ADOPTED LEVELS for 200Fr
Author: F.G. Kondev | Citation: Nucl. Data Sheets 192, 1 (2023) | Cutoff date: 1-Aug-2023
Full ENSDF file | Adopted Levels (PDF version)
| S(n)= 8710 keV 30 | S(p)= -400 keV 30 | Q(α)= 7622 keV 4 | |||
| Reference: 2021WA16 |
| E(level) (keV) | Jπ(level) | T1/2(level) |
| 0 | (3+) | 49.6 ms 21 % α ≥ 97.5 % ε ≤ 2.5 |
| <110? | (10-) | 0.10 s +18-4 % α ≈ 100 |
| ≤253? | 0.6 µs +5-2 % IT ≈ 100 |
Additional Level Data and Comments:
| E(level) | Jπ(level) | T1/2(level) | Comments |
| 0 | (3+) | 49.6 ms 21 % α ≥ 97.5 % ε ≤ 2.5 | %ε+%β+ from 2014Ka23, based on the non-observation of Eα(200Rn). Non-observation of Eα(200Rn) also reported in 2005De01 and 2019Gh11,2015Gh03 (%ε+%β+ |< 2.1%). E(level): %ε+%β+ from 2014Ka23, based on the non-observation of Eα(200Rn). Non-observation of Eα(200Rn) also reported in 2005De01 and 2019Gh11,2015Gh03 (%ε+%β+ |< 2.1%). |
| 110 | (10-) | 0.10 s +18-4 % α ≈ 100 | Eα1=7550 keV correlated with Eα2=6880 keV in 1996En01. The assignment to 200Fr is tentative. |
2019Gh11: 200Fr produced in U(p,X),E=1.4 GeV at ISOLDE-CERN facility using UCx target and pulsed proton beam. Francium atoms were ionized and accelerated to 30 keV, followed by mass separation using High-Resolution Separator (HRS). Measured: Eα, T1/2 using Si surface barrier detectors. FWHM≈33 keV for Eα=5-8 MeV range.
2014Ka23: 200Fr produced in 147Sm(56Fe,p2n) at GSI with E(56Fe)=260-263 MeV. Target=370 μg/cm2 thick enriched to 96.4% in 147Sm, and backed with 40 μg/cm2 thick carbon backing and covered with a 10 μg/cm2 layer of carbon. It was mounted on a rotating wheel. Evaporation residues were separated using SHIP facility at GSI, and implanted into the detection system consisting of 16-strip position sensitive Si detectors (PSSD), a pack of six Si strip detectors (BOX) at the back to detect escaping α particles, and three time-of-flight detectors in front of PSSDs. Measured position and time correlations between evaporation residues (Er) and α events, Eα, half-lives of ground states of 200Fr and 196At, (Er)γ-coin, αγ-coin, Er-α-α correlations.
2014Gh09: 200Fr produced in U(p,X),E=1.4 GeV at ISOLDE-CERN facility using UCx target and pulsed proton beam. Francium atoms were ionized and accelerated to 30 keV, followed by mass separation. Purified ion beams were transported to the detection station and implanted into 20 μg/cm2 thick carbon foils. Fission fragments and α particles were measured by two silicon detectors of 300 μm thickness and γ rays were detected by a high-purity germanium detectors. Measured Eγ, Iγ, Eα, Iα, fission fragments. Deduced β-delayed fission branching ratio.
2005De01: 200Fr produced in a bombardment with a 1.4 GeV pulsed proton beam on 51 g/cm2 thorium/graphite target; Detectors: on-line mass separator, recoils were implanted on a carbon foil for 100 ms and subsequent α decays were detected using a 400 mm2, 1 mm thick silicon detector for a 1100 ms time period; Measured: Eα, T1/2
1996En01: 200Fr produced using 170Yb(35Cl,4n), E(35Cl)=205 and 213 MeV; Target: 72 % enriched in 170Yb; Detectors: gas filled mass separator, position sensitive silicon detectors with a typical resolution (FWHM) of 35 keV; Measured: Eα, T1/2. Assignment to 200Fr is based on the observed Eα-Eα correlation with the characteristic daughter α-decay.
1995Mo14: 200Fr produced using 169Tm(36Ar,5n), E(36Ar)=186 MeV; Beam intensity: 1.3×1011 ions/s; Target: self-supporting, 2 mg/cm2 thick; Detectors: gas filled recoil separator, position sensitive Si detectors with a typical energy resolution (FWHM) of 70 keV and position resolution (FWHM) of 0.2 mm (horizontal direction) and 0.5 mm (vertical direction), microchannel plate assembly located about 60 cm upstream from the Si detectors; Measured: Eα, T1/2. Assignment to 200Fr is based on the observed Eα-Eα correlation with the characteristic daughter (196At) α-decay.