Control System for the Next Generation In-flight Separator Super-FRS applied to New Isotope Search with the FRS

The construction of the upcoming FAIR facility entails an upgrade of the existing GSI accelerator facility. One of the upgrades is the integration of the new LSA control system framework, which is licensed and adapted from CERN, in order to provide a unified control environment for all accelerators, rings and transfer lines at both the GSI and FAIR facility. As part of this work, it was possible to incorporate the FRS as a machine-model within LSA by developing and implementing Parameter hierarchies and Makerules to enable streamlined and maximum parallel operations. For this purpose a FRS General Target Hierarchy was implemented to virtually map targets, target ladders, degraders, degrader disks, degrader ladders, detectors and detector ladders as realistically as possible with additional Makerules to facilitate automated online energy-loss calculations, secondary beam production within targets, operator driven magnetic rigidity overwriting and ion-optical target alignment calculations. Additionally slits, pneumatic drives and stepper motors were introduced into the machine-model, as well. Benchmarking proved for the machine-model and LSA to be equivalent to previous control systems by reproducing old experimental settings within an accuracy of 10^-4 and 10^-3 for the magnetic rigidity and current, respectively. Contemporary experiments can be even identically reproduced within the measurement and setting precision. Additional testing with a Ar-40 and U-238 primary beam showed the machine-model's capabilities in correctly transporting primary and secondary beam fragments to the destined experimental station without previous setting calculation via LISE++, proving all functionalities operative. This foundation was used during FAIR Phase-0 experiments at the GSI to produce and using the methods described here it was possible to preliminarily identify up to 21 new isotopes with a relativistic Pb-208 primary beam at 1050 AMeV impinging on a beryllium target of 4 g/cm^2 thickness with a niobium stripper backing of 225 mg/cm^2 thickness to first produce Re-200, -201, -202, W-198, -199, Ta-195, -196, -197, Hf-191, -192, -193, Lu-189, -190, -191, Yb-186, -187, Tm-182, -183, -184, -185 and Er-181

Mean range bunching of exotic nuclei produced by in-flight fragmentation and fission — Stopped-beam experiments with increased efficiency

The novel technique of mean range bunching has been developed and applied at the projectile fragment separator FRS at GSI in four experiments of the FAIR phase-0 experimental program. Using a variable degrader system at the final focal plane of the FRS, the ranges of the different nuclides can be aligned, allowing to efficiently implant a large number of different nuclides simultaneously in a gas-filled stopping cell or an implantation detector. Stopping and studying a cocktail beam overcomes the present limitations of stopped-beam experiments. The conceptual idea of mean range bunching is described and illustrated using simulations. In a single setting of the FRS, 37 different nuclides were stopped in the cryogenic stopping cell and were measured in a single setting broadband mass measurement with the multiple-reflection time-of-flight mass spectrometer of the FRS Ion Catcher.</p

Mass tagging:Verification and calibration of particle identification by high-resolution mass measurements

The access to exotic nuclei at radioactive ion beam facilities is crucial for the state of the art research across several fields of physics such as in nuclear structure, the understanding of fundamental interactions and nuclear astrophysics. The particle identification is of high importance, besides the challenging production of these rare and short-lived nuclei. At in-flight facilities, the particle identification is based on measuring the time-of-flight, energy-deposition and magnetic rigidity. These quantities are calibrated to convert them into A/Q and Z of the ions. To ensure a correct calibration, the unambiguous identification, also called tagging, of one species is necessary. Here, we present a novel tagging method by high-resolution mass measurements using an MR-TOF-MS after thermalization of the ions in a cryogenic stopping cell. The method was successfully established and tested at the fragment separator FRS at GSI with the FRS Ion Catcher in experiments using different FRS operation modes.</p

Radioactive Beams for Image-Guided Particle Therapy : The BARB Experiment at GSI

Several techniques are under development for image-guidance in particle therapy. Positron (β+) emission tomography (PET) is in use since many years, because accelerated ions generate positron-emitting isotopes by nuclear fragmentation in the human body. In heavy ion therapy, a major part of the PET signals is produced by β+-emitters generated via projectile fragmentation. A much higher intensity for the PET signal can be obtained using β+-radioactive beams directly for treatment. This idea has always been hampered by the low intensity of the secondary beams, produced by fragmentation of the primary, stable beams. With the intensity upgrade of the SIS-18 synchrotron and the isotopic separation with the fragment separator FRS in the FAIR-phase-0 in Darmstadt, it is now possible to reach radioactive ion beams with sufficient intensity to treat a tumor in small animals. This was the motivation of the BARB (Biomedical Applications of Radioactive ion Beams) experiment that is ongoing at GSI in Darmstadt. This paper will present the plans and instruments developed by the BARB collaboration for testing the use of radioactive beams in cancer therapy.peerReviewe

A new Time-of-flight detector for the R 3 B setup

© 2022, The Author(s).We present the design, prototype developments and test results of the new time-of-flight detector (ToFD) which is part of the R3B experimental setup at GSI and FAIR, Darmstadt, Germany. The ToFD detector is able to detect heavy-ion residues of all charges at relativistic energies with a relative energy precision σΔE/ ΔE of up to 1% and a time precision of up to 14 ps (sigma). Together with an elaborate particle-tracking system, the full identification of relativistic ions from hydrogen up to uranium in mass and nuclear charge is possible.11Nsciescopu