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

Plaß, W. R.; Mardor, I.; Geißel, H.; Scheidenberger, C.; Amanbayev, Daler; Andrés, Samuel Ayet San; Äystö, J.; Balabanski, D. L.; Beck, Sönke; Bergmann, J.; Charviakova, Volha; Constantin, P.; Eronen, T.; Grahn, T.; Greiner, Florian; Haettner, E.; Hornung, C.; Hucka, Jean-Paul; Jokinen, A.; Kankainen, A.; Miskun, Ivan; Moore, I. D.; Pikthtelev, Alexander; Pohjalainen, I.; Purushothman, Sivaji; Patyk, Z.; Reiter, M. P.; Rink, Ann-Kathrin; Rinta‐Antila, S.; Spătaru, A.; Weick, H.; Winfield, J. S.; Yavor, M.I.

doi:10.1007/s10751-019-1597-4

Cited by 11 publications

(10 citation statements)

References 29 publications

(30 reference statements)

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“…Several experimental runs will be performed during FAIR phase 0 at GSI/FAIR. These experiments include mass measurements at N = 126 below 208 Pb [93] and for N = Z nuclides below 100 Sn [94]. Moreover the system will be used to identify reactions and decay products and thereby measure β-delayed neutron emission probabilities [95] and multinucleon transfer reaction product cross sections [96].…”

Section: Discussionmentioning

confidence: 99%

High-resolution, accurate multiple-reflection time-of-flight mass spectrometry for short-lived, exotic nuclei of a few events in their ground and low-lying isomeric states

Andrés¹,

Hornung²,

Ebert³

et al. 2019

Phys. Rev. C

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121

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Mass measurements of fission and projectile fragments, produced via 238 U and 124 Xe primary beams, have been performed with the multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) of the Fragment Separator (FRS) Ion Catcher with a mass resolving power (FWHM) of up to 410 000 and an uncertainty of down to 6 × 10 −8. The nuclides were produced and separated in flight with the fragment separator FRS at 300 to 1000 MeV/u and thermalized in a cryogenic stopping cell. The data-analysis procedure was developed to determine with highest accuracy the mass values and the corresponding uncertainties for the most challenging conditions: down to a few events in a spectrum and overlapping distributions, which can be distinguished from a single peak only by a broader peak shape. With this procedure, the resolution of low-lying isomers is increased by a factor of up to 3 compared to standard data analysis. The ground-state masses of 31 short-lived nuclides of 15 different elements with half-lives of down to 17.9 ms and count rates as low as 11 events per nuclide were determined. This is the first direct mass measurement for seven nuclides. The excitation energies and the isomer-to-groundstate ratios of six isomeric states with excitation energies of as little as 280 keV were measured. For nuclides with known mass values, the average relative deviation from the literature values is (4.5 ± 5.3) × 10 −8. The measured two-neutron separation energies and their slopes near and at the N = 126 and Z = 82 shell closures indicate a strong element-dependent binding energy of the first neutron above the closed proton shell Z = 82. The experimental results deviate strongly from the theoretical predictions, especially for N = 126 and N = 127.

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Section: Discussionmentioning

confidence: 99%

High-resolution, accurate multiple-reflection time-of-flight mass spectrometry for short-lived, exotic nuclei of a few events in their ground and low-lying isomeric states

Andrés¹,

Hornung²,

Ebert³

et al. 2019

Phys. Rev. C

Self Cite

121

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“…Nevertheless, the unique features in our implementation are broadband and high-resolving-power measurements in a non-scanning manner [21], fast extraction at the FRS-IC [15],fast mass measurement at the MR-TOF-MS [21], and extraordinary cleanliness of the CSC [25]. The latter feature is the source for the essential element independence of the CSC, including comparison of a noble element (Rn), and a most reactive one (Th) [26].…”

Section: Description Of the Methodsmentioning

confidence: 99%

Determining spontaneous fission properties by direct mass measurements with the FRS Ion Catcher

et al. 2020

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We present a direct method to measure fission product yield distributions (FPY) and isomeric yield ratios (IYR) for spontaneous fission (SF) fragments. These physical properties are of utmost importance to the understanding of basic nuclear physics, the astrophysical rapid neutron capture process ('r process') of nucleosynthesis, neutron star composition, and nuclear reactor safety. With this method, fission fragments are produced by spontaneous fission from a source that is mounted in a cryogenic stopping cell (CSC), thermalized and stopped within it, and then extracted and transported to a multiple-reflection time-of-flight mass-spectrometer (MR-TOF-MS). We will implement the method at the FRS Ion Catcher (FRS-IC) at GSI (Germany), whose MR-TOF-MS relative mass accuracy (~ 10-7) and resolving power (~ 600,000 FWHM) are sufficient to separate all isobars and numerous isomers in the fission fragment realm. The system's essential element independence and its fast simultaneous mass measurement provide a new direct way to measure isotopic FPY distributions, which is complementary to existing methods. It will enable nuclide FPY measurements in the high fission peak, which is hardly accessible by current techniques. The extraction time of the CSC, tens of milliseconds, enables a direct measurement of independent fission yields, and a first study of the temporal dependence of FPY distributions in this duration range. The ability to resolve isomers will further enable direct extraction of numerous IYRs while performing the FPY measurements. The method has been recently demonstrated at the FRS-ICr for SF with a 37 kBq 252Cf fission source, where about 70 different fission fragments have been identified and counted. In the near future, it will be used for systematic studies of SF with a higher-activity 252Cf source and a 248Cm source. The method can be implemented also for neutron induced fission at appropriate facilities.

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“…The FRS Ion Catcher (FRS-IC) [19,20] is a test facility for the Low-Energy Branch of the Super-FRS [21,22] at FAIR. It is installed at the end of the symmetric branch of the fragment separator FRS [23] at GSI and consists of three major parts: a gas-filled cryogenic stopping cell (CSC) [6,24,25], an RFQ beamline [24] and a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) [26,27].…”

Section: Methodsmentioning

confidence: 99%

Separation of atomic and molecular ions by ion mobility with an RF carpet

Miskun,

Dickel,

Andres

et al. 2020

Preprint

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Gas-filled stopping cells are used at accelerator laboratories for the thermalization of ion beams. Common challenges of many stopping cells are a high molecular background of extracted ions and limitations of extraction efficiency due to space-charge effects. At the FRS Ion Catcher at GSI, a new technique for removal of ionized molecules prior to their extraction out of the stopping cell has been developed. This technique utilizes the RF carpet for the separation of atomic ions from molecular contaminant ions through their difference in ion mobility. Results from the successful implementation and test during the experiment with a 600 MeV/u 124 Xe primary beam are presented. Suppression of molecular contaminants by three orders of magnitude has been demonstrated. Essentially backgroundfree measurement conditions with less than 1 % of background events within a mass-to-charge range of 25 u/e have been achieved. The technique can also be used to reduce the space-charge effects at the extraction nozzle and in the downstream beamline, thus ensuring high efficiency of ion transport and highly-accurate measurements under space-charge-free conditions.

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

Cited by 11 publications

References 29 publications

High-resolution, accurate multiple-reflection time-of-flight mass spectrometry for short-lived, exotic nuclei of a few events in their ground and low-lying isomeric states

High-resolution, accurate multiple-reflection time-of-flight mass spectrometry for short-lived, exotic nuclei of a few events in their ground and low-lying isomeric states

Determining spontaneous fission properties by direct mass measurements with the FRS Ion Catcher

Separation of atomic and molecular ions by ion mobility with an RF carpet

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