{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T00:48:20Z","timestamp":1760230100280,"version":"build-2065373602"},"reference-count":14,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2022,7,8]],"date-time":"2022-07-08T00:00:00Z","timestamp":1657238400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"EUROfusion Consortium","award":["633053","UIDB\/50010\/2020","UIDP\/50010\/2020"],"award-info":[{"award-number":["633053","UIDB\/50010\/2020","UIDP\/50010\/2020"]}]},{"name":"Funda\u00e7ao para a Ciencia e Tecnologia","award":["633053","UIDB\/50010\/2020","UIDP\/50010\/2020"],"award-info":[{"award-number":["633053","UIDB\/50010\/2020","UIDP\/50010\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In a Heavy Ion Beam Diagnostic (HIBD), the plasma potential is obtained by measuring the energy of the secondary ions resulting from beam-plasma collisions by an electrostatic energy analyzer with split-plate detector (SPD), which relates the secondary ion beam energy variation to its position determined by the difference in currents between the split plates. Conventionally, the data from SPD are analyzed with the assumption that the secondary beam current is uniform. However, the secondary beam presents an effective projection of the primary beam, the current of which, as a rule, has a bell-like non-uniform profile. This paper presents: (i) the general features of the secondary beam profile formation, considered in the simplistic approximation of the circular primary beam and the secondary ions that emerge orthogonal to the primary beam axis, (ii) details of spit-plate detection and the influence of the secondary beam non-uniformity on plasma potential measurements, (iii) supported experimental data from the tokamak ISTTOK HIBD for primary and secondary beam profiles and the SPD transfer characteristic, obtained for the 90\u00b0 cylindrical energy analyzer (90\u00b0 CEA) and (iv) the implementation of a multiple cell array detector (MCAD) with dedicated resolution for the measurements of secondary beam profile and MCAD operation in multi-split-plate detection mode for direct measurements of the SPD transfer characteristic.<\/jats:p>","DOI":"10.3390\/s22145135","type":"journal-article","created":{"date-parts":[[2022,7,11]],"date-time":"2022-07-11T00:06:21Z","timestamp":1657497981000},"page":"5135","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Affect of Secondary Beam Non-Uniformity on Plasma Potential Measurements by HIBD with Split-Plate Detector"],"prefix":"10.3390","volume":"22","author":[{"given":"Igor","family":"Nedzelskiy","sequence":"first","affiliation":[{"name":"Instituto de Plasma e Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2688-1160","authenticated-orcid":false,"given":"Artur","family":"Malaquias","sequence":"additional","affiliation":[{"name":"Instituto de Plasma e Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]},{"given":"Rafael","family":"Henriques","sequence":"additional","affiliation":[{"name":"Instituto de Plasma e Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]},{"given":"Ridhima","family":"Sharma","sequence":"additional","affiliation":[{"name":"Culham Science Centre, Abingdon OX14 3DB, UK"}]}],"member":"1968","published-online":{"date-parts":[[2022,7,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1088\/0029-5515\/10\/2\/015","article-title":"A direct measurement of plasma space potential","volume":"10","author":"Jobes","year":"1970","journal-title":"Nucl. Fusion"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Melnikov, A.V. (2019). Electric Potential in Toroidal Plasmas, Springer International Publishing.","DOI":"10.1007\/978-3-030-03481-8"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"516","DOI":"10.1063\/1.1139262","article-title":"Heavy ion beam probe energy analyzer for measurements of plasma potential fluctuations","volume":"58","author":"Solensten","year":"1986","journal-title":"Rev. Sci. Instrum."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"350","DOI":"10.1109\/27.310640","article-title":"The heavy ion beam diagnostic for the tokamak ISTTOK","volume":"22","author":"Cabral","year":"1994","journal-title":"IEEE Trans. Plasma Sci."},{"key":"ref_5","first-page":"123","article-title":"90\u00b0 cylindrical analyzer for the plasma potential fluctuations measurements by heavy ion beam diagnostic on the tokamak ISTTOK","volume":"123","author":"Nedzelskiy","year":"2016","journal-title":"Fusion Eng. Des."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"671","DOI":"10.1016\/S0920-3796(96)00558-3","article-title":"Evolution of the poloidal magnetic field profile of the ISTTOK plasma followed by heavy ion beam probing","volume":"34\u201335","author":"Malaquias","year":"1997","journal-title":"Fusion Eng. Des."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"043504","DOI":"10.1063\/1.1889230","article-title":"Consideration of magnetic field fluctuation measurements in torus plasma with a heavy ion beam probe","volume":"76","author":"Shimizu","year":"2005","journal-title":"Rev. Sci. Instrum."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"112016","DOI":"10.1016\/j.fusengdes.2020.112016","article-title":"Plasma potential and fluctuations measurements by HIBD with 90\u00b0 cylindrical energy analyzer on the ISTTOK tokamak","volume":"160","author":"Sharma","year":"2020","journal-title":"Fusion Eng. Des."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1853","DOI":"10.1063\/1.1538342","article-title":"Improved 20 keV injection system for the heavy-ion-beam diagnostic of the tokamak ISTTOK","volume":"74","author":"Cabral","year":"2003","journal-title":"Rev. Sci. Instrum."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"033505","DOI":"10.1063\/1.2185153","article-title":"Multichannel time-of-flight technique for plasma potential profile measurements by heavy ion beam diagnostic on the tokamak ISTTOK","volume":"77","author":"Nedzelskiy","year":"2006","journal-title":"Rev. Sci. Instrum."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"C11018","DOI":"10.1088\/1748-0221\/12\/11\/C11018","article-title":"Design and optimization of the electrostatic input module for the ISTTOK Tokamak HIBD cylindrical energy analyzer","volume":"12","author":"Sharma","year":"2017","journal-title":"JINST"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"112709","DOI":"10.1016\/j.fusengdes.2021.112709","article-title":"Properties of the 90\u00b0 cylindrical energy analyzer with internal deceleration of the beam in real conditions of operation","volume":"170","author":"Nedzelskiy","year":"2021","journal-title":"Fusion Eng. Des."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"3502","DOI":"10.1063\/1.1787953","article-title":"Analysis of heavy ion beam probe potential measurement errors in the Madison Symmetric Torus","volume":"75","author":"Zhang","year":"2004","journal-title":"Rev. Sci. Instrum."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"424","DOI":"10.1109\/27.310650","article-title":"High sensitivity detectors for measurement of space potential fluctuations","volume":"22","author":"Keating","year":"1994","journal-title":"IEEE Trans. Plasma Sci."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/14\/5135\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:44:23Z","timestamp":1760139863000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/14\/5135"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,7,8]]},"references-count":14,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2022,7]]}},"alternative-id":["s22145135"],"URL":"https:\/\/doi.org\/10.3390\/s22145135","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2022,7,8]]}}}