共查询到20条相似文献,搜索用时 31 毫秒
1.
Mazzocchi C Grzywacz R Liddick SN Rykaczewski KP Schatz H Batchelder JC Bingham CR Gross CJ Hamilton JH Hwang JK Ilyushkin S Korgul A Królas W Li K Page RD Simpson D Winger JA 《Physical review letters》2007,98(21):212501
An alpha-decay branch of (1.4+/-0.4) x 10(-4) has been discovered in the decay of 109I, which predominantly decays via proton emission. The measured Q(alpha) value of 3918+/-21 keV allows the indirect determination of the Q value for proton emission from 105Sb of 356+/-22 keV, which is approximately of 130 keV more bound than previously reported. This result is relevant for the astrophysical rapid proton-capture process, which would terminate in the 105Sn(p,gamma)106Sb(p,gamma)107Te(alpha decay)103Sn cycle at the densities expected in explosive hydrogen burning scenarios, unless unusually strong pairing effects result in a 103Sn(p,gamma)104Sb(p,gamma)105Te(alpha decay)101Sn) cycle. 相似文献
2.
S. N. Liddick R. Grzywacz C. Mazzocchi R. D. Page K. P. Rykaczewski J. C. Batchelder C. R. Bingham I. G. Darby G. Drafta C. Goodin C. J. Gross J. H. Hamilton A. A. Hecht J. K. Hwang S. Ilyushkin D. T. Joss A. Korgul W. Królas K. Lagergren K. Li M. N. Tantawy J. Thomson J. A. Winger 《The European physical journal. Special topics》2007,150(1):131-134
The α-decay chain 109Xe → 105Te → 101Sn was identified at the Holifield Radioactive Ion Beam Facility. Advances in digital electronics have made possible the identification
of both alpha emitters in the same experiment despite the disparate half-lives of 13 ±2 ms and 620 ±70 ns for 109Xe and 105Te, respectively. Two α-decay transitions were observed from 109Xe with Qα values of 4067 ±10 and 4217 ±8 keV. One transition between the ground states of 105Te and 101Sn was observed with a Qα value of 4889 ±6 keV. Using the measured half-lives, branching ratios, and Qα values the reduced α-decay widths, δ2, were determined. Comparison of the δ2 value for 105Te with 213Po indicates a “superallowed" character in the α emission of 105Te. 相似文献
3.
Tischhauser P Azuma RE Buchmann L Detwiler R Giesen U Görres J Heil M Hinnefeld J Käppeler F Kolata JJ Schatz H Shotter A Stech E Vouzoukas S Wiescher M 《Physical review letters》2002,88(7):072501
Angular distributions of 12C(alpha,alpha)12C have been measured for E(alpha) = 2.6-8.2 MeV, at angles from 24 to 166, yielding 12 864 data points. R-matrix analysis of the ratios of elastic scattering yields a reduced width amplitude of gamma12 = 0.47 +/- 0.06 MeV(1/2) for the Ex = 6.917 MeV (2+) state in 16O(a = 5.5 fm). The dependence of the chi2 surface on the interaction radius a has been investigated and a deep minimum is found at a = 5.42(+0.16)(-0.27) fm. Using this value of gamma12, radiative alpha capture and 16N beta-delayed alpha-decay data, the S factor is calculated at E(c.m.) = 300 keV to be S(E2)(300) = 53(+13)(-18) keV b for destructive interference between the subthreshold resonance tail and the ground state E2 direct capture. 相似文献
4.
Darby IG Grzywacz RK Batchelder JC Bingham CR Cartegni L Gross CJ Hjorth-Jensen M Joss DT Liddick SN Nazarewicz W Padgett S Page RD Papenbrock T Rajabali MM Rotureau J Rykaczewski KP 《Physical review letters》2010,105(16):162502
By studying the (109)Xe→(105)Te→(101)Sn superallowed α-decay chain, we observe low-lying states in (101)Sn, the one-neutron system outside doubly magic (100)Sn. We find that the spins of the ground state (J=7/2) and first excited state (J=5/2) in (101)Sn are reversed with respect to the traditional level ordering postulated for (103)Sn and the heavier tin isotopes. Through simple arguments and state-of-the-art shell-model calculations we explain this unexpected switch in terms of a transition from the single-particle regime to the collective mode in which orbital-dependent pairing correlations dominate. 相似文献
5.
P. Mohr 《The European Physical Journal A - Hadrons and Nuclei》2007,34(1):23-28
α-decay half-lives for 104, 105, 106Te and 108, 109, 110Xe close above the doubly-magic 100Sn are calculated from systematic double-folding potentials. The derived α preformation factors are compared to results for
212, 213, 214Po and 216, 217, 218Rn above the doubly-magic 208Pb. α-decay energies of Q
α = 5.42±0.07MeV and 4.65±0.15MeV are predicted for 104Te and 108Xe; the corresponding half-lives are T
1/2 ≈ 5ns for 104Te and of the order of 60μs for 108Xe. Additionally, the properties of rotational bands in 104Te are analyzed, and the first excited 2+ state in 104Te is predicted at E
x = 650±40keV; it decays preferentially by γ emission with a reduced transition strength of 10 Weisskopf units to the ground
state of 104Te and with a minor branch by α emission to the ground state of 100Sn. 相似文献
6.
Coincidences have been detected between γ-rays and β-delayed protons emitted after the decay of very neutron-deficient nuclei. In the three cases studied the decay proceeds to the ground state with branches to the first excited (2+) state of the even daughter nucleus of (58±7) % (115Xe to 709 keV in 114Te), (14±3) % (117Xe to 679 keV in 116Te), and (50±10) % (181Hg to 158 keV in 180Pt). Upper limits of 2 and 6 % can be placed on the branches to the 4+ states of 114Te and 180Pt. For the cases of 115,117Xe, coincidences with annihilation radiation were also observed; the measured positon/proton ratio determines the difference Q—Bp, between the energy available for electron capture and the proton separation energy for the daughter. For 115Xe the result is 6.20±0.13 MeV, for 117Xe 4.10±0.20 MeV. 相似文献
7.
Sensitivity to temporal variation of the fundamental constants may be strongly enhanced in transitions between narrow close levels of different nature. This enhancement may be realized in a large number of molecules due to cancellation between the ground state fine-structure omega{f} and vibrational interval omega{v} [omega=omega{f}-nomega{v} approximately 0, delta omega/omega=K(2delta alpha/alpha+0.5 delta mu/mu), K>1, mu=m{p}/m{e}]. The intervals between the levels are conveniently located in microwave frequency range and the level widths are very small. Required accuracy of the shift measurements is about 0.01-1 Hz. As examples, we consider molecules Cl(+)(2), CuS, IrC, SiBr, and HfF(+). 相似文献
8.
Adam NE Alexander JP Berkelman K Cassel DG Duboscq JE Ecklund KM Ehrlich R Fields L Gibbons L Gray R Gray SW Hartill DL Heltsley BK Hertz D Jones CD Kandaswamy J Kreinick DL Kuznetsov VE Mahlke-Krüger H Meyer TO Onyisi PU Patterson JR Peterson D Pivarski J Riley D Ryd A Sadoff AJ Schwarthoff H Shi X Stroiney S Sun WM Wilksen T Weinberger M Athar SB Patel R Potlia V Stoeck H Yelton J Rubin P Cawlfield C Eisenstein BI Karliner I Kim D Lowrey N Naik P Sedlack C Selen M White EJ Wiss J Shepherd MR 《Physical review letters》2006,97(25):251801
We present measurements of the inclusive branching fractions for the decays D+-->Xe+ nu(e) and D0-->Xe+ nu(e), using 281 pb(-1) of data collected on the psi(3770) resonance with the CLEO-c detector. We find B(D0-->Xe+ nu(e)) = (6.46+/-0.17+/-0.13)% and B(D+-->Xe+ nu(e)) = (16.13+/-0.20+/-0.33)%. Using the known D meson lifetimes, we obtain the ratio Gamma(D+)sl/Gamma(D0)sl = 0.985+/-0.028+/-0.015, confirming isospin invariance at the level of 3%. The positron momentum spectra from D+ and D0 have consistent shapes. 相似文献
9.
H. Kettunen T. Enqvist M. Leino K. Eskola P.T. Greenlees K. Helariutta P. Jones R. Julin S. Juutinen H. Kankaanpää H. Koivisto P. Kuusiniemi M. Muikku P. Nieminen P. Rahkila J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):457-467
The low-energy nuclear structure and decay properties of the neutron-deficient isotopes 195At and 191Bi have been studied. 195At was produced in the reaction 142Nd(56Fe,p2n)195At and 191Bi as the daughter activity of 195At. The activities were implanted in a position-sensitive silicon detector after being separated from the primary beam by
a gas-filled recoil separator. The 1/2+ intruder state was determined to be the ground state in 195At with an alpha-decay energy of E
α = 6953(3) keV and a half-life T
1/2 = 328(20) ms. Another state with an alpha-decay energy E
α = 7075(4) keV and a half-life T
1/2 = 147(5) ms was found to decay to a 148.7(5) keV excited state in 191Bi for which a spin and parity of 7/2- were deduced. Consequently, the same 7/2- character was assigned to the initial state at 32(7) keV in 195At on the basis of unhindered alpha-decay. The 9/2- state, being the ground state in heavier odd-mass astatine isotopes, was not observed.
Received: 16 September 2002 / Accepted: 19 December 2002 / Published online: 25 March 2003
RID="a"
ID="a"e-mail: heikki.kettunen@phys.jyu.fi
RID="b"
ID="b"Present address: Laboratory of Radiochemistry, P.O. Box 55, FIN-00014, University of Helsinki, Finland.
RID="c"
ID="c"Present address: Radiation and Nuclear Safety Authority, P.O. Box 14, FIN-00881 Helsinki, Finland.
Communicated by W. Henning 相似文献
10.
Beck BR Becker JA Beiersdorfer P Brown GV Moody KJ Wilhelmy JB Porter FS Kilbourne CA Kelley RL 《Physical review letters》2007,98(14):142501
The energy splitting of the 229Th ground-state doublet is measured to be 7.6+/-0.5 eV, significantly greater than earlier measurements. Gamma rays produced following the alpha decay of 233U (105 muCi) were counted in the NASA/electron beam ion trap x-ray microcalorimeter spectrometer with an experimental energy resolution of 26 eV (FWHM). A difference technique was applied to the gamma-ray decay of the 71.82 keV level that populates both members of the doublet. A positive correction amounting to 0.6 eV was made for the unobserved interband decay of the 29.19 keV state (29.19-->0 keV). 相似文献
11.
A. Alzner E. Bodenstedt B. Gemünden J. van den Hoff H. Reif 《Zeitschrift für Physik A Hadrons and Nuclei》1985,322(3):467-478
The static hyperfine field ofB hf 4.2k (ErHo) = 739(18)T of a ferromagnetic holmium single crystal polarized in an external magnetic field of ± 0.48T at ~4.2K was used for integral perturbed γ-γ angular correlation (IPAQ measurements of the g-factors of collective states of166Er. The 1,200y 166m Ho activity was used which populates the ground state band and the γ vibrational band up to high spins. The results: $$\begin{gathered} g(4_g^ + ) = + 0.315(16) \hfill \\ g(6_g^ + ) = + 0.258(11) \hfill \\ g(8_g^ + ) = + 0.262(47)and \hfill \\ g(6_\gamma ^ + ) = + 0.254(32) \hfill \\ \end{gathered}$$ exhibit a significant reduction of the g-factors with increasing rotational angular momentum. The followingE2/M1 mixing ratios of interband transitions were derived from the angular correlation coefficients: $$\begin{gathered} 5_\gamma ^ + \Rightarrow 4_g^ + :\delta (810keV) = - (36_{ - 7}^{ + 11} ) \hfill \\ 7_\gamma ^ + \Rightarrow 6_g^ + :\delta (831keV) = - (18_{ - 2}^{ + 3} )and \hfill \\ 7_\gamma ^ + \Rightarrow 8_g^ + :\delta (465keV) = - (63_{ - 12}^{ + 19} ). \hfill \\ \end{gathered}$$ The results are discussed and compared with theoretical predictions. 相似文献
12.
D. Gföller H. Langhoff F. Smend W. Weirauch W. -D. Schmidt-Ott 《Zeitschrift für Physik A Hadrons and Nuclei》1969,227(1):45-54
Theγ spectra emitted in the decay of122Xe and122I have been investigated using Ge(Li) detectors and a Ge(Li)-NaI coincidence apparatus. 14γ transitions with energies between 61.8 and 416.9 keV have been identified in the decay of122Xe, 44 transitions between 564.0 and 3,291.0 keV in the decay of122I. Level schemes having 7 excited levels for122I and 21 excited levels for122Te are proposed. 相似文献
13.
L. Käubler H. Prade J. Reif R. Schwengner G. Winter H. Grawe J. Heese H. Kluge K. -H. Maier R. Schubart K. -M. Spohr 《Zeitschrift für Physik A Hadrons and Nuclei》1995,351(2):123-124
An extended level scheme of109Sn is presented showing high-spin states up to Ex≈ 8 MeV and spins up toJπ=(41/2+). Their decay to the 5/2+ ground state has been observed identifying a 12.8 keV 7/2+ → 5/2+ transition. A half-life of T1/2=7(1) ns has been measured for the 17/2+ state atE x =2114 keV. The experimental data are compared with the predictions of shell-model calculations. 相似文献
14.
B. Reussière F. Ibrahim P. Kilcher F. Le Blanc J. Oms J. Sauvage A. Wojtasiewicz 《Zeitschrift für Physik A Hadrons and Nuclei》1995,351(2):127-128
The decay of181Ir has been studied on-line with mass-separated sources from the ISOCELE facility. The level scheme of181 Os has been established. The isomeric state has been located at 48.9 keV above the ground state. Thus the isomeric and ground states are identified as the 7/2?(T1/2 =2.7 m) and 1/2?(T1/2=105 m) levels respectively. 相似文献
15.
Akikawa H Ajimura S Chrien RE Eugenio PM Franklin GB Franz J Gang L Imai K Khaustov P May M Pile PH Quinn B Rusek A Sasao J Sawafta RI Schmitt H Tamura H Tang L Tanida K Yuan L Zhou SH Zhu LH Zhu XF 《Physical review letters》2002,88(8):082501
With a germanium detector array (Hyperball), we observed two gamma-ray peaks corresponding to the two transitions (5/2(+)-->1/2(+) and 3/2(+)-->1/2(+)) in the (9)(Lambda)Be hypernucleus which was produced by the 9Be(K-,pi(-)) reaction. The energies of the gamma rays are 3029 +/- 2 +/- 1 keV and 3060 +/- 2 +/- 1 keV. The energy difference was measured to be 31.4(+2.5)(-3.6) keV, which indicates a very small Lambda-spin-dependent spin-orbit force between a Lambda and a nucleon. This is the smallest level splitting by far ever measured in a hypernucleus. 相似文献
16.
在Cs蒸气中,二步激发Cs原子至8S态,研究了其碰撞转移和高位原子态的产生过程.在1016~1017 cm-3密度范围内,测量了碰撞激发转移8S 6S→6D 6S的速率系数.由测得的荧光强度随密度的变化关系,得到k6D=(2.4±0.5)×10-10 cm3·s-1.同时研究了碰撞能量合并过程5D 5D→nL 6S(nL=9D,11S,7F),5D态是由8S→7P→5D的辐射跃迁产生的.由以前测量过的6P 5D 6S 7D的转移速率系数以及6P态的原子密度,结合荧光强度比得到碰撞能量合并过程的速率系数,对于9D,11S和7F各态,其平均值分别为(6.4±3.2)×10-10,(1.0±0.5)×10-10和(8.4±4.2)×10-10 cm3·s-1. 相似文献
17.
用4415.6(?)CW激光线获得了~(39)K_2分子C~1II_u(v′=0,J′=105)-X~1∑_g~+(v″=1~10,J″=105)Q支激光诱导荧光(LIF)光谱.用最小二乘法拟合出了~(39)K_2分子X~1∑_g~+态振动常数和C~1II_u态电子谱项值T_e.光谱分析表明C~1II_u态T_e=22968cm~(-1)是合适的.用~(39)K_2分子Morse势计算了(V′=0,J′=105)-(v″=1~10,J″=105)跃迁的Franck-Condon因子和跃迁强度,强度计算值和激光诱导荧光光谱测量值之间有令人满意的符合,进一步的r重心近似分析给出了~(39)K_2分子C~1II_u→X~1∑_g~+电偶极跃迁矩R_(?)随核间距r的归一化变化率为-0.157~-0.168 debye/(?)(4.22(?)相似文献
18.
GdAl3(BO3)4 polycrystals co-doped with Yb3+ and Eu3+ has been synthesised by combustion method with urea. Upon the excitation at 465 nm (Eu3+/7F6-->5D2 transition), emission bands centered at 590, 613, 697 and 702 nm in the wavelength region of 550-750 nm have clearly been observed, assigned to the electronic transitions of 5D0-->7FJ (J=1, 2, 4 and 5) of Eu3+ ions, respectively. Meanwhile, an intense emission centred at 980 nm along with a shoulder at 1,040 nm has also been observed by exploiting a cross-relaxation process between the transitions of Eu3+/5D0-->7F6 and Yb3+/2F7/2-->2F5/2. On the contrary, an intense red up-conversion emission centred at 613 nm originated from the 5D0-->7F2 transition of Eu3+ has been observed upon excitation with 980 nm laser diode. The quadratic dependence of the red up-conversion intensity on the pump-laser power reveals a cooperative energy transfer mechanism from a pair of Yb3+ ions to one Eu3+ ion. 相似文献
19.
W. -D. Schmidt-Ott W. Weirauch F. Smend H. Langhoff D. Gföller 《Zeitschrift für Physik A Hadrons and Nuclei》1968,217(3):282-293
The decay of125m Xe produced by the reaction122Te(α, n)125m Xe using a target enriched in122Te (95.4%) and the decay of127m Xe produced by the reaction127J(d, 2n)127m Xe have been investigated: 125m Xe decays with a half-life ofT 1/2=(56±3) sec by ayy- cascade withE γ1=(140.4 ±0.5) keV andE γ2=(110.5 ±0.5) keV. The experimental conversion coefficients yield multipolarities ofE3 for the 140.4 keV isomeric transition and predominantlyM1 for the 110.5 keV-transition. 127m Xe decays with a half-life ofT 1/2=(71±2) sec. The decay also proceeds by aγγ-cascade with an isomeric E3 transition ofE γ1=(172.5±0.3) keV and a predominantlyM1 transition ofE γ2=(124.6±0.3) keV. In the decay of127g Xe an additional branching of the electron capture to a level at (618.1±0.3) keV was observed. The relative probability forK-captureP K618/PK375=0.40 ±0.07 yields a total transition energyQ EC=(664 ±4)keV. A spin of 1/2+ was assigned to the ground state. 相似文献