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The Partial Truncated Icosahedron (ParTI) phoswich array has been designed for the detection of low energy charged pions and other light charged particles for the study of pionic fusion reactions. The array consists of 15 plastic/CsI(Tl) phoswich detector units arranged in approximately one hemisphere of a truncated icosahedron geometry. The phoswich detectors’ particle identification capabilities have been characterized. A pulse shape discrimination technique has demonstrated isotopic identification for Z = 1 and Z = 2 particles and elemental identification up to at least Z = 3. Utilization of digital electronics allows for increased sensitivity in event triggering and independent verification of pion detection. A calibration technique for the array has also been developed.

The traditional isoscaling technique has been used to analyze all isotopically identified particles from 70 Zn+ 70 Zn and 64 Zn+ 64 Zn collisions at 35 MeV/u. Two additional techniques, using an energy-averaged ratio and using the data present in the tail of energy spectra, are compared to the traditional method and show similar results. Isoscaling fit parameters α and β are found both globally and for each individual series of constant Z and N . The data are then split up between emitted fragments and projectile-like fragments. Isoscaling values for the two different types of fragments are shown to be different, emphasizing the importance of experimentally distinguishing between projectile-like fragments and emitted fragments in order to achieve accurate isoscaling parameters.

One of the problems we are facing today is the energy consumption minimization, while maintaining the indoor thermal comfort in buildings. A potential solution to this issue is use of phase change materials (PCMs) in thermal energy storage (TES), where cold gets accumulated during the summer nights in order to reduce cooling load during the day. In winter, on the other hand, heat from solar air collector is stored for evening and morning hours when solar radiation is not available. The main objective of the paper is to examine experimentally whether it is possible to use such a storage unit for heating as well as for cooling. For this purpose 30 plates filled with paraffin (melting point around 22°C) were positioned into TES and applied with the same initial and boundary conditions as they are expected in reality. Experimental work covered flow visualization, measurements of air velocity in the channels between the plates, parametric analysis in conjunction with TES thermal response and measurements of the pressure drops. The results indicate that this type of storage technology could be advantageously used in real conditions. For optimized thermal behavior, only plate thickness should be reduced.

Symmetry energy, temperature and density at the time of the intermediate mass fragment formation are determined in a self-consistent manner, using the experimentally reconstructed primary hot isotope yields and anti-symmetrized molecular dynamics (AMD) simulations. The yields of primary hot fragments are experimentally reconstructed for multifragmentation events in the reaction system Zn 64 + Sn 112 at 40 MeV / nucleon . Using the reconstructed hot isotope yields and an improved method, based on the modified Fisher model, symmetry energy values relative to the apparent temperature, a sym / T , are extracted. The extracted values are compared with those of the AMD simulations, extracted in the same way as those for the experiment, with the Gogny interaction with three different density-dependent symmetry energy terms. The a sym / T values change according to the density-dependent symmetry energy terms used. Using this relation, the density of the fragmenting system is extracted first. Then symmetry energy and apparent temperature are determined in a self consistent manner in the AMD model simulations. Comparing the calculated a sym / T values and those of the experimental values from the reconstructed yields, ρ / ρ 0 = 0.65 ± 0.02 , a sym = 23.1 ± 0.6 MeV and T = 5.0 ± 0.4 MeV are evaluated for the fragmenting system experimentally observed in the reaction studied.

Fermi energy heavy ion collisions provide a valuable tool to research nuclear reaction dynamics and the hot nuclear matter Equation of State (EOS) at sub/supra-normal densities. In this energy regime, multi-fragmentation becomes important and the ejected light particles and intermediate mass fragments (IMFs) with Z > 2 carry a great deal of information on the thermal and chemical evolution of the reaction system under investigation. Existing detectors [1] include those with excellent isotopic resolution with limited angular coverage or excellent geometric acceptance with moderate isotopic resolution. Much information has been extracted from experiments performed with these detectors [2–9]. Ideally, a detector array with both excellent isotopic resolution and with a nearly 4π angular coverage of discrete telescopes with a high granularity is desirable. NIMROD–ISiS at the Cyclotron Institute, TAMU, is designed for such purposes and provides a powerful detector array capable of both charged particle and neut...

The neutron detection efficiency of a DEMON detector, averaged over the whole volume, was calculated using GEANT and applied to determine neutron multiplicities in an intermediate heavy ion reaction. When a neutron source is set at a distance of about 1 m from the front surface of the detector, the average efficiency, eav , is found to be significantly lower (20-30%) than the efficiency measured at the center of the detector, e0 . In the GEANT simulation the ratio R= eav / e0 was calculated as a function of neutron energy. The experimental central efficiency multiplied by R was then used to determine the average efficiency. The results were applied to a study of the 64 Zn+ 112 Sn reaction at 40 A MeV which employed 16 DEMON detectors. The neutron multiplicity was extracted using a moving source fit. The derived multiplicities are compared well with those determined using the neutron ball in the NIMROD detector array in a separate experiment. Both are in good agreement with multiplicities predicted by a transport model calculation using an antisymmetric molecular dynamics (AMD) model code. © 2013 Elsevier B.V.

A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron–proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A = 50 . The caloric curve extracted with the momentum quadrupole fluctuation thermometer shows that the temperature varies linearly with quasi-projectile asymmetry N − Z A . An increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei.

Isoscaling is derived within a recently proposed modified Fisher model where the free energy near the critical point is described by the Landau O ( m 6 ) theory. In this model m = N f − Z f A f is the order parameter, a consequence of (one of) the symmetries of the nuclear Hamiltonian. Within this framework we show that isoscaling depends mainly on this order parameter through the ‘external (conjugate) field’ H. The external field is just given by the difference in chemical potentials of the neutrons and protons of the two sources. To distinguish from previously employed isoscaling relationships, this approach is dubbed: m-scaling. We discuss the relationship between this framework and the standard isoscaling formalism and point out some substantial differences in interpretation of experimental results which might result. These should be investigated further both theoretically and experimentally.

The experimental results reveal the isospin dependence of the nuclear phase transition in terms of the Landau Free Energy description of critical phenomena. Near the critical point, different ratios of the neutron to proton concentrations lead to different critical points for the phase transition which is analogous to the phase transitions in He 4- He 3 liquid mixtures. The antisymmetrized molecular dynamics (AMD) and GEMINI models calculations were also performed and the results will be discussed as well.

A very brief summary Of Our Current research on clustering in low density matter formed in near Fermi energy heavy ion collisions is presented. At the lowest densities and temperatures large alpha mass fractions are observed. Temperature and density dependent symmetry free energies have been derived from isoscaling analyzes of the yields of nuclei with A = 4. The symmetry free energies are far above those obtained in common effective interaction calculations, reflecting cluster formation, primarily of alpha particles, not included in such calculations.

The upgraded NIMROD–ISiS 4 π detector array is described. The array is composed of 228 detector modules annularly arranged into 14 rings. Telescopes of Si–CsI and Si–Si–CsI provide excellent isotopic resolution throughout the detector array. To enhance event characterization, the entire charged particle array is housed inside the TAMU Neutron Ball.

The detector system used at the first focus of the BigSol superconducting solenoid beam line at the Texas A & M superconducting cyclotron is presented. The system is composed of a position sensitive PPAC followed by an ionization chamber (IC) with a YAP(Ce) array in its back plane. The position sensitivity of the PPAC as well the energy resolution of the IC is investigated as a function of the counting rate. Pulse height, pulse height resolution and time resolution of the YAP(Ce) crystals are studied for a variety of heavy ion beams ranging from 20 Ne to 197 Au at energies from 15 AMeV to 40 AMeV. The pulse shape discrimination method using a Flash ADC is also explored, in order to identify decay products (alpha particles and electron/gamma) from the fragments implanted in the scintillator.

We review the main results obtained by the BRAHMS collaboration on the properties of hot and dense hadronic and partonic matter produced in ultrarelativistic heavy ion collisions at RHIC. A particular focus of this paper is to discuss to what extent the results collected so far by BRAHMS, and by the other three experiments at RHIC, can be taken as evidence for the formation of a state of deconfined partonic matter, the so called quark-gluon-plasma (QGP). We also discuss evidence for a possible precursor state to the QGP, i.e. the proposed Color Glass Condensate., 32 pages, 18 figures

We present the results obtained by the BRAHMS experiment at the Relativistic Heavy Ion Collider (RHIC) for three colliding systems, namely: Au + Au , d + Au and p + p at [Formula: see text]. The main focus here is to give an overview of the main results on the reaction dynamics and on the properties of hot and high energy density matter produced in utra-relativistic heavy ion collisions. Measurement of particle production, particle spectra over a large rapidity interval as well as high pt measurements related to nuclear modification in Au + Au and d + Au collision are discussed. The observed number of charged particles produced per unit of rapidity at the central rapidity region indicates that a high energy density (> 5 GeV/fm3) system is created at the initial stage of the Au + Au reaction. From the particle spectra we deduced significant radial expansion (β ≈ 0.75) which is consistent with the large initial energy density. For Au + Au at η = 0 we observe the suppression of the high p T particles as compared to the elementary collisions, whereas for the d + Au reaction the Cronin type enhancement is observed. We also discuss to what extent these results can be taken as evidence for the quark gluon plasma (QGP). Finally, we present the nuclear modification effects in d + Au reaction as a function of rapidity and consider whether the observed suppression at forward rapidities constitutes sufficient evidence for a possible precursor state to the QGP, i.e. the Color Glass Condensate (CGC).

Recent results on limiting temperatures and caloric curves are discussed with respect to the question of identifying critical behavior in the disassembly of nuclei. We suggest that the best candidates for exploring such behavior are light nuclei in which the Coulomb Energies are less disruptive.

The BRAHMS experiment at RHIC was conceived to pursue the understanding of nuclear matter under extreme conditions by detailed measurements of charged hadrons over the widest possible range of rapidity and transverse momentum. The experiment consists of two spectrometers with complementary charged hadron detection capabilities as well as a series of global detectors for event characterization. A series of tracking detectors, time-of-flight arms and Cherenkov detectors enables momentum determination and particle identification over a wide range of rapidity and transverse momentum. Technical details and performance results are presented for the various detector subsystems. The performance of the entire system working together is shown to meet the goals of the experiment.

We report on experiments in which the Texas Petawatt laser irradiated a mixture of deuterium or deuterated methane clusters and helium-3 gas, generating three types of nuclear fusion reactions: D(d,^{3}He)n, D(d,t)p, and ^{3}He(d,p)^{4}He. We measured the yields of fusion neutrons and protons from these reactions and found them to agree with yields based on a simple cylindrical plasma model using known cross sections and measured plasma parameters. Within our measurement errors, the fusion products were isotropically distributed. Plasma temperatures, important for the cross sections, were determined by two independent methods: (1) deuterium ion time of flight and (2) utilizing the ratio of neutron yield to proton yield from D(d,^{3}He)n and ^{3}He(d,p)^{4}He reactions, respectively. This experiment produced the highest ion temperature ever achieved with laser-irradiated deuterium clusters.

The luminous response to α, β and γ rays from radioactive sources and E/A  20 MeV, 3  Z  7 heavy ions of KI(Eu) crystals was studied. Measurements include optical spectral response and Eu concentration dependence. When coupled with a transmission Si surface-barrier E detector, the light-output response L observed from an optimized KI(Eu) sample is found to provide adequate Z resolution in a ΔE vs. L plot. A comparison with the results of a similar study on KBr(Eu) and CsI(Tl) crystals is presented.

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 quasi-projectiles (QPs) with different neutron-proton asymmetries were analyzed within the framework of the Landau free energy approach. Fits to the free energy of fragments as a function of fragment asymmetry 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. Additionally, we make use of a recent method based on quantum fluctuations of fermions to derive temperatures and densities of selected QPs. Critical scaling of these observables is found for systems which differ in neutron to proton asymmetry. The derived critical exponent β = 0.35 ± 0.01, belongs to the liquid-gas universality class.

Fragment yield data, selected with different values of the isospin asymmetry of the quasiprojectile from 78, 86 Kr +58, 64 Ni reactions at E lab = 35 MeV/nucleon, have been analyzed within the framework of Landau free energy approach. Fits to the free energy data indicated the system to be in the regime of a first-order phase transition. The plot of free energy versus isospin asymmetry of the fragments showed a systematic change with increasing isospin asymmetry of the fragmenting source. This observation demonstrated the role of quasiprojectile isospin asymmetry as an external field which governed the minima positions in the free energy plot. The position of the central minimum was found to be in close agreement with the average isospin asymmetry of the fragments calculated excluding neutrons and protons. Significant deviations from the free energy plot were observed for N = Z fragments, particularly for the lighter ones, which could be corrected after inclusion of odd–even effects in the analysis. Analysis of yield data of N = Z nuclei gave a reasonable estimate of temperature. Analysis of free energy data gated with excitation energy of the fragmenting source showed a dependence of fit parameters of Landau free energy equation on the excitation energy as well as isospin asymmetry of the source.

With consideration of immunologically favorable localization, tissues from human prostatic adenomas were transplanted in the anterior ocular chamber of male guinea pigs. Not in any instance were viabl