A versatile triple radiofrequency quadrupole system for cooling, mass separation and bunching of exotic nuclei

Haettner, E.; Plaß, W. R.; Czok, U.; Geißel, H.; Kinsel, Wadim; Petrick, Martin; Schäfer, Thorsten; Scheidenberger, C.

doi:10.1016/j.nima.2017.10.003

Cited by 31 publications

(23 citation statements)

References 56 publications

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“…In Fig. 2, a schematic view of the FRS-IC with its three main parts is shown: (i) the gas-filled cryogenic stopping cell (CSC) [29][30][31][32] for thermalization of the exotic nuclei produced at relativistic energies, (ii) a beamline, based on radio frequency quadrupoles (RFQ) [32][33][34][35] for mass-selective transport and differential pumping, equipped with detectors (channeltrons and silicon detectors) for ion counting and α-decay spectroscopy and with ion sources for diagnostic purposes, and (iii) the MR-TOF-MS [14,36,37] for several purposes, such as diagnostics of the upstream beamline, ion identification and counting, and direct mass measurements.…”

Section: Methodsmentioning

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: Methodsmentioning

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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“…The RFQ beam line and MR-TOF-MS will be based on instruments that are experimentally demonstrated. The RFQ beam line may be ~1 m long, and its expected transmission will be ~90% [125]. The MR-TOF-MS may be of similar length, and its expected efficiency will be ~50% [126].…”

Section: Study Of Neutron-rich Fission Fragments and Relation To The mentioning

confidence: 99%

The Soreq Applied Research Accelerator Facility (SARAF): Overview, research programs and future plans

Mardor¹,

Aviv²,

Avrigeanu³

et al. 2018

Eur. Phys. J. A

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The Soreq Applied Research Accelerator Facility (SARAF) is under construction in the Soreq Nuclear Research Center at Yavne, Israel. When completed at the beginning of the next decade, SARAF will be a user facility for basic and applied nuclear physics, based on a 40 MeV, 5 mA CW proton/deuteron superconducting linear accelerator. Phase I of SARAF (SARAF-I, 4 MeV, 2mA CW protons, 5 MeV 1mA CW deuterons) is already in operation, generating scientific results in several fields of interest. The main ongoing program at SARAF-I is the production of 30 keV neutrons and measurement of Maxwellian Averaged Cross Sections (MACS), important for the astrophysical s-process. The world leading Maxwellian epithermal neutron yield at SARAF-I (5×10 10 epithermal neutrons/sec), generated by a novel Liquid-Lithium Target (LiLiT), enables improved precision of known MACSs, and new measurements of lowabundance and radioactive isotopes. Research plans for SARAF-II span several disciplines: Precision studies of beyond-Standard-Model effects by trapping light exotic radioisotopes, such as 6 He, 8 Li and 18,19,23 Ne, in unprecedented amounts (including meaningful studies already at SARAF-I); extended nuclear astrophysics research with higher energy neutrons, including generation and studies of exotic neutron-rich isotopes relevant to the rapid (r-) process; nuclear structure of exotic isotopes; high energy neutron cross sections for basic nuclear physics and material science research, including neutron induced radiation damage; neutron based imaging and therapy; and novel radiopharmaceuticals development and production.

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“…Thermalization is performed in a cryogenic stopping cell (CSC) [17][18][19]. The isotopes are then extracted, diagnosed and transported by a versatile RFQ beam-line [20]. Their mass is measured precisely with a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) [21] that can also provide an isobarically (and isomerically) clean beam for further experiments [22].…”

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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A versatile triple radiofrequency quadrupole system for cooling, mass separation and bunching of exotic nuclei

Cited by 31 publications

References 56 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

The Soreq Applied Research Accelerator Facility (SARAF): Overview, research programs and future plans

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

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