Browsing by Author "Ertan, Erol."

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    Cross sections for neutron-deuteron elastic scattering in the energy range 135 - 250 MeV
    (Thesis (Ph.D.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2013., 2013.) Ertan, Erol.; Akdoğan, Taylan.
    New results for neutron-deuteron elastic scattering cross sections at energies from 135 to 250 MeV and center-of-mass angles from 80 to 130 have been measured at the WNR facility of the Los Alamos Neutron Science Center at the Los Alamos National Laboratory [1, 2]. The measurements were made with a pulsed neutron beam which allowed the use of time-of- ight techniques and with a cryogenic liquid deuterium and liquid hydrogen target. The neutron-proton elastic cross-section data were used for normalization purposes. An array of pure CsI crystal along with a set of thin scintillator detectors used for charged particle identi cation on one side of the beam, and a set of long horizontal plastic scintillator bars were used as a neutron detector wall on the other side of the beam. Our measurements are compared to both previous measurements and theoretical predictions at relevant energies and favors the predictions including three-nucleon forces.
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    On local inflation and cosmolagical perturbations
    (Thesis (M.S.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2007., 2007.) Ertan, Erol.; Kaya, Ali.
    It is known that a scale free spectrum of the density perturbations gives appropriate initial conditions for the structure formation in the universe. In this thesis, we determine the power spectrum of the density perturbations entering into a local patch of inflating region embedded in a radiation dominated Robertson-Walker universe. Generally, the physical wavelengths of these perturbations exceed the Hubble radius upon entrance, therefore, their amplitudes freeze out immediately. The corresponding power spectrum turns out to be scale dependent which may point out a conflict with the observations in scenarios using local inflation.