Discovery of 109Xe and 105Te: superallowed alpha decay near doubly magic 100Sn.

Two new alpha emitters 109Xe and 105Te were identified through the observation of the 109Xe --> 105Te --> 101Sn alpha-decay chain. The 109Xe nuclei were produced in the fusion-evaporation reaction 54Fe(58Ni,3n)109Xe and studied using the Recoil Mass Spectrometer at the Holifield Radioactive Ion Beam Facility. Two transitions at Ealpha = 4062 +/- 7 keV and Ealpha = 3918 +/- 9 keV were interpreted as the l = 2 and l = 0 transitions from the 7/2+ ground state in 109Xe (T1/2 = 13 +/- 2 ms) to the 5/2+ ground state and a 7/2+ excited state, located at 150 +/- 13 keV in 105Te. The observation of the subsequent decay of 105Te marks the discovery of the lightest known alpha-decaying nucleus. The measured transition energy Ealpha = 4703 +/- 5 keV and half-life T1/2 = 620 +/- 70 ns were used to determine the reduced alpha-decay width delta2. The ratio delta105Te(2)/delta213Po(2) of approximately 3 indicates a superallowed character of the alpha emission from 105Te.

[1]  C. Mazzocchi,et al.  Search For Enhanced Alpha Preformation in the N=Z+1 Nuclei 113Ba, 109Xe, 105Te , 2006 .

[2]  R. Grzywacz,et al.  Nuclear structure far off stability --Implications for nuclear astrophysics , 2006 .

[3]  C. Mazzocchi,et al.  Measurements of 110Xe and 106Te decay half-lives , 2005 .

[4]  S. Juutinen,et al.  First identification of {gamma}-ray transitions in {sup 107}Te , 2004 .

[5]  A. H. Wapstra,et al.  The AME2003 atomic mass evaluation . (II). Tables, graphs and references , 2003 .

[6]  A. H. Wapstra,et al.  The Nubase evaluation of nuclear and decay properties , 2003 .

[7]  Robert Grzywacz,et al.  Applications of digital pulse processing in nuclear spectroscopy , 2003 .

[8]  M. Lipoglavšek,et al.  Population of the 168-keV(g7/2)excited state in103Snin theαdecay of107Te , 2002 .

[9]  C. Mazzocchi,et al.  Alpha decay of 114Ba , 2002 .

[10]  D. S. Brenner,et al.  decay studies of 109,107Sb , 2002 .

[11]  L. Bildsten,et al.  The endpoint of the rp-process on accreting neutron stars , 2001, astro-ph/0102418.

[12]  M. Moszynski,et al.  Excited States in 103Sn: Neutron Single-particle Energies with Respect to 100Sn , 2001 .

[13]  J. L. Blankenship,et al.  Performance of the Recoil Mass Spectrometer and its detector systems at the Holifield Radioactive Ion Beam Facility , 2000 .

[14]  A. N. Andreyev,et al.  A triplet of differently shaped spin-zero states in the atomic nucleus 186Pb , 2000, Nature.

[15]  E. Paul,et al.  γ -ray spectroscopy in 111 Te , 2000 .

[16]  Brown,et al.  Gamow-Teller strength in the region of 100Sn. , 1994, Physical review. C, Nuclear physics.

[17]  Varga,et al.  Absolute alpha decay width of 212Po in a combined shell and cluster model. , 1992, Physical review letters.

[18]  H. Clerc,et al.  Some remarks on the error analysis in the case of poor statistics , 1984 .

[19]  D. Schardt,et al.  Alpha decay of neutron-deficient isotopes with 52 ≦ Z ≦ 55, including the new isotopes 106Te (T12 = 60 μs) and 110Xe , 1981 .

[20]  D. Schardt,et al.  Alpha decay studies of tellurium, iodine, xenon and cesium isotopes☆ , 1979 .

[21]  R. Macfarlane,et al.  NEW REGION OF ALPHA RADIOACTIVITY , 1965 .

[22]  G. Gamow,et al.  Zur Quantentheorie des Atomkernes , 1928 .