Multiphonon and ``hot''-phonon Isovector Electric-Dipole Excitations

We argue that a substantial increase in the cross section for Coulomb excitation in the region of the Double Giant Dipole Resonance should be expected from Coulomb excitation of excited states involved in the spreading of the one-phonon resonance, in a manifestation of the Brink-Axel phenomenon. This generates an additional fluctuating amplitude and a corresponding new term to be added incoherently to the usual cross-section. The appropriate extension of an applicable reaction calculation is considered in order to estimate this effect.Comment: 6 pages, Latex, 1 figure available on reques

Response of Multi-strip Multi-gap Resistive Plate Chamber

A prototype of Multi-strip Multi-gap Resistive Plate chamber (MMRPC) with active area 40 cm $\times$ 20 cm has been developed at SINP, Kolkata. Detailed response of the developed detector was studied with the pulsed electron beam from ELBE at Helmholtz-Zentrum Dresden-Rossendorf. In this report the response of SINP developed MMRPC with different controlling parameters is described in details. The obtained time resolution ($\sigma_t$) of the detector after slew correction was 91.5$\pm$3 ps. Position resolution measured along ($\sigma_x$) and across ($\sigma_y$) the strip was 2.8$\pm$0.6 cm and 0.58 cm, respectively. The measured absolute efficiency of the detector for minimum ionizing particle like electron was 95.8$\pm$1.3 $\%$. Better timing resolution of the detector can be achieved by restricting the events to a single strip. The response of the detector was mainly in avalanche mode but a few percentage of streamer mode response was also observed. A comparison of the response of these two modes with trigger rate was studiedComment: 19 pages, 26 figure

Double Giant Dipole Resonance in ^{208}Pb

Double-dipole excitations in ^{208}Pb are analyzed within a microscopic model explicitly treating 2p2h-excitations. Collective states built from such 2p2h-excitations are shown to appear at about twice the energy of the isovector giant dipole resonance, in agreement with the experimental findings. The calculated cross section for Coulomb excitation at relativistic energies cannot explain simultaneously the measured single-dipole and double-dipole cross sections, however.Comment: 7 pages, Latex, 5 postscript figure

Greek Thrace Xoraxane Romane

Romani is an Indo-Aryan language spoken in several European countries as well as in the Americas, Asia and Australia, showing substantial dialectal variation. This illustration deals with Xoraxane Romane (Turkish Romani) spoken in Greek Thrace. Xoraxane Romane, which belongs to the Vlax branch of Romani, has been heavily influenced by contact with Turkish and also shows influences from Greek. As a result, Xoraxane Romane exhibits a mixed system that includes phonemes borrowed from both Turkish and Greek but without exhibiting complex phonological phenomena such as Turkish vowel harmony

Use of high temperature heat pump technology for efficient drying of cathodes for Li-ion batteries

The demand for lithium-ion batteries (LIBs) is increasing fast. Therefore, the decrease of energy consumption in the battery manufacturing is crucial for reducing the green house gas (GHG) emissions. The drying process of battery electrodes account for up to 46.8 % of the total energy consumption during production. Norway plans to prohibit the use of fossil fuels for energy purposes in industry in 2030. In this thesis, the use of heat pump technique for providing the thermal energy for the drying of the cathodes and the subsequently necessary condensation of N-Methyl-2-Pyrrolidone (NMP) is investigated. Four different implementation schemes have been studied comprising different heat pump cycles for both heating and cooling of the drying air, a CO2-transcritical system, an ammonia-water absorption-compression heat pump (ACHP) system, one system with one heat pump using mixtures of low GWP working fluids and one using two separate heat pumps for the heating and cooling. In the last case the high temperature (HT) heat pump for the heating process uses mixtures of low GWP working fluids and the low temperature (LT) heat pumps working fluid is a low GWP fluid. The results of this work indicate that not all proposed solutions are feasible. A CO2-transcritical and an ACHP system can not provide efficient drying of cathodes. The one heat pump system solution using mixtures and the two separate heat pump system solution can provide efficient drying of cathodes. The two separate heat pump system solution demonstrates superior performance while reducing the required energy consumption for the heating and cooling of the dryer air by 91 % compared to the reference case. The one heat pump system solution shows a possible reduction of the required energy for heating and cooling of 79 %. In both cases surplus heat is generated and can be used for various purposes such as heating, steam production or serving as a heat source for another high temperature heat pump (HTHP

The resonance triplet at E_alpha = 4.5 MeV in the 40Ca(alpha,gamma)44Ti reaction

The 40Ca(alpha,gamma)44Ti reaction is believed to be the main production channel for the radioactive nuclide 44Ti in core-collapse supernovae. Radiation from decaying 44Ti has been observed so far for two supernova remnants, and a precise knowledge of the 44Ti production rate may help improve supernova models. The 40Ca(alpha,gamma)44Ti astrophysical reaction rate is determined by a number of narrow resonances. Here, the resonance triplet at E_alpha = 4497, 4510, and 4523 keV is studied both by activation, using an underground laboratory for the gamma counting, and by in-beam gamma spectrometry. The target properties are determined by elastic recoil detection analysis and by nuclear reactions. The strengths of the three resonances are determined to omega gamma = (0.92+-0.20), (6.2+-0.5), and (1.32+-0.24) eV, respectively, a factor of two more precise than before. The strengths of this resonance triplet may be used in future works as a point of reference. In addition, the present new data directly affect the astrophysical reaction rate at relatively high temperatures, above 3.5 GK.Comment: 12 pages, 11 figures; submitted to Phys. Rev.

Fragmentation of exotic oxygen isotopes

Abrasion-ablation models and the empirical EPAX parametrization of projectile fragmentation are described. Their cross section predictions are compared to recent data of the fragmentation of secondary beams of neutron-rich, unstable 19,20,21O isotopes at beam energies near 600 MeV/nucleon as well as data for stable 17,18O beams

Anharmonicities of giant dipole excitations

The role of anharmonic effects on the excitation of the double giant dipole resonance is investigated in a simple macroscopic model.Perturbation theory is used to find energies and wave functions of the anharmonic ascillator.The cross sections for the electromagnetic excitation of the one- and two-phonon giant dipole resonances in energetic heavy-ion collisions are then evaluated through a semiclassical coupled-channel calculation.It is argued that the variations of the strength of the anharmonic potential should be combined with appropriate changes in the oscillator frequency,in order to keep the giant dipole resonance energy consistent with the experimental value.When this is taken into account,the effects of anharmonicities on the double giant dipole resonance excitation probabilities are small and cannot account for the well-known discrepancy between theory and experiment

Efficiency determination of resistive plate chambers for fast quasi-monoenergetic neutrons

Composite detectors made of stainless steel converters and multigap resistive plate chambers have been irradiated with quasi-monoenergetic neutrons with a peak energy of 175MeV. The neutron detection efficiency has been determined using two different methods. The data are in agreement with the output of Monte Carlo simulations. The simulations are then extended to study the response of a hypothetical array made of these detectors to energetic neutrons from a radioactive ion beam experiment.Comment: Submitted to Eur.Phys.J. A; upgraded version correcting some typos and updating ref.