109826413
Pre-installation tests and calibration of the ALICE TOF modules
Abstract Before installation into the ALICE experiment, all 87 modules of the TOF system had to undergo a series of tests. Initial check-ups included control of the gas tightness, readout connections quality, and high-voltage tests. Further tests were performed on a specially constructed Cosmic Ray Test Facility, where main characteristics of the modules were scanned under the working high voltage by means of cosmic muons. All TOF channels proved to provide the detection efficiency of more than 97% and time resolution of 80–110 ps, which complies with the ALICE requirements.
16382276
Multiplicity studies and effective energy in ALICE at the LHC
In this work we explore the possibility to perform “effective energy” studies in very high energy collisions at the CERN large hadron collider (LHC). In particular, we focus on the possibility to measure in pp collisions the average charged multiplicity as a function of the effective energy with the ALICE experiment, using its capability to measure the energy of the leading baryons with the zero degree calorimeters. Analyses of this kind have been done at lower centre-of-mass energies and have shown that, once the appropriate kinematic variables are chosen, particle production is characterized by universal properties: no matter the nature of the interacting particles, the final states have identical features. Assuming that this universality picture can be extended to ion–ion collisions, as suggested by recent results from RHIC experiments, a novel approach based on the scaling hypothesis for limiting fragmentation has been used to derive the expected charged event multiplicity in AA interactions at LHC. This leads to scenarios where the multiplicity is significantly lower compared to most of the predictions from the models currently used to describe high energy AA collisions. A mean charged multiplicity of about 1000–2000 per rapidity unit (at η∼0) is expected for the most central Pb–Pb collisions at $\sqrt{s_{{\text{NN}}}} = 5.5\,\text{TeV}$.
124469673
The ALICE Time-Of-Flight system: Construction, assembly and quality tests
109357009
Data quality monitor as the final quality assurance procedure for the ALICE-TOF detector
All the steps which led to the construction of the ALICE-TOF detector were strictly followed by a set of quality assurance procedures to guarantee high and uniform performances. Once a module of the detector (whose basic element is the Multigap Resistive Plate Chamber) is assembled, a final test concerning the data readout applies. While the detector is taking data, both during test and physics runs, a check of the quality of the data is needed. For this purpose some monitoring tools have been developed. These tools have been used since the beginning of the TOF commissioning and finally they have also been successfully used during the first global data-taking test-runs of ALICE.
121872628
The ALICE Time-Of-Flight detector: status and expected performance at the LHC startup
A. Akindinova, A. Alicib,c, P. Antoniolic, S. Arcellib,c, M. Basileb,c, G. Cara Romeoc, L. Cifarellib,c, F. Cindoloc, A. De Carod, D. De Gruttolad, S. De Pasqualed, M. Fusco Girardd, B. Guerzonib,c, D. Hatzifotiadouc, H.T. Junge, W.W. Junge, D.S. Kime, D.W. Kime, H.N. Kime, J.S. Kime, S. Kiseleva, G. Laurentic, K. Leee, S.C. Leee, D. Malkevicha, A. Margottic, R. Naniac, A. Nedosekina, F. Noferinic,g , P. Paganod, A. Pescic, O. Pinazzac, R. Preghenellac,f,∗, M. Ryabinina, E. Scapparonec, G. Sciolib,c, A. Silenzib,c, M. Tchoumakova, K. Voloshina, M.C.S. Williamsc, B. Zagreeva, C. Zampollig,h, A. Zichichib,c,f . a Institute for Theoretical and Experimental Physics, Moscow, Russia b Dipartimento di Fisica dell’Universita, Bologna, Italy c Sezione INFN, Bologna, Italy d Dipartimento di Fisica dell’Universita and INFN, Salerno, Italy e Department of Physics, Kangnung National University, Republic of Korea f Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Rome, Italy g INFN–CNAF, Bologna, Italy h CERN, Geneva, Switzerland
108880980
A topological trigger based on the Time-of-Flight detector for the ALICE experiment
The goal of the ALICE Time-of-Flight detector, based on MRPC technology, is to perform the charged-particle identification at midrapidity, in the region |η| < 0.9. This large area (∼150 m 2 ), finely segmented detector (∼157,000 channels), provides fast signals which will contribute to the Level 0 and Level 1 trigger decisions. We use the TOF detector information to perform an online estimate of the total track multiplicity and to identify simple and peculiar topologies, like those produced by minimum bias p-p, Ultra Peripheral ion-ion collisions and cosmic muons. The system architecture foresees a first layer of 72 VME boards interfacing the detector front-end to a second layer, which receives and processes all the information and takes trigger decisions.
23580320
Isomers in 128Pd and 126Pd: evidence for a robust shell closure at the neutron magic number 82 in exotic palladium isotopes.
The level structures of the very neutron-rich nuclei 128Pd and 126Pd have been investigated for the first time. In the r-process waiting-point nucleus 128Pd, a new isomer with a half-life of 5.8(8) μs is proposed to have a spin and parity of 8(+) and is associated with a maximally aligned configuration arising from the g(9/2) proton subshell with seniority υ=2. For 126Pd, two new isomers have been identified with half-lives of 0.33(4) and 0.44(3) μs. The yrast 2(+) energy is much higher in 128Pd than in 126Pd, while the level sequence below the 8(+) isomer in 128Pd is similar to that in the N=82 isotone 130Cd. The electric quadrupole transition that depopulates the 8(+) isomer in 128Pd is more hindered than the corresponding transition in 130Cd, as expected in the seniority scheme for a semimagic, spherical nucleus. These experimental findings indicate that the shell closure at the neutron number N=82 is fairly robust in the neutron-rich Pd isotopes.
15843852
Shape evolution in 116,118Ru: Triaxiality and transition between the O(6) and U(5) dynamical symmetries
P.-A. Söderström,1,* G. Lorusso,1 H. Watanabe,1,2 S. Nishimura,1 P. Doornenbal,1 G. Thiamova,3 F. Browne,1,4 G. Gey,1,3 H. S. Jung,5 T. Sumikama,6 J. Taprogge,1,7,8 Zs. Vajta,1,9 J. Wu,1,10 Z. Y. Xu,11 H. Baba,1 G. Benzoni,12 K. Y. Chae,13 F. C. L. Crespi,12,14 N. Fukuda,1 R. Gernhäuser,15 N. Inabe,1 T. Isobe,1 A. Jungclaus,8 D. Kameda,1 G. D. Kim,16 Y.-K. Kim,16,17 I. Kojouharov,18 F. G. Kondev,19 T. Kubo,1 N. Kurz,18 Y. K. Kwon,16 G. J. Lane,20 Z. Li,21 A. Montaner-Pizá,22 K. Moschner,23 F. Naqvi,24 M. Niikura,11 H. Nishibata,25 A. Odahara,25 R. Orlandi,26 Z. Patel,27 Zs. Podolyák,27 H. Sakurai,1,11 H. Schaffner,18 G. S. Simpson,3 K. Steiger,15 H. Suzuki,1 H. Takeda,1 A. Wendt,23 A. Yagi,25 and K. Yoshinaga28 1RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan 2Department of Physics, Beihang University, Beijing 100191, China 3LPSC, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, F-38026 Grenoble Cedex, France 4School of Computing, Engineering and Mathematics, University of Brighton, Brighton BN2 4JG, United Kingdom 5Department of Physics, Chung-Ang University, Seoul 156-756, Republic of Korea 6Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578, Japan 7Departamento de Fı́sica Teórica, Universidad Autónoma de Madrid, E-28049 Madrid, Spain 8Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain 9Institute for Nuclear Research, Hungarian Academy of Sciences, P. O. Box 51, Debrecen, H-4001, Hungary 10Department of Physics, Peking University, Beijing 100871, China 11Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan 12INFN Sezione di Milano, I-20133 Milano, Italy 13Department of Physics, Sungkyunkwan University, Suwon 440-746, Republic of Korea 14Dipartimento di Fisica, Università di Milano, I-20133 Milano, Italy 15Physik Department E12, Technische Universität München, D-85748 Garching, Germany 16Rare Isotope Science Project, Institute for Basic Science, Daejeon 305-811, Republic of Korea 17Department of Nuclear Engineering, Hanyang University, Seoul 133-791, Republic of Korea 18GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany 19Nuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA 20Department of Nuclear Physics, R.S.P.E., Australian National University, Canberra, A.C.T. 0200, Australia 21School of Physics, Peking University, Beijing 100871, China 22Instituto de Fı́sica Corpuscular, CSIC-University of Valencia, E-46980 Paterna, Spain 23Institut für Kernphysik, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany 24Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520-8120, USA 25Department of Physics, Osaka University, Machikaneyama-machi 1-1, Toyonaka, Osaka 560-0043, Japan 26Instituut voor Kern en Stralingsfysica, KU Leuven, University of Leuven, B-3001 Leuven, Belgium 27Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom 28Department of Physics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
117824458
A confirmative spin-parity assignment for the key 6.15 MeV state in $^{18}$Ne of astrophysical importance
Proton resonant states in $^{18}$Ne have been investigated by the resonant elastic scattering of $^{17}$F+$p$. The $^{17}$F beam was separated by the CNS radioactive ion beam separator (CRIB), and bombarded a thick H$_2$ gas target at 3.6 MeV/nucleon. The recoiled light particles were measured by using three sets of ${\Delta}$E-E Si telescope at scattering angles of $\theta$$_{lab}$$\approx 3^\circ$, 10$^\circ$ and 18$^\circ$, respectively. Four resonances, {\it i.e.}, at $E_{x}$=6.15, 6.30, 6.85, and 7.05 MeV, were observed clearly. By $R$-matrix analysis of the excitation functions, $J^{\pi}$=1$^-$ was firmly assigned to the 6.15 MeV state which is a key state in calculating the reaction rate of $^{14}$O($\alpha$,$p$)$^{17}$F reaction. This reaction was thought to be one of the most probable key reactions for the breakout from the hot-CNO cycle to the $rp$-process in type I x-ray bursts In addition, a new excited state observed at $E_{x}$=6.85 MeV was tentatively assigned as 0$^{-}$, which could be the analog state of 6.880 MeV, 0$^{-}$ in mirror $^{18}$O.
120873348
Installation and commissioning of EURICA – Euroball-RIKEN Cluster Array
Abstract EURICA is a project at RIKEN Nishina Center aimed at studying a wide range of exotic nuclei through β -decay measurements and high-resolution γ -ray spectroscopy. The setup is located behind the BigRIPS fragment separator and the ZeroDegree spectrometer at the RIBF. EURICA consists of the HPGe cluster detectors from the previous Euroball and RISING projects, together with double-sided silicon-strip detectors for β -decay counting and lifetime measurements. In total, this setup provides us with the possibility to study several aspects of the exotic nuclei produced at the RIBF.
120011305
β-decay spectroscopy at RIBF: The EURICA project
EURICA is a project at the RIKEN Nishina Center aimed at studying a wide range of exotic nuclei through β-decay measurements and high-resolution γ-ray spectroscopy. During its first two years of operation, about 80 days of beam time have been dedicated to the project allowing the exploration of several very exotic regions of the nuclear chart, which include key nuclei such as 78Ni, 100Sn, 110Zr, 128Pd, and 138Sn. Data analysis of the EURICA experiments is currently ongoing.