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1.
S. Rahaman V.-V. ElomaaT. Eronen J. HakalaA. Jokinen A. KankainenJ. Rissanen J. SuhonenC. Weber J. Äystö 《Physics letters. [Part B]》2011,703(4):412-416
The Q values of the 116Cd and 130Te double-beta decaying nuclei were determined by using a Penning trap mass spectrometer. The new atomic mass difference between 116Cd and 116Sn of 2813.50(13) keV differs by 4.5 keV and is 30 times more precise than the previous value of 2809(4) keV. The new value for 130Te, 2526.97(23) keV is close to the Canadian Penning trap value of 2527.01 ± 0.32 keV (Scielzo et al., 2009) [1], but differs from the Florida State University trap value of 2527.518 ± 0.013 keV (Redshaw et al., 2009) [2] by 0.55 keV (2σ). These values are sufficiently precise for ongoing neutrinoless double-beta decay searches in 116Cd and 130Te. Hence, our Q values were used to compute accurate phase-space integrals for these double-beta decay nuclei. In addition, experimental two-neutrino double-beta decay nuclear matrix elements were determined and compared with the theoretical values. The neutrinoless double-beta decay half-lives for these nuclei were estimated using our precise phase-space integrals and considering the range of the best available matrix elements values. 相似文献
2.
V.S. Kolhinen T. EronenD. Gorelov J. HakalaA. Jokinen A. KankainenJ. Rissanen J. SuhonenJ. Äystö 《Physics letters. [Part B]》2011
The double-electron-capture Q value for the 136Ce decay to 136Ba has been determined at JYFLTRAP. The measured value 2378.53(27) keV excludes the energy degeneracy with the 0+ excited state of the decay daughter 136Ba at 2315.32(7) keV in a resonant 0νECEC decay by 11.67 keV. The new Q value differs from the old adopted value 2419(13) keV (Atomic Mass Evaluation 2003) by 40 keV and is 50 times more precise. Our calculations show that the precise Q value renders the resonant 0νECEC decay of 136Ce undetectable by the future underground detectors. We measured also the double-β decay Q value of 136Xe to be 2457.86(48) keV which agrees well with the value 2457.83(37) keV measured at the Florida State University. 相似文献
3.
R. Schuch I. Bergström K. Blaum T. Fritioff Sz. Nagy A. Solders M. Suhonen 《Hyperfine Interactions》2006,173(1-3):73-83
We report here about measurements of reaction and decay Q values by precise determination of pairs of atomic masses. These were performed with the Penning trap mass spectrometer SMILETRAP.
Measurements with Penning traps give reliable and accurate masses, in particular Q values, due to the fact that certain systematic errors to a great deal cancel in the mass difference between the two atoms
defining the Q value. Some Q values that are of fundamental interest will be discussed here, for example, a new Q value for the 6Li (n,γ) 7Li reaction, for the β-decay of tritium, related to properties of the electron neutrino mass, and for the neutrino-less double
β-decay of 76Ge, related to the question of whether the neutrino is a Majorana particle or not. In case of the latter two we report the
most accurate Q values, namely 18,589.8(12) eV for the tritium decay and 2,038.997(46) keV for the neutrino-less double β-decay of 76Ge. 相似文献
4.
In a unicellular cyanobacterium, the mobile fraction of phycobilisome (PBS) was found to be maximum at a particular redox value of QA (i.e., 0.52). An upward or downward shift in the redox value leads to a decrease in this mobile fraction of PBS. Furthermore, the regulatory effect of the redox state of QA on PBS mobility was found to be independent of the effect exerted by the plastoquinone pool. These findings indicate for the first time that PBS mobility is regulated by the QA redox state in cyanobacteria. A possible working mechanism underlying this control is discussed. 相似文献
5.
A. Jokinen C. Weber T. Eronen V. -V. Elomaa U. Hager J. Hakala S. Rahaman S. Rinta-Antila J. Rissanen J. Äystö 《Hyperfine Interactions》2006,173(1-3):143-151
JYFLTRAP is a Penning trap system at the accelerator laboratory in Jyväskylä, Finland that enables high-precision experiments with stored, exotic species that are produced at the IGISOL facility. On one hand, these can be performed within the trap itself, like e.g. mass spectrometry. On the other hand, the trap can be used to provide the highly purified species for further experiments, e.g. for trap-assisted nuclear decay spectroscopy. This contribution focuses on these two possible applications with the presentation of some recent results on superallowed beta decays. 相似文献
6.
D. Frekers P. Puppe J.H. Thies P.P. Povinec F. Šimkovic J. Staniček I. Sýkora 《Nuclear Physics A》2011
Experimental results on the measurement of the double-electron capture (εε) decay process of 74Se are described. This decay is particularly interesting, because 74Se is almost degenerate to the second excited state at 1204 keV in the daughter nucleus 74Ge. Such a degeneracy favors a neutrinoless decay because of the large phase-space suppression for a decay with two neutrinos. Subsequent de-excitation would generate a 2γ-ray cascade of 608 and 596 keV, whose coincident detection provides a unique signature for this particular εε process. The 2γ-ray cascade has been searched for by a HPGe γ-ray detector in coincidence with a NaI detector using 3 kg of natural selenium. 相似文献
7.
The temporal power-law decay is one class of interesting decay processes, usually indicating a long-time correlation and benefiting for a system to perform functions in various time-scales. In this work, I collect the data of the view times versus lectures of some scientific courses on YouTube, according to some special principles. These data can reflect the dynamical property of the spontaneous learning behavior, influenced by the decay of learning interest. The view times versus lectures show an obviously power-law decay process. The power approximates to 1, a universal constant. This finding brings the learning process into the interesting power-law family. It will be of interest in the fields of the human dynamics, psychology and education. 相似文献
8.
We have modelled a continuously pumped Nd:YAG actively Q-switched by a variable interferometric mirror made up of a scanning Michelson or Fabry-Pérot mirror. We have characterised the three-mirror laser dynamics by using a bifurcation diagram constructed from the plot of peak power-enhancement factor as a function of mirror speed. One observes different chaotic windows separated by period-doubling bifurcations, and stable periodic regime. It is demonstrated that the best performance of the Q-switched laser is obtained rather for low than for high mirror speed (pulse width of 20 ns, and high peak power up to 400 times greater than the continuous emission). 相似文献
9.
We report on a scheme for efficient acousto-optical Q-switching. A flash lamp pumped Nd:YAG oscillator with an acousto-optic modulator (AOM) fourfold pass configuration is presented. The setup combines two important advantages: enhancement of the diffraction efficiency by additional AOM passes and a compact oscillator design in spite of an extension of the optical path length. A flash lamp pumped oscillator with an average output power of 7 W and a beam quality of M2 = 1.2 is developed. The system operates with a 100 Hz repetition rate for the flash lamps. In each pumping pulse a pulse train of 1 up to 40 Q-switched laser pulses is generated. The pulse duration is from 15 to 120 ns. In comparison to a former setup (AOM double pass) the AOM fourfold pass configuration allows single pulses with energy above 20 mJ and a pulse peak power of more than 1 MW. In addition, the beam profile is improved due to a better separation of the incident and diffracted beam caused by the AOM. The laser is dedicated as master oscillator in a master oscillator power amplifier (MOPA) system where pulse peak powers in the MW range should be achieved. 相似文献
10.
The measurements of the L X-ray intensity ratio I(Lα)/I(Lβ), I(Lα)/I(Lγ), I(Lα)/I(Lι), I(Lβ)/I(Lγ) and I(Lι)/I(Lγ) for elements Dy, Ho, Yb, W, Hg, Tl and Pb were experimentally determined both by photon excitation, in which 59.5 keV γ-rays from a filtered radioisotope 241Am was used, and by the radioactive decay of 160Tb, 160Er, 173Lu, 182Re, 201Tl, 203Pb and 207Bi. L X-rays emitted by samples were counted by a Si(Li) detector with resolution 160 eV at 5.9 keV. Obtained values were compared with the calculated theoretical values. Theoretical values of the I(Lα/Lβ), I(Lα/Lγ), I(Lα/Lι), I(Lβ/Lγ) and I(Lι/Lγ) intensity ratios were calculated using theoretically tabulated values of subshell photoionization cross-section, fluorescence yield, fractional X-ray emission rates, Coster–Kronig transition probabilities. It was observed that present values agree with previous theoretical and other available experimental results. 相似文献
11.
Mode frequency shifts and Q-factor changes in 2D microflower cavity and its deformed cavity are analyzed. The effective mode-splitting of double-degenerate WG modes is obtained and the Q-factor changes of matched and mismatched modes are discussed for the microflower cavity. The Q-factor stability of the splitted WGH(8,1) modes due to two types of local deformations is studied, showing that the local deformations can badly spoil the mode Q-factor if the deformations are not controlled properly. The output directionality of the splitted WGH(8,1) modes due to the local deformations also is presented, and a basically unidirectional light output of OO mode under local deformation DA (deformation happens at one “valley” of the microflower cavity) is obtained. 相似文献
12.
A consistent microscopic diagrammatic approach is applied for the first time to the calculation of the nucleon emission spectra in the non-mesonic weak decay of Λ-hypernuclei. We adopt a nuclear matter formalism extended to finite nuclei via the local density approximation, a one-meson exchange weak transition potential and a Bonn nucleon–nucleon strong potential. Ground state correlations and final state interactions, at second order in the nucleon–nucleon interaction, are introduced on the same footing for all the isospin channels of one- and two-nucleon induced decays. Single and double-coincidence nucleon spectra are predicted for 12ΛC and compared with recent KEK and FINUDA data. The key role played by quantum interference terms allows us to improve the predictions obtained with intranuclear cascade codes. Discrepancies with data remain for proton emission. 相似文献
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15.
Ab-initio calculations are performed to investigate the structural, electronic and magnetic properties of spin-polarized diluted magnetic semiconductors composed of II-VI compounds Cd1−xCoxX (X=S, Se, Te) at x=0.25. From the calculated results of band structure and density of states, the half-metallic character and stability of ferromagnetic state for Cd1−xCoxS, Cd1−xCoxSe and Cd1−xCoxTe alloys are determined. It is found that the tetrahedral crystal field gives rise to triple degeneracy t2g and double degeneracy eg. Furthermore, we predict the values of spin-exchange splitting energies Δx(d) and Δx(p−d) and exchange constants N0α and N0β produced by the Co 3d states. Calculated total magnetic moments and the robustness of half-metallicity of Cd1−xCoxX (X=S, Se, Te) with respect to the variation in lattice parameters are also discussed. We also extend our calculations to x=0.50, 0.75 for S compounds in order to observe the change due to increase in Co. 相似文献
16.
We expect that BR(χ_(c2)(2P)→gluongluon) ≥2% if the Particle Data Group as well as the Ba Bar and Belle collaborations have correctly identified the state. In reality, this branching ratio corresponds to the one forχ_(c2)(2P) decaying into light hadrons. We also discuss the detection possibilities of these decays. 相似文献
17.
Luminescent properties of KGd1−x(WO4)2:Eux and KGd1−x(WO4)2−y(MoO4)y:Eux phosphors in UV-VUV regions
KGd1−x(WO4)2−y(MoO4)y:Eu3+x(0.1?x?0.75, y=0 and 0.2) phosphors are synthesized through traditional solid-state reaction and their luminescent properties in ultraviolet (UV) and vacuum ultraviolet (VUV) regions are investigated. Under 147 nm excitation, these phosphors show characteristic red emission with good color purity. In order to improve their emission intensity, the MoO42− (20 wt%) is introduced into the anion of KGd1−x(WO4):Eu3+x. The Mo6+ and Eu3+ co-doped KGd(WO4)2 phosphors show higher emission intensity in comparison with the singly Eu3+-doped KGd(WO4)2 in VUV region. The chromaticity coordination of KGd0.45(WO4):Eu3+0.55 is (x=0.669, y=0.331), while that of KGd0.45(WO4)1.8(MoO4)0.2:Eu3+0.55 is (x=0.666, y=0.334) in VUV region. 相似文献
18.
We present a general argument which suggests that the Bartels–Lipatov–Vacca Odderon intercept should be equal to one to all orders in the perturbation theory. The argument is based on the validity of the so-called omega-expansion in the high energy limit. It can be further supported by the analogous pattern observed in the case of the anomalous dimensions which is a consequence of the momentum sum rule. In addition, we conjecture that the BFKL kernel should satisfy the transverse momentum sum rule. Finally, it is shown that the higher order kinematical effects do not change the BLV Odderon intercept. 相似文献
19.
J.W.-H. Leung 《Journal of Molecular Spectroscopy》2005,229(1):108-114
The absorption spectrum of the (2, 0) and (2, 1) bands of the B2Σ+-X2Σ+ transition of YO between 442 and 478 nm were recorded using laser vaporization/reaction with free-jet expansion and cavity ring down laser absorption spectroscopy. Local rotational perturbations have been found for both spin components of the v = 2 level of the B2Σ+ state. The observed perturbations could be ascribed to a degenerate perturbing state interacting with the B2Σ+ state. Least-squares fit of the observed upper state term values yielded molecular constants for the v = 2 level of the B2Σ+ state and the perturbing 2Π state. Earlier ab initio calculations [J. Chem. Phys. 89 (1988) 2160] indicated that the C2Π state is nearby, it is plausible that the C2Π state is the perturbing state. 相似文献
20.
Marie Šime?ková David Jacquemart Laurence S. Rothman Robert R. Gamache 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,98(1):130-155
This paper describes the calculation of the statistical weights and the Einstein A-coefficients for the 39 molecules and their associated isotopologues/isotopomers currently present in the line-by-line portion of the HITRAN database. Calculation of the Einstein A-coefficients was carried out using the HITRAN line intensities and the necessary statistical weights. The Einstein A-coefficient and the statistical weights of the upper and lower levels of the transition were added in the new format of the line parameters for the most recent edition of the HITRAN database. 相似文献