Mass Parameterizations and Predictions of Isotopic Observables

We discuss the accuracy of mass models for extrapolating to very asymmetric nuclei and the impact of such extrapolations on the predictions of isotopic observables in multifragmentation. We obtain improved mass predictions by incorporating measured masses and extrapolating to unmeasured masses with a mass formula that includes surface symmetry and Coulomb terms. We find that using accurate masses has a significant impact on the predicted isotopic observables.Comment: 12 pages, 4 figure

Comparisons of Statistical Multifragmentation and Evaporation Models for Heavy Ion Collisions

The results from ten statistical multifragmentation models have been compared with each other using selected experimental observables. Even though details in any single observable may differ, the general trends among models are similar. Thus these models and similar ones are very good in providing important physics insights especially for general properties of the primary fragments and the multifragmentation process. Mean values and ratios of observables are also less sensitive to individual differences in the models. In addition to multifragmentation models, we have compared results from five commonly used evaporation codes. The fluctuations in isotope yield ratios are found to be a good indicator to evaluate the sequential decay implementation in the code. The systems and the observables studied here can be used as benchmarks for the development of statistical multifragmentation models and evaporation codes.Comment: To appear on Euorpean Physics Journal A as part of the Topical Volume "Dynamics and Thermodynamics with Nuclear Degrees of Freedo

Isospin Effects in Nuclear Multifragmentation

We develop an improved Statistical Multifragmentation Model that provides the capability to calculate calorimetric and isotopic observables with precision. With this new model we examine the influence of nuclear isospin on the fragment elemental and isotopic distributions. We show that the proposed improvements on the model are essential for studying isospin effects in nuclear multifragmentation. In particular, these calculations show that accurate comparisons to experimental data require that the nuclear masses, free energies and secondary decay must be handled with higher precision than many current models accord.Comment: 46 pages, 16 figure

2008-2009 President\u27s Report

The Linfield College President\u27s Annual Report is a collection of information about the year in review, including academics, student life and athletics, enrollment, finances, philanthropy, and leadership

On noise treatment in radio measurements of cosmic ray air showers

Precise measurements of the radio emission by cosmic ray air showers require an adequate treatment of noise. Unlike to usual experiments in particle physics, where noise always adds to the signal, radio noise can in principle decrease or increase the signal if it interferes by chance destructively or constructively. Consequently, noise cannot simply be subtracted from the signal, and its influence on amplitude and time measurement of radio pulses must be studied with care. First, noise has to be determined consistently with the definition of the radio signal which typically is the maximum field strength of the radio pulse. Second, the average impact of noise on radio pulse measurements at individual antennas is studied for LOPES. It is shown that a correct treatment of noise is especially important at low signal-to-noise ratios: noise can be the dominant source of uncertainty for pulse height and time measurements, and it can systematically flatten the slope of lateral distributions. The presented method can also be transfered to other experiments in radio and acoustic detection of cosmic rays and neutrinos.Comment: 4 pages, 6 figures, submitted to NIM A, Proceedings of ARENA 2010, Nantes, Franc

The LOPES experiment - recent results, status and perspectives

The LOPES experiment at the Karlsruhe Institute of Technology has been taking radio data in the frequency range from 40 to 80 MHz in coincidence with the KASCADE-Grande air shower detector since 2003. Various experimental configurations have been employed to study aspects such as the energy scaling, geomagnetic dependence, lateral distribution, and polarization of the radio emission from cosmic rays. The high quality per-event air shower information provided by KASCADE-Grande has been the key to many of these studies and has even allowed us to perform detailed per-event comparisons with simulations of the radio emission. In this article, we give an overview of results obtained by LOPES, and present the status and perspectives of the ever-evolving experiment.Comment: Proceedings of the ARENA2010 conference, Nantes, Franc

Investigation of the Properties of Galactic Cosmic Rays with the KASCADE-Grande Experiment

The properties of galactic cosmic rays are investigated with the KASCADE-Grande experiment in the energy range between $10^{14}$ and $10^{18}$ eV. Recent results are discussed. They concern mainly the all-particle energy spectrum and the elemental composition of cosmic rays.Comment: Proc. RICAP 09, Nucl. Instr. and Meth. in pres

The spectrum of high-energy cosmic rays measured with KASCADE-Grande

The energy spectrum of cosmic rays between 10**16 eV and 10**18 eV, derived from measurements of the shower size (total number of charged particles) and the total muon number of extensive air showers by the KASCADE-Grande experiment, is described. The resulting all-particle energy spectrum exhibits strong hints for a hardening of the spectrum at approximately 2x10**16 eV and a significant steepening at c. 8x10**16 eV. These observations challenge the view that the spectrum is a single power law between knee and ankle. Possible scenarios generating such features are discussed in terms of astrophysical processes that may explain the transition region from galactic to extragalactic origin of cosmic rays.Comment: accepted by Astroparticle Physics June 201

Air Shower Measurements with the LOPES Radio Antenna Array

LOPES is set up at the location of the KASCADE-Grande extensive air shower experiment in Karlsruhe, Germany and aims to measure and investigate radio pulses from Extensive Air Showers. Since radio waves suffer very little attenuation, radio measurements allow the detection of very distant or highly inclined showers. These waves can be recorded day and night, and provide a bolometric measure of the leptonic shower component. LOPES is designed as a digital radio interferometer using high bandwidths and fast data processing and profits from the reconstructed air shower observables of KASCADE-Grande. The LOPES antennas are absolutely amplitude calibrated allowing to reconstruct the electric field strength which can be compared with predictions from detailed Monte Carlo simulations. We report about the analysis of correlations present in the radio signals measured by the LOPES 30 antenna array. Additionally, LOPES operates antennas of a different type (LOPES-STAR) which are optimized for an application at the Pierre Auger Observatory. Status, recent results of the data analysis and further perspectives of LOPES and the possible large scale application of this new detection technique are discussed.Comment: 8 pages, 10 figures, Contribution to the Arena 2008 conference, Rome, June 200

Os sistemas agroflorestais como alternativa de sustentabilidade em ecossistemas de várzea no Amazonas.

Os sistemas agroflorestais (SAFs) representam uma alternativa agroecológica de produção, sob regime sustentável, para os agricultores familiares na várzea dos Rios Solimões/Amazonas, principalmente no que se refere ao manejo florestal, à diversidade de produtos e à geração de renda. Diante disso, o objetivo deste trabalho foi compreender as diferentes formas de apropriação e de manejo dos recursos naturais através dos SAFs, nos subsistemas roça, sítio e lagos, como componente para a sustentabilidade dos agricultores familiares da localidade Costa da Terra Nova, município do Careiro da Várzea, Amazonas. O método empregado foi o Estudo de Caso com aplicação de questionários, entrevistas e observação participante. A produção familiar na Costa da Terra Nova é representada pelos SAFs, constituído pelos os subsistemas: roça quintal e lago, que proporcionam produtos tanto para subsistência quanto para comercialização local, e estabelecendo a agricultura como fundamental atividade na localidade. O principal produto para comercialização é obtido das hortaliças cultivadas na época da vazante no subsistema roça nas comunidades São Francisco e Nossa Senhora da Conceição; e do extrativismo pesqueiro no subsistema lago, na época da cheia, principalmente na comunidade São José. A criação de animal se dá no subsistema sítio e é apenas para subsistência, sendo as aves e os suínos os principais animais domésticos criados nas três comunidades. Portanto os SAFs tradicionais, constituídos pelos subsistemas, roça, sitio e lago, são responsáveis pela sustentabilidade socioeconômica da localidade pesquisada, servindo, como alternativa agrícola melhor adaptada às condições locais das áreas de várzea na Amazônia