Bulletin of the American Physical Society
4th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 59, Number 10
Tuesday–Saturday, October 7–11, 2014; Waikoloa, Hawaii
Session KF: Mini-Symposium on Targets for the Next Generation of RIB Experiments |
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Chair: Tomohiro Uesaka, RIKEN Room: King's 2 |
Saturday, October 11, 2014 9:00AM - 9:30AM |
KF.00001: Overview of Target Development for Next Generation Radioactive Beam Experiments Invited Speaker: Jerry Nolen With the increased intensities of radioactive ion beams at present and future facilities a wide variety of target technologies are being brought to bear for the experimental studies undertaken with these beams. For astrophysical reaction studies, classical thin foil targets are still going to be extensively used, mainly as hydrogen- or deuterium-rich plastics (or metals). But more complex target systems such as windowless gas jets, liquid or cryogenic solid targets are being developed. Cryogenic gas cells have also been employed though one must contend with issues relating to the windows used. Active targets usually integrated with time projection chambers are being used with rare beams for their high detection efficiency and also for low energy processes. In an active target, the gas acts as both a target and detector and allows for investigations of nuclear structure and transfer reactions with very high efficiency and at high resolution due to the thickness of the target. Polarized targets, in the form of gas-phase, foil, and crystal targets, are being used and further developed for use at rare isotope facilities. And finally, in heavy-element research, more exotic beams even at moderate intensities can be used with the standard $^{208}$Pb as well as exotic actinide targets to perhaps open previously unanticipated reaction channels for the production, chemistry, and spectroscopic studies of isotopes of the heaviest elements. For use with high quality secondary beams, very small samples of rare actinide isotopes in conjunction with high efficiency gamma ray detectors can be used for such research. This talk will be an overview to introduce the topics to be covered in detail in the contributions to this mini-symposium. Prepared in collaboration with John P. Greene, Physics Division, ANL. [Preview Abstract] |
Saturday, October 11, 2014 9:30AM - 9:45AM |
KF.00002: Development of MAIKo with GEM Motoki Murata, Satoshi Adachi, Tatsuya Furuno, Yuki Ishii, Takahiro Kawabata, Miho Tsumura, Hooi Jin Ong, Isao Tanihata, Ayyad Limonge Francesc Yasid We are developing a new active target MAIKo to search for the alpha condensed state (ACS) in 20Ne. The ACS is a novel concept of the conformation of the nuclear system, and is theoretically predicted to appear near the $n\alpha$ decay threshold in the self-conjugate $A=4n$. In these states, all the alpha clusters are condensed into the lowest orbits, and their densities become diluted by a factor of 3--5. MAIKo is a kind of gas detectors in which the detection gas plays a role of the target. MAIKo is able to cover the full solid angle around the reaction point, and to detect low-energy particles emitted from the target. MAIKo is very useful to search for the ACS, because the ACS is expected to decay by emitting low-energy $n\alpha$ particles. In the present work, we constructed a new drift cage of MAIKo to introduce a gas electron multiplier (GEM). The design of the drift cage was optimized to make uniform electric field by utilizing the realistic field calculation. Since the GEM enhances the gas gain of MAIKo, it enables MAIKo to be operated at the low pressure. It is helpful to detect low-energy alpha particles because ranges of suchparticles are longer at low pressure. The detailed structure and detector performance of MAIKo with GEM will be reported in the present talk. [Preview Abstract] |
Saturday, October 11, 2014 9:45AM - 10:00AM |
KF.00003: Development of MAIKo: The active target with $\mu$-PIC for RI beam experiments Tatsuya Furuno, Takahiro Kawabata, Satoshi Adachi, Tatsuo Baba, Yuki Ishii, Hidetoshi Kubo, Yoshihiro Matsuoka, Tetsuya Mizumoto, Motoki Murata, Tatsuya Sawano, Atsushi Takada, Toru Tanimori, Miho Tsumura, Hidetomo D. Watanabe, Yassid Ayyad, Takashi Hashimoto, Yohei Matsuda, Hooi Jin Ong, Junki Tanaka, Isao Tanihata The active target system MAIKo ($\mu$-PIC based Active target for Inverse Kinematics.) is under development at RCNP to perform missing mass spectroscopy at forward angles in RI beam experiments. This method will be promising to study excited states above particle-decay thresholds. MAIKo works as TPC where detection gas plays a role of the target gas. Since the scattering occurs inside the TPC, the active target can detect even low-energy recoil particles. To achieve high position resolution by the TPC, micro-pixel chamber ($\mu$-PIC) is introduced to multiply and detect the drifted electrons. In November 2013, a test experiment was performed using a $^4$He beam to study the detector performance under high counting rate. Scattering events were also acquired to develop tracking algorithm which can extract scattering angle and excitation energy from the track information. Results of the experiment will be discussed in the present talk. [Preview Abstract] |
Saturday, October 11, 2014 10:00AM - 10:15AM |
KF.00004: CNS Active Target for deuteron induced reactions with high intensity beams Shinsuke Ota A gaseous active target based on GEM-TPC, named CAT, is being developed for the forward angle measurement of deuteron induced reactions in inverse kinematics, such as deuteron inelastic scattering (d,d') and charge exchange reaction (d,2p), especially with exotic beam. To perform missing mass spectroscopy in inverse kinematics, one needs to measure the momentum vector of very low energy recoiled particle (deuteron in our case). The CAT is operated with 0.4-atm deuterium gas and the low energy threshold for detection is about 0.5 MeV. Recently, the amplification part is modified to perform high luminosity measurement with 10$^{6}$-Hz beam. The property of GEM in deuterium gas was studied and 10$^4$ gain was achieved with three GEMs. The track of recoiled particle is deduced using charge division method with triangular shape readout pads. The measured position resolution was 300 $\mu$m. The pilot experiments with $^{14}$O and 10$^{6}$-Hz $^{132}$Xe beam were performed at HIMAC with high intensity beam. The recoiled deuteron was successfully measured. In this talk, the results of pilot experiments and farther development for intense beam injection will be reported. [Preview Abstract] |
Saturday, October 11, 2014 10:15AM - 10:30AM |
KF.00005: Search for Cluster Structure in $^{14}$C by Investigation of ${^{10}}$Be + ${^4}$He Resonant Scattering with the Prototype AT-TPC A. Fritsch, S. Beceiro-Novo, D. Suzuki, W. Mittig, T. Ahn, D. Bazin, Z. Chajecki, W. Lynch, A. Shore, J.J. Kolata, A. Howard, A. Roberts, X. Tang, F. Becchetti A half-scale prototype Active Target-Time Projection Chamber (AT-TPC) was built at the National Superconducting Cyclotron Laboratory (NSCL) as part of the development of the full-scale AT-TPC device. The prototype AT-TPC was used to investigate $^{14}$C cluster structures by way of a 38 MeV $^{10}$Be beam incident on a 90:10 He:CO$_2$ active target gas at the University of Notre Dame in October 2011. The $^{10}$Be beam was produced by Notre Dame's TwinSol and delivered to the prototype AT-TPC. Multiple resonances in scattering $^{10}$Be on ${^4}$He were observed. Spins and parities of resonances were determined. The resonances' relevance to $^{14}$C clustering will be discussed and presented. This work was partially supported by the US NSF under Contract No. PHY-0923087. [Preview Abstract] |
Saturday, October 11, 2014 10:30AM - 10:45AM |
KF.00006: An Active Target- Time Projection Chamber (AT-TPC) for reaccelerated beams Saul Beceiro-Novo, T. Ahn, F. Abu-Nimeh, D. Bazin, J. Bradt, Z. Chajecki, A. Fritsch, Z. Kohley, J.J. Kolata, W. Lynch, W. Mittig, D. Suzuki, N. Usher Reaccelerated radioactive beams near the Coulomb barrier, which will soon be available from the ReA3 accelerator at NSCL, will open up new opportunities for the study of nuclear structure near the driplines. Since these beams can only be produced at modest intensities, efficient techniques must be used for measurement. The Active Target- Time Projection Chamber (AT-TPC), which was developed at MSU, solves this problem by providing the increased luminosity of a thick target while maintaining a good energy resolution by tracking the reaction vertex over an essentially 4$\pi$ solid angle. The AT-TPC and similar detectors allow us to take full advantage of the radioactive ion beams at present and future nuclear physics facilities to explore the frontier of rare isotopes where much of the spectroscopic information is unknown. We used a prototype of the AT-TPC to study resonances in light nuclei, and some illustrative results will be shown. The AT-TPC technology will be presented together with new experimental results and the commissioning of the detector and its 10240 electronic channels. [Preview Abstract] |
Saturday, October 11, 2014 10:45AM - 11:00AM |
KF.00007: Fusion Studies with an Active-Target Time Projection Chamber J.J. Kolata, A.M. Howard, A. Roberts, W. Mittig, T. Ahn, D. Bazin, S. Beceiro-Novo, Z. Chajecki, A. Fritsch, W.G. Lynch, A. Shore, F.D. Becchetti, M. Febbraro, R.O. Torres-Isea, J. Riggins Near- and sub-barrier fusion of a radioactive $^{10}$Be beam with $^{40}$Ar has been studied at the \textit{TwinSol} facility of the University of Notre Dame, using the prototype active-target time projection chamber (pAT-TPC) developed at the National Superconducting Cyclotron Laboratory at Michigan State University. Preliminary results from this experiment will be presented and the lessons learned in the data analysis will be discussed. Application of the method to fusion in other systems involving low-rate radioactive beams will be discussed in the light of these lessons. This work was partially supported by the US NSF under Contract No. PHY09-69456 and MRI award No. PHY09-23087. [Preview Abstract] |
Saturday, October 11, 2014 11:00AM - 11:15AM |
KF.00008: An overview of the JENSA gas jet target system with preliminary 20Ne(p,t)18Ne results P. Thompson, D.W. Bardayan, J.C. Blackmon, K.A. Chipps, U. Greife, A. Kontos, R.L. Kozub, L.E. Linhardt, M. Matos, S.D. Pain, S.T. Pittman, A. Sachs, H. Schatz, K.T. Schmitt, M.S. Smith The Jet Experiments in Nuclear Structure and Astrophysics (JENSA) gas jet target system was designed to provide a gas target that was pure, localized, and dense. Several commissioning experiments with the JENSA target, performed at Oak Ridge National Laboratory, were undertaken to demonstrate the unique capability of JENSA for transfer reaction studies. JENSA has since been moved from Oak Ridge National Laboratory to the ReA3 reaccelerated beam hall at the National Superconducting Cyclotron Laboratory (NSCL). An overview of the JENSA design and operation will be presented, as well as preliminary results from a 20Ne(p,t)18Ne transfer reaction commissioning measurement performed with JENSA. Research supported by the U.S. Department of Energy. [Preview Abstract] |
Saturday, October 11, 2014 11:15AM - 11:30AM |
KF.00009: $^{19}$Ne states studied with the new JENSA gas jet target D.W. Bardayan, P.D. O'Malley, K.A. Chipps, M. Matos, S.D. Pain, W.A. Peters, S.T. Pittman, K. Schmitt, M.S. Smith, S. Ahn, K.L. Jones, A. Sachs, P. Thompson, A. Kontos, H. Schatz, R.L. Kozub, B. Manning, S. Ota, U. Greife, J.C. Blackmon, L. Linhardt The observation of $^{18}$F decay in novae would provide a direct test of nova models. To interpret such observations, the nuclear reactions that create and destroy $^{18}$F in novae must be understood. The destruction primarily occurs through the $^{18}$F($p,\alpha$)$^{15}$O reaction via resonances from states in $^{19}$Ne. Significant uncertainties remain concerning the properties of these states near the proton threshold at 6411 keV. We have used the newly-constructed JENSA (Jet Experiments in Nuclear Structure and Astrophysics) gas jet target at Oak Ridge National Laboratory to study these levels via the $^{20}$Ne($p,d$)$^{19}$Ne reaction. Deuterons were detected in the SIDAR Silicon Detector Array and the angular distributions were analyzed to determine the spins of astrophysically-relevant levels. The data and preliminary analysis will be presented. [Preview Abstract] |
Saturday, October 11, 2014 11:30AM - 11:45AM |
KF.00010: Polarized proton target for radioactive ion beam experiments Satoshi Sakaguchi, Tomohiro Uesaka, Takashi Wakui, Tomomi Kawahara, Kenichiro Tateishi, Sergey Chebotaryov, Evgeniy Milman, Hideyuki Sakai The world of atomic nuclei is enriched by the strong spin-dependent interaction in nuclear force. For studying roles of such interactions, one of the best approaches is the direct reaction of spin-polarized light ions. From more than half century ago, a number of scattering experiments using polarized proton/deuteron beams have been performed in all over the world. A polarized target for radioactive-ion beam experiments will enable us to apply this powerful approach to the field of unstable nuclei. At RIKEN and CNS, Univ. of Tokyo, we have constructed a solid polarized proton target based on a unique polarizing method. The target has an advantage of the operation under a low magnetic field of 0.1 T, which allows the detection of low-energy recoil protons in the inverse kinematics. Currently achieved polarization is about 20\%. The target has already been applied to RI-beam experiments at intermediate energies such as 70--200 MeV/nucleon. In this talk, we will introduce the overview of the polarized target system and present status of the experimental programs such as study of spin-orbit interaction in proton elastic scattering and determination of spin-orbit splitting by (p,2p) knock-out reaction. New physics opportunities expected with low-energy beams will also be covered. [Preview Abstract] |
Saturday, October 11, 2014 11:45AM - 12:00PM |
KF.00011: A new reaction spectroscopy facility, IRIS, with solid H$_{2}$/D$_{2}$ targets R. Kanungo, S. Ishimoto, A. Sanetullaev Nucleon transfer reactions of rare isotopes are sensitive ways of exploring the evolution of shell structure. Two nucleon transfer reactions probe the pairing correlation in exotic nuclei. Due to the simplicity of their structure, the hydrogen isotopes, p,d,t, are the best choice for these reactions. For unstable nuclei, the reactions needs to be performed in inverse kinematics with p,d,t serving as the targets. The presentation will describe a new facility, IRIS , that pioneers in using thin windowless solid H$_{2}$ and D$_{2}$ targets [1] $\sim$ 50-100 $\mu$m, for direct reactions with re-accelerated beams of exotic nuclei. The presentation will describe the basic structure of the target and the reaction detection detectors. The solid H$_{2}$/D$_{2}$ targets eliminate the background that is present from reactions on carbon in the polyethylene foil targets. In addition, the effectively thicker targets help to increase the reaction yield. \\[4pt] [1] S. Ishimoto- et al., RCNP Progress Report 2010. [Preview Abstract] |
Saturday, October 11, 2014 12:00PM - 12:15PM |
KF.00012: Solid hydrogen target for missing mass spectroscopy in inverse kinematics Yohei Matsuda We have developed a solid hydrogen target system called ``Solid Hydrogen Target for Recoil detection In Coincidence with Inverse Kinematics'' (SH TRIC K). Many experiments require thin and large SHTs (e.g. 1 mm in thickness and 30 mm in diameter) to perform missing mass spectroscopy with radioactive ion beams. However, it has been difficult to make such a SHT due to thermal radiation from environment and non-uniformity of the target thickness. In order to overcome the problem, we made a ortho-para converter and a simple mechanical press. The former is used to increase a ratio of para H$_{2}$ in H$_{2}$ gas. Note that the thermal conductivity of pure para H$_{2}$ is more than 100 times larger than that of normal H$_{2}$. The latter is used to make the surface of the SHT uniform. Finally, we succeeded in making homogeneous pure H$_{2}$ targets thanks to the improvement. By using the SHTs, we have performed experiments of elastic scattering of protons with RI beams (ESPRI) at HIMAC, GSI, and RIBF. In my presentation, I will show the development and the experimental results. Furthermore, I will also talk about recent newly development for some experiments using the cryogenic system at RCNP. [Preview Abstract] |
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