Jon Petter Omtvedt

• Attallah, Mohamed F.; Elchine, Dominik; Grödler, Dennis; Margreiter, Raphael; Maslo, Melisa & Michel, Marco [Show all 9 contributors for this article] (2024). Trace-scale extraction of carrier-free tungsten radioisotope as a homolog of Sg using ionic liquid from acid solutions: Kinetic study. Separation and Purification Technology. ISSN 1383-5866. 331. doi: 10.1016/j.seppur.2023.125418.
• Bartl, P.; Němec, M.; Zach, V.; Bulíková, A.; Šifnerová, L. & Štursa, J. [Show all 8 contributors for this article] (2023). Fast on-line dissolution of KCl aerosol particulates for liquid-phase chemistry with homologues of superheavy elements. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 1055. doi: 10.1016/j.nima.2023.168500.
• Bartl, Pavel; Běhal, R; Matlocha, T; Němec, Mojmír; Šváb, P & Zach, Václav [Show all 10 contributors for this article] (2023). MARGE — a new ModulAr Robotic Gas-jet targEt system for chemistry studies with homologues of superheavy elements. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 1052. doi: 10.1016/j.nima.2023.168280.
• Nedkvitne, Eirik Nøst; Eriksen, Dag Øistein & Omtvedt, Jon Petter (2023). Grade and Tonnage Comparison of Anthropogenic Raw Materials and Ores for Cu, Zn, and Pb Recovery. Resources. ISSN 2079-9276. 12(3). doi: 10.3390/resources12030033. Full text in Research Archive
• Salina, Olga Nikolaevna; Grønås, Terje; Pottgießer, Vivien; Němec, Mojmír; Vahlbruch, Jan-Willem & Walther, Clemens [Show all 7 contributors for this article] (2022). RoboLab: providing remote access to a physical radiochemistry laboratory for teaching and training. Journal of Radioanalytical and Nuclear Chemistry. ISSN 0236-5731. doi: 10.1007/s10967-022-08589-3. Full text in Research Archive
• Yakushev, A.; Lens, L.; Düllmann, Ch. E.; Khuyagbaatar, J.; Jäger, E. & Krier, J. [Show all 59 contributors for this article] (2022). On the adsorption and reactivity of element 114, flerovium. Frontiers in Chemistry. ISSN 2296-2646. 10. doi: 10.3389/fchem.2022.976635. Full text in Research Archive
• Espegren, Fredrik; Kärkelä, Teemu; Pasi, Anna-Elina; Tapper, Unto; Kučera, Jan & Lerum, Hans Vigeland [Show all 8 contributors for this article] (2021). Tellurium transport in the RCS under conditions relevant for severe nuclear accidents. Progress in nuclear energy (New series). ISSN 0149-1970. 139, p. 1–12. doi: 10.1016/j.pnucene.2021.103815.
• Krupp, Dominik; Düllmann, Christoph E.; Lens, Lotte; Omtvedt, Jon Petter; Yakushev, Alexander & Scherer, Ulrich W. (2021). Speeding up liquid-phase heavy element chemistry: Development of a vacuum to liquid transfer chamber (VLTC). Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 1011. doi: 10.1016/j.nima.2021.165486.
• Tereshatov, Evgeny E.; Semelova, Miroslava; Čubová, Kateřina; Bartl, Pavel; Nemec, Mojmir & Stursa, Jan [Show all 10 contributors for this article] (2021). Valence states of cyclotron-produced thallium. New Journal of Chemistry. ISSN 1144-0546. 45(7), p. 3377–3381. doi: 10.1039/d0nj05198e.
• Khuyagbaatar, Jadambaa; Yakushev, Alexander; Düllmann, Ch. E.; Ackermann, Dieter; Andersson, Lise-Lotte & Asai, Masato [Show all 71 contributors for this article] (2020). Search for elements 119 and 120. Physical Review C. ISSN 2469-9985. 102(6). doi: 10.1103/PhysRevC.102.064602. Full text in Research Archive
• Lerum, Hans Vigeland; Andersen, Niels Højmark; Eriksen, Dag Øistein; Hansen, Eddy Walther & Omtvedt, Jon Petter (2020). NMR study of the influence and interplay of water, HCl and LiCl with the extraction agent Aliquat 336 dissolved in toluene. Journal of Molecular Liquids. ISSN 0167-7322. 317. doi: 10.1016/j.molliq.2020.114160.
• Haba, H.; Fan, F.; Kaji, D.; Kasamatsu, Y.; Kikunaga, H. & Komori, Yukiko [Show all 31 contributors for this article] (2020). Production of Bh 266 in the Cm 248 (Na 23,5n) Bh 266 reaction and its decay properties. Physical Review C. ISSN 2469-9985. 102(2). doi: 10.1103/PhysRevC.102.024625. Full text in Research Archive
• Lerum, Hans Vigeland; Sand, Svetlana; Eriksen, Dag Øistein; Wibetoe, Grethe & Omtvedt, Jon Petter (2020). Comparison of single‑phase and two‑phase measurements in extraction, separation and back‑extraction of Cd, Zn and Co from a multi‑element matrix using Aliquat 336. Journal of Radioanalytical and Nuclear Chemistry. ISSN 0236-5731. 324, p. 1203–1214. doi: 10.1007/s10967-020-07168-8.
• Kucera, Jan; Pasi, Anna-Elina; Espergen, Fredrik; Kärkelä, Teemu; Lerum, Hans Vigeland & Omtvedt, Jon Petter [Show all 7 contributors for this article] (2020). Tellurium determination by three modes of instrumental neutron activation analysis in aerosol filters and trap solutions for the simulation of a severe nuclear accident. Microchemical Journal. ISSN 0026-265X. doi: 10.1016/j.microc.2020.105139.
• Khuyagbaatar, Jadambaa; Yakushev, Alexander; Düllmann, Christoph E.; Ackermann, Dieter; Andersson, Lise-lotte & Asai, Masato [Show all 72 contributors for this article] (2019). Fusion reaction Ca-48+Bk-249 leading to formation of the element Ts (Z=117). Physical Review C. ISSN 2469-9985. doi: 10.1103/PhysRevC.99.054306. Full text in Research Archive
• Skarnemark, Gunnar; Malmbeck, Rikard; Johansson, Jan Marcus; Omtvedt, Jon Petter; Trautmann, Norbert G. & Ödegaard-Jensen, Arvid [Show all 7 contributors for this article] (2019). SIMSISAK - a Method to Model Nuclide Transport in the SISAK System. Solvent extraction and ion exchange. ISSN 0736-6299. 37(3-4), p. 232–244. doi: 10.1080/07366299.2019.1639358. Full text in Research Archive
• Såmark-Roth, Anton; Sarmiento, Luis G.; Rudolph, Dirk; Ljungberg, Jimmy; Carlsson, B. Gillis & Fahlander, Claes [Show all 48 contributors for this article] (2018). Low-lying states in 219Ra and 215Rn: Sampling microsecond α -decaying nuclei. Physical Review C. ISSN 2469-9985. 98:044307(4), p. 1–11. doi: 10.1103/PhysRevC.98.044307.
• Lerum, Hans Vigeland; Andersen, Niels Højmark; Eriksen, Dag Øistein; Hansen, Eddy Walther; Petersen, Dirk & Wibetoe, Grethe [Show all 7 contributors for this article] (2018). Study of Cadmium Extraction with Aliquat 336 from Highly Saline Solutions. Journal of Solution Chemistry. ISSN 0095-9782. 47(8), p. 1395–1417. doi: 10.1007/s10953-018-0795-z.
• Cubova, Katerina; Semelova, Miroslava; Nemec, Mojmir; John, Jan; Milacic, Juraj & Omtvedt, Jon Petter [Show all 7 contributors for this article] (2018). Extraction of thallium and indium isotopes as the homologues of nihonium into the ionic liquids. Journal of Radioanalytical and Nuclear Chemistry. ISSN 0236-5731. doi: 10.1007/s10967-018-6270-x.
• Lens, Lotte; Yakushev, Alexander; Düllmann, Christoph E.; Asai, Masato; Ballof, Jochen & Block, Michael [Show all 53 contributors for this article] (2018). Online chemical adsorption studies of Hg, Tl, and Pb on SiO2 and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA. Radiochimica Acta. ISSN 0033-8230. 106(12), p. 949–962. doi: 10.1515/ract-2017-2914.
• Di Nitto, Antonio; Khuyagbaatar, Jadambaa; Ackermann, Dieter; Andersson, Lise-Lotte; Badura, Eugen & Block, Michael [Show all 64 contributors for this article] (2018). Study of non-fusion products in the 50Ti+249Cf reaction. Physics Letters B. ISSN 0370-2693. 784, p. 199–205. doi: 10.1016/j.physletb.2018.07.058. Full text in Research Archive
• Forsberg, Ulrika; Rudolph, D; Andersson, LL; Di Nitto, A; Dullmann, Ch E & Fahlander, C [Show all 54 contributors for this article] (2016). Recoil-α-fission and recoil-α-α-fission events observed in the reaction 48Ca + 243Am. Nuclear Physics A. ISSN 0375-9474. 953, p. 117–138. doi: 10.1016/j.nuclphysa.2016.04.025.
• Langrock, Gert; Wiehl, Norbert; Kling, Hans-Otto; Mendel, Matthias; Nähler, Andrea & Tharun, Udo [Show all 11 contributors for this article] (2015). Digital liquid-scintillation counting and effective pulse-shape discrimination with artificial neural networks. Radiochimica Acta. ISSN 0033-8230. 103(1), p. 15–25. doi: 10.1515/ract-2014-2281.
• Rudolph, Dirk; Forsberg, Ulrika; Golubev, Pavel; Sarmiento, Luis G.; Yakushev, Alexander & Andersson, Lise-Lotte [Show all 51 contributors for this article] (2015). Selected spectroscopic results on element 115 decay chains. Journal of Radioanalytical and Nuclear Chemistry. ISSN 0236-5731. 303(2), p. 1185–1190. doi: 10.1007/s10967-014-3445-y. Show summary

  Thirty correlated α-decay chains were observed in an experiment studying the fusion-evaporation reaction 48Ca + 243Am at the GSI Helmholtzzentrum für Schwerionenforschung. The decay characteristics of the majority of these 30 chains are consistent with previous observations and interpretations of such chains to originate from isotopes of element Z = 115. High-resolution α-photon coincidence spectroscopy in conjunction with comprehensive Monte-Carlo simulations allow to propose excitation schemes of atomic nuclei of the heaviest elements, thereby probing nuclear structure models near the ‘Island of Stability’ with unprecedented experimental precision.

• Ooe, Kazuhiro; Abdo, Mohamed Fathy Attallah; Asai, M; Goto, N; Sen Gupta, Nalinava & Haba, H. [Show all 33 contributors for this article] (2015). Development of a new continuous dissolution apparatus with a hydrophobic membrane for superheavy element chemistry. Journal of Radioanalytical and Nuclear Chemistry. ISSN 0236-5731. 303(2), p. 1317–1320. doi: 10.1007/s10967-014-3469-3. Show summary

  A new technique for continuous dissolution of nuclear reaction products transported by a gas-jet system was developed for superheavy element (SHE) chemistry. In this technique, a hydrophobic membrane is utilized to separate an aqueous phase from the gas phase. With this technique, the dissolution efficiencies of short-lived radionuclides of 91m,93mMo and 176W were measured. Yields of more than 80 % were observed for short-lived radionuclides at aqueous-phase flow rates of 0.1–0.4 mL/s. The gas flow-rate had no influence on the dissolution efficiency within the studied flow range of 1.0–2.0 L/min. These results show that this technique is applicable for on-line chemical studies of SHEs in the liquid phase.

• Toyoshima, A.; Ooe, K.; Miyashita, S.; Asai, M; Abdo, Mohamed Fathy Attallah & Goto, N [Show all 33 contributors for this article] (2015). Chemical studies of Mo and W in preparation of a seaborgium (Sg) reduction experiment using MDG, FEC, and SISAK. Journal of Radioanalytical and Nuclear Chemistry. ISSN 0236-5731. 303(2), p. 1169–1172. doi: 10.1007/s10967-014-3438-x. Show summary

  The extraction and reduction behavior of Mo and W, lighter homologs of Sg, was studied in continuous on-line experiments at the JAEA tandem accelerator to develop a new chemistry assembly consisting of a membrane degasser (MDG), a flow electrolytic column (FEC), and the continuous liquid–liquid extraction apparatus (SISAK). Extraction yields of Mo and W from 0.1 M HCl/0.9 M LiCl into 4-isopropyltropolone (hinokitiol, HT) in toluene were investigated. In the reduction experiment, Mo(VI) was successfully reduced to a lower oxidation state while W(VI) showed no reduction under the given conditions.

• John, Jan; Lehto, Jukka; Koivula, Teija & Omtvedt, Jon Petter (2015). Cooperation in education and training in nuclear- and radiochemistry in Europe. Journal of Radioanalytical and Nuclear Chemistry. ISSN 0236-5731. 304(1), p. 459–466. doi: 10.1007/s10967-014-3624-x. Show summary

  The motivation, history and status of coordination of education and training in nuclear- and radiochemistry in Europe are reviewed. The achievements of the Euratom FP7 project “Cooperation In education in Nuclear CHemistry (CINCH)” are described. Attention is paid to the results of the survey of universities teaching nuclear chemistry and their respective curricula evaluation, to the plan to introduce the EuroMaster in nuclear- and radiochemistry quality label recognized and guaranteed by the European Association for Chemical and Molecular Sciences (EuCheMS), and to CINCH NucWik—an interactive database proposed and implemented as an open structure in the form of a “Wiki”.

• Yakushev, Alexander; Gates, Jacklyn M.; Türler, Andreas; Schädel, Matthias; Düllmann, Christoph Emanuel & Ackermann, Dieter [Show all 44 contributors for this article] (2014). Superheavy element flerovium (Element 114) is a volatile metal. Inorganic Chemistry. ISSN 0020-1669. 53(3), p. 1624–1629. doi: 10.1021/ic4026766.
• Khuyagbaatar, Jadambaa; Yakushev, A; Dullmann, CE; Ackermann, D; Andersson, LL & Asai, M [Show all 72 contributors for this article] (2014). Ca 48 + Bk 249 fusion reaction leading to element Z=117: Long-lived α -decaying Db 270 and discovery of Lr 266. Physical Review Letters. ISSN 0031-9007. 112:172501(17). doi: 10.1103/PhysRevLett.112.172501.
• Rudolph, D; Forsberg, U; Golubev, P; Sarmiento, LG; Yakushev, A & Andersson, L [Show all 51 contributors for this article] (2014). Alpha-photon coincidence spectroscopy along element 115 decay chains. Acta Physica Polonica B. ISSN 0587-4254. 45(2), p. 263–272. doi: 10.5506/APhysPolB.45.263.
• Rudolph, Dirk; Forsberg, U; Golubev, P; Sarmiento, LG; Yakushev, A & Andersson, LL [Show all 51 contributors for this article] (2013). Spectroscopy of Element 115 Decay Chains. Physical Review Letters. ISSN 0031-9007. 111(11:112502). doi: 10.1103/PhysRevLett.111.112502.
• Usoltsev, I; Eichler, R; Dressler, R; Piguet, D; Wittwer, D & Türler, Andreas [Show all 10 contributors for this article] (2012). Preparation of Pd-based intermetallic targets for high intensity irradiations. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 691, p. 5–9. doi: 10.1016/j.nima.2012.06.060.
• Forsberg, U; Golubev, P.; Sarmiento, L.G.; Jeppsson, J.; Rudolph, D. & Andersson, L.-L. [Show all 33 contributors for this article] (2012). FIRST EXPERIMENT AT TASCA TOWARDS X-RAY FINGERPRINTING OF ELEMENT 115 DECAY CHAINS. Acta Physica Polonica B. ISSN 0587-4254. 43(2), p. 305–311. doi: 10.5506/APhysPolB.43.305.
• Sen Gupta, Nalinava; Wragg, David; Tilset, Mats & Omtvedt, Jon Petter (2011). 4,7,13,18-Tetraoxa-1,10-diazoniabicyclo[8.5.5]icosane hexafluoridosilicate. Acta Crystallographica Section E: Structure Reports Online. ISSN 1600-5368. 67. doi: 10.1107/S1600536811026006.
• Sen Gupta, Nalinava; Wragg, David; Tilset, Mats & Omtvedt, Jon Petter (2011). 4,7,13,18-Tetraoxa-1,10-diazoniabicyclo[ 8.5.5]icosane bis(hexafluoridophosphate). Acta Crystallographica Section E: Structure Reports Online. ISSN 1600-5368. 67. doi: 10.1107/S1600536811025992.
• Gates, Jacklyn; Düllmann, Christoph E.; Omtvedt, Jon Petter; Yakushev, A; Turler, A & Eberhardt, K [Show all 48 contributors for this article] (2011). First superheavy element experiments at the GSI recoil separator TASCA: The production and decay of element 114 in the Pu-244(Ca-48,3-4n) reaction. Physical Review C. Nuclear Physics. ISSN 0556-2813. 83(5). doi: 10.1103/PhysRevC.83.054618.
• Even, Julia; Ballof, J; Brüchle, Willy; Buda, R. A.; Düllmann, Christoph E. & Eberhardt, Klaus [Show all 34 contributors for this article] (2011). The recoil transfer chamber — An interface to connect the physical preseparator TASCA with chemistry and counting setups. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 638(1), p. 157–164. doi: 10.1016/j.nima.2011.02.053.
• Samadani, Fereshteh; Alstad, Jorolf; Bjørnstad, Tor; Stavsetra, Liv & Omtvedt, Jon Petter (2010). Development of a SISAK extraction system for chemical studies of element 108, hassium. Radiochimica Acta. ISSN 0033-8230. 98(12), p. 757–764. doi: 10.1524/ract.2010.1787.
• Düllmann, Christoph E.; Schädel, Matthias; Yakushev, Alexander; Türler, Andreas; Eberhardt, Klaus & Kratz, Jens v. [Show all 45 contributors for this article] (2010). Production and Decay of Element 114: High Cross Sections and the New Nucleus (277)Hs. Physical Review Letters. ISSN 0031-9007. 104(25). doi: 10.1103/PhysRevLett.104.252701.
• Graeger, Reimar; Ackermann, Dieter; Chelnokov, M; Chepigin, V; Düllmann, Christoph E. & Dvorak, Jan [Show all 30 contributors for this article] (2010). Experimental study of the U-238(S-36,3-5n)(269-271)Hs reaction leading to the observation of (270)Hs. Physical Review C. Nuclear Physics. ISSN 0556-2813. 81(6). doi: 10.1103/PhysRevC.81.061601.
• Omtvedt, Jon Petter (2009). Laboratorieøvelser som fjernundervisning - Erfaringer fra utvikling av det fjernstyrte laboratoriumet RoboLab. In Koch, Susanne Anette Kjekshus (Eds.), Ringer i vann. Lenge leve fleksibel læring ved Universitetet i Oslo. 7Letras. ISSN 978-82-997407-3-9. p. 49–58.
• Zheng, Li; Alstad, Jorolf; Bjørnstad, Tor; Polakova, Darina; Stavsetra, Liv & Omtvedt, Jon Petter (2008). Extraction of Nb and Ta, homolgues of Db, from sulphuric acid solutions with TOA in toluene using SISAK. Radiochimica Acta. ISSN 0033-8230. 96. doi: 10.1524/ract.2008.1463.
• Omtvedt, Jon Petter; Alstad, Jorolf; Bjørnstad, Tor; Düllmann, Christoph E.; Gregorich, Kenneth E. & Hoffman, Darleane C. [Show all 15 contributors for this article] (2007). Chemical properties of the transactinide elements studied in liquid phase with SISAK. European Physical Journal D : Atomic, Molecular and Optical Physics. ISSN 1434-6060. 45(1), p. 91–97. doi: 10.1140/epjd/e2007-00214-6.
• Omtvedt, Jon Petter; Alstad, Jorolf; Bjørnstad, Tor; Düllmann, Christoph E.; Folden, C. M. & Gregorich, Kenneth E. [Show all 14 contributors for this article] (2006). SISAK Liquid-Liquid Extraction Studies of Rutherfordium and Future Plans to Study Heavier Transactinides. In May, I.; Alvares, R. & Bryan, N. (Ed.), Recent Advances in Actinide Science. Royal Society of Chemistry (RSC) Publishing. ISSN 0-85404-678-X. p. 278–280. Show summary

  Actinide elements and their chemistry have a significant number of applications. Bringing together contributions from the leading experts in the field, Recent Advances in Actinide Science covers six main topics; Analysis, the environment and biotransformations Coordination and organometallic chemistry Heavy elements Nuclear fuels, materials and waste forms Separations and solution chemistry Spectroscopy, magnetism and superconductivity Covering a wide range of research from pure academic studies to applied industrial science and technology, this book distils the knowledge and achievements gained in actinide science over the last four years. This high level book is aimed at researchers, both industrial and academic, and provides a comprehensive overview of the current status of actinide science.

• Polakova, Darina; Alstad, Jorolf; Bjørnstad, Tor; Skarnemark, Gunnar; Stavsetra, Liv & Sudowe, Ralf [Show all 10 contributors for this article] (2006). Development of a System for Chemical Studies of Rutherfordium by Liquid-Liquid Extraction From Sulphuric Acid Solutions with SISAK. In May, I.; Alvares, R. & Bryan, N. (Ed.), Recent Advances in Actinide Science. Royal Society of Chemistry (RSC) Publishing. ISSN 0-85404-678-X. p. 281–283. Show summary

  Actinide elements and their chemistry have a significant number of applications. Bringing together contributions from the leading experts in the field, Recent Advances in Actinide Science covers six main topics; Analysis, the environment and biotransformations Coordination and organometallic chemistry Heavy elements Nuclear fuels, materials and waste forms Separations and solution chemistry Spectroscopy, magnetism and superconductivity Covering a wide range of research from pure academic studies to applied industrial science and technology, this book distils the knowledge and achievements gained in actinide science over the last four years. This high level book is aimed at researchers, both industrial and academic, and provides a comprehensive overview of the current status of actinide science.

• Zheng, Li; Alstad, Jorolf; Bjørnstad, Tor; Polakova, Darina; Stavsetra, Liv & Omtvedt, Jon Petter (2006). Influence of KCl on the Extraction of Rutherfordium Homologues Hafnium and Zirconium From Sulphuric Acid with Tri-Octylamine in Toluene. In May, I.; Alvares, R. & Bryan, N. (Ed.), Recent Advances in Actinide Science. Royal Society of Chemistry (RSC) Publishing. ISSN 0-85404-678-X. p. 284–286. Show summary

  Actinide elements and their chemistry have a significant number of applications. Bringing together contributions from the leading experts in the field, Recent Advances in Actinide Science covers six main topics; Analysis, the environment and biotransformations Coordination and organometallic chemistry Heavy elements Nuclear fuels, materials and waste forms Separations and solution chemistry Spectroscopy, magnetism and superconductivity Covering a wide range of research from pure academic studies to applied industrial science and technology, this book distils the knowledge and achievements gained in actinide science over the last four years. This high level book is aimed at researchers, both industrial and academic, and provides a comprehensive overview of the current status of actinide science.

• Pershina, V; Polakova, Darina & Omtvedt, Jon Petter (2006). Theoretical predictions of complex formation of group-4 elements Zr, Hf, and Rf in H2SO4 solutions. Radiochimica Acta. ISSN 0033-8230. 94, p. 407–414.
• Stavsetra, Liv; Gregorich, KE; Alstad, Jorolf; Breivik, H; Eberhardt, K & Folden, CM [Show all 20 contributors for this article] (2005). Liquid-scintillation detection of preseparated (257)Rf with the SISAK-system. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 543, p. 509–516.
• Gregorich, Kenneth E.; Loveland, Walter; Peterson, D; Zielinski, P. M.; Nelson, SL & Chung, YH [Show all 19 contributors for this article] (2005). Attempt to confirm superheavy element production in the Ca-48+U-238 reaction. Physical Review C. Nuclear Physics. ISSN 0556-2813. 72.
• Stavsetra, Liv; Hult, Elin A. & Omtvedt, Jon Petter (2005). Real-Time Gain Shift Correction for On-Line Alpha-Liquid Scintillation Spectroscopy. Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment. ISSN 0168-9002. 551, p. 137–143.

View all works in Cristin

• Lehrum, Hans Vigeland; Andersen, Niels Højmark; Eriksen, Dag Øistein; Hansen, Eddy Walther & Omtvedt, Jon Petter (2020). NMR Studies of Aliquat 336 in toluene after contact with saline solutions - Determination of ionic content.
• Lerum, Hans V.; Sand, Svetlana; Eriksen, Dag Øistein; Hansen, Eddy Walther; Wibetoe, Grethe & Omtvedt, Jon Petter (2018). Determination of Distribution Ratios in Liquid-liquid Extraction of Hydrometallurgical Process Solutions using ICP-MS and Radiotracer Techniques.
• John, Jan; Retegan, Teodora; Lehto, Jukka; Omtvedt, Jon Petter & Skipperud, Lindis (2016). CINCH–II Project – A Milestone in the Coordination of Education and Training in Nuclear- and Radiochemistry in Europe.
• Lerum, Hans Vigeland; Bouzga, Aud Mjærum; Jørgensen, Sissel; Petersen, Dirk; Eriksen, Dag Øistein & Hansen, Eddy Walther [Show all 8 contributors for this article] (2016). Study of cadmium extraction from aqueous solutions with high chloride concentration using radiotracer and NMR .
• Lerum, Hans Vigeland; Bouzga, Aud Mjærum; Jørgensen, Sissel; Petersen, Dirk; Eriksen, Dag Øistein & Hansen, Eddy Walther [Show all 8 contributors for this article] (2016). LIQUID-LIQUID EXTRACTION OF CADMIUM CHLORIDE COMPLEXES STUDIED BY NMR.
• Retegan, Teodora; Ekeberg, Christian; John, Jan; Cuba, Vaclav; Nemec, Mojmir & Lehto, Jukka [Show all 14 contributors for this article] (2015). Cooperation in Education and Training in Nuclear and Radiochemistry in Europe – A Continuous Process.
• John, Jan; Cuba, Vaclav; Nemec, Mojmir; Retegan, Teodora; Ekeberg, Christian & Lehto, Jukka [Show all 16 contributors for this article] (2014). Cooperation in Education and Training in Nuclear- and Radiochemistry in Europe.
• John, Jan; Retegan, Teodora; Lehto, Jukka; Omtvedt, Jon Petter & Skipperud, Lindis (2013). CINCH-II: Next step in the coordination of education in nuclear and radiochemistry in Europe.
• John, Jan; Vaclav, Cuba; Nemec, Mojmir; Retegan, Teodora; Ekeberg, Christian & Lehto, Jukka [Show all 14 contributors for this article] (2013). Coordination of Education in Nuclear And Radiochemistry In Europe.
• John, Jan; Retegan, Teodora; Lehto, Jukka; Koivula, Teija; Scully, Paul J. & Walther, Clemens [Show all 13 contributors for this article] (2013). Next step in the coordination of education in nuclear and radiochemistry in Europe.
• Bjørnstad, Tor; Eriksen, Dag Øystein & Omtvedt, Jon Petter (2013). Radiochemistry and hydrometallurgy - two synergetic fields.
• Wærsted, Frøydis Meen; Omtvedt, Jon Petter; Wibetoe, Grethe & Vogt, Rolf David (2013). The role of particles and phosphorus bound to particles in eutrophication.
• Omtvedt, Jon Petter; Alstad, Jorolf; Bjørnstad, Tor; Dullmann, C.E.; Gregorich, K.E. & Gupta, N.S. [Show all 11 contributors for this article] (2010). Superheavy Element Chemistry with SISAK.
• Omtvedt, Jon Petter (2008). Hvordan får vi energi fra thorium? Naturfag. ISSN 1504-4564. 1, p. 28–32. Show summary

  Denne artikkelen er skrevet med tanke på å gi grunnleggende informasjon om kjerneenergiverk som benytter thorium som brennstoff. Målet er at læreren skal forstå de viktigste mulighetene og begrensningene på en slik måte at hun/han kan formidle dette videre. Artikkelen vil ikke diskutere for eller imot kjerneenergiverk, den diskusjonen overlates til andre fora. Det er forfatterens håp at artikkelen vil bidra til at både tilhengere og motstandere av kjerneenergi kan diskutere med utgangspunkt i et tryggere faglig grunnlag og dermed heve debattens kvalitet og verdi.

• Stølen, Svein; Gorbitz, Carl Henrik; Omtvedt, Jon Petter & Ødegaard, Knut Jørgen Røed (2008). Verdt å vite spesial: Grunnstoffene og periodesystemet. [Radio]. NRK P2.
• Omtvedt, Jon Petter & Helgesen, Ole K. (2008). Spenning om thorium. [Newspaper]. Teknisk ukeblad.
• Omtvedt, Jon Petter & Sæther, Jens Marius Sæther (2008). Klart for atomkamp på tinget. [Newspaper]. Dagsavisen.
• Omtvedt, Jon Petter & Strande, Mona (2008). Norge må forske på kjernekraft. [Newspaper]. Teknisk ukeblad.
• Jemterud, Torkild; Rose, Sunniva & Omtvedt, Jon Petter (2008). Verdt å vite 2008-12-19. [Radio]. NRK P2.
• Omtvedt, Jon Petter (2008). Recent developments in automated liquid-liquid extraction studies of transactinide elements. Show summary

  Liquid-liquid extraction (LLE) studies of Rf (Z=104), after physical preseparation with the Berkeley Gas-filled Separator, were performed. Based on the experience gained in these successful experiments, the computer controlled SISAK LLE system has been improved and developed further in order to be able to study transactinide elements heavier than Rf. In particular, the transfer from the recoil transfer chamber (RTC) (which transfer the recoils from the separator to a aerosol seeded gas-jet) to the chemistry apparatus and the acquisition system for the liquid scintillation detectors have been improved. The results from the RTC developments will be presented together with other improvements made to the SISAK centrifuge system and liquid-scintillation detectors.

• Omtvedt, Jon Petter (2008). Kjernekraft fra thorium.
• Omtvedt, Jon Petter (2008). Thorium og kjernekraft - trenger Norge slik kompetanse?
• Samadani, Fereshteh & Omtvedt, Jon Petter (2007). Developing a SISAK extraction system for chemical study of element 108, hassium.
• Omtvedt, Jon Petter (2007). Fast and continuous liquid-liquid extraction with the computer controlled SISAK system.
• Opel, Karsten; Akermann, Dieter; Brüchle, Willy; Dressler, R; Düllmann, Christoph E. & Dvpral, K [Show all 21 contributors for this article] (2007). Recoil Transfer Chamber Design at TASCA.
• Opel, Karsten & Omtvedt, Jon Petter (2007). New Control System for SISAK.
• Omtvedt, Jon Petter & Hammerfjeld, Jon R. (2006). Lagde verdens tyngste grunnstoff. [Newspaper]. Dagbladet.no.
• Omtvedt, Jon Petter; Alstad, Jorolf; Bjørnstad, Tor; Dullmann, C.E.; Folden III, C.M. & Gregorich, K.E. [Show all 15 contributors for this article] (2006). “Chemical Properties of the Transactinide Elements Studied in Liquid Phase with SISAK”,
• Zheng, Li; Alstad, Jorolf; Bjørnstad, Tor; Polakova, Darina; Stavsetra, Liv & Omtvedt, Jon Petter (2006). ”Influence of KCl on the extraction of rutherfordium homologues hafnium and zirconium from sulphuric acid with tri-octylamine in toluene”,
• Vogt, Rolf David; Solomonova, Polina; Gjessing, Egil & Omtvedt, Jon Petter (2006). Preparative gel fractionation of NOM for ecological studies - The fate of mercury in aquatic ecosystems. Show summary

  Forty years ago it was shown that dissolved humic substances (HS) in water could be separated into a number of different size fractions using the gel-matrix Sephadex (1). Since then a number of different techniques and methods have been introduced for the purpose to define and describe the physical properties and chemical composition of HS. During the last few decades the awareness of the ecological importance of this complicated organic matter has increased and it is realized that more knowledge on biological properties and biological functions of HS are needed. We have re-introduced preparative gel-filtration, in order to be able to learn more about the fate of micro pollutants in fresh-water ecosystems. Mercury (Hg) is an element of considerable health concern, mostly due to its global distribution and its bio-magnification potentials in water. The important role of HS both as carrier and as mediator of Hg transport from soil to the surface water is demonstrated by elevated Hg concentrations in humic-rich waters. The purpose of the work to be presented is to fractionate “Hg-spiked” dissolved natural organic matter (NOM), and to investigate the Hg distribution on the NOM in detail. The biological properties of the resulting fractions will later be studied in co-operation with ecologists.

• Omtvedt, Jon Petter (2005). OCL@SAFE: Transactinide homologues available at the Oslo Cyclotron Laboratory for model studies.
• Årnes, Silje Kathrine & Omtvedt, Jon Petter (2023). A Study on Metal Recovery from Ilmenite Mud Waste: Characterisation, Hydrochloric Acid Leaching, and Oxidation Roasting. Kjemisk Institutt, Universitetet i Oslo.
• Dirdal, Ragnhild Elise & Omtvedt, Jon Petter (2023). Selective Recovery of Copper from Municipal Solid Waste Incineration Bottom Ash. Kjemisk Institutt, Universitetet i Oslo. Show summary

  A hydrometallurgical process was investigated as a method to selectively recover copper from municipal solid waste incineration (MSWI) bottom ash. In Norway, bottom ash is mainly disposed of instead of being utilized. When landfilled, hazardous components, such as copper and zinc, can potentially be released to the environment and cause groundwater pollution. Therefore, extraction of copper and zinc would be a favorable solution for both disposal and utilization of bottom ash, as well as a potential source for secondary materials. In order to be economically feasible to recover metals from bottom ash, other metals and components probably need to be recovered as well. Acidic leaching solutions are most commonly used, however, alkaline solutions are generally more selective, less corrosive and have a lower reagent consumption according to previous studies. Ammonia-ammonium carbonate (AAC) is stated to be a suitable choice of leach solution for selective recovery of copper and zinc. The different substances of the AAC solution can be recovered, recombined and used in subsequent processing. In the present study, AAC leaching of bottom ash followed by a cementation procedure in order to selectively precipitate copper was investigated. Co-dissolution of zinc was also monitored during the study due to possible subsequent recovery based on procedures established in previous studies. MSWI bottom ash originating from different incineration plants in Norway was characterized and used in the study. The bottom ash was leached with an aqueous solution of ammonia (NH3) and ammonium carbonate ((NH4)2CO3). In order to efficiently extract copper from bottom ash, the AAC leaching procedure was optimized in terms of particle size, total ammonia concentration, leaching temperature, pulp density (solid/liquid ratio), and leaching time. The optimal leaching conditions were found to be 4.7 M, 60 C, 100 g bottom ash per liter leach solution and 180 minutes of leaching time, before the liquid and solid phases were separated. The pregnant leach solution (PLS) was quantitatively analyzed with inductively coupled plasma optical emission spectroscopy (ICP-OES). Extraction of more than 98 % of the copper from bottom ash was achieved. The copper was subsequently precipitated from the PLS by a cementation procedure with metallic zinc dust. After cementation, the PLS was quantitatively analyzed with ICP-OES and the solid residue was qualitatively analyzed using X-ray diffraction. More than 90% of copper was recovered from the PLS by cementation.

• Raskovic-Lovre, Zeljka; Omtvedt, Jon Petter & Eriksen, Dag Øistein (2019). Extraction of zinc from highly saline and acidic solutions. Universitetet i Oslo.
• Rafique, Waqas; Riss, Patrick & Omtvedt, Jon Petter (2018). Synthesis of Fluorine-18 Labelled Radiotraces and Their Pre-Clinical and Clinical Characterization. Kjemisk institutt, Universitetet i Oslo. ISSN 1501-7710. 2018(2013). Show summary

  Positron emission tomography (PET) is one of the most sensitive in vivo imaging techniques available to clinicians and researchers. It helps in understanding the biological interactions and mechanism of various diseases through use of radiolabelled compounds called radiotracers. Herein is described the development of facile radiolabelling approaches for straightforward access to 18F-labelled trifluoromethyl radiotracers. Direct nucleophilic radiofluorination of difluorovinyl precursors was achieved for 18F-trifluoromethylation of aliphatic compounds, and applied to the radiosynthesis of [18F]lansoprazole and N-methyl[18F]lansoprazole. The compounds were used to analyze the blood-brain barrier penetration in healthy persons and for the detection of tau-neurofibrillary tangles in Alzheimer’s patients. For 18F-trifluoromethylation of aromatic compounds, in situ synthesis of Cu[18F]CF3 was achieved and used in 18F-trifluoromethylation of iodo-arenes using a single vial one-step method. The procedure was applied for radiosynthesis of a derivative of AH7921, which is a sub-type selective mu-opioid receptor agonist. The developed procedures are applicable to available radiosynthesis hardware, and provide access to desired compounds within 40 minutes in high radiochemical yields. In addition, a series of new compounds were synthesized with aim to discover the new radioligands based on modifications to the lead compounds i.e. lansoprazole and AH7921. Several interesting candidates with good combination of affinity and selectivity were identified from each series, and radiolabelled with fluorine-18. The newly developed 18F-labelled compounds have good potential to provide the in vivo characterization of tau-neurofibrillary tangles and quantification of the opioid receptors using the PET imaging.

• Ræstad, Svein Harald; Omtvedt, Jon Petter; Wibetoe, Grethe & Eriksen, Dag Øystein (2017). Investigation of Leaching of Rare Earth Elements from Phosphate Rock with Nitric Acid using Neutron Activation. Universitetet i Oslo.
• Thorén, Masayo & Omtvedt, Jon Petter (2017). Assessment of a Potential Radiological Attack - Investigation of Scenarios Pertaining to Contamination of Infant Milk Formula. Universitetet i Oslo.
• Kristiansen, Håvard; Omtvedt, Jon Petter & Eriksen, Dag Øistein (2015). Radiochemical analysis of cadmium in nitric and phosphoric acid. Universitetet i Oslo. Show summary

  The goal of this research project was to find a way to produce fertilizer with low concentrations of cadmium from phosphate rock with relatively high cadmium concentrations. A method for the production of a radioactive cadmium tracer was developed and implemented. The tracer was used to investigate how cadmium behaves in a critical step of a process for fertilizer production. A method for measuring the radioactivity from 109Cd was developed, tested and implemented. The 109Cd radiotracer and the detection method were used to investigate solvent extraction from nitric and phosphoric acid, as well as from an industrial fertilizer-production solution. After a screening of a selection of possible commercial extractants, di-(2-ethylhexyl)phosphoric acid (HDEHP) and di-(2,4,4-trimethyl pentyl)dithiophosphinic acid (Cyanex 301) where studied closely. The results were interpreted in order to propose chemical equations for how HDEHP and Cyanex 301 react with cadmium and the acid matrix.

• Lehto, Jukka; Omtvedt, Jon Petter; Popic, Jelena Mrdakovic; Nemec, Mojmir & Koivula, Teija (2015). Workshop on Nuclear Chemistry Education and Training in Europe, CINCH-II Deliverable D4.5. NMBU/CERAD.
• Lerum, Hans Vigeland & Omtvedt, Jon Petter (2014). Preparations for a Reduction and Liquid-Liquid Separation Experiment for Element 106, Seaborgium. Universitetet i Oslo. Show summary

  The purpose of this thesis was to check if it was possible to prepare a mechanical and chemical system that can reduce Seaborgium, element 106, and separate between the reduced and the oxidized state. To do this the liquid-liquid extraction system SISAK has been coupled to a flow electrolytic column, which is able to reduce single atoms. To overcome the high difference in flow rate between these two systems a membrane degasser has been utilized which managed to severely reduce the amount of fluid needed. Several extraction schemes have been tested. These had the goal that they should manage to strongly extract only one of the oxidation states. As a model for Sg experiments Mo and W have been used. During the work of this thesis it has been shown that it is possible to reduce and separate between two oxidation states of Mo. Furthermore, slight separation has been achieved for W in some systems. This have been done to model Sg in such a way that it is realistic to believe that Sg will behave in the same way. In addition a proof of concept has been achieved were the newly developed membrane degasser, the flow electrolytic column and the SISAK centrifuge have been coupled together. This managed to reduce enough Mo and separate between the reduced and oxidized Mo species at a flow rate of 0.2 mL/s and with the aquatic solution 0.1 M HCl + 0.9 M LiCl and an organic solution of 0.01 M hinokitiol in Toluene. Some kinetic studies have been performed at 0.2 mL/s flow rate with HDEHP as an extractant in toluene and an aquatic solution of 0.1 m H2SO4. Additionally retention on the carbon electrode is discussed. The work presented in this thesis have been performed as a part of a large collaboration between the nuclear chemistry group at the university of Oslo, Norway and between the superheavy element group in Tokai, Japan. An importan part of this work has therefore been to set up a working SISAK set-up in Tokai and a working flow electrolytic column in Oslo.

• Wærsted, Frøydis Meen; Vogt, Rolf David; Wibetoe, Grethe & Omtvedt, Jon Petter (2014). The role of particles and phosphorus bound to particles in eutrophication. Universitetet i Oslo.
• Samadani, Fereshteh; Alstad, Jorolf; Schulz, Frøydis; Nilssen, Johannes; Omtvedt, Jon Petter & Ottesen, Heidi B. [Show all 23 contributors for this article] (2010). Pilot-Test Experiment with Os of a SISAK Setup for Hs-Chemistry Studies. GSI Helmholtzzentrum für Schwerionenforschung.
• Samadani, Fereshteh; Omtvedt, Jon Petter & Bjørnstad, Tor (2010). Liquid Chemistry of Hassium Tetroxide using Osmium in Model Experiments with SISAK. Universitetet i Oslo.
• Yakushev, Alexander; Dvorak, Jan; andrey, semchenkov; Türler, Andreas; ackermann, dieter & brüchle, willie [Show all 17 contributors for this article] (2007). Window Design for the TASCA Recoil Transfer Chamber (RTC). Jahresbericht 2006 Univ. Mainz, Institut für Kernchemie.
• Düllmann, Christoph E.; ackermann, dieter; brüchle, willie; Hessberger, F. P.; Jäger, Egon & Khuyagbaatar, J [Show all 26 contributors for this article] (2007). TASCA Recoil Transfer Chamber Commissioning. 1. Small Image Mode. Univ. Mainz Jahresbericht 2006, Institut für Kernchemie.
• Semchenkov, Andrey; ackermann, dieter; Brüchle, W.; Düllmann, Christoph E.; Jäger, Egon & Schimpf, E [Show all 15 contributors for this article] (2007). First TASCA Commissioning Experiments in the Small Image Size Mode. Gesellschaft f¨ur Schwerionenforschung mbH (GSI). ISSN 0174-0814. 2007(1).
• pershina, valeria; Polakova, Darina & Omtvedt, Jon Petter (2007). Theoretical Predictions of Complex Formation of Group-4 Elements Zr, Hf, and Rf in H2SO4 Solutions - GSI report. Gesellschaft für Schwerionenforschung mbH (GSI). ISSN 0174-0814. 2006(1).
• Zheng, Li; Omtvedt, Jon Petter; Alstad, Jorolf & Bjørnstad, Tor (2007). Preparation for Liquid-Liquid Extraction Studies of Dubnium Using Homologue Models with the SISAK System. 7Letras.
• Samadani, Fereshteh; Omtvedt, Jon Petter & Bjørnstad, Tor (2006). Developing a SISAK extraction system for studies of element 108, hassium. 7Letras. Show summary

  The SISAK (i.e. Short-lived Isotope Studied by the AKufve -technique) system was used for investigation of the reaction between osmium tetroxide and NaOH as a model for chemical study of hassium. The result was a two- stage extraction procedure. In the first extraction stage, OsO4 was extracted from NaOH solutions of different concentrations into toluene and the following equilibrium constants for the reaction of OsO4 and NaOH were obtained: K´= (2.35 ± 0.04) • 104 for formation of Na[OsO4(OH)] and K″= 6 ±4 for formation of Na2[OsO4(OH)2] out of Na[OsO4(OH)]. The purpose of the second extraction stage was to transfer the activity from the aqueous phase into the organic phase in an efficient way. In order to fulfill this purpose the basic aqueous phase from the first extraction stage was acidified with HCl, HClO4 or H2SO4 and the activity was extracted into toluene either with or without tri-n-octylamine (TOA) as an extracting agent. The extraction efficiency in this stage was around 90% in both cases although there were indications that extraction with TOA had a somewhat higher distribution ratio. An attempt was also made to use Aliquat 336 as an extracting agent to transfer activity into the organic phase. This experiment showed that Aliquat 336 can extract the activity very efficiently. There was, however, a problem with the purity of the liquid phases.

• Stavsetra, Liv & Omtvedt, Jon Petter (2005). Achievements using the continuous SISAK alpha-liquid scintillation technique, and its application in detection of 257Rf atoms. Faculty of Mathematics and Natural Sciences.

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