Search results for "Q value"
showing 10 items of 39 documents
$Q$-value of the superallowed $\beta$ decay of 62Ga
2006
Masses of the radioactive isotopes 62Ga, 62Zn and 62Cu have been measured at the JYFLTRAP facility with a relative precision of better than 18 ppb. A Q_EC value of (9181.07 +- 0.54) keV for the superallowed decay of 62Ga is obtained from the measured cyclotron frequency ratios of 62Ga-62Zn, 62Ga-62Ni and 62Zn-62Ni ions. The resulting Ft-value supports the validity of the conserved vector current hypothesis (CVC). The mass excess values measured were (-51986.5 +-1.0) keV for 62Ga, (-61167.9 +- 0.9) keV for 62Zn and (-62787.2 +- 0.9) keV for 62Cu.
Proton decay of 108I and its significance for the termination of the astrophysical rp-process
2019
Abstract Employing the Argonne Fragment Mass Analyzer and the implantation-decay-decay correlation technique, a weak 0.50(21)% proton decay branch was identified in 108I for the first time. The 108I proton-decay width is consistent with a hindered l = 2 emission, suggesting a d 5 2 origin. Using the extracted 108I proton-decay Q value of 597(13) keV, and the Q α values of the 108I and 107Te isotopes, a proton-decay Q value of 510(20) keV for 104Sb was deduced. Similarly to the 112,113Cs proton-emitter pair, the Q p ( I 108 ) value is lower than that for the less-exotic neighbor 109I, possibly due to enhanced proton-neutron interactions in N ≈ Z nuclei. In contrast, the present Q p ( Sb 104 …
High-precision electron-capture Q value measurement of 111In for electron-neutrino mass determination
2022
A precise determination of the ground state $^{111}$In ($9/2^+$) electron capture to ground state of $^{111}$Cd ($1/2^+$) $Q$ value has been performed utilizing the double Penning trap mass spectrometer, JYFLTRAP. A value of 857.63(17) keV was obtained, which is nearly a factor of 20 more precise than the value extracted from the Atomic Mass Evaluation 2020 (AME2020). The high-precision electron-capture $Q$ value measurement along with the nuclear energy level data of 866.60(6) keV, 864.8(3) keV, 855.6(10) keV, and 853.94(7) keV for $^{111}$Cd was used to determine whether the four states are energetically allowed for a potential ultra-low $Q$-value $\beta^{}$ decay or electron-capture deca…
Theoretical analysis of the possible ultra-low-Q-value decay branch of 135Cs
2011
Abstract We have investigated the feasibility of observing an ultra-low- Q -value beta-decay branch of 135 Cs by applying the microscopic quasiparticle–phonon model with a realistic two-body nuclear interaction. This work was motivated by an earlier combined experimental and theoretical work on decays of 115 In. The inaccuracy of the ground-state-to-ground-state Q value limits our ability to draw definite conclusions, and therefore modern precision measurements for it are called for. We present the computed partial half-lives of each channel for the most likely ranges of Q values.
Accurate Q value for the 74Se double-electron-capture decay
2010
Abstract The Q value of the neutrinoless double-electron-capture ( 0 ν ECEC ) decay of 74Se was measured by using the JYFLTRAP Penning trap. The determined value is 1209.169(49) keV, which practically excludes the possibility of a complete energy degeneracy with the second 2 + state (1204.205(7) keV) of 74Ge in a resonant 0 ν ECEC decay. We have also computed the associated nuclear matrix element by using a microscopic nuclear model with realistic two-nucleon interactions. The computed matrix element is found to be quite small. The failure of the resonant condition, combined with the small nuclear matrix element and needed p-wave capture, suppresses the decay rate strongly and thus excludes…
Towards high-precision mass measurements on 74Rb for a test of the CVC hypothesis and the unitarity of the CKM matrix
2004
At the highest possible precisions, atomic-mass measurements can be used to perform fundamental studies. Examples for such studies are a check of the conserved-vector-current (CVC) hypothesis and the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, both postulates of the Standard Model. The comparative half-lives Ft of superallowed β decays constitute the nuclear-physics access to these tests. The Q value of the β decay of 74 Rb, one of the three experimentally accessible parameters that enter into the Ft values, has been measured with the ISOLTRAP experiment at ISOLDE/CERN. The ultimate mass precision requirement and the way to achieve it are outlined.
Mirror decay of 75Sr
2003
The β-decay of 75Sr to its mirror nucleus 75Rb was studied at the ISOLDE PSB facility at CERN by means of β-delayed γ and proton spectroscopy. The decay Q-value and β-delayed γ intensity were measured for the first time. These results, 10.60±0.22 MeV and 4.5+1.9 -0.7%, together with accurate measurements of the β-decay half-life and β-delayed proton branching ratio yielded the Gamow-Teller strength 0.35±0.05 for the mirror transition. Implications of the results on studies of deformation effects and on the path of the rapid proton capture process are discussed.
Actinide Production in Collisions ofU238withCm248
1982
Cross sections for the production of heavy actinides in damped collisions of $^{238}\mathrm{U}$ ions with $^{248}\mathrm{Cm}$ targets are reported and compared with similar data for other projectiles. The relatively small differences in the formation rates of a given isotope made by different projectiles indicate a balance between increased mass transfer probability with increasing projectile mass and a concurrent decrease in survivability because of an increase in excitation energy.
Search for Superheavy Elements in theU238+U238Reaction
1980
A search was made for spontaneously fissioning superheavy elements in damped collisions of two uranium nuclei. Different techniques were applied covering the elements 108 to 118 and approx. =126, and a half-life range from 1 ms to more than 1 yr. No evidence for superheavy elements was found at upper cross-section limits of 10/sup -32/, 10/sup -33/, and 10/sup -35/ cm/sup 2/ for half-lives from 1 to 100 ms, 100 ms to 1 d, and 1 d to 1 yr, respectively.
High-precision mass measurements of 25Al and 30P at JYFLTRAP
2016
The masses of the astrophysically relevant nuclei 25Al and 30P have been measured with a Penning trap for the first time. The mass-excess values for 25Al ( $\Delta = -8915.962(63)$ keV) and 30P ( $\Delta = -20200.854(64)$ keV) obtained with the JYFLTRAP double Penning trap mass spectrometer are in good agreement with the Atomic Mass Evaluation 2012 values but $ \approx$ 5-10 times more precise. A high precision is required for calculating resonant proton-capture rates of astrophysically important reactions 25Al (p, $ \gamma$ )26Si and 30P(p, $ \gamma$ )31S . In this work, $ Q_{(p,\gamma)} = 5513.99(13)$ keV and $ Q_{(p,\gamma)} = 6130.64(24)$ keV were obtained for 25Al and 30P , respectivel…