article","created":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T12:49:41Z","timestamp":1790599781000},"update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Photodiode based multi-modal diagnostic for low-energy neutral beam injection in the LTX-\n                    <i>\u03b2<\/i>\n                    spherical tokamak"],"prefix":"10.1063","volume":"97","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7474-2785","authenticated-orcid":false,"given":"A.","family":"Maan","sequence":"first","affiliation":[{"name":"Princeton Plasma Physics Laboratory 1 , Princeton, New Jersey 08540,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0908-3004","authenticated-orcid":false,"given":"T.","family":"Le","sequence":"additional","affiliation":[{"name":"Princeton Plasma Physics Laboratory 1 , Princeton, New Jersey 08540,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8091-8169","authenticated-orcid":false,"given":"D. 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