Voltage scanning and technical upgrades at the Collinear Resonance Ionization Spectroscopy experiment

To optimize the performance of the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at CERN-ISOLDE, technical upgrades are continuously introduced, aiming to enhance its sensitivity, precision, stability, and efficiency. Recently, a voltage-scanning setup was developed and commissioned at CRIS, which improved the scanning speed by a factor of three as compared to the current laser-frequency scanning approach. This leads to faster measurements of the hyperfine structure for systems with high yields (more than a few thousand ions per second). Additionally, several beamline sections have been redesigned and manufactured, including a new field-ionization unit, a sharper electrostatic bend, and improved ion optics. The beamline upgrades are expected to yield an improvement of at least a factor of 5 in the signal-to-noise ratio by suppressing the non-resonant laser ions and providing time-of-flight separation between the resonant ions and the collisional background. Overall, the presented developments will further improve the selectivity, sensitivity, and efficiency of the CRIS technique.Comment: 10 pages. Under review at NIM B as part of the proceedings of EMIS 2022 at RAON, South Kore

On the feasibility of online terbium extraction at ISOL@MYRRHA

Terbium is an element that has four isotopes with interesting properties for medical applications, 149, 152, 155, 161Tb. These radioisotopes are however far from being sufficiently accessible, thereby hindering the pursuit of research on radiolabelling as well as clinical or preclinical investigations. Their lack of market availability is explained by difficulties in producing these radioisotopes with high purity and specific activity. While 161Tb can be produced using neutron capture in nuclear reactors, for 149, 152, 155Tb, a production route involving the ISOL technique is under study within the Tb-IRMA-V project. The ongoing R & D towards the production and extraction of these isotopes from an ISOL target at the ISOL@MYRRHA facility is reported in this contribution

β-delayed fission and α decay of 178Tl

A detailed nuclear-decay spectroscopy study of the neutron-deficient isotope 178Tl has been performed using the highly selective Resonance Ionization Laser Ion Source and ISOLDE mass separator (CERN), which allowed a unique isobarically pure beam of 178Tl to be produced. The first identification of the β-delayed fission of this isotope was made and its probability PβDF(178Tl)=0.15(6)% was determined. An asymmetric fission fragment mass distribution of the daughter isotope 178Hg (populated by the β decay of 178Tl) was deduced based on the measured fission fragment energies. The fine-structure α-decay pattern of 178Tl allowed the low-energy states in the daughter nucleus 174Au to be studied

Reconditioning of the Leuven Isotope Separator as a test bench for radioactive ion beam development

Producing novel medical radionuclides in the quantities necessary for pre-clinical and clinical use requires an ion source able to handle high ion throughputs, operated efficiently, to deliver high specific activity samples. This is only possible with the understanding of how different parameters affect the ion source performance. Offline mass separators are needed to run systematic studies that would help us to derive the laws governing those ion sources. At KU Leuven, we are refurbishing the Leuven Isotope Separator, a mass separator previously used for implantations of radioisotopes in solid-state samples and Mössbauer spectroscopy. In the past couple of years, the machine has undergone significant updates and has been adapted to integrate the target ion source units used at CERN-ISOLDE. This paper discusses the modifications to the Leuven Isotope Separator, as well as its potential as a test bench for the study of radioactive ion beams in the future

Production Cross-Section Measurements for Terbium Radionuclides of Medical Interest Produced in Tantalum Targets Irradiated by 0.3 to 1.7 GeV Protons and Corresponding Thick Target Yield Calculations

This work presents the production cross-sections of Ce, Tb and Dy radionuclides produced by 300 MeV to 1.7 GeV proton-induced spallation reactions in thin tantalum targets as well as the related Thick Target production Yield (TTY) values and ratios. The motivation is to optimise the production of terbium radionuclides for medical applications and to find out at which energy the purity of the collection by mass separation would be highest. For that purpose, activation experiments were performed using the COSY synchrotron at FZ Jülich utilising the stacked-foils technique and γ spectrometry with high-purity germanium detectors. The Al-27(p,x)Na-24 reaction has been used as monitor reaction. All experimental data have been systematically compared with the existing literature

Recent exploits of the ISOLTRAP mass spectrometer

The Penning-trap mass spectrometer ISOLTRAP, located at the isotope-separator facility ISOLDE (CERN), is presented in its current form taking into account technical developments since 2007. Three areas of developments are presented. The reference ion sources have been modified to guarantee a sufficient supply of reference ions for mass measurements and systematic studies. Different excitation schemes have been investigated for manipulation of the ion motion in the Penning trap, to enhance either the purification or measurement process. A multi-reflection time-of-flight mass separator has been implemented and can now be routinely used for purification and as a versatile tool for beam analysis. (C) 2013 Elsevier B.V. All rights reserved

Production cross-section measurements of proton-induced reactions on natural tantalum in the 0.3 GeV–1.7 GeV energy range

This work reports the production cross-section data for seventy-one radionuclides produced by 0.3 GeV–1.7 GeV protons impinging on thin tantalum targets. For that purpose, activation experiments were performed using the COSY synchrotron at FZ Jülich utilizing the stacked-foils technique and γ-ray spectrometry with high-purity germanium detectors. The Al-27(p,x)Na-24 reaction has been used as monitor reaction. All experimental data have been systematically compared with the existing literature. The excitation functions of Te-116, I-123, Dy-153 and Er-158 are reported for the first time. •Experimental data for proton-induced reactions on natural tantalum up to 1.7 GeV.•Use of the stacked-foils technique and γ-ray spectrometry.•First reported values for the production of Te-116, I-123, Dy-153 and Er-158

First application of the Laser Ion Source and Trap (LIST) for on-line experiments at ISOLDE

The Laser Ion Source and Trap (LIST) provides a new mode of operation for the resonance ionization laser ion source (RILIS) at ISOLDE/CERN, reducing the amount of surface-ionized isobaric contaminants by up to four orders of magnitude. After the first successful on-line test at ISOLDE in 2011 the LIST was further improved in terms of efficiency, selectivity, and reliability through several off-line tests at Mainz University and at ISOLDE. In September 2012, the first on-line physics experiments to use the LIST took place at ISOLDE. The measurements of the improved LIST indicate more than a twofold increase in efficiency compared to the LIST of the 2011 run. The suppression of surface-ionized francium contaminants has enabled the first in-source laser spectroscopy of217Po and219Po. © 2013 Elsevier B.V. All rights reserved.This work was supported by the Wolfgang-Gentner-Programme of the Bundesministerium für Bildung und Forschung (BMBF, Germany), the BRIX network, and the European comission within FP7 (ENSAR No. 262010).Peer Reviewe

Resonant laser ionization and mass separation of 225^{225}Ac

$^{225}$Ac is a radio-isotope that can be linked to biological vector molecules to treat certain distributed cancers using targeted alpha therapy. However, developing $^{225}$Ac-labelled radiopharmaceuticals remains a challenge due to the supply shortage of pure $^{225}$Ac itself. Several techniques to obtain pure $^{225}$Ac are being investigated, amongst which is the high-energy proton spallation of thorium or uranium combined with resonant laser ionization and mass separation. As a proof-of-principle, we perform off-line resonant ionization mass spectrometry on two samples of $^{225}$Ac, each with a known activity, in different chemical environments. We report overall operational collection efficiencies of 10.1(2)% and 9.9(8)% for the cases in which the $^{225}$Ac was deposited on a rhenium surface and a ThO$_{2}$ mimic target matrix respectively. The bottleneck of the technique was the laser ionization efficiency, which was deduced to be 15.1(6)%