Design Study and Fabrication of the Target/Ion Source to Generate a Li-8 Beam

Jeong-Jeung Dang 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.8

The Korea Multi-purpose Accelerator Complex (KOMAC) has developed a target/ion source (TIS) to generate a Li-8 radioactive isotope beam. The basic concept of the TIS is that the Li isotope is produced at a beryllium-oxide target irradiated by a 100-MeV proton beam, and Li atoms are ionized at a surface ionization ion source (SIS). Various numerical studies were conducted to design the TIS. The FLUKA code was utilized to estimate the Li-8 production rate and to find an optimum target thickness. Also, a simple Monte Carlo code was developed to estimate the ionization eciency of the SIS. In addition, a zero-dimensional power balance model of the TIS was developed, and a three-dimensional finite-element method was applied to obtain detailed thermal analysis results. On the basis of the thermal analysis, the related design and operation parameters were determined. The TIS designed by using various numerical studies was fabricated and tested. The TIS will be irradiated by a proton beam and generate Li-8 beam for fi-NMR facility.

Nuclear Astrophysics Experiments for Explosive Hydrogen Burning

한인식,Aram KIM 한국물리학회 2016 새물리 Vol.66 No.12

Explosive phenomena, such as X-ray bursts and novae, are generated by nuclear fusion processes known as the rapid proton capture (rp) process, which are responsible for creating elements up to and beyond the iron isotopes. There are some key nuclear reactions, such as the $^{15}$O($\alpha,\gamma$)$^{19}$Ne and $^{14}$O($\alpha$,p)$^{17}$F reactions, for understanding the mechanism of these hydrogen burnings, especially when the breakout from the HCNO cycle to the rp-process occurs. Measuring these two reaction rates and many other reactions in the rp-process path requires radioactive ion beams. Our experiments with radioactive $^{14}$O and $^{15}$O beams and some future considerations with radioactive ion (RI) beams are described.

In-flight 법을 이용한 26Si 방사성 핵종빔 생성에 관한 연구

권영관,정효순,윤종철,문준영,이춘식 한국물리학회 2010 새물리 Vol.60 No.4

High-purity and high-intensity radioactive ion (RI) beams are definitely needed for investigating nuclear reactions in explosive nuclear synthetic processes under various stellar environments, such as nova explosions and X-ray bursts. We investigated the production of a 26Si radioactive ion beam for studying the astrophysically-important nuclear reaction, 26Si(p)27P. The beam was produced in the CRIB (Center for Nuclear Physics (CNS) Radioactive Ion Beam Separator), which was been designed to the provide low-energy radioactive ion beams of 5-10 MeV/u and to study nuclear physics and nuclear astrophysics and where was installed at study CNS, the Universtiy of Tokyo in RIKEN. To increase the beam quality, we used a cryogenic primary gas target and a Wein filter. Finally, the beam purity and the intensity of the 26Si radioactive ion beams were 0.48% and 2×10⁴ pps, respectively. 고전류 및 고순도의 방사성 핵종빔은 천체핵합성 과정에 수반되는 핵반응 연구에 적합하며, 특히 신성폭발과 엑스선 폭발 (X-ray bursts)와 같은 극한적인 천체환경에서 일어나는 핵반응 연구에 필수적이다. 본 논문은 최근 천체핵물리학적으로 그 중요성이 부각되고 있는 26Si(p)27P 핵반응연구를 위해 방사성 핵종빔인 26Si 빔의 생성에 관한 연구이다. 26Si 방사성 핵종빔은 동경대 부설 핵과학연구소 (Center for Nuclear Study, 이하 CNS)의 in-flight 분리법을 이용한 저에너지 방사성 핵종분리장치인 CRIB (CNS Radio-Isotope Beam separator)을 통하여 생성하였다. 방사성 핵종의 생성율을 높이기 위해 액체질소 온도로 냉각한 극저온 1차 기체 표적 (cryogenic primary gas target)을 사용하였고 또한 빔 순도를 높이기 위해 속도분리장치인 Wien filter를 사용하였다. 그 결과 순도 0.48%, 빔 세기 2 × 10⁴pps의 26Si을 얻었다.

Background Considerations for the 2H(7Be,3H)6Be Experimental Data II: Three-body Continuum

채경육,V. Guimar˜aes 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.9

The present article reports second background considerations for the experimentally obtained 2H(7Be,3H)6Be differential cross sections. The one-neutron transfer reaction was measured in inverse kinematics by using radioactive 7Be (t1/2 = 53.2 days) beams at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory in 2004 in order to search for the resonances in the unbound 6Be nucleus. Resonances in this nucleus would affect the 3He(3He,2p)4He reaction rate of the proton-proton chain occurring in stars such as our sun. The result shows, however, that the direct transfer to 6Be resonances is not particularly strong compared to other reaction channels that can produce tritons in the exit channels. The goals of the present work is to better understand the cross section data from transfer reaction measurements by adopting background considerations using the three-body continuum.

Searching for Resonances in the Unbound 6Be Nucleus by Using a Radioactive 7Be Beam

채경육,D. W. Bardayan,J. C. Blackmon,M. S. Smith,A. E. Champagne,J. J. Das,R. P. Fitzgerald,D. W. Visser,V. Guimaraes,K. L. Jones,S. D. Pain,J. S. Thomas,M. S. Johnson,R. L. Kozub,R. J. Livesay,Z. Ma,C. 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.11

Knowledge of the ³He(³He,²<i>p</i>)⁴He reaction is important for understanding stellar burning and solar neutrino production. Previous measurements have found a surprisingly large rise in the cross section at low energies that could be due to a low-energy resonance in the ³He + ³He (⁶Be) system or electron screening. In the ⁶Be nucleus, however, no excited states have been observed above the first 2⁺ state at <i>E_x</i> = 1.67 MeV up to 23 MeV, even though several are expected. The ²H(⁷Be,³H)⁶Be reaction has been studied for the first time to search for resonances in the ⁶Be nucleus that may affect our understanding of the ³He(³He,²<i>p,</i>)⁴He reaction. A 100-MeV radioactive ⁷Be beam from the Holifield Radioactive Ion Beam Facility (HRIBF) was used to bombard CD₂ targets, and tritons were detected by using the silicon detector array (SIDAR). A combination of reaction mechanisms appears to be necessary to explain the observed triton energy spectrum.

Remote handling systems for the Selective Production of Exotic Species (SPES) facility

Lilli Giordano,Centofante Lisa,Manzolaro Mattia,Monetti Alberto,Oboe Roberto,Andrighetto Alberto 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.1

The SPES (Selective Production of Exotic Species) facility, currently under development at Legnaro National Laboratories of INFN, aims at the production of intense RIB (Radioactive Ion Beams) employing the Isotope Separation On-Line (ISOL) technique for interdisciplinary research. The radioactive isotopes of interest are produced by the interaction of a multi-foil uranium carbide target with a 40 MeV 200 mA proton beam generated by a cyclotron proton driver. The Target Ion Source (TIS) is the core of the SPES project, here the radioactive nuclei, mainly neutron-rich isotopes, are stopped, extracted, ionized, separated, accelerated and delivered to specific experimental areas. Due to efficiency reasons, the TIS unit needs to be replaced periodically during operation. In this highly radioactive environment, the employment of autonomous systems allows the manipulation, transport, and storage of the TIS unit without the need for human intervention. A dedicated remote handling infrastructure is therefore under development to fulfill the functional and safety requirement of the project. This contribution describes the layout of the SPES target area, where all the remote handling systems operate to grant the smooth operation of the facility avoiding personnel exposure to a high dose rate or contamination issues

Study of a-cluster Structure in 22Mg Using a Radioactive Ion Beam

차수미,K. Y. Chae,김민주,M. S. Kwag,E. J. Lee,K. Abe,S. Hayakawa,H. Shimizu,H. Yamaguchi,L. Yang,S. H. Bae,S. H. Choi,D. N. Binh,N. N. Duy,Z. Ge,V. H. Phong,K. I. Hahn,B. Hong,B. Moon,N. Iwasa,D. Kahl,L. H. 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.8

The ff-clusterization of an atomic nucleus has been studied for a long time, even from the earliest days of nuclear physics. Our understanding of the ff-cluster structure is, however, mainly limited to the self-conjugate A = 4n (n = 2; 3; 4; ) light nuclei and some of the neutron-rich radionuclides such as 10Be, 11B, and 14C. In order to study the ff-cluster structure of a neutron-deficient 22Mg nucleus, we have measured the 18Ne(ff, ff)18Ne scattering in inverse kinematics by using radioactive 18Ne beams and the 4He gas target at the Center for Nuclear Study radioactive ion beam separator of the University of Tokyo. Recoiling ff particles from the scattering were detected by using silicon strip detectors, which constitute E-E telescopes for particle identification. By adopting a thick target method, we were able to investigate a wide range of excitation energies Ex = 9:9 - 16.5 MeV in 22Mg in this work.

Study of the 2H(7Be,p+3He+4He)n Reaction for Resonances in 8B

K. Y. Chae,J. H. Lee 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.8

The solar neutrino is a good probe for understanding the internal structure and the energy production mechanism of stars with masses of about that of the sun because it does not interact with other materials of the star. The production rate of the solar neutrino is largely uncertain due to the lack of nuclear structure information on the 8B nucleus. In the search for resonances in the highly unstable nucleus 8B, which affect the production of solar neutrino, the 2H(7Be; p+3He+4He)n reaction was studied by using a radioactive 7Be beam produced at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory. Two layers of annular silicon strip detectors were used for particle identification, and the excitation energy of 8B was reconstructed by requiring triple coincidence for p, 3He, and 4He.

Background Considerations for the 2H(7Be,3H)6Be Experimental Data Using the Phase Space Model

K. Y. Chae,V. Guimaraes 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.9

The 2H(7Be,3H)6Be reaction was measured at the Holifield Radioactive Ion Beam Facility of theOak Ridge National Laboratory in 2004 to search for the resonances in the unbound 6Be nucleus. The results showed, however, no resonance was evident in the experimental data, which impliedthat the direct transfer to 6Be levels was not particularly strong compared to other reaction mechanismsthat produced tritons in their exit channels. In the present work, theoretical calculationswith background considerations are performed to better understand the cross-section data for the2H(7Be,3H)6Be reaction using the phase space model.