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Exotic Radionuclides from Accelerator Waste for Science and Technology - ERAWAST

English title Exotic Radionuclides from Accelerator Waste for Science and Technology - ERAWAST
Applicant Schumann Dorothea
Number 159738
Funding scheme Project funding (Div. I-III)
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Inorganic Chemistry
Start/End 01.05.2015 - 30.04.2018
Approved amount 387'340.00
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All Disciplines (2)

Discipline
Inorganic Chemistry
Nuclear Physics

Keywords (5)

nuclear astrophysics; nuclear data; radiochemistry; half-life measurements; cross sections

Lay Summary (German)

Lead
Kernphysikalische Daten haben grosse Bedeutung in verschiedenen Wissenschaftszweigen, die mit radioaktiven Materialien umgehen. Zum Beispiel erfordert die Untersuchung astrophysikalischer Prozesse bei Sternexplosionen oder die Erklärung der Isotopenhäufigkeiten auf der Erde die Kenntnis fundamentaler Daten wie Halbwertszeiten und Wirkungsquerschnitten. Die Halbwertszeiten sehr langlebiger Radionuklide sind häufig nur ungenau bekannt, weil das entsprechende Probenmaterial fehlt.
Lay summary

Inhalt und Ziel des Forschungsprojekts

Wir wollen mit unserem Projekt die erforderliche Menge 146Sm – ein Radionuklid mit erheblicher Bedeutung für den astrophysikalisch bedeutsamen p-Prozess, aus bestrahlten Tantal-Proben extrahieren. Das Material soll dann zur Messung der Halbwertszeit verwendet werden. Dafür kommen Alpha-Spektrometrie und Massenspektrometrie zum Einsatz. Ausserdem wollen wir die Produktionsraten von Radionukliden in protonenbestrahltem Tantal und Wolfram in Abhängigkeit von der Projektilenergie messen und so die Wirkungsquerschnitte bestimmen.

Bedeutung der Ergebnisse

Die bis jetzt nur sehr ungenau bekannte Halbwertszeit des 146Sm wird besser bestimmt. Damit ist die bessere Erklärung astrophysikalischer Prozesse der stellaren Elementsynthese möglich. Die Informationen über die Produktion von Radionukliden in Tantal und Wolfram unter Protonenbeschuss verbessern die Datenbasis auf dem Gebiet der Wirkungsquerschnitte.
Direct link to Lay Summary Last update: 30.03.2015

Responsible applicant and co-applicants

Employees

Publications

Publication
Radiochemical Determination of Long-Lived Radionuclides in Proton-Irradiated Heavy-Metal Targets: Part I—Tantalum
Talip Zeynep, Dressler Rugard, David Jean Christophe, Vockenhuber Christof, Müller Gubler Elisabeth, Vögele Alexander, Strub Eric, Vontobel Peter, Schumann Dorothea (2017), Radiochemical Determination of Long-Lived Radionuclides in Proton-Irradiated Heavy-Metal Targets: Part I—Tantalum, in Analytical Chemistry, 89(24), 13541-13549.
Analysis of the 148 Gd and 154 Dy Content in Proton-Irradiated Lead Targets
Talip Z., Pfister S., Dressler R., David J. C., Vögele A., Vontobel P., Michel R., Schumann D. (2017), Analysis of the 148 Gd and 154 Dy Content in Proton-Irradiated Lead Targets, in Analytical Chemistry, 89(12), 6861-6869.

Collaboration

Group / person Country
Types of collaboration
Robert Steele, University of California (Los Angelos) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Niko Kivel, NES, PSI Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Christof Vockenhuber, ETHZ Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Michael Paul, Hebrew University of Jerusalem Israel (Asia)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Eric Strub ZSR Hannover Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Yong Dai, PSI NES Bereich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
MARC XI Talk given at a conference Radiochemical separation of Sm from p-irradiated Ta targets, towards a high-precision half-life measurement of 146Sm 09.04.2018 Kona, United States of America Schumann Dorothea; Talip Zeynep;
9th International Conference on Isotopes and Expo Talk given at a conference Determination of the long-lived radionuclides from proton-irradiated heavy metal targets 12.11.2017 Doha, United Arab Emirates Schumann Dorothea; Talip Zeynep;
ND2016 Talk given at a conference Cross Sections for the proton-induced production of long-lived radionuclides in heavy metal targets 11.06.2016 Brügge, Belgium Schumann Dorothea; Talip Zeynep;
SESTEC-2016 Talk given at a conference Separation of the long-lived lanthanides from proton-irradiated metal targets 17.05.2016 Guwahati, India Talip Zeynep; Schumann Dorothea;


Communication with the public

Communication Title Media Place Year
Other activities nuclear-data-for-nuclear-installations International 2018

Associated projects

Number Title Start Funding scheme
149217 Analytics and separation of long-lived radionuclides produced by proton irradiation in lead targets - ASPIT - 01.01.2014 Project funding (Div. I-III)
178749 Exotic Radionuclides from Accelerator Waste for Science and Technology - ERAWAST II: the half-lives of long-lived lanthanides 01.12.2018 Project funding (Div. I-III)
129588 Analytics and separation of long-lived radionuclides produced by proton irradiation in lead targets 01.01.2011 Project funding (Div. I-III)
177229 Towards implementing new isotopes for environmental research: The half-life of 32Si 01.09.2018 Sinergia

Abstract

PSI operates one of the most powerful high-energetic proton accelerators world-wide. The surrounding components like targets, shielding or construction materials become highly activated, and, due to the complex nuclear reactions taking place, contain very rare and exotic radionuclides in considerable amounts, which are urgently needed in several scientific research fields. Therefore, an initiative called ERAWAST (exotic radionuclides from accelerator waste for science and technology) was launched by the RadWasteAnalytics group at PSI several years ago with the aim to establish a collaboration between PSI as “isotope producer” and users of those exotic radionuclides. However, the RadWasteAnalytics group does not act only as an isotope deliverer, but is actively involved in the follow-up scientific applications, for instance as a member of the n_TOF collaboration at CERN or in half-life measurements. Several remarkable successes during the last years like the re-measurement of the 60Fe half-life (press release PSI, University Munich and Spiegel online in 2010) and the first study of the astrophysical important nuclear reaction 44Ti(alpha,p)47V in inverse kinematics at CERN-ISOLDE (press release PSI, CERN and New Scientist 2014) encourage us to work for developing an expert center for radiochemical separation and target preparation at PSI, aimed to produce the urgently necessary sample material for front end experiments in nuclear astrophysics, nuclear physics, and other related science fields. In the present proposal, we focus on two matrix materials, W and Ta, activated by protons. In order to improve the nuclear data basis for spallation induced production of long-lived radionuclides in these two materials, we intend first to determine excitation functions for isotopes like 148/150Gd, 146Sm and 154Dy. Additionally, volatiles like 129I or 36Cl shall be studied. For this part of the work, we use thin samples, which were irradiated with protons of different energies at the proton irradiation facilities in Uppsala and Saclay (in collaboration with the University of Köln, Germany) about 20 years ago. The results will have a high impact on the performance of the planned rotating W target for the European Spallation Source to be built in Lund (Sweden).For the second part of the project, we plan to extract lanthanide isotopes from highly activated Ta samples produced at PSI in the frame of the material research program STIP. We expect to obtain up to 1017 atoms of the pure alpha-emitters 148/150Gd, 146Sm and 154Dy, respectively. Comparable amounts of beta- and gamma-emitting long-lived lanthanides are expected to be available as well. These isotopes provide unique material for astrophysical studies with a high impact to understanding the nuclear processes of the element synthesis in the lanthanide region.Finally, we want to improve the accurateness and precision of the half-life value for 146Sm by performing two independent measurements with identical samples, one at PSI in collaboration with the University of California (Los Angelos), USA, and the other one at the Hebrew University Jerusalem, Israel. These results will contribute to clarify the present astrophysical and geophysical discrepancies of the two last measurements, which differ by more than 30%.
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