TRIAC Progress Report - KEK

More documents

Recommendations

Info

3. Experiments at the TRIAC Since the first public operation of the TRIAC, 50 days of operation per year, in maximum, has been allowed for experiments, including the operation for 10 days for the development of the RIB generation and acceleration at the TRIAC. The experimental proposals were carefully reviewed, once a year, by the program advisory committee (PAC). As listed in Table 3-1, 15 proposals have been approved and, among them, 13 proposals have been already performed. Two remaining proposals (KJ02 and KJ03) have been already scheduled to be performed soon. There were 3 additional proposals only using ISOL beams without reacceleration by post-accelerators. The approved proposals are grouped according to relevant research field and respectively summarized as followings: nuclear astrophysics (RNB-K01, K05, J01, KJ03 and KJ04), nuclear and fundamental physics (RNB-K02/03, K04, and K08), and materials science (RNB-K06, K07, J02/03, KJ01/02). The experiments using RIBs without re-acceleration are also briefly described at the end. 3-1. Nuclear astrophysics In recent decades, nuclear reactions involving the unstable nucleus 8 Li have attracted considerable attention among nuclear physicists since they are considered to influence largely the synthesis of heavy elements in neutron-rich high-temperature environments. Such environments in the temperature of T9 = 1-3 (in unit of 10 9 K) could happen, for example, in the early stage of supernova explosion and/or in the early universe of inhomogeneous Big-Bang model. Continuous efforts have been made to experimentally determine the relevant reaction rates at energies below the Coulomb barrier. The low-energy 8 Li beam available at the TRIAC provides unique opportunities to measure directly the relevant cross sections in the energy regime of astrophysical interest. The RNB-K01 (Spokesperson: H. Ishiyama (KEK) and T. Hashimoto (JAEA), Collaboration (Institution (number of collaborators)): KEK (9), JAEA (8), Osaka Electro-comm. Univ. (3), Osaka Univ. (2), GSI (1), NAO (1)) was the first attempt to measure the cross sections of 8 Li(d, t) 7 Li reaction, which has been thought to play an important role in destroying 8 Li nuclei and therefore limiting the synthesis of elements over the mass of 8. By using the 8 Li beam from the TRIAC, the measurements were made at seven different energies of 0.18, 0.24, 0.30, 0.40, 0.46, 0.60, and 0.75 MeV/nucleon, respectively corresponding to center-of-mass energies (Ecm) of 0.3, 0.4, 0.5, 0.7, 0.8, 1.0, and 1.1 MeV. Those Ecm cover the Gamow peaks of T9 = 1-3. 52
Table 3-1. List of experiments performed at the TRIAC. Approved experiments are identified by the subject numbers assigned; RNB-Kxx and RNB-Jyy indicate the subject number approved by the KEK-PAC and the JAEA-PAC, respectively. Additional experiments numbered by RNB-KJxx are approved recently by a joint PAC. Subject No. Title of subject Spokesperson(Affiliation) RNB-K01 Direct measurement of astrophysical reaction rates through 8 Li H. Ishiyama (KEK) RNB-K02/K03 Nuclear spectroscopy through β-delayed decay of spin-polarized nuclei around doubly magic nucleus 132 Sn The typical intensity was 1x10 5 particles per second (pps), energy resolution 0.85 % in standard deviation (σ), and diameter of beam spot at the target position 3.4 mm in σ. A deuteron target (deuterated polyethylene (CD2)) with a thickness of 130 µg/cm 2 was used. The detection system employed in the measurements is shown in Fig. 3-1. Figure 3-2 shows the measured cross sections together with previous results [3-1]. The present experiment provides the first data in the low-energy region below Ecm = 1.5 MeV and covers the Gamow peaks in the temperature range of T9 = 1-3. An enhancement was observed at around Ecm = 0.9 MeV in the excitation function, where the cross sections are significantly larger than at the higher Ecm. Figure 3-3 shows the resultant reaction rate, which is compared with the rate estimated by the extrapolation of data at higher energies [3-1]. 53 Y. Hirayama (KEK) K. Matsuta (Osaka Univ.) RNB-K04 R&D for a test of time reversal symmetry using polarized nuclei J. Murata (Rikkyo Univ.) RNB-K05 Measurement of the 8 Li(α, n) 11 B reaction cross section for astrophysical interest T. Fukuda (Osaka Electro-Com.Univ.) RNB-K06 Local fields at 111 Cd implanted in Highly Oriented Pyrolytic Graphite W. Sato (Osaka Univ.) RNB-K07 Diffusion Coefficient Measurements on Perovskite-type Structured Lithium Ion Conductor S. Takai (Tottori Univ.) RNB-K08 Search for highly excited states of 11 Be via 9 Li+d reaction T. Teranishi (Kyushyu Univ.) RNB-J01 Search for highly excited states in 10 Be using deuteron elastic reaction to RNB-J02/J03 RNB-KJ01 8 Li Diffusion studies in Li ionic conductors by using short-lived radioactive beam of 8 Li RNB-KJ02 In-situ measurements of Li diffusion in Li micro-batteries & Nano-scale diffusion experiments in Li ionic conductors by using 8 Li H. Miyatake (JAEA/KEK) H. Sugai (JAEA) S.C. Jeong (KEK) H. Ishiyama (KEK) S.C. Jeong (KEK) RNB-KJ03 “Extremely” safe Coulomb excitation of 142 Ba N. Imai (KEK) RNB-KJ04 Measurement of the cross section of 12 C (a,γ) reaction H. Makii (JAEA)
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 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 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
show all

TRIAC Progress Report - KEK

Create successful ePaper yourself

Delete template?

Save as template?