Ph.D. Theses

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3D optical profilometry using fiber optics lloyd's mirror method
(Thesis (Ph.D.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2017., 2017.) Köseoğlu, Gülşen.; İnci, Naci.
A ber optic Lloyd's mirror assembly is investigated to obtain various optical interference patterns for the detection of three-dimensional shapes of rigid bodies. Two types of the ber optic Lloyds systems are used in this work. The rst one consists of a single mode optical ber and a highly re ecting at mirror to produce bright and dark strips. The second one is constructed by locating a single mode optical ber in a v-groove, which is formed by two orthogonal at mirrors to allow the generation of square type interference patterns for the desired applications. The structured light patterns formed by these two ber optic Lloyds techniques are projected onto three-dimensional objects. Fringe patterns are deformed due to the object0s surface topographies, which are captured by a digital CCD camera and are processed with the following signal processing techniques to accomplish their three-dimensional surface topographic maps: Fourier Transform Pro lometry, Phase Stepping Pro lometry, and Continuous Wavelet Transform Pro lometry. The method is developed for extracting 3D height distribution of various objects at the micron scale with a resolution of 5 m by elegantly interrogating the rst ber optic assembly to an optical microscope and a CCD camera. It is demonstrated that the proposed technique is quite suitable and practical to produce a structured light pattern with an adjustable frequency. By increasing the distance between the ber and the mirror with a micrometer stage in the Lloyd0s mirror assembly, the separation between the two bright fringes is lowered down to the micron scale without using any additional elements as part of the optical projection unit. The phase analysis of the acquired image is carried out by One Dimensional Continuous Wavelet Transform.
A hybrid optical tweezers and photoacoustic microscopy system
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2017., 2017.) Kipergil, Esra Aytaç.; Ünlü, Mehmet Burçin.
Photoacoustic microscopy (PAM) is a promising imaging modality that combines optical and ultrasound imaging. It takes advantage of high optical contrast and high ultrasonic spatial resolution. Conventionally, piezoelectric transducers are used to de tect photoacoustic waves. Here, it is aimed to utilize a particle trapped by an optical tweezers (OT) system as a sensor by tracking the change in its displacements caused by the photoacoustic radiation force. By this way, it is possible to put the detector as close as a few microns to the absorber which is not possible with any other currently existing detection mechanisms. An all-ﬁber integrated laser with custom-developed electronics and software is developed speciﬁcally for the hybrid PAM and OT system. The laser is home-built for maximum ﬂexibility in adjustment of its parameters; pulse duration (5-10 ns), energy (up to 10 µJ) and repetition frequency (up to 1 MHz) in dependently from each other. It covers a broad spectral region from 450 to 1100 nm and can also emit wavelengths of 532, 355, and 266 nm. Photoacoustic radiation force caused by the change in the density of time-averaged kinetic and potential energy of the acoustic wave when encountered with a compressible or incompressible sphere is analyzed theoretically. Then, experiments are conducted on several particles and cells to manipulate them inside an absorbing medium. Apart from system development for diagnostics, to turn a hand on the treatment side, proton-induced acoustics is studied which has a potential to get real-time feedback for intratreatment adjustments and to reduce range uncertainty via high spatial resolution in ultrasound. In this regard, an analytic solution for the proton-induced acoustic wave is presented; then it is combined with an analytic approximation of the Bragg curve. The inﬂuence of the beam energy, pulse duration and beam diameter variation on the acoustic waveform are investigated.
A new methodology for climate model selection and application to temperature, heat wave, WBGT and labor productivity analysis
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2018., 2018.) Altınsoy, Hamza.; Kurnaz, M. Levent.
In this thesis, the answers to four main research questions are sought. The ﬁrst eﬀort is about the ﬁnding the most accurate model combinations to project intended climate variables. A new methodology is proposed and testiﬁed to achieve this purpose. CORDEX Project is the main model data source and monthly temperature is the observed climate variable over Europe, Africa, West Asia, Central and South America. The suggested methodology outreaches the favorite EWA (Equally Weighted Average) approach in climate studies. It is found that CSIRO as GCM and CLM as RCM is the best choice to simulate temperature patterns. Besides, another methodology is proposed to select daily data sets of the most successful model combinations. Moreover, a new deﬁnition of “extremely hot day” is proposed. The selected model combinations, new deﬁnition of extremely hot day and TLVs of NIOSH are used to estimate the future heat waves, Wet Bulb Globe Temperature (WBGT) and labor productivity. It is found that adverse eﬀects of climate change over the Northern Europe, the Mediterranean Coastal, the Sub-Saharan and Northern Africa, the southern Arabian Peninsula, Brazil, Iran, Afghanistan, Pakistan and the eastern Turkey will be more devastating than the remaining parts of the World.
A ramond-nevu schwarz string one end fixed
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2005., 2005.) Arapoğlu, A. Savaş.; Turgut, Osman Teoman.; Saçlıoğlu, Cihan,
We study an open string with one end free and the other fixed on a D0-brane as a qualitative guide to the spectrum of hadrons containing one very heavy quark. We first consider the bosonic degrees of freedom, then introduce the fermionic degrees offreedom through the world sheet supersymmetry. The mixed boundary conditions break half of the world sheet supersymmetry and allow only odd-moded a and even-moded d oscillators in the Ramond sector, while the Neveu-Schwarz oscillators b's become odd-integer moded. Boson-fermion masses can still be matched if space-time is 9 dimensional; thus SO(8) triality still plays a role in the spectrum, although full space-time supersymmetry does not survive. We quantize the system in a temporal-like gauge where X^0 ~ t. Although the gauge choice eliminates negative-norm states at the outset, there are still even-moded Virasoro and even(odd) moded super-Virasoro constraints to be imposed in the NS(R) sectors. The Casimir energy is now positive in both sectors; there are no tachyons. States for a' M^2 b 13/4 are explicitly constructed and found to be organized into SO(8) irreps by (super)constraints, which include a novel ``" operator in the NS and I in the R-sectors. GSO projections are not allowed. The pre-constraint states above the ground state have matching multiplicities, indicating spacetime supersymmetry is broken by the (super)constraints. A distinctive physical feature of the system is a slope twice that of the open RNS string. When both ends are fixed, all leading and subleading trajectories are eliminated, resulting in a spectrum qualitatively similar to the J/ and particles.
A study of non-cool core galaxy clusters and the feedback from their central active galactic nuclei
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2019., 2019.) Tümer, Ayşegül.; Ercan, E. Nihal.
The study of the brightest cluster galaxy (BCG) coronae of non-cool core (NCC) galaxy clusters and their central active galactic nuclei (AGN) is crucial for the under standing of the BCG’s role on galaxy cluster evolution as well as the activation of the cooling and heating mechanism in the central regions of galaxy clusters. In this thesis, the X-ray properties of the intracluster medium (ICM) of a sample of NCC galaxy clusters and their BCG interstellar medium (ISM), along with their central AGN is investigated using archival XMM-Newton observations. For this purpose, a joint spec troscopic and imaging method is proposed and applied to the sample. It is found that, AGN plays an important role on the ICM structure and the heating of the central regions of the clusters, although at smaller spatial scales compared to that of cool core clusters. In addition, BCG coronae seem to preserve their structural integrity and are isothermal, despite the disturbed morphology and merger history of the cluster. Fur thermore, a chemically rich BCG tail structure is discovered that extends up to 40 kpc even though they are assumed to be rare in galaxy populations.
A study on susy search strategies in the CMS, HPD noise spectrum and electron reconstruction efficiency
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2010., 2010.) Deliömeroğlu, Mehmet.; Gülmez, Erhan.
The hybrid photo diodes in the HCAL will play an important role in detection of the jets and missing energy. It is very important to understand and monitor their charge spectrum. The charge spectrum of the HPD detectors in the HB and HE with high statistics and their noise rate have been studied. In this study a method to monitor the HPD charge spectrum was developed. The relation between jets and electron reconstruction efficiency is quite important. The jets in the events may effect the reconstruction efficiency and quality of the electron reconstruction. The analysis showed that for each increase in the number of jets the efficiency of electrons decrease by about 1-7%. SUSY is a symmetry relating the standard model particles to their superpartners. It must be a broken symmetry since no supersymmetric particle has been observed yet. A constrained model of SUSY breaking, mSUGRA predicts experimental signals in the CMS detector for detecting the evidence for SUSY. One of these, dielectron with large missing energy and jets is studied with MC simulation. It is shown that SUSY can be discovered with 1 fb-1 data at ps = 10 TeV. Different clustering algorithms for the jets and missing energy are used and compared for the best result.
Adiabatic solutions in general relativity and boundary symmetries
(Thesis (Ph.D.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2020., 2020.) Kutluk, Emine Şeyma.; Bleeken, Dieter Van den.
We investigate adiabatic solutions to general relativity for a spacetime with spatial slices with boundary, by Manton approximation. This approximation tells us for a theory with a Lagrangian in the natural form, a motion that is described as a slow motion on the space of vacua-static solutions that minimize the energy- is a good approximate solution. To apply this to the case of general relativity we rst bring it to the natural form by splitting space and time and choosing Gaussian normal coordinates, where a spacetime is described by the metric on its spatial slices. Then following Manton we propose slow solutions such that each slice is a slowly changing di eomorphism of a reference slice, and thus each solution is described by a vector eld on the spatial slice. These solutions will have the property that the action will become a functional of the vector elds on the boundaries of the spatial slices. Moreover using the Hodge- Morrey-Friedrichs decomposition we will show that the constraints of general relativity will identify a unique solution for a given boundary value. Then we comment on the structure of the space of vacua which we show to be a (pseudo)-Riemannian homogeneous space. We illustrate our procedure for a speci c reference slice we choose: the 3d Euclidean round ball.
Analytic solutions of scalar field cosmology with minimal and nonminimal coupling and deformed discrete and finite quantum systems
(Thesis (Ph.D.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2022., 2022) İldeş, Medine.; Turgut, Osman Teoman.; Arık, Metin.
In this thesis first, we study analytic solutions of cosmology. We investigate the most general cosmological model with real scalar field which is minimally coupled to gravity and Brans- Dicke cosmology. Field equations consist of three differential equations. We switch independent variable from time to scale factor by change of variable ˙a/a = H(a). Thus a new set of differential equations are analytically solvable with known methods. a(t) can be explicitly found as long as methods of integration techniques are available. We investigate the dynamics of the universe at early times as well as at late times in light of these formulas. We find mathematical machinery which turns on and turns off early accelerated expansion. On the other hand late time accelerated expansion is explained by cosmic domain walls. φ 4 potential is studied in Brans-Dicke Cosmology. In this thesis we also study discrete and finite quantum systems. We define a deformed kinetic energy operator for a discrete position space with a finite number of points. The structure may be either periodic or nonperiodic with well-defined end points. It is shown that for the nonperiodic case the translation operator becomes nonunitary due to the end points. This uniquely defines an algebra which has the desired unique representation. Energy eigenvalues and energy wave functions for both cases are found. In addition, we uncover the mathematical structure of the Schwinger algebra and introduce almost unitary Schwinger operators which are derived by considering translation operators on a finite lattice.
Black holes and cosmic censorship
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2013., 2014.) Düztaş, Koray.; Semiz, İbrahim.
This thesis starts with a brief review of causality conditions, gravitational collapse and singularity theorems. Cosmic censorship conjecture is introduced and the need for such a conjecture to preserve the deterministic nature of physics is explained. Examples of thought experiments which are designed to test the validity of cosmic censorship conjecture, are given. These examples involving cases of both particles and fields, are considered to have conceptual importance. Spinor algebra and analysis is reviewed. Newman-Penrose formalism is introduced. The derivations of Teukolsky’s solutions for test fields in Kerr space-time are given. Using these solutions an original thought experiment involving an extremal Kerr black hole and a test electromagnetic is constructed. It is shown that cosmic censorship conjecture is not violated in this case. The examples of thought experiments with particles that start with nearly extremal black holes instead of extremal ones are given. Another original thought experiment is constructed using integer-spin test fields and a nearly extremal Kerr black hole. It is found that cosmic censorship conjecture is violated in this case as long as radiative and self-force effects are ignored. Finally the case of neutrino fields are considered as an example of half integer-spin. It is shown that neutrino fields lead to a generic violation of the conjecture which is unique among all the attempts since the conjecture was introduced.
Black holes in an expanding universe
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2016., 2016.) Şenikoğlu, Yorgo.; Turgut, Teoman.; Arık, Metin.
By performing transformations on the isotropic forms of di erent metrics, new cosmological black hole solutions were obtained by generalizing the static solution, the Schwarzchild solution, the McVittie and the Kerr solutions. We present cosmological black holes solutions that satisfy the known behaviours of the scale factor through the history of our Universe, the Radiation, Matter and Dark Energy dominated eras. In the static case we presented solutions satisfying all of the energy conditions, then a time generalization and analysis of the previous isotropic solution gave us the behaviour in time of the Schwarzschild black hole solution. By a choice of parameter, we obtained a non-singular equation of state parameter even though the energy density and pressure tend to in nity at the horizon. In that case the solution suggests that in the expanding universe, the equation of state parameter is negative and may eventually be satis ed by a dark energy dominated representation of the Universe. For the classical McVittie and Kerr solutions, an inductive reasoning led us to obtain all the solutions, Radiation, Matter and Dark energy dominated eras, by introducing two conformal factors and generalizing the metrics. Finally, the Weyl curvature and the volume expansion are calculated for the cosmological black holes and the e ects, increases or decreases, of the volume expansions for all the cases are discussed. It is shown at the end that a multitude of black holes can impact the Universe as a whole by increasing or decreasing its volume.
Black holes, cosmology and Brans-Dicke theories in 4+1 dimensional universe
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2007., 2007.) Çiftci, Dilek.; Arık, Metin.
We consider the embedding of 3+1 dimensional cosmology in 4+1 dimensional Jordan-Brans-Dicke theory. We show that exponentially growing and power law scale factors are implied. We solve the Brans-Dicke equations and we realize that only a linear warp factor satisfies these equations. In both exponentially expanding and power law expanding cases we find out that the scalar field is a function of the warp factor and the scale factor. Whereas the 4 + 1 dimensional scalar field is approximately constant for each case, the effective 3 + 1 dimensional scalar field is constant for exponentially growing scale factor and time dependent for power law scale factor. We calculate the effective gravitational constant and realize that same results are valid. We construct a static solution for 4 + 1 dimensional bulk such that the 3 + 1 dimensional world has a linear warp factor and describes the Schwarzschild-dS4 black hole. The 4 + 1 dimensional space-time is taken to be flat. For zero mass this four dimensional universe and Friedmann-Robertson-Walker universe are related with an explicit coordinate transformation. Also we realize that if there is a contribution from the mass term, both energy momentum and cosmological constant vanish in the bulk. We explain the four dimensional cosmological constant originates from the hidden brane and its effects cause the localized mass densities in our visible brane. Using hierarchy between the Planck mass and electroweak energy scale, we obtain the size of the extra dimension as close to Hubble length but smaller than it. We emphasize that for linear warp factors the effect of bulk on the brane world shows up as the dS4 background which is favored by the Big Bang cosmology.
Bound state solutions of the Schrödinger equation for potentials with dirac delta functions
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2007., 2007.) Uncu, Haydar.; Demiralp, Ersan.
A general method for the bound state solutions of the SchrÄodinger equation for analytically solvable potentials with any ¯nite number of Dirac delta functions is intro- duced for n-dimensional systems. Then, the potentials with Dirac delta functions are used to model some physical systems. The eigenvalue equations for harmonic and linear potentials with a ¯nite number of Dirac delta functions located randomly are derived for one dimensional systems. For the latter potential, the behavior of the eigenvalues of the ground and the ¯rst excited states for various strengths and locations of Dirac delta functions is investigated. The eigenvalues and the number of bound states for a PT -symmetric system with two Dirac delta functions are studied. In case of a contact interaction, to get the changes from a liner potential, the changes in the masses of s states for charmonium is presented. It is also shown that the Fermi energy of a trian- gular well changes if there is an impurity in the well. By describing a dimple potential with a Dirac delta function, it is shown that tight and deep dimple potentials can in- crease the condensate fraction and critical temperature of a Bose-Einstein condensate. We conclude that addition of the point interactions which can be modelled by Dirac delta functions changes the properties of the physical systems considerably.
Boundary effects on Bose-Einstein condensation in ultra-static space-times
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2016., 2016.) Ertuğrul, Emine.; Akant, Levent.
In this theses relativistic boson anti-boson system, inside d dimensional box B with volume V and surface area A, which is a sub-manifold of d dimensional manifold M is studied. Mellin-Barnes Transformations and short time asymptotic of heat kernel are used as mathematical tools. Both Neumann and Dirichlet boundary conditions are considered. Analysis are done for the free energy and charge. Charge is expressed as a function of temperature. E ects of boundaries on temperature is calculated perturbatively. Same methods are employed for studying the neutral gas; free energy and number of particles are studied and again the e ect of boundary on temperature is calculated. Apart from these, upper and lower bounds for depletion coe cient of ideal relativistic bose gas in thermodynamic limit is given with the help of Li-Yau and Colbois-Maerten bounds.
CERN LINAC4 beam dynamics studies and commissioning up to 12 MeV
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2015., 2015.) Yıldız, Veli.; Özcan, Veysi Erkcan.; Arık, Metin.
Linac4 is a normal conducting, 160 MeV H{u100000} ions accelerator that is being constructed within the scope of the LHC Injectors Upgrade project. Linac4 will be connected to the Proton Synchrotron Booster during the next long LHC shutdown and it will replace the current 50 MeV proton linac, Linac2. Linac4 is being commissioned progressively with the installation of the accelerating structures into the Linac4 tunnel. Movable diagnostic benches, with various instruments, are used at each step to allow the detailed characterization of operational parameters that will play a key role in the overall future performance. The rst three stages of the commissioning, up to 12 MeV beam energy, were completed by the end of 2014 with a temporary version of the ion source. Using the permanent diagnostic instruments and a movable diagnostic bench, the Low Energy Beam Transport (LEBT) at 45 keV, the Radio Frequency Quadrupole (RFQ) and Medium Energy Beam Transport (MEBT) at 3 MeV, as well as the rst tank of the Drift Tube Linac (DTL) at 12 MeV were fully characterized.
Chaotic structures in conductivity mechanisms
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2005., 2005.) Yıldırım, H. Ahmet.; Skarlatos, Yani.; Hacinliyan, Avadis.
Chaotic behavior in the transient current through thin Aluminum-PMMA-Alu-minum films has been analyzed for times ranging up to 30000s, in the temperaturerange 293-363 K for applied voltages in the range 10-80V. The general shape of the data suggests a slow decay to a steady state value superimposed with broadband os-cillations. The aperiodic and broadband behavior of the transient current remindsone of an underlying chaotic structure. Indeed time series analysis reveals a positiveLiapunov exponent consistently and reproducibly throughout this range which give sstrong evidence for chaoticity. Power law relaxation as refiected by the autocorrelationfunction and the positive Liapunov exponent show parallel behaviors as a function ofapplied electric field and temperature. The stretched exponential behavior of the data suggests that the process can beseen as random walk between random sites. The qualitative behavior of the data canbe understood in terms of a quenched disorder picture as first suggested by Erzan et.al.
Chaoticity analysis of the current through pure, hydrogenated and hydrophobically modified PEG-SI thin films under varying relative humidity
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2009., 2009.) Atak, Kaan.; Skarlatos, Yani.; Hacinliyan, Avadis.
Polyethylene Glycol is known to have an irregular current characteristic under constant voltage and slowly varying relative humidity. In this study the current through a thin film of Gamma-isocyanatopropyltriethoxysilane added polyethylene glycol (PEG-Si), its hydrogenated, and hydrophobically modified forms is measured as a function of increasing relative humidity at equal time steps and analyzed for chaoticity. In previous studies it has been suggested that, after reaching a certain relative humidity level, a phase transition occurs from a semi crystalline state to a gel state. We propose that the irregular behavior of current through PEG-Si thin films as a function of increasing relative humidity could best be analyzed for chaoticity using both time series analysis and detrended fluctuation analysis; the relative humidity is kept as a slowly varying parameter. The presence of more then one regime is suggested by the calculation of the maximal Lyapunov exponents. Furthermore, the maximal Lyapunov exponent in each of the regimes was positive, thus confirming the presence of low dimensional chaos. The regime change signaled by the changing values of the maximal Lyapunov exponent occurs around a relative humidity of 70% consistent with the phase transition from semi crystalline state to gel state. Detrended fluctuation analysis has also been performed; this also confirms the presence of at least two different regimes, in agreement with the behavior of the maximal Lyapunov exponent in the time series analysis. Our study also confirms that the improvement in stability of the current through PEG-Si can be performed by hydrogenating and hydrophobically modifying PEG-Si.
Chemical enrichment history and gas mass fraction of the galaxy cluster abell 3112
(Thesis (Ph.D.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2017., 2017.) Ezer, Cemile.; Ercan, E. Nihal.
Clusters of galaxies are the largest concentrations of con ned matter in the Universe. Their deep potential well locks all metals produced by stars and galaxies within the intra-cluster medium. The spatial distribution of the metals residing in the intra-cluster medium records all the information on a cluster's nucleosynthesis and chemical enrichment history. In this work, we constrain the radial distribution of supernova enrichment via supernova type Ia and core collapse supernova explosions from a total of 1.2 Ms Suzaku XIS and 72 ks Chandra observations of the cool-core galaxy cluster Abell 3112 out its virial radius ( 1470 kpc). We adopt a recently developed snapec XSPEC model for this study. In this study, it is found that the ratio of the observed supernova type Ia explosions to the core collapse supernova explosions has a uniform distribution at a level of 0.12 { 0.16 out to the cluster's virial radius. The observed fraction of type Ia supernova explosions is in agreement with the corresponding fraction found in our Galaxy and the chemical enrichment of our Galaxy. The non-varying supernova enrichment suggests that the intra-cluster medium in cluster outskirts was enriched by metals at an early stage before the cluster itself was formed during the period of intense star formation activity. Additionally, we nd that the 2D delayed detonation model CDDT produces signi cantly worse ts to the X-ray spectra compared to simple 1D W7 models. An explicit investigation with these X-ray observations can also be used to probe the approximate baryon fraction of the cluster. In this study, the gas mass fraction is determined as fgas = 0:21+0:16 {u100000}0:11 at R500.
Cononical structure and integrability of new-dimensional field theories
(Thesis (Ph.D.)- Bogazici University. Institute for Graduate Studies in Science and Engineering, 1984., 1984.) Neyzi, Fahrünisa.; Arık, Metin.
Cosmology and spontaneous symmetry breaking
(Thesis (Ph.D.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 1998., 1998.) Saygılı, Kamuran.; Arık, Metin.
In the first problem we investigate a model which incorporates spontaneous symmetry breaking and gravitation in the context of scalar-tensor theory. Present day value of the gravitational constant is induced by the vacuum expectation value of the scalar field. Cosmology is dominated by the scalar field both in the early and the present universe and the scalar field supplies the critical density of the universe today. In the second problem we applied the long-wavelength approximation to low energy effective string action in the context of Hamilton-Jacobi theory. The Hamilton-Jacobi equation is explicitly invariant under scale factor duality. We present the leading order general solution near a singularity, which also contains the quasi-isotropic one. The duality transformation is written as a coordinate transformation in an abstract space of fields.
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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