TRIAC Progress Report - KEK

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offline data analysis, about 1-Mega V-track events were successfully reconstructed. The Mott scattering angular distribution is shown in Fig. 3-20, for both spin-up and -down settings of the tilted-foil system for polarized 8 Li beam. If shapes of the distributions are different from each other, it means that the time reversal symmetry is violated. The value obtained from the preliminary analysis is concluded to be zero within the present statistics. Fig. 3-20. Angular distributions of the V-track events of electrons scattered backwards by the lead foil. The R&D for the test of the time reversal symmetry using polarized 8 Li nuclei at TRIAC [3-25] is successfully performed, as the first measurement using event-by-event V-track reconstruction without suffering from dominant backgrounds. The present system developed for the experiments at the TRIAC, shows a good performance as an electron transverse polarimeter which is going to be used at the TRIUMF. By utilizing the 8 Li beam with higher intensity and better polarization (10 7 pps with 80 % polarization) at the TRIUMF, the R-parameter will be determined with a precision of 0.01%. The project has been already started at the TRIUMF as S1183 MTV experiment from 2009. First physics run is successfully performed in 2010 with highest statistical precision, utilizing the experimental technique developed at the TRIAC. 3-2-3. Search for the highly excited state in 11 Be via 9 Li + d reaction (K08) An excited level at 18.2 MeV in 11 Be has been suggested from observations of beta-delayed deuteron, triton, and α emissions in 11 Li beta decay experiments [3-26]. This level is above and close to the 9 Li+d threshold at 17.9 MeV and possibly enhances 74
the beta-delayed deuteron emission probabilities [3-27] (Fig. 3-21). This level is also a candidate of a “halo analog state” of 11 Li, which is populated by a Gamow-Teller (GT) transition of the two halo neutrons in 11 Li, namely 11 Li ( 9 Li+2n) 11 Be* ( 9 Li+d) [3-28]. 20.68 11 Li β − 18.15 0 11 Be 75 17.916 9 Li+d 8 Li+t, 2α+3n, 6 He+α+n, 9 Be+2n, 10 Be+n Fig. 3-21. Level diagram of beta-delayed particle-emitting 11 Li. Clear determination of the energy, width, and spin-parity may be therefore useful for studying the GT transitions of 11 Li and its halo structure. However the signature of the level was not so clear in the beta decay experiments; the energy and width of the level were deduced from the spectrum, which contained unresolved deuterons and tritons without any well identified peaks, and from an unresolved 4,6 He spectrum in the decay 11 Li (β) 11 Be * 6 He+α+n, which did not show any peak corresponding to the level because of the three body decay. Moreover, a recent observation of beta delayed deuterons did not indicate any resonance signature [3-29]. Further experimental investigation with a different approach is necessary. Fig. 3-22. Experimental setup for studying 9 Li+d reactions. In the present experiment we have studied 9 Li+d reactions to search for a resonance signature attributed to the 18.2-MeV level. We measured deuteron, triton, alpha spectra from 9 Li+d elastic scattering, 9 Li(d,t), and 9 Li(d,α) reactions, respectively. The 9 Li+d reaction experiment was performed at the TRIAC. A primary beam of 7 Li at 70 MeV from the JAEA tandem accelerator bombarded an ISOL target of BN.
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TRIAC Progress Report TRIAC collabo
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i KEK Progress Report 2011-1 June 2
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PREFACE The Tokai Radioactive Ion A
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1. Introduction Following the succe
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maximum available beam power for th
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container of ion source and uranyl
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gaseous and volatile elements (e.g.
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= 10.6 m) were 4.5 %, that for 146
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with different plasma volumes [2-6]
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ECR plasma: We used natural helium
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higher efficiency for gaseous eleme
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The asymmetric component representi
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ut differs from the electron-loss p
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consumption in the cavity is less t
Page 29 and 30: measured with Faraday cups, FC1, FC
Page 31 and 32: y turning off the supply of RF powe
Page 33 and 34: Encouraged by the new finding, as t
Page 35: 2-4-4. Development of superconducti
Page 40 and 41: accelerating the radioactive ion be
Page 42 and 43: Fig. 2-29. Photos of the pre-bunche
Page 44 and 45: For the proposed experiment, the po
Page 46: a diagonal direction. The monitors
Page 49: charge state of xenon ions by using
Page 52 and 53: electrode as shown in Fig. 2-40) sh
Page 54 and 55: CO2 (10 %) and 16 kPa, respectively
Page 56 and 57: Although the gain shift of THGEM#3
Page 58 and 59: 3. Experiments at the TRIAC Since t
Page 60 and 61: Fig. 3-1. Schematic view of the det
Page 62 and 63: -element abundances up to the third
Page 64: higher reliability of the experimen
Page 67 and 68: GEM-MSTPC among the accumulated dat
Page 69 and 70: upstream of the pre-buncher, avoidi
Page 72 and 73: The process of nuclear polarization
Page 74 and 75: annealed platinum foil (stopper foi
Page 78 and 79: the observed CP-violating phenomena
Page 82 and 83: Secondary 9 Li ions extracted from
Page 84 and 85: Fig.3-24. γ ray energy spectra coi
Page 86 and 87: In the experiments of RNB-J02/03 (S
Page 88 and 89: atio), a diffusion coefficient was
Page 91 and 92: Although the data for β-LiAl and
Page 93 and 94: In the experiment of RNB-K06 ((Spok
Page 95 and 96: difference spectra, more specifical
Page 97 and 98: Mass, which is one of the most fund
Page 99: gamma rays. 111 In, which decays to
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TRIAC Progress Report - KEK

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