TRIAC Progress Report - KEK

More documents

Recommendations

Info

3-4. Experiments with the ISOL beam (without re-acceleration by the <strong>TRIAC</strong>) The ISOL ion sources developed for the <strong>TRIAC</strong> could provide good opportunities to perform some experiments by using the beam without re-acceleration. In this subsection, two experiments for nuclear decay-spectroscopy study using the SIS with UCx, and an experiment using the FEBIAD with an enriched 96 Mo target for materials science are described. 3-4-1. Qβ measurements of 160-165 Eu and 163 Gd Fig. 3-35. Fermi-Kurie plots of the measured total absorption spectra [3-48]. The data points used for fitting and adopted lines are shown by closed circles and solid lines, respectively. The endpoint energies and the deduced Qβ values are given in the figures. 90
Mass, which is one of the most fundamental quantities for atomic nuclei, provides good insight on the evolution of the nuclear structure. In addition, the mass is one of the key parameters to build the scenarios of nucleosynthesis in universe. The mass of 160-165 163 Eu and Gd isotopes have been determined for the first time by measuring Qβ values using a total absorption BGO detector. Among them, isotopes of 163-165 Eu were newly observed. The isotopes produced by proton-induced fission of 238 U of about 600 mg/cm 2 thickness were ionized by the SIS and mass-separated by the JAEA-ISOL. The isotopes were implanted onto an aluminum-coated Mylar tape, and were periodically moved to the center position of the total absorption BGO detector. The detector composed of twin BGO scintillation detectors of 120 mm in diameter and 100mm in length which faced each other with a distance of 4 mm. The solid angle of the detector was 96 %. For measurements of 160-165 Eu, the time interval of the tape transport was set to be two or three times longer than the half-lives of these isotopes, while, in the case of 163 Gd, the times for collection, cooling, and measurement were set by 4, 2, and 2 minutes, respectively, to allow the decay out of the parent nucleus 163 Eu (T1/2 = 6 s), which has a larger Qβ value than 163 Gd. The Fermi-Kurie plots of the total absorption spectra of 158, 159 Pm, 159, 161 Sm 160-165 163 166 Eu, Gd and Tb are shown in Fig. 3-35. Qβ values of 158, 159 Pm, 159, 161 Sm, and 166 Tb were found to be consistent with our previous experimental results. The evaluated Qβ values given by Audi et al. [3-49] were in agreement with the present results. The mass predictions by Duflo et al. [3-50] and Dussel et al. [3-51] were also consistent with the experimental values. 3-4-2. Lifetime measurements of 162, 164 Gd (2 + ) The collectivity is one of useful quantities to explore the vibration of the nuclear structure. In the case of the even-even nuclei, the transition probability from the first 2 + state reflects the quadrupole collectivity. The lifetimes of the first 2 + states at 71.5 keV in 162 Gd and 73.3 keV in 164 Gd were measured by means of β–γ delayed coincidence technique for mass-separated 162 Eu and 164 Eu isotopes. As described previously, the fission products of 162,164 Eu were ionized by SIS embedded UCx and transported to the tape system. The tape was moved every 20 s and 9 s for 162 Gd and 164 Gd, respectively. The detection position was equipped with a Pilot-U 60 mm × 63 mm × 1-mm thickness plastic scintillator and a 38-mm diameter × 5-mm thickness BaF2 scintillator to detect β and γ rays, respectively. The time interval spectra for the first 2 + state in 162 Gd and in 164 Gd were obtained 91
Page 1 and 2:
TRIAC Progress Report TRIAC collabo
Page 3 and 4:
i KEK Progress Report 2011-1 June 2
Page 5 and 6:
PREFACE The Tokai Radioactive Ion A
Page 7 and 8:
1. Introduction Following the succe
Page 9 and 10:
maximum available beam power for th
Page 11 and 12:
container of ion source and uranyl
Page 13 and 14:
gaseous and volatile elements (e.g.
Page 15 and 16:
= 10.6 m) were 4.5 %, that for 146
Page 17 and 18:
with different plasma volumes [2-6]
Page 19 and 20:
ECR plasma: We used natural helium
Page 21 and 22:
higher efficiency for gaseous eleme
Page 23 and 24:
The asymmetric component representi
Page 25 and 26:
ut differs from the electron-loss p
Page 27 and 28:
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 80 and 81: offline data analysis, about 1-Mega
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: difference spectra, more specifical
Page 99: gamma rays. 111 In, which decays to
show all

TRIAC Progress Report - KEK

Create successful ePaper yourself

Delete template?

Save as template?