Periodic Reporting for period 2 - LISA (Laser Ionization and Spectroscopy of Actinide elements)
Reporting period: 2021-11-01 to 2024-09-30
The LISA consortium conducts research to increase our understanding of the atomic and nuclear properties of the actinides. These are a group of radioactive elements crucial to our basic understanding of nuclear chemistry and applications including nuclear power. Of long-standing interest to the fields of fundamental atomic and nuclear physics, their study is an essential prerequisite for understanding the so-called superheavy elements. Within the different work packages (WP) of the LISA consortium, complementary research methods were applied to produce and study the actinides, which are elusive due to their chemical similarities, complex atomic structure and hugely varying scarcity. LISA brought together specialists of the field to train the next generation of young researchers. Techniques combining nuclear chemical preparation, laser spectroscopy, and mass spectrometry, supported by theoretical studies, have yielded insights into chemical behaviour and nuclear structure.
A key objective of LISA was to demonstrate the societal value of its research, focusing on radioecological surveys through ultra-trace analysis and 225Ac for targeted alpha therapy (TAT). Progress included fast switching between laser schemes for rapid sample analysis and advancements in analyzing Pu isotopic ratios. LISA also succeeded in producing Ac in its atomic and molecular forms, providing highly pure samples for medical applications.
A key objective of LISA was to demonstrate the societal value of its research, focusing on radioecological surveys through ultra-trace analysis and 225Ac for targeted alpha therapy (TAT). Progress included fast switching between laser schemes for rapid sample analysis and advancements in analyzing Pu isotopic ratios. LISA also succeeded in producing Ac in its atomic and molecular forms, providing highly pure samples for medical applications.
The production and first observation of ion beams of Ac, Np, and Pu at ISOLDE were significant milestones of LISA. Ac was successfully extracted as molecular fluoride ion beam (AcF⁺), enabling their first study through laser spectroscopy. Upgrades at ISOLDE's Offline 2 mass separator allowed detailed studies of molecular formation. Additionally, molecular actinide ion beams like AcF⁺ and AcFF⁺ were produced, broadening the scope of experimental studies on actinides and their applications in nuclear research and medicine.
High-resolution in-source laser spectroscopy using PI-LIST at ISOLDE enabled precise hyperfine structure analysis of Ac isotopes, advancing nuclear structure research. This method expanded the possibilities for studying rare isotopes and was complemented by its application to lanthanides. The technique set the stage for ongoing experimental campaigns and further exploration of actinides.
At GANIL, through strong collaboration with facilities like KUL, in-gas-jet laser spectroscopy was optimized, achieving high resolution for actinide research. Offline commissioning of the S3-LEB setup included developing high-performance Ti:Sapphire lasers with resolutions below 300 MHz, optimizing ion beam transmission to 80%. Breakthroughs in gas jet design enabled high-resolution studies at GSI, culminating in a 5-fold resolution improvement for No-isotopes. These efforts validated setups for future heavy element research.
Laser technology innovations, such as intra-cavity frequency tripling in Ti:Sapphire lasers and the development of the HighPower C-WAVE OPO, significantly improved laser spectroscopy capabilities. Collaborative campaigns using the C-WAVE system at the university of Mainz, measured elements like Np and Fm, achieving unprecedented precision in spectral measurements. These advancements facilitated research on nuclear properties and isotope production.
Efficient ionization schemes for 10 of the 15 actinide elements were developed, aiding ultra-trace analysis of radiotoxic isotopes and supporting theoretical models of complex atomic systems. Collaboration between theory and experiment improved understanding of hyperfine fields and level structures. Despite challenges, studies on actinide anions and negative ion spectroscopy remain a priority for future research.
The production and use of 225Ac for TAT expanded, with a second supply-line established at CERN MEDICIS. This development supported PRISMAP projects and identified inconsistencies in nuclear data, prompting a new experimental campaign at the ISOLDE Decay Station, with measurements foreseen in 2024.
LISA techniques extended beyond actinides to elements like Sr and Cs, aiding the analysis of nuclear fuel particulates and incidents like Chernobyl. These investigations provided insights into reactor behavior and radioactive releases, contributing to nuclear safety and environmental understanding.
WP5 of LISA focused on refining techniques for atomic spectroscopy and production of heavy actinide samples. Key achievements included molecular plating of 239Pu recoil sources, hyperfine parameter measurements for 235U, and advancements in gas jet systems for spectroscopy at facilities like GANIL and GSI.
Efforts to study lawrencium (Z=103) using the RADRIS method made significant progress, improving ion transport and detection efficiency. Although no resonances have been observed, larger search regions were excluded. The improved RADRIS technique allowed access to previously unreachable Fm isotopes, with findings published in Nature in 2024.
High-resolution in-source laser spectroscopy using PI-LIST at ISOLDE enabled precise hyperfine structure analysis of Ac isotopes, advancing nuclear structure research. This method expanded the possibilities for studying rare isotopes and was complemented by its application to lanthanides. The technique set the stage for ongoing experimental campaigns and further exploration of actinides.
At GANIL, through strong collaboration with facilities like KUL, in-gas-jet laser spectroscopy was optimized, achieving high resolution for actinide research. Offline commissioning of the S3-LEB setup included developing high-performance Ti:Sapphire lasers with resolutions below 300 MHz, optimizing ion beam transmission to 80%. Breakthroughs in gas jet design enabled high-resolution studies at GSI, culminating in a 5-fold resolution improvement for No-isotopes. These efforts validated setups for future heavy element research.
Laser technology innovations, such as intra-cavity frequency tripling in Ti:Sapphire lasers and the development of the HighPower C-WAVE OPO, significantly improved laser spectroscopy capabilities. Collaborative campaigns using the C-WAVE system at the university of Mainz, measured elements like Np and Fm, achieving unprecedented precision in spectral measurements. These advancements facilitated research on nuclear properties and isotope production.
Efficient ionization schemes for 10 of the 15 actinide elements were developed, aiding ultra-trace analysis of radiotoxic isotopes and supporting theoretical models of complex atomic systems. Collaboration between theory and experiment improved understanding of hyperfine fields and level structures. Despite challenges, studies on actinide anions and negative ion spectroscopy remain a priority for future research.
The production and use of 225Ac for TAT expanded, with a second supply-line established at CERN MEDICIS. This development supported PRISMAP projects and identified inconsistencies in nuclear data, prompting a new experimental campaign at the ISOLDE Decay Station, with measurements foreseen in 2024.
LISA techniques extended beyond actinides to elements like Sr and Cs, aiding the analysis of nuclear fuel particulates and incidents like Chernobyl. These investigations provided insights into reactor behavior and radioactive releases, contributing to nuclear safety and environmental understanding.
WP5 of LISA focused on refining techniques for atomic spectroscopy and production of heavy actinide samples. Key achievements included molecular plating of 239Pu recoil sources, hyperfine parameter measurements for 235U, and advancements in gas jet systems for spectroscopy at facilities like GANIL and GSI.
Efforts to study lawrencium (Z=103) using the RADRIS method made significant progress, improving ion transport and detection efficiency. Although no resonances have been observed, larger search regions were excluded. The improved RADRIS technique allowed access to previously unreachable Fm isotopes, with findings published in Nature in 2024.
The LISA project achieved significant advancements in actinide research, particularly in ion beam production, atomic spectroscopy, and laser technologies, with strong socio-economic impacts through applications like medical isotope production.
Some of the key innovations include:
- De Laval Nozzles: Designed using advanced fluid dynamics, hypersonic nozzles enable medium-high resolution laser spectroscopy combined with sensitive ion detection. Validated at GSI and GANIL, they promise improved studies of heavy elements' atomic and nuclear structure.
- Molecular Plating Techniques: Essential for producing thin targets and alpha-recoil sources; refined for high activity, purity, and homogeneity. These targets are critical for actinide experiments in university and accelerator laboratories.
- High-power CW OPO laser: reliable, solid-state alternative to dye lasers, offering enhanced spectral control for radioactive ion beam studies.
- Molecular ion beam production: production of AcF+ and AcFF+ ion beams, particularly extraction 225Ac, which is used in cancer treatment
The LISA-4-Society Action program emphasized societal benefits, focusing on trace analysis and TAT. While plans for a Chernobyl site visit were disrupted by geopolitical tensions, the project raised public awareness about nuclear safety and engaged in educational outreach concerning the Zaporizhzhia plant. Additionally, LISA co-organized a workshop in Fukushima, highlighting radioecology and disaster preparedness while producing informative materials for local communities.
In TAT, LISA promoted the use of 225Ac through educational media, including a video featuring a Swiss medical doctor, inspiring discussions about clinical trials at Geneva’s university hospital. CERN also highlighted the therapeutic potential of 225Ac in its public lecture series.
Laser technologies and ion source advancements like PI-LIST and in-gas-jet spectroscopy facilitated high-resolution isotope studies, enriching nuclear structure research and providing critical data for theoretical models. These achievements also trained skilled researchers and fostered international collaboration, with findings incorporated into global atomic databases like NIST.
Overall, LISA’s efforts advanced actinide science while addressing societal challenges, particularly through enhanced medical isotope production and nuclear safety research.
Some of the key innovations include:
- De Laval Nozzles: Designed using advanced fluid dynamics, hypersonic nozzles enable medium-high resolution laser spectroscopy combined with sensitive ion detection. Validated at GSI and GANIL, they promise improved studies of heavy elements' atomic and nuclear structure.
- Molecular Plating Techniques: Essential for producing thin targets and alpha-recoil sources; refined for high activity, purity, and homogeneity. These targets are critical for actinide experiments in university and accelerator laboratories.
- High-power CW OPO laser: reliable, solid-state alternative to dye lasers, offering enhanced spectral control for radioactive ion beam studies.
- Molecular ion beam production: production of AcF+ and AcFF+ ion beams, particularly extraction 225Ac, which is used in cancer treatment
The LISA-4-Society Action program emphasized societal benefits, focusing on trace analysis and TAT. While plans for a Chernobyl site visit were disrupted by geopolitical tensions, the project raised public awareness about nuclear safety and engaged in educational outreach concerning the Zaporizhzhia plant. Additionally, LISA co-organized a workshop in Fukushima, highlighting radioecology and disaster preparedness while producing informative materials for local communities.
In TAT, LISA promoted the use of 225Ac through educational media, including a video featuring a Swiss medical doctor, inspiring discussions about clinical trials at Geneva’s university hospital. CERN also highlighted the therapeutic potential of 225Ac in its public lecture series.
Laser technologies and ion source advancements like PI-LIST and in-gas-jet spectroscopy facilitated high-resolution isotope studies, enriching nuclear structure research and providing critical data for theoretical models. These achievements also trained skilled researchers and fostered international collaboration, with findings incorporated into global atomic databases like NIST.
Overall, LISA’s efforts advanced actinide science while addressing societal challenges, particularly through enhanced medical isotope production and nuclear safety research.