The science case of the FRS Ion Catcher for FAIR Phase-0

The FRS Ion Catcher at GSI enables precision experiments with thermalized projectile and fission fragments. At the same time it serves as a test facility for the Low-Energy Branch of the Super-FRS at FAIR. The FRS Ion Catcher has been commissioned and its performance has been characterized in five experiments with 238U and 124Xe projectile and fission fragments produced at energies in the range from 300 to 1000 MeV/u. High and almost element-independent efficiencies for the thermalization of short-lived nuclides produced at relativistic energies have been obtained. High-accuracy mass measurements of more than 30 projectile and fission fragments have been performed with a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) at mass resolving powers of up to 410,000, with production cross sections down to the microbarn-level, and at rates down to a few ions per hour. The versatility of the MR-TOF-MS for isomer research has been demonstrated by the measurement of various isomers, determination of excitation energies and the production of a pure isomeric beam. Recently, several instrumental upgrades have been implemented at the FRS Ion Catcher. New experiments will be carried out during FAIR Phase-0 at GSI, including direct mass measurements of neutron-deficient nuclides below 100Sn and neutron-rich nuclides below 208Pb, measurement of β-delayed neutron emission probabilities and reaction studies with multi-nucleon transfer.Peer reviewe

Critical limb ischaemia and the response to bone marrow-derived cell therapy according to tcPO 2 measurement

International audienc

Dissemination of extreme levels of extracellular vesicles: tissue factor activity in patients with severe COVID-19

International audienceAbstract Coronavirus disease 2019 (COVID-19) has become one of the biggest public health challenges of this century. Severe forms of the disease are associated with a thrombo-inflammatory state that can turn into thrombosis. Because tissue factor (TF) conveyed by extracellular vesicles (EVs) has been implicated in thrombosis, we quantified the EV-TF activity in a cohort of hospitalized patients with COVID-19 (n = 111) and evaluated its link with inflammation, disease severity, and thrombotic events. Patients with severe disease were compared with those who had moderate disease and with patients who had septic shock not related to COVID-19 (n = 218). The EV-TF activity was notably increased in patients with severe COVID-19 compared with that observed in patients with moderate COVID-19 (median, 231 [25th to 75th percentile, 39-761] vs median, 25 [25th to 75th percentile, 12-59] fM; P < .0001); EV-TF was correlated with leukocytes, D-dimer, and inflammation parameters. High EV-TF values were associated with an increased thrombotic risk in multivariable models. Compared with patients who had septic shock, those with COVID-19 were characterized by a distinct coagulopathy profile with significantly higher EV-TF and EV-fibrinolytic activities that were not counterbalanced by an increase in plasminogen activator inhibitor-1 (PAI-1). Thus, this article is the first to describe the dissemination of extreme levels of EV-TF in patients with severe COVID-19, which supports the international recommendations of systematic preventive anticoagulation in hospitalized patients and potential intensification of anticoagulation in patients with severe disease

Depth dose measurements in water for 11C and 10C beams with therapy relevant energies

Owing to the favorable depth-dose distribution and the radiobiological properties of heavy ion radiation, ion beam therapy shows an improved success/toxicity ratio compared to conventional radiotherapy. The sharp dose gradients and very high doses in the Bragg peak region, which represent the larger physical advantage of ion beam therapy, make it also extremely sensitive to range uncertainties. The use of beta(+) - radioactive ion beams would be ideal for simultaneous treatment and accurate online range monitoring through PET imaging. Since all the unfragmented primary ions are potentially contributing to the PET signal, these beams offer an improved image quality while preserving the physical and radiobiological advantages of the stable counterparts. The challenging production of radioactive ion beams and the difficulties in reaching high intensities, have discouraged their clinical application. In this context, the project Biomedical Applications of Radioactive ion Beams (BARB) started at GSI (Helmholtzzentrum fur Schwerionenforschung GmbH) with the main goal to assess the technical feasibility and investigate possible advantages of radioactive ion beams on the pre-clinical level. During the first experimental campaign C-11 and C-10 beams were produced and isotopically separated with the FRagment Separator (FRS) at GSI. The beta(+)-radioactive ion beams were produced with a beam purity of 99% for all the beam investigated (except one case where it was 94%) and intensities potentially sufficient to treat a small animal tumors within few minutes of irradiation time, similar to 10(6) particle per spill for the C-10 and similar to 10(7) particle per spill for the C-11 beam, respectively. The impact of different ion optical parameters on the depth dose distribution was studied with a precision water column system. In this work, the measured depth dose distributions are presented together with results from Monte Carlo simulations using the FLUKA software

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

A novel method for the measurement of half-lives and decay branching ratios of exotic nuclei

A novel method for simultaneous measurement of masses, Q-values, isomer excitation energies, half-lives and decay branching ratios of exotic nuclei has been demonstrated. The method includes first use of a stopping cell as an ion trap, combining storage of mother and daughter nuclides for variable durations in a cryogenic stopping cell (CSC), and afterwards the identification and counting of them by a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). We utilized our method to record the decay and growth of the 216Po and 212Pb isotopes (alpha decay) and of the 119m2Sb isomer ( t1/2=850±90 ms) and 119gSb isotope (isomer transition), obtaining half-lives consistent with literature values. The amount of non-nuclear-decay losses in the CSC up to ∼10 s is negligible, which exhibits its extraordinary cleanliness. For 119Sb isotopes, we present the first direct measurements of the mass of its ground state, and the excitation energy and decay branching ratios of its second isomeric state (119m2Sb). This resolves discrepancies in previous excitation energy data, and is the first direct evidence that the 119m2Sb isomer decays dominantly via γ emission. These results pave the way for the measurement of branching ratios of exotic nuclei.peerReviewe

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