NN2012 List of Poster Presentations

Index:

Heavy and Superheavy Elements

HSP01 Kai Zhao, China Institute Of Atomic Energy, China

Study of deformed U+U with different orientation around Coulomb barrier energy

HSP02 T. A. Werke, Cyclotron Institute, Texas A&M University, USA

Effects of Odd-Z Projectiles on Fusion-Evaporation Cross Sections

Relativistic Heavy-Ion Physics

RHIP01 Oana Ristea, University of Bucharest, Faculty of Physics, Romania

Study of the freeze-out process in heavy ion collisions at relativistic energies

RHIP02 Catalin Ristea, University of Bucharest, Faculty of Physics, Romania

Hubble flow in relativistic heavy ion collisions

RHIP03 Kyong Chol Han, Texas A&M University, USA

Jet fragmentation via quark recombination

RHIP04 Xiaoping Zhang, Tsinghua University China, presented by a colleague

Final state interactions on particle production in d+Au collisions at RHIC

RHIP05 Sayed S. Saleh, KING ABDULAZIZ UNIVERSITY, Saudi Arabia

Relativistic a-particles distributions and correlations for the projectile (12C, 16O, 28Si, and 22Ne) fragmentations at Dubna energies (4.1-4.5 A GeV/c)

Nuclear Structure

NSP01  Pragya Das, Indian Institute of Technology Bombay, India

Large triaxial deformation in 126I

NSP02 Tusar Ranjan Routray, Sambalpur University, India

Finite nucleus calculation with the simple effective interaction

NSP03 Harish Mohan Mittal, National Institute of Technology, Jalandhar, India

Adiabatic invariant behavior of dynamical moment of inertia of superdeformed nuclear state

Nuclear Energy and Applications of Nuclear Science and Technologies

NEP01 Fei Ma, Institute of Modern Physics, Chinese Academy of sciences, People Republic of China

The experimental study of spallation reactions, neutron production in thick target irradiated with proton beam at IMP

NEP02 Zhang Yaling, Institute of Modern Physics, Chinese Academy of Sciences, China

NEP03 Mahmoud Pour Arsalan, University of Tennessee, USA

An improved thermodynamic model for estimating the emitted light particle source radius, and coalescence radius, in low energy heavy ion collisions

NEP04 Marie Nguyen, University of Vietnam

A study of the reaction (p, n) on heavy targets for designing the Accelerator Driven System

NEP05 Paresh Prajapati, Phisics Department, Faculty of Science, The M.S. University of Baroda, Vadodara-390002, India

Mass distribution in the fast neutron induced fission of 232-Th

New Facilities and Detectors

NFD01 J.J. Das, UNIRIB, ORISE, Oak Ridge, TN 37830, USA

He Jet Ion Source in FRIB era

EOS of Neutron-Rich Nuclear Matter, Clusters in Nuclei and Nuclear Reactions

EOSP01 Justin Mabiala, Texas A&M University, Cyclotron Institute, USA

Towards the Liquid-Gas Phase Transition: Experimental aspects

EOSP02 Simin Wang, State Key Laboratory of Nuclear Physics and Technology/School of Physics/Peking University, China

Clustering around Double Shell Closures with a Local Potential

EOSP03 Andrew Raphelt, Texas A&M University, Cyclotron Institute, USA

Effects of Excitation Energy on the Symmetry Energy

EOSP04 Paul Cammarata, Texas A&M University, Cyclotron Institute, USA

PLF Decay Channels as an Experimental Probe using Time of Flight Measurements

EOSP05 Lauren Heilborn, Texas A&M University, Cyclotron Institute, USA

Particle-particle correlation functions as an experimental probe of the nuclear symmetry energy

EOSP06 Larry May, Texas A&M University, Cyclotron Institute, USA

Equation of State effects on Nucleon Transport

EOSP07 A. Zarrella, Texas A&M University, Cyclotron Institute, USA

Neutron Detection Efficiency of the Neutron Ion Multidetector for Reaction Oriented Dynamics (NIMROD) Detection System

EOSP08 T. R. Routray, School of Physics, Sambalpur University, Orissa, India

Neutron-proton effective mass splitting and thermal evolution in neutron rich matter

EOSP09 Anupriya Jain, Thapar University, Patiala, India

Consequence of isospin dependent cross section and charge asymmetry on anisotropic flow

Nuclear Reactions and Structure of Unstable Nuclei

RSP01 Marco Mazzocco, University of Padova,  Italy

Elastic Scattering for the System 7Be + 58Ni at 23.2 MeV Beam Energy

RSP02 Jian Ling Lou, Peking University, China

Probing the Ground State of 8He via 8He(p,d)7He and 8He(p,t)6He reactions

Nuclear Astrophysics

NAP01 Ellen Simmons, Cyclotron Institute - Texas A&M University, USA

The Beta-Delayed Proton and Gamma Decay of 27P For Nuclear Astrophysics

NAP02 A. Spiridon, Cyclotron Institute - Texas A&M University, USA

A new detection system for very low-energy protons from β-delayed p-decay

NAP03 Neha Gupta, Indian Institute of Technology Roorkee, India

Antikaons in neutron stars studied with extended relativistic mean-field models

NAP04 Joshua Hooker, Texas A&M University – Commerce, USA

Moment of Inertia of the Inner Crust 'Napkin Ring'

Heavy and Superheavy Elements

HSP01

China Institute Of Atomic Energy, China

Abstract's Title: Study of deformed U+U with different orientation around Coulomb barrier energy

The influence of initial orientation in three configurations (nose-nose, nose-side, and side-side) on the reaction dynamics, lifetime of composite system and the probability for producing primary fragments is studied with deformed 238U + 238U by using ImQMD model. We find that deformed projectile or target with initial nose orientation evolves to spherical nuclei at touching configuration in most events at lower reaction energies. As a consequence, the lifetime of transiently formed composite system weakly depend on the initial orientation. Nevertheless, the probability of trans-actinide primary fragment for side-side configuration is larger than the one for nose-nose configuration.

HSP02

T. A. Werke1,2, D. A. Mayorov1,2, M. C. Alfonso1,2, M. E. Bennett1, C. M. Folden III1

1 Cyclotron Institute, Texas A&M University, College Station, TX 77843-3366, USA
2 Department of Chemistry, Texas A&M University, College Station, TX 77842-3012, USA

Abstract’s Title: Effects of Odd-Z Projectiles on Fusion-Evaporation Cross Sections

The synthesis of superheavy elements via hot fusion with a
48Ca beam and actinide targets has resulted in the discovery of six new elements in the last fourteen years.   In order to gain some insight into the production mechanism of superheavy elements, we can draw analogies by examining reactions of lighter systems within the current framework of fusion-evaporation reactions theory.  Previously measured 4n exit channel cross sections for the 48Ca and 50Ti reactions on 162Dy have exhibited enhanced fission probabilities in the de-excitation of the compound nucleus due to collective effects.  The next direction in this research is to study the effects on the production cross sections of odd-Z projectiles with lanthanide targets.  Reactions with the relatively neutron-deficient 45Sc projectile will push the compound nucleus farther away from the N=126 closed shell.  This suggests that collective effects should diminish relative to the products from the more neutron rich even-Z projectiles.  However, the neutron deficiency will decrease the fission barrier and increase the neutron separation energy.   This poster will discuss the theoretical model of fusion-evaporation residue cross sections and will discuss the latest results on excitation functions for odd-Z projectiles on lanthanide targets.  Conclusions will be drawn towards the production of Z=119 and beyond.

Relativistic Heavy-Ion Physics

RHIP01

Oana Ristea, Al Jipa, C Ristea, I. Lazanu, M Calin, T Esanu;

University of Bucharest, Faculty of Physics, Romania

Abstract's Title: Study of the freeze-out process in heavy ion collisions at relativistic energies

The characteristics of the system produced in high energy heavy ion collisions at kinetic freeze-out can be explored by the analysis of transverse momentum distributions of the identified charged hadrons. An interesting phenomenon at this stage of the system evolution is the collective transverse expansion as it is entirely generated during the collision and therefore reflect the collision dynamics.  We will investigate the freeze-out process in heavy ion collisions at CBM-FAIR energies. This strongly interacting sistem produced in collision is characterized, at the CBM-FAIR energy range, by high baryon density and moderate temperature. There are questions with respect to the space-time evolution, e.g. how fast the hot-and-dense matter thermalizes and freezes-out, if a phase transition to QGP state occurs and therefore an analysis of soft physics observables such as single pT spectra may contribute to elucidate the answers to these questions.  In this work, we will present a study of blast-wave fits performed to the transverse momentum spectra obtained from simulated heavy ion collisions using the most important simulation codes from this field. In addition, comparisons with results from Au-Au collisions at RHIC energies will be presented to provide more detailed insight into the properties of the space-time evolution such as collective dynamics of the dense matter.

RHIP02

Catalin Ristea, Al Jipa, O Ristea, C Besliu, V Baban

University of Bucharest, Faculty of Physics,  Romania

Abstract's Title: Hubble flow in relativistic heavy ion collisions

Heavy-ion collisions at high energies offer a unique opportunity to probe highly excited dense nuclear matter and study its properties. Experimental data collected at RHIC from heavy-ion collisions have shown that the system produced in Au-Au collisions is thermalized and undergoes a strong longitudinal and transverse expansion. Collective flow develops in such collisions via re-interactions among partons or/and hadrons and therefore characterizing flow is a crucial step towards understanding the formation of partonic matter.  The fireball expansion could be characterized by the Hubble law. The measurable observables that can provide information about thermalization and collective flow are the transverse momentum spectra of produced particles. The expansion rate at “thermal freeze-out” provides the nuclear collision analogue of the Hubble constant for the Big Bang, while the corresponding freeze-out temperature parallels the temperature of the cosmic microwave background at the point of photon decoupling.  In this work we use a temporal scale for nuclear collisions inspired by the Hubble cosmology. We will make an estimate of a Hubble parameter for relativistic nuclear collisions similar to cosmological Hubble constant, based on temporal connections between the evolution of nuclear matter produced in a relativistic heavy ion collision and the Universe evolution after the Big Bang. We will use experimental data from Au-Au collisions at RHIC energies and also some predictions using the most important simulation codes used in this field.

RHIP03

Kyong Chol Han

Texas A&M University, USA

Abstract’s Title: Jet fragmentation via quark recombination

Hadron production from energetic jets in high-energy nuclear collisions is usually modeled by phenomenological fragmentation functions, such as those of AKK [1]. Recently, we have shown, however, that vacuum fragmentation functions can be reproduced in an event-by-event approach that uses a perturbative shower evolution in the vacuum, a modeling of additional non-perturbative effects in the shower, and finally recombination of the quarks and antiquarks into hadrons. Specifically, we use PYTHIA electron-positron events to generate vacuum showers. When the perturbative evolution is stopped at certain momentum scale, we force gluons to decay into quark-antiquark pairs. The recombination probability for two partons to coalesce into a meson is then calculated from the momentum-space part of the Wigner function of the meson, similar to the Greco-Ko-Levai approach to quark coalescence [2]. Using a Monte-Carlo routine, we coalesce the partons based on these probabilities into π, ρ, a1, K and K* mesons. With a smaller number of un-coalesced quarks, typically leading quarks that are far removed in momentum space from the rest of the shower, fragmented to hadrons using AKK fragmentation functions at the appropriate scale, and after decay of resonances, the resulting pion and kaon spectra compare favorably with the AKK fragmentation functions that have been parameterized from electron-positron data.  Our approach can be extended to study the medium modification of fragmentation functions in the presence of a QGP by allowing the shower partons to recombine with the thermal partons in the QGP.

References
[1] S. Albino, B.A. Kniehl, and G. Kramer, Nucl. Phys. B 725, 181 (2005).
[2] V. Greco, C.M. Ko, P. Levai, Phys. Rev. Lett.  90, 202302 (2003).

RHIP04

Xiaoping Zhang

Tsinghua University China

Abstract’s Title: Final state interactions on particle production in $d$+Au collisions at RHIC

The study of $p$($e$)+A like collisions is essential to understand the dynamical evolution from cold nuclear matter to the hot and dense quark gluon plasma in high-energy nuclear collisions. Especially, in an initial colliding nucleus travelling near the speed of light, the existence of the color glass condensate, a state of high density gluonic matter, is still under intense debate. To extract information on the properties of initial colliding nucleus accurately from current experimental data, one needs a detailed simulation on the nuclear collision by including all important physical processes with sophisticated models, such as the transport model [1, 2]. It allows to study the final state effects, for example, the hadronization mechanisms and hadronic and/or partonic rescatterings in relativistic nuclear collisions, in a quantitative way. With increasing energy density and number of particles created in relativistic nuclear collisions, the final state interactions between partons and/or hadrons become more and more important. However, in most calculations on particle production in $d$+Au collisions at $\sqrt{s_{NN}}=200$ GeV at BNL Relativistic Heavy Ion Collider (RHIC), the final state hadronic rescattering effect is not considered.

In this talk, we will report a systematical study on the mechanism of hadron formation and subsequent haronic/partonic interactions in $d$+Au collisions at $\sqrt{s_{NN}}=200$ GeV at RHIC in the framework of a multiphase transport model [3]. With Lund string fragmentation for hadronization, we find significant contribution of final state hadronic rescatterings on the central-to-peripheral nuclear modification factors ($R_{CP}$) of different particles ($\pi, K, p, \phi, \Lambda, \Xi, \Omega$). Recent data on particle species dependence of $R_{CP}$ at mid-rapidity in $d$+Au collisions at RHIC [4] can be understood in terms of this final-state hadronic rescatterings. This shows the importance of final state hadronic interactions in $d$+Au collisions, since none of the initial-state models would predict a species-dependent $R_{CP}$ at present. In addition, we will discuss the rapidity, transverse momentum and particle species dependence of the final state effects in details.

[1] Z. W. Lin, and C.~M. Ko, Phys. Rev. C
68, 054904 (2003).
[2] Z. W. Lin, C.~M. Ko, B. A. Li, B. Zhang, and S. Pal, Phys. Rev. C
72, 064901 (2005).
[3] X. Zhang, J. Chen, Z. Ren, N. Xu, Z. Xu, Q. Zheng, and X. Zhu, Phys. Rev. C
84, 031901(R) (2011).
et al., Phys. Lett. B 616, 8 (2005); \emph{ibid.}, Phys. Lett. B 637,161 (2006); STAR Collaboration, X. Zhang, Phi-meson Production in d+Au Collisions", ATHIC2010. PHENIX Collaboration, S. S. Adler \emph{et al.}, Phys. Rev. C 74, 024904 (2006).

RHIP05

Sayed .S.Saleh*, Mohamed H.Solimman** and Sau J.Yagmour *

* King Abdul Aziz University, Saudi Arabia

** Cairo University, Egypt

Abstract’s Title: Relativistic a-particles distributions and correlations for the projectile ( 12C, 16O, 28Si, and 22Ne) fragmentations at Dubna energies (4.1-4.5 A GeV/c)

The relativistic a-particles distributions and correlations of the projectile fragments resulting from the peripheral interactions of (4.5 A GeV/c) 12C, 16O, 28Si , and (4.1 A GeV/c) 22 Ne projectiles with emulsion have been analyzed and modeled. The distributions of a-particles, the associated-mesons, and the range of the transverse momentum have been obtained. It has been found that, the a-particles distributions obey the logarithmic function, while the associated- mesons distributions obey Gauss function, and the distributions of the range of the a-particles transverse moment shows decaying functions. The correlations between the a-particles numbers and min, max PT of a-particles are also calculated. From this study we could predict that, the dissociation into a-particles is preferably a cascade process; especially; for heavy projectiles.

Nuclear Structure

NSP01

Bhushan Kanagalekar, Pragya Das, Bhushan Bhujang, S. Muralithar, R. P. Singh and R. K. Bhowmik
Indian Institute of Technology Bombay

Abstract’s Title: Large triaxial deformation in 126I

The phenomena of signature inversion and decoupling have been observed in some of the odd-odd nuclei in the mass region 130 [1, 2].  Theoretically, these phenomena have been understood by assuming the nuclei to be either axially symmetric or to have small triaxial deformation (triaxiality parameter less than 30 degree in Lund’s convention).  Interestingly, we find a large value of the triaxial deformation parameter of about 45 degree in
126I.
Prior to our work, the decay scheme of
126I was largely unknown except for the unpublished results in the Annual report (2002) of Australian National Lab, Canberra.  We performed an experiment using a fusion evaporation reaction 124Sn(7Li, 5n)126I at the beam energy of 50 MeV delivered by the 15 UD Pelletron accelerator at the Inter University Accelerator Centre (IUAC), New Delhi, India.  The Indian National Gamma Array [3], consisting of 15 Compton suppressed HPGe Clover detectors, was used for the experiment.  The data were collected in the event-by-event mode for the triple gamma coincidences.  We constructed the decay scheme using the coincidence and intensity relationships among the gamma rays.  The spins to the levels were assigned using the Directional Correlation Ratios.  The parity was determined by finding the polarization asymmetry parameter.  The decay scheme consisted of 5 negative parity and 2 positive parity bands.  The most intense yrast positive parity band consisted of M1 transitions with E2 crossovers.  A small amount of signature splitting was observed at low spins, which became large at high spins.  Signature inversion occured at 13 units of angular momentum.  Above the inversion point, the even values of spins were favoured.  To get a consistency with the Cranking picture, i. e. even spins (signature quantum number = 0) is favoured, we assigned the valence particle configuration as proton in d5/2 and neutron in h11/2.  This assignment was not in agreement with the particle configuration mentioned in the Annual report (2002) of Australian National Lab, Canberra.  We performed Total Routhian Surface calculations (TRS) to find the value of the deformation parameters corresponding to the energy minimum.  The parameter beta remained almost constant in the entire range of spins with a value of 0.15.  The value of the triaxial deformation parameter gamma changes from about +50 degree at low spins to - 40 degree at high spins.  In the TRS calculation based on the rigid body rotation, the positive and the negative values of gamma correspond to the rotation around the shortest axis and the intermediate axis, respectively, in the Lund’s convention.  These results were employed in our Particle-Rotor model (PRM) calculation, which is based on the irrotational-flow model of moment of inertia.  To have the correct correspondence between the TRS and the PRM calculations we used gamma=45 degree (gamma-reversed) below the signature inversion and gamma=45 degree above.  Although the highest moment of inertia corresponds to the intermediate axis in the irrotational-flow model, Ikeda and Aberg [4] have discussed how the rotation around the shortest axis can be realized at low spins.  A good agreement of the signature splitting and the signature inversion between the experiment and PRM calculation was obtained [5].
Another negative parity band near to the yrast band exhibited decoupling behaviour.   Only the even spin states decaying by the E2 transitions were observed.  We performed the PRM calculation to obtain the energy states.  We could achieve the decoupling behaviour only when we used the deformation parameter beta = 0.15 and gamma = 45 degree (gamma-reversed).  However, there was a large discrepancy between the energy values of the states corresponding to the experiment and theory.  The dominant component in the wavefunction was valence proton in g7/2 and valence neutron in h11/2.
A small signature splitting was observed in the yrast positive parity band with an irregular behaviour.  The pattern became regular at high angular momentum states with odd spins as favoured states.  This observation was consistent with the particle assignment as valence proton in h11/2 and valence neutron in h11/2.  Again, the best agreement was obtained when we used the deformation parameter beta = 0.15 and gamma = 45 degree using the PRM.

References:
[1] H. J. Chantler et al., Phys. Rev. C66, 014311 (2002).
[2] Vinod Kumar et al., Phys. Rev. C 82, 054302 (2010).
[3] S. Muralithar et al., Nucl. Instr. and Meth. A 622, 281 (2010).
[4] A. Ikeda and S. Aberg, Nucl. Phys. A 480, 85 (1988).
[5] B. Kanagalekar et al., Proceedings of the DAE Symposium on Nucl. Phys. 56, 440 (2011), December 26-30, Vishakhapatnam, India.

NSP02

Tusar Ranjan Routray

Sambalpur University, India

Abstract’s Title: Finite nucleus calculation with the simple effective interaction,

The nuclear mean field properties and equation of state of nuclear matter under extreme conditions have been studied by using the simple effective interaction. The extensions of the study to finite nucleus case for Gaussian form of the simple effective interaction has been reported in this work. The interaction contains a single Gaussian term in its finite range part in contrast to the double Gaussian form of Gogny effective interaction.  The finite nucleus properties calculated ab intio, without changing the nuclear matter properties, is found to compete with the predictions of the existing standard relativistic and non-relativistic model results. We are reporting the results of isotopic shift in Pb-isotopes, two neutron separation energy in Zr-isotopes, single particle spectra in 208Pb alongwith the bulk properties of doubly closed nuclei. It is found that our results for isotopic shift and all other properties are similar to the experimental values.

NSP03

Harish Mohan Mittal

Dr. B.R. Ambedkar National Institute of Technology, Jalandhar-144011,  INDIA

Abstract's Title: Adiabatic invariant behavior of dynamical moment of inertia of superdeformed nuclear state

One of the most intriguing difference between the properties of superdeformed (SD) nuclei in the A=150 and A=190 region is the behavior of dynamical moment of inertia J(2) as a function of rotational frequency Һω. The rate of increase of J(2) with Һω has been observed in A=190 mass region. Somewhat steeper slope of J(2) in an even-even SD nuclei has been observed as compared to odd-even SD nuclei. So, the study of odd-odd SD nuclei should be very revealing. Here, we propose an approach to describe the behavior of J(2) of superdeformed nuclear state 194Tl. A behavior of dynamical moment of inertia is found to be adiabatic invariant.

Nuclear Energy and Applications of Nuclear Science and Technologies

NEP01

Fei Ma

Institute of Modern Physics, Chinese Academy of sciences, People Republic of China

Abstract's Title: The experimental study of spallation reactions, neutron production in thick target irradiated with proton beam at IMP

A research platform has been established to study the neutron field in spallation process for ADS. Several test experiments have been carried out to determine the neutron flux and spectrum of a typical 238Pu-Be source. The neutron intensity was measured by the water-bath gold method, and the neutron spectrum was obtained by the TOF method coupled with the activation analysis of Al, Au, Mn and In foils. A series experiments to measure neutron yields from thick targets will be carried out with proton beam having energy from 0.2 to 1.0 GeV in the following year.

NEP02

Zhang Yaling

Institute of Modern Physics, Chinese Academy of Sciences, China

Abstract's Title: Study on ADS Spallation Targets

The Accelerator Driven Systems(ADS) has obvious environment and source benefit, which is being getting more and more concern in China.  The spallation targets of ADS was studied using FLUKA code. Since the basic physical properties of the target material vary according to the target geometry, the effects of target geometry on the target properties were compared firstly. Then the spallation neutron yield and energy deposition were calculated with the proton bombardment of lead, bismuth and LBE targets of 1.0m length and 0.2m diameter at beam energies of 0.2, 0.4, 0.8, 1.0, 1.2, 1.4 and 1.6GeV. The simulated results were compared with the available experimental data and other model’s calculations.

NEP03

Mahmoud Pour Arsalan

The University of Tennessee, US

Abstract's Title: An improved thermodynamic model for estimating the emitted light particle source radius, and coalescence radius, in low energy heavy ion collisions

In an abrasion-ablation model of high energy heavy ion collisions the extremely hot and dense overlapping collision region expands violently, and cools off. As it cools light high energy particles are emitted from the collision region where the relative momenta of the nucleons are less than the coalescence radius in momentum space. A thermodynamic coalescence model relates the probability of the light particle emission to the source radius of the region emitting these light particles.  At high beam energies, coulomb repulsion and the binding energies of the emitted particles do not affect the thermodynamic coalescence model estimates.  However, at energies below 25 MeV/nucleon, the Coulomb repulsion and the emitted particle binding energy must be considered.  The objective of our study is to estimate the emitting source radius and from it the coalescence radius at low beam energies, 25 MeV/nucleon or less, by using an improved thermodynamic coalescence model which includes Coulomb repulsion and the emitted particle’s binding energy. Estimates of emitting source radii and coalescence radii for light energetic particles from a variety of collision pairs and incident energies are presented using the model.

NEP04

Marie Nguyen

University of Vietnam

Abstract's Title: A STUDY OF REACTION  (p, n) on  HEAVY TARGETS FOR DESIGNING THE ACCELERATOR DRIVEN SYSTEM

Since the early 1990’s, Accelerator Driven System (ADS) – subcritical assemblies driven by high power proton accelerators through a spallation target – have been proposed by Carlo Rubbia et al. The greatest difference between ADS and the conventional reactor is that ADS not only produces no waste but also destroys radioative waste that is accumulated in nuclear industry.  As a sub-critical assembly, ADS can eliminate nuclear accidents that occurred in many countries  such as Three Mile Island (1979), the Chernobyl disaster (1986), Fukushima nuclear accidents (2011) ADS is controlled and activated by neutrons generated in the target by the (p, n) reaction. So, the study of (p, n) reaction on the heavy different targets with the different bombarding energy ranges of proton is important and necessary for the design and development of ADS.  Our work is a systematic study of (p, n) reaction on the heavy targets such as 204Pb, 206Pb, 207Pb, 208Pb, 180W, 182W, 184W, 186W, 235U, 238U, 197Au with the proton bombardment energy ranges from 0.5 to 1.5 GeV with 0.1 GeV energy step [1], [2], [3], [4].  The obtained result is a set of data about the number of neutrons generated, energy and angular distribution of neutrons in the (p, n) reaction and other parameters.  To calculate, a model with the screening effect (the screening effect model) has been built and developed [2].  Using this model allows to reduce amount of computing while improving the accuracy of the calculations.

References:

[1]. Nguyen Thi Ai Thu, Nguyen Mong Giao, Huynh Thi Xuan Tham (2010) “Studying angular distribution of neutron for (p, n) reaction from 0.5 GeV to 1.5 GeV on some heavy targets 238U, 206Pb, 197Au, 186W”

-  IAEA - ICTP- IC/2010/064-Trieste- Italy-2010, pp.1-12 ;

- International Symposium on Nuclear Symmetry Energy (NuSYM10) – RIKEN Nishina Center, Japan, July 26-28, 2010.

[2]. Nguyen Mong Giao, Le Thi Thanh Truc, Nguyen Thi Ai Thu (2010), “Screening effect in (p, n) reactions on heavy element targets 206Pb, 238U, 184W, 197Au”, ICTP – IC/2010/057–Trieste- Italy-2010, pp.1-12.

[3]. Nguyen Mong Giao, Chau Van Tao, Nguyen Thi Ai Thu, Tran Thanh Dung (2010), “A study of neutron production in proton reactions with heavy targets”,

- The 8th National Conference on Nuclear Science and Technology, NhaTrang  20-22, November 2009.

- Nuclear Science and Technology-ISSN 1810-5408, No 2,(2009), p. 42-49.

-  ICTP – IC/2010/056, - Trieste-Italy-2010, pp.1-7.

[4]. Nguyen Thi Ai Thu (2010) “ Angular distribution of neutrons from (p, n) reactions on heavy element targets   with screening effect” Proceedings of Topical Conference on Nuclear Physics , High Energy and Astrophysics organized by Vietnam Physical Society, Vietnam Nuclear Society and Vietnam Astronomical Society at Hanoi University of Technology and Science, Hanoi  9-11, November 2010, pp.116-120.

NEP05

Paresh Prajapati

Phisics Department, Faculty of Science, The M.S. University of Baroda, Vadodara-390002, India

Abstract's Title: Mass distribution in the fast neutron induced fission of 232-Th

The yield of fission products are needed for decay heat calcluations, which are necessary for the design of Accelerator Driven Subcritical system (ADS).Further, the yields of fission products are also needed for mass and charge distribution studies. In view of this, the yields of various fission products in the fast neutron-induced fission of 232-Th were determined using a recoil catcher and off-line gamma-ray spectrometric technique. The quass-monoenergetic neutrons (En=5.9, 9.85 and 15.5 MeV) were produced using 7-Li(p,n) reaction at BARC-TIFR, Pelletron facility at Mumbai. From the yield data, mass yield distributions were obtained using charge distribution corrections. The present measured data were compared with literature data on different fast neutron-induced and mono-energetic neutron induced-fissions of 232-Th to examine the role of excitation energy.

New Facilities and Detectors

NFD01

J.J. Das a, H. K. Carter a, J. R. Beene b, B. M. Sherrill c

a UNIRIB, ORISE, Oak Ridge, TN 37830

b ORNL, Oak Ridge, Tn 37830

c NSCL, Michigan State University, East Lansing, MI 48824

Abstract's Title:  He Jet Ion Source in FRIB era

The He Jet ion source with the invention of  'side-jet' by Chalk River Laboratories has some unique capabilities as an Isotope Separator On Line (ISOL) technique. One key feature was a fixed holdup time independent of elements. This means, for example, the ability to transport refractory elements from target to the ionization region enabling beams of essentially all elements.  A cell filled with He at high pressure, stopped the reaction products and injected them into a capillary (~ 2 mm dia. X up to 100’s of feet long) which transported them to a separate ion source.  As the reaction products did not touch the walls this allowed even refractory elements to be transported without permanently adhering to the walls.  In the 1990’s this technique was replaced by ion guide techniques, such as the Ion guide Isotope Separator On Line (IGISOL).  The basic idea is a single gas filled cell that serves both to stop  recoiling nuclei and to maintain a large fraction of them in a single (1+) charge state by using ultra pure helium gas.  A primary difference between the two techniques is that the stopping region cell and the ionization region (cell) in the He Jet technique are separated by a capillary. We point out two applications where this separation of cells is critically important.  For high beam rates entering the stopping cell the ionization efficiency is dependent on the intensity of the incident beam.  For example, at FRIB where the intensity of secondary beams incident on the stopping cell will, in many cases exceed 109 /s, it will be important to have a source of ions whose efficiency does not decrease significantly with beam intensity.  Another possible new application is multiuser capabilities.  This  will allow a second beam species not used by the primary experiment to enter the stopping cell and be transported to a secondary experimental station. Specific applications will be described.

EOS of Neutron-Rich Nuclear Matter, Clusters in Nuclei and Nuclear Reactions

EOSP01

Justin Mabiala

Texas A&M University Cyclotron Institute, United States of America

Abstract’s Title: Towards the Liquid-Gas Phase Transition: Experimental aspects

The critical phenomenon of the nuclear liquid-gas phase transition has been investigated in the reactions 64Zn+64Zn, 64Ni+64Ni and 70Zn+70Zn at beam energy of 35 MeV/nucleon.  Yields of fragments arising from fragmenting quasiprojectiles (QPs) with different isospin asymmetry were analyzed within the framework of the Landau free energy approach.  Fits to the free energy of fragments showed three minima indicating the system to be in a regime of a first order phase transition. The QP temperature estimates were extracted from the analysis of N=Z fragment data.  Furthermore, temperatures and densities for the QPs were derived from a recent quantum method which is based on fluctuations in the fragment momentum and fragment multiplicity distributions of light fermions.  These results which account for an experimental signature of a nuclear phase transition will be presented.

EOSP02

Simin Wang

State Key Laboratory of Nuclear Physics and Technology/School of Physics/Peking University, China

Abstract's Title: Clustering around Double Shell Closures with a Local Potential

Using a local cluster potential, cluster structures around double shell closures have been studied. Calculations in energy spectra including corresponding electromagnetic transitions are in good agreement with experimental data. Besides Ne-20, Ti-44, Zn-60 and Po-212, which have been widely analyzed by cluster models, we have also found two other good candidates, Ti-52 and Te-136, for alpha-cluster structure in neutron-rich regions. Our results support the existence of He-6 cluster and the subshell N = 32 above doubly magic nucleus Ca-48. Moreover, the study of Te-136 indicates that the observed unexpectedly small B(E2) from 2+ to 0+ states is caused by cluster motion. By using a macroscopic 3-body cluster model, low-lying states in Mg-24 have been well reproduced in a doubly magic core+2alpha decomposition with the same local potential, demonstrating such cluster configuration

EOSP03

Andrew Raphelt

Texas A&M University, United States

Abstract's Title: Effects of Excitation Energy on the Symmetry Energy

The symmetry energy of nuclear matter has been shown to decrease with the increasing of excitation energy of fragments produced in a reaction.  This has been shown for several experimental data sets, but a more complete study of the change across a wide range of values could provide a more conclusive result.  Simulations of reactions at intermediate energies can be used to see this effect and have been studied using both a dynamical model, Constrained Molecular Dynamics (CoMD), and a dynamical model followed by a statistical model used for de-excitation, Deep-Inelastic Transfer followed by the Statistical Multifragmentation Model (DIT/SMM).  Analysis was performed using a yield ratio method called isoscaling, and from this method, a term for the symmetry energy can be found.  This term is shown to vary with changing excitation energy of the fragments from the reaction, showing the dependence of the symmetry energy on the excitation energy.

EOSP04

Paul Cammarata

Texas A&M Cyclotron Institute, USA

Abstract's Title: PLF Decay Channels as an Experimental Probe using Time of Flight Measurements

Heavy Ion Collisions play an important role by providing a unique tool to probe nuclear interactions away from saturation.  Lower energies (~10-15A MeV) provide a means of probing around and below normal nuclear density.  In particular, these collisions can provide a sensitive means of probing the isovector part of the interaction, and therefore, the symmetry terms of the nuclear Equation of State (EoS).  Simulations of 124, 112Sn +64,58Ni using CoMD and SMF calculations, at three different symmetry energies, have been used to study the symmetry energy dependence of projectile like fragment  (PLF) fragmentation channels as well as the mass and velocity correlations of the neck fragment and subsequent PLF decay.  The results will be presented with respect to their use as a probe the possibility of experimentally measuring the density dependence of the symmetry energy using picosecond time resolution Time of Flight spectroscopy in a multi-detector array.

EOSP05

Lauren Heilborn

Texas A&M University, United States

Abstract's Title: Particle-particle correlation functions as an experimental probe of the nuclear symmetry energy

Correlation functions caused by interactions between the wavefunctions of individual nucleons have long been known to give spatial and temporal information about the excited sources from which they were emitted. Theoretical predictions have suggested that the contribution of the symmetry potential to the behavior of nucleon-nucleon interactions may be large enough that neutron-neutron, proton-proton, and neutron-proton correlation functions may all be sensitive to the symmetry energy in the nuclear equation-of-state. Constrained Molecular Dynamics (CoMD) simulations of neutron-rich and neutron-poor calcium on nickel systems have been run using two different equations-of-state with different density dependencies of the symmetry energy to investigate the possibility of experimentally probing the symmetry energy dependence of these correlation functions using detectors with high angular resolution. The results of this investigation will be presented.

EOSP06

Larry May

Cyclotron Institute, Texas A&M University, US

Abstract's Title: Equation of State effects on Nucleon Transport

Previous studies have examined the nucleon transport in charge symmetric beam-on-target reaction systems as a probe for the symmetry energy of nuclear matter. Using the iBUU transport model, isospin transport in charge symmetric as well as mass symmetric systems of Zn and Ni isotopes at 35 MeV/nucleon will be explored. Comparisons of the behavior of charge symmetric (70,64Zn + 70,64Zn) to mass symmetric (64Zn,64Ni + 64Zn,64Ni) reaction systems will be studied. The effect of different equations of state will also be studied. This set of reaction systems will be used to determine what effect the difference in charge between projectile and target may have on the proton transport as compared to the neutron transport. These studies will be carried out with a view for use in the analysis of experimental data acquired using the NIMROD-ISiS array and TAMU Neutron Ball at the Cyclotron Institute at Texas A&M.

EOSP07

A. Zarrella, S. Wuenschel, Z. Kohley, P. Marini, S.J. Yennello

Cyclotron Institute, Texas A & M University, USA,

Abstract's Title: Neutron Detection Efficiency of the Neutron Ion Multidetector for Reaction Oriented Dynamics (NIMROD) Detection System

The NIMROD detection system has been used extensively to study nuclear reactions at the Cyclotron Institute located at Texas A&M University. A well understood neutron multiplicity is important for event characterization in heavy ion collisions as it can help determine impact parameters and product composition.  In order to obtain a reasonable neutron multiplicity, though, it is necessary to understand the efficiency of neutron detection.  This efficiency varies with the energy of the neutrons and, in NIMROD, with the angle at which the neutron is emitted.  A GEANT filter was built to account for these energy and geometry parameters.  In order to take neutrons into account on an event by event basis, the neutron efficiency must be known for different sources. A variety of medium mass system reactions at 35 MeV/nucleon have been simulated with the Heavy Ion Phase Space Exploration (HIPSE) code and have been analyzed using the NIMROD filter.  These analysis codes are designed to simulate actual geometric and dynamic acceptances of the NIMROD apparatus.  Initial results of the project show that the detector is between ~68% to ~81% efficient depending on the reaction system and the neutron source.

EOSP08

T. R. Routray , S. K. Tripathy, B. Behera
School of Physics, Sambalpur University, Sambalpur – 768019,
Orissa, India

Abstract’s Title: Neutron-proton effective mass splitting and thermal
evolution in neutron rich matter

The thermal evolution of properties of neutron rich asymmetric nuclear matter such as entropy density, internal energy density, free energy density and pressure are studied in the non-relativistic mean field theory using finite range effective interactions. In this framework the thermal evolution of nuclear matter properties is directly connected to the neutron and proton effective mass properties. Depending on the magnitude of neutron-proton effective mass splittings, two distinct behaviours in the thermal evolution of nuclear matter properties are noticed.

EOSP09

Anupriya Jain

Thapar University, Patiala, India

Abstract's Title: Consequence of isospin dependent cross section and charge asymmetry on anisotropic flow

Using the isospin dependent quantum molecular dynamics model, we study the effect of charge asymmetry and isospin dependent cross-section on different aspects of anisotropic flow (v1, v2, v3 and v4). Simulations have been carried out for the reactions of 124Xm+124Xm, where m = (47, 50, 53, 56 and 59) and 40Yn+40Yn, where n = (14, 16, 18, 20 and 23). A systematic effort has been made to pin down the anisotropic flow scaling along with the isospin-dependent cross section and charge asymmetry in heavy ion collisions. Our study shows that anisotropic flow depends strongly on the isospin of cross-section.

Nuclear Reactions and Structure of Unstable Nuclei

RSP01

M. Mazzocco, N. Fierro, L. Acosta, T. Glodariu, A. Guglielmetti, M. La Commara, I. Martel, C. Mazzocchi, P. Molini, A. Pakou, C. Parascandolo, N. Patronis, V.V. Parker, D. Pierroutsakou, M. Romoli, A.M. Sanchez-Benitez, M. Sandoli, C. Signorini, R. Silvestri, F. Soramel, E. Stiliaris, E. Strano, L. Stroe, D. Torresi, E. Vardaci, K. Zerva

Abstract's Title: Elastic Scattering for the System 7Be + 58Ni at 23.2 MeV Beam Energy

The reaction dynamics for system 7Be + 58Ni was studied at 23.2 MeV secondary beam energy.  The weakly bound Radioactive Ion Beam 7Be (Sa = 1.586 MeV) was produced for the first time by impinging a high intensity (100 pnA) 7Li primary beam at 32.4 MeV on a H-filled cryogenic gas target.  The 7Be was then selected from other contaminant species and focused on a 1-mg/cm2 thick 58Ni target by means of the facility EXOTIC [1] at the Laboratori Nazionali di Legnaro (LNL, Italy).  A secondary beam intensity of about 3*105 pps was achieved.   Charge reaction products were detected by means of 4 Delta (40 um) - E (1000 um) silicon telescopes of the detector array DINEX [2].  7Be has a large probability to break into two stable well-bound charged fragments with similar masses, 3He and 4He, in the proximity of a strong Coulomb or nuclear field.  This feature makes the 7Be breakup channel the cleanest breakup case that can be studied among all light weakly bound nuclei.  So far we evaluated the 7Be elastic scattering angular distribution and a reaction cross section of 491 ± 31 mb was evaluated with the coupled-channel code FRESCO [3].  This value is in agreement with earlier measurements performed at lower secondary beam energies [4].

References

[1] F. Farinon et al., Nucl. Instrum. Meth. B 266, 4097 (2008).

[2] A. M. Sanchez-Benitez et al., J. Phys. G : Nucl. Part. Phys. 31, S1953 (2005).

[3] I. J. Thompson, I. J. Thompson, Comput. Phys. Rep. 2, 167 (1998).

[4] E. F. Aguilera et al., Phys. Rev. C 79, 021601(R) (2009).

RSP02

Jian Ling Lou

Peking University, China

Abstract's Title: Probing the Ground State of 8He via 8He(p,d)7He and 8He(p,t)6He reactions

A recoil proton tagged knockout reaction for 8He was performed in 2009 by Peking University Nuclear Physics experimental team [1]. The 8He beam at 82.3 A MeV with intensity of 3*10^5 pps and purity of 56% was provided by RIPs beam line in RIKEN, Japan. The differential cross sections for reactions 8He(p, d)7He g.s,  8He(p, d)7He excited ,  8He(p,t)6He2+ were measured in a wide angular range from 15 degree to 130 degree in c.m system. The cross section of 8He(p,t)6Heg.s reaction was extremely lower than 8He(p,t)6He2+ reaction, and was hardly obtained via the present data . The experimental results were compared to the primary theoretical calculations with the code FRESCO. The primary results show that the configuration of (1p3/2)2(1p1/2)2 may have some probability in the ground state wave function of 8He.

[1] Z.Cao, Y.Ye et al, Physics Letters B, In Press, doi:10.1016/j.physletb.2011.12.009

Nuclear Astrophysics and Equation of State of Nuclear Matter

NAP01

E. Simmons,1 L. Trache,1 A. Banu1*, M. McCleskey,1 B. Roeder,1 A. Spiridon,1 R.E. Tribble,1 T. Davinson,2 P. J. Woods,2 G. J. Lotay,2 J. Wallace,2 D. Doherty,2 and A. Saastamoinen3

1Cyclotron Institute, Texas A &M University, Texas, United Stated.

2School of Physics, University of Edinburgh, Edinburgh, United Kingdom

3Department of Physics, University of Jyvaskyla, Finland

Abstract’s Title: The Beta-Delayed Proton and Gamma Decay of 27P For Nuclear Astrophysics

The creation site of 26Al is still under debate. It is thought to be produced in hydrogen burning and in explosive helium burning in novae and supernovae, and possibly also in the H-burning in outer shells of red giant stars. Also, the reactions for its creation or destruction are not completely known. When 26Al is created in novae, the reaction chain is: 24Mg(p,γ)25Al(β+v)25Mg(p,γ)26Al, but this chain can be by-passed by another chain: 25Al(p,γ)26Si(p,γ)27P and it can also be destroyed directly. The reaction 26mAl(p,γ)27Si* is another avenue to bypass the production of 26Al and it is dominated by resonant capture. We find and study these resonances by an indirect method, through the β-decay of 27P. A clean and abundant source of 27P was for the first time produced and separated with MARS. A new implantation-decay station which allows increased efficiency for low energy protons and for high-energy gamma-rays was used. We measured gamma-rays and β-delayed protons emitted from states above the proton threshold in the daughter nucleus 27Si to identify and characterize the resonances. The lifetime of 27P was also measured with accuracy under 2%.

NAP02

A. Spiridon1, L. Trache1, E. Simmons1, M. McCleskey1, B.T. Roeder1, R.E. Tribble1, E. Pollacco2 , G. Pascovici3

1 Cyclotron Institute, Texas A&M University, College Station, TX 77843-3366, USA
2 CEA/IRFU Saclay, Gif-sur-Yvette, France
3 IKP, Universitaet zu Koeln, Germany

Cyclotron Institute - Texas A&M University

Abstract’s Title: A new detection system for very low-energy protons from β-delayed p-decay

The study of β-delayed p-decay has been one of the focuses of the nuclear astrophysics group at the Cyclotron Institute, Texas A&M University. We have been using this particular indirect method to find and determine the properties of resonances dominating proton capture on proton-rich sd-shell nuclei, which in turn help determine the rates of important reactions for H-burning in the stars. The experimental procedure involves separating short-lived proton-rich radioactive nuclei, implanting them in a proton detector and measuring their gamma- and proton-decay. In the past we have used Si detectors to successfully detect protons with energies as low as ~2-400 keV, but with a large background from positrons.
In an effort to lower the beta background and improve the resolution at low-energies, we have recently developed a gas based detection system in collaboration with people from CEA Saclay and IKP Koln, called AstroBox. The detector was tested using the β-delayed proton-emitter
23Al previously studied well with the Si set-up. The detector and the experimental procedure will be described.  The results showed a significantly reduced beta background. There is no background down to about 100 keV, the low energy (206 keV, 267 keV) proton peaks were positively identified, well separated and the resolution was improved. States with β-branchings as low as 0.03% were observed, and we are seeking the presence of the proton-decay branch of the IAS.  With the success of this test experiment, the next step is to further improve the detection system and perform a more in-depth test.

NAP03

Neha Gupta

Indian Institute of Technology Roorkee, India

Abstract’s Title: Antikaons in neutron stars studied with extended relativistic mean-field models

We discuss the role of higher order couplings in conjunction with antikaon condensation using recent versions of relativistic mean field models. We focus on an interaction (G2) in which all parameters are obtained by fitting finite nuclear data and successfully applied to reproduce variety of nuclear properties. Our results show that the higher order couplings play a significant role at higher densities where antikaons dominate the behavior of equation of state. We compare our results with other interactions (NLl, NL3, G1 and FSUGold) and show that the new couplings bring down the mass of neutron star (NS), which is further reduced in the presence of antikaons to yield results consistent with present observational constraints. We show that the composition of NS vary with the parameter sets.

NAP04

Joshua Hooker

Texas A&M University - Commerce

Abstract’s Title: Moment of Inertia of the Inner Crust 'Napkin Ring'

Glitches in pulsars are occasional, sudden increases in their rotation frequency as the pulsar otherwise steadily spins down.  A broad class of glitch models suppose the sudden spin-ups are due to angular momentum transfer between some of the crustal superfluid neutrons and the rigid crust plus anything that couples to it on timescales shorter than the pulsar period. Using a set of neutron star equations of state which span the experimentally constrained range of asymmetric nuclear matter properties, we calculate the moment of inertia of crustal superfluid neutrons for slowly rotating neutron stars, which is related to the glitch size in such models. We restrict the calculation to just those superfluid neutrons that form strongly pinned vortices in the crust, which corresponds to a `napkin ring' shaped annulus of the crust, and compare the resultant estimates of glitch sizes with observations. We explore the effect of the coupling of the crust neutrons to core components of the star on the glitch size.