Suat Özkorucuklu

We observe a signal for the doubly charmed baryon Xi(+)(cc) in the charged decay mode Xi(+)(cc)-->Lambda(+)(c)K-pi(+) in data from SELEX, the charm hadroproduction experiment at Fermilab. We observe an excess of 15.9 events over an expected background of 6.1+/-0.5 events, a statistical significance of 6.3sigma. The observed mass of this state is 3519+/-1 MeV/c(2). The Gaussian mass width of this state is 3 MeV/c(2), consistent with resolution; its lifetime is less than 33 fs at 90% confidence.

We observe a signal for the doubly charmed baryon Ξcc+ in the decay mode Ξcc+→pD+K− to complement the previous reported decay Ξcc+→Λc+K−π+ in data from SELEX, the charm hadroproduction experiment at Fermilab. In this new decay mode we observe an excess of 5.62 events over a combinatoric background estimated by event mixing to be 1.38±0.13 events. The mixed background has Gaussian statistics, giving a signal significance of 4.8σ. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4×10−4. The observed mass of this state is 3518±3MeV/c2, consistent with the published result. Averaging the two results gives a mass of 3518.7±1.7MeV/c2. The observation of this new weak decay mode confirms the previous SELEX suggestion that this state is a double charm baryon. The relative branching ratio for these two modes is 0.36±0.21.

A bstract We describe a proposal to add a set of very forward detectors to the CMS experiment for the high-luminosity era of the Large Hadron Collider to search for beyond the standard model long-lived particles, such as dark photons, heavy neutral leptons, axion-like particles, and dark Higgs bosons. The proposed subsystem is called FACET for F orward- A perture C MS E x T ension, and will be sensitive to any particles that can penetrate at least 50 m of magnetized iron and decay in an 18 m long, 1 m diameter vacuum pipe. The decay products will be measured in detectors using identical technology to the planned CMS Phase-2 upgrade.

We report the first observation of a charm-strange meson D(+)(sJ)(2632) at a mass of 2632.5+/-1.7 MeV/c(2) in data from SELEX, the charm hadro-production experiment E781 at Fermilab. This state is seen in two decay modes, D(+)(s)eta and D0K+. In the D(+)(s)eta decay mode we observe a peak with 101 events over a combinatoric background of 54.9 events at a mass of 2635.4+/-3.3 MeV/c(2). There is a corresponding peak of 21 events over a background of 6.9 at 2631.5+/-2.0 MeV/c(2) in the decay mode D0K+. The decay width of this state is <17 MeV/c(2) at 90% confidence level. The relative branching ratio Gamma(D0K+)/Gamma(D(+)(s)eta) is 0.14+/-0.06. The mechanism that keeps this state narrow is unclear. Its decay pattern is also unusual, being dominated by the D(+)(s)eta decay mode.

The Sigma^- mean squared charge radius has been measured in the space-like Q^2 range 0.035-0.105 GeV^2/c^2 by elastic scattering of a Sigma^- beam off atomic electrons. The measurement was performed with the SELEX (E781) spectrometer using the Fermilab hyperon beam at a mean energy of 610 GeV/c. We obtain <r^2> = (0.61 +/- 0.12 (stat.) +/- 0.09 (syst.)) fm^2. The proton and pi^- charge radii were measured as well and are consistent with results of other experiments. Our result agrees with the recently measured strong interaction radius of the Sigma^-.

We present data from Fermilab experiment E781 (SELEX) on the hadroproduction asymmetry for Λ̄c− compared to Λc+ as a function of xF, and on pt2 distributions for Λc+. These data were measured in the same apparatus using incident π−, Σ− beams at 600 GeV/c and proton beam at 540 GeV/c. The asymmetry is studied as a function of xF. In the forward hemisphere with xF⩾0.2 both baryon beams exhibit very strong preference for producing charm baryons rather than charm antibaryons, while the pion beam asymmetry is much smaller. In this energy regime the results show that beam fragments play a major role in the kinematics of Λc formation, as suggested by the leading quark picture.

Total cross sections for Σ− and π− on beryllium, carbon, polyethylene and copper as well as total cross sections for protons on beryllium and carbon have been measured in a broad momentum range around 600GeV/c . These measurements were performed with a transmission technique in the SELEX hyperon-beam experiment at Fermilab. We report on results obtained for hadron–nucleus cross sections and on results for σtot(Σ−N) and σtot(π−N) , which were deduced from nuclear cross sections.

The RADiCAL Collaboration is conducting R\&D on high performance electromagnetic (EM) calorimetry to address the challenges expected in future collider experiments under conditions of high luminosity and/or high irradiation (FCC-ee, FCC-hh and fixed target and forward physics environments). Under development is a sampling calorimeter approach, known as RADiCAL modules, based on scintillation and wavelength-shifting (WLS) technologies and photosensor, including SiPM and SiPM-like technology. The modules discussed herein consist of alternating layers of very dense (W) absorber and scintillating crystal (LYSO:Ce) plates, assembled to a depth of 25 $X_0$. The scintillation signals produced by the EM showers in the region of EM shower maximum (shower max) are transmitted to SiPM located at the upstream and downstream ends of the modules via quartz capillaries which penetrate the full length of the module. The capillaries contain DSB1 organic plastic WLS filaments positioned within the region of shower max, where the shower energy deposition is greatest, and fused with quartz rod elsewhere. The wavelength shifted light from this spatially-localized shower max region is then propagated to the photosensors. This paper presents the results of an initial measurement of the time resolution of a RADiCAL module over the energy range 25 GeV $\leq$ E $\leq$ 150 GeV using the H2 electron beam at CERN. The data indicate an energy dependence of the time resolution that follows the functional form: $\sigma_{t} = a/\sqrt{E} \oplus b$, where a = 256 $\sqrt{GeV}$~ps and b = 17.5 ps. The time resolution measured at the highest electron beam energy for which data was currently recorded (150 GeV) was found to be $\sigma_{t}$ = 27 ps.

We report new precision measurements of the lifetimes of the ${\ensuremath{\Lambda}}_{c}^{+}$ and ${D}^{0}$ from SELEX, the charm hadroproduction experiment at Fermilab. Based upon 1630 ${\ensuremath{\Lambda}}_{c}^{+}$ and 10 210 ${D}^{0}$ decays we observe lifetimes of $\ensuremath{\tau}[{\ensuremath{\Lambda}}_{c}^{+}]\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}198.1\ifmmode\pm\else\textpm\fi{}7.0\ifmmode\pm\else\textpm\fi{}5.6\mathrm{fs}$ and $\ensuremath{\tau}[{D}^{0}]\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}407.9\ifmmode\pm\else\textpm\fi{}6.0\ifmmode\pm\else\textpm\fi{}4.3\mathrm{fs}$.

Coherent Λπ− production on Pb of 600 GeV Σ− hyperons has been studied with the SELEX facility at Fermilab. Using the Primakoff formalism, we set a 90% CL upper limit on the radiative decay width Γ[Σ(1385)−→Σ−γ]<9.5 keV, and estimate the cross section for γΣ−→Λπ− at s≈1.385 GeV to be 56±16 μb.

The aim of this study was to investigate possible effects of 50 Hz-1 mT magnetic field (MF) on action potential in isolated rat sciatic nerve. We used 16 Wistar rats in the study. They were divided into control (n = 10) and MF (n = 6) groups. The sciatic nerve of left legs in the MF group was exposed to 50 Hz-1 mT MF for 30 min by using a Helmholtz applicator and then action potentials in control and experimental groups were recorded extracellularly. Maximum amplitude and hyperpolarization time and action potential were significantly (p ≤ 0.025) lower in the MF group than in control. However, conduction time, minimum amplitude, depolarization and repolarization times of the action potential was not different between control and MF groups evaluated. In conclusion, 50-1 mT MF caused to decrease amplitude value and hyperpolarization time of action potential in the rat nerve.

Silicon devices (both pixels and microstrips) have been widely used in the past years in High Energy Physics experiments and also in other applications involving the detection of ionizing radiation such as medical imaging and dosimetry. The simulation of the silicon devices response to ionizing radiation is an important step needed to understand the performances in terms of signal, noise, spatial and energy resolution as a function of several technology parameters like doping profile, geometrical dimensions, bias voltage. These simulations are routinely carried out using two separate approaches (and tools): radiation interaction with a geometrically segmented silicon material (GEANT4, FLUKA, PENELOPE) taking into account the physical processes and giving as output the deposited energy; transport of generated electron/hole pairs through the device with electronic signal formation (SENTAURUS-TCAD). In this work we propose a new combined approach using both methods, applied to the case of CMOS pixel sensor, to obtain a better understanding of the behavior of the devices.

Coherent π+π−π− production in the interactions of a beam of 600GeV π− mesons with C, Cu and Pb nuclei has been studied with the SELEX facility (Experiment E781 at Fermilab). The a2(1320) meson signal has been detected in the Coulomb (low q2) region. The Primakoff formalism used to extract radiative decay width of this meson yields Γ=284±25±25keV, which is the most precise measurement to date.

We report a precise measurement of the D±s meson lifetime. The data were taken by the SELEX experiment (E781) spectrometer using 600 GeV/c Σ−, π− and p beams. The measurement has been done using 918 reconstructed D±s. The lifetime of the D±s is measured to be 472.5±17.2±6.6 fs, using K∗(892)0K± and φπ± decay modes. The lifetime ratio of Ds± to D0 is 1.145±0.049.

Using data taken by SELEX during the 1996–1997 fixed target run at Fermilab, we study the production of charmed hadrons on copper and carbon targets with Σ −, p, π −, and π + beams. Parametrizing the dependence of the inclusive production cross section on the atomic number A as A α , we determine α for D +, D 0, D + , D +(2010), Λ + , and their respective anti-particles, as a function of their transverse momentum p t and scaled longitudinal momentum x F . Within our statistics there is no dependence of α on x F for any charm species for the interval 0.1<x F <1.0. The average value of α for charm production by pion beams is α meson=0.850±0.028. This is somewhat larger than the corresponding average α baryon=0.755±0.016 for charm production by baryon beams (Σ −, p).

Terradex project aims to realise an accurate and programmable multiparametric tool which will measure relevant physical quantities such as observation time, energy and type of all decay products of three naturally occurring decay chains of uranium and thorium series present in nature as well as the decay products of man-made radioactivity. The measurements described in this work are based on the performance tests of the first version of an instrument that is designed to provide high counting accuracy, by introducing self-triggering, delayed time-coincidence technique, of products of a given decay chain. In order to qualify the technique and to calibrate the Terradex, a 222Rn source is used. The continuous and accurate monitoring of radon concentration in air is realised by observing the alpha and beta particles produced by the decay of 222Rn and its daughters and tag each of them with a precise occurrence time. The validity of delayed coincident technique by using the state of the art electronics with application of novel data sampling and analysis methods are discussed. The flexibility of sampling protocols and the advantages of online calibration capability to achieve the highest level of precision in natural and man-made radiation measurements are also described.

In this study, high-precision radiation detector (HIPRAD), a new-generation semiconductor microstrip detector, was used for detecting radon (Rn-222) activity. The aim of this study was to detect radon (Rn-222) activity experimentally by measuring the energy of particles in this detector. Count-ADC channel, eta-charge, and dose–response values were experimentally obtained using HIPRAD. The radon simulation in the radiation detector was theoretically performed using the Geant4 software package. The obtained radioactive decay, energy generation, energy values, and efficiency values of the simulation were plotted using the root program. The new-generation radiation detector proved to have 95% reliability according to the obtained dose–response graphs. The experimental and simulation results were found to be compatible with each other and with the radon decays and literature studies.

We report the measurement of the one-dimensional charged kaon correlation functions using 600GeV/c Σ−, π− and 540GeV/c p beams from the SELEX (E781) experiment at the Fermilab Tevatron. K±K± correlation functions are studied for three transverse pair momentum, kT, ranges and parameterized by a Gaussian form. The emission source radii, R, and the correlation strength, λ, are extracted. The analysis shows a decrease of the source radii with increasing kaon transverse pair momentum for all beam types.

Sperm motility is an important character for the assessment of milt quality and indicator to the expected rate of fertilization. Many factors can affect the sperm motility, including nature of water used as sperm activator medium after stripping the milt from the male fish. The aim of this study was to gain motility to spermatozoa and improve sperm kinematic parameters by applying a non-chemical method. The effects of magnetic field on samples of hatchery water exposed to magnetic field of 2.71, 4.51 and 8.11 mT for the duration of 12, 24 and 36 hours on Salmo trutta labrax sperm motility were investigated with computer-assisted sperm analysis (CASA) system; 4.51 mT exposure for 36 hours (A2H3) was greater in motility kinematic parameters (p < 0.05) and progressive kinematic parameters (VAP, VSL and VCL) with values of (93.1244 ± 37.222, 88.6111 ± 36.137, 96.8378 ± 35.396 μm/s) and (102.9167 ± 32.546, 100.9767 ± 31.894, 105.8778 ± 30.401 μm/s) respectively. But there was no (p ≥ 0.05) in the slow phase just in the VCL parameter had (p ≤ 0.05) (35.8789 ± 39.127 μm/s) among other parameters. There was (p ≤ 0.05) in starting motility time until vibration point (s) for 4.51 mT in 12 hour (A2H1) (27.3333 ± 1.527 s), but total time of motility was greater for 4.51 mT in 36 hour (A2H3) with (p ≤ 0.05) (49.6667 ± 2.081 s) compared with other treatments.

The Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) will operate two InfraRed Free Electron Lasers (IR-FEL) covering the range of 3-250 microns. The facility will consist of an injector fed by a thermionic triode gun with two-stage RF bunch compression, two superconducting accelerating ELBE modules operating at continuous wave (CW) mode and two independent optical resonator systems with different undulator period lengths. The electron beam will also be used to generate Bremsstrahlung radiation. In this paper, we discuss design goals of the project and present status and road map of the project.

Many in vitro studies have used dentine permeability to evaluate the efficacy of various restorative and preventative procedures. The easiest way to evaluate dentine permeability is to calculate its hydraulic conductance (Lp) using fluid filtration methods. Research has examined electronic hydraulic conductance measurement methods that give more precise and reliable results for the permeability of dentine than the classical method. To our knowledge, no study has examined the dentine permeability of carious primary teeth.This in vitro study determined the dentine permeability of carious primary molars precisely with a new electronic hydraulic conductance measurement system and compared them with healthy primary molars.The study examined 60 carious and noncarious primary second molars with no restorations, fractures, or cracks at different root resorption stages.The results showed that the dentine permeability increased with the severity of caries in primary teeth.The dentine permeability of carious primary teeth was higher than that of noncarious primary teeth. Therefore, treatment of primary teeth should be performed more quickly.

The production of Ds− relative to Ds+ as a function of xF with 600 GeV/c Σ− beam is measured in the interval 0.15<xF<0.7 by the SELEX (E781) experiment at Fermilab. The integrated charge asymmetries with 600 GeV/c Σ− beam (0.53±0.06) and π− beam (0.06±0.11) are also compared. The results show the Σ− beam fragments play a role in the production of Ds−, as suggested by the leading quark model.

We report the first observation of two Cabibbo-suppressed decay modes, Ξc+→Σ+π−π+ and Ξc+→Σ−π+π+. We observe 59±14 over a background of 87, and 22±8 over a background of 13 events, respectively, for the signals. The data were accumulated using the SELEX spectrometer during the 1996–1997 fixed target run at Fermilab, chiefly from a 600GeV/c Σ− beam. The branching ratios of the decays relative to the Cabibbo-favored Ξc+→Ξ−π+π+ are measured to be B(Ξc+→Σ+π−π+)/B(Ξc+→Ξ−π+π+)=0.48±0.20, and B(Ξc+→Σ−π+π+)/B(Ξc+→Ξ−π+π+)=0.18±0.09, respectively. We also report branching ratios for the same decay modes of the Λc+ relative to Λc+→pK−π+.

In today's world, quartz-core fibers are extensively used in scientific studies due to their high radiation resistance. Thanks to the quartz core's ability to generate Cherenkov photons and propagate these photons, as well as those entering the fiber from outside, it is frequently studied in the context of high-energy and nuclear physics for detector designs. In this paper, a detailed simulation was developed using the Geant4 simulation application, focusing on the photon production and propagation capabilities of quartz-core fibers. Molex's recently developed FBP (FBP600660710) broadband quartz-core fibers were integrated in the simulation environment. The production and propagation of Cherenkov photons were tested by having a charged particle pass through a specific impact point and angle on a quartz-core fiber. Based on the obtained data, reflectors were integrated onto the open end surface of the fiber to reduce photon losses, and tests were conducted again. The effects of fiber length on the photon-carrying capacity of the fiber were also tested.

Objective: The in vitro permeability characteristics of dentin have been studied extensively and used to evaluate the efficacy of various preventative and restorative procedures. The aim of this in vitro study was to precisely determine the dentin permeability of fluorotic premolar teeth using an electronic hydraulic conductance measurement system with photosensors and to compare the data with healthy premolars.Methods: In total, 40 fluorotic and healthy premolar teeth with complete root formation that were extracted for orthodontic purposes and had no caries, restoration, fractures, or cracks were selected for this study. Teeth were classified according to a modified form of the dental fluorosis index of Thylstrup and Fejerskov. The dentin discs were placed in an electronic hydraulic conductance measurement system equipped with photosensors, which was designed for measurements of dentin permeability. The amount of distilled water passed through each dentin disc (μL/min) under a constant pressure was determined. Dentin permeability data of the fluorotic and healthy teeth were recorded and analyzed statistically.Results: The present study showed that fluorosis influenced the volume of fluid that passed through the dentin and the dentin permeability was decreased, whereas dental fluorosis severity was increased in permanent teeth.Conclusion: The number of teeth with fluorosis is increasing, depending on fluorine sources, so more appropriate treatments will need to be evaluated by standardizing the methods employed in related studies.

Turkish Accelerator Center (TAC) Project has started with support of the Ministry of Development (MD) of Turkey under the coordination of Ankara University. TAC is an inter-university collaboration with 12 Turkish Universities. An IR FEL facility (TARLA) based on Sc linac with 15-40 MeV energy under construction in Ankara as the first facility of TAC. It is expected that the TARLA facility will be commissioned in 2017. In addition to the TARLA, it is planned that Turkish Accelerator Center will include a third generation synchrotron radiation facility based on 3 GeV electron synchrotron (TAC SR), a fourth generation SASE FEL facility based on 3 GeV electron linac (TAC SASE FEL), a multi-purpose proton accelerator facility with 3 MeV - 2 GeV beam energy (TAC PAF) and an electron-positron collider as a super charm factory (TAC PF) Construction phase of the proposed GeV scale accelerator facilities will cover next decades. In this presentation, main goals and road map of Turkish Accelerator Center will be explained.

The Turkish Accelerator Complex (TAC) was proposed to Turkish State Planning Organization (DPT) as a regional facility for accelerator based fundamental and applied research center in 1997 [1]. After completing Feasibility Report (FR, 2000) [2,3], and Conceptual Design Repot (CDR, 2005) [4], third phase of project is started in 2006 as an inter-universities project with support of DPT. TAC collaboration includes ten Turkish Universities: Ankara, Gazi, stanbul, Bo azici, Do u , Uluda , Dumlupinar, Ni de, Erciyes and S. Demirel and around hundred scientists and students. Third phase of project has two main scientific goals: to write Technical Design Report (TDR) of TAC and to establish an Infrared Free Electron Laser (IR FEL) facility as a first step. The TAC complex will include a 1 GeV electron linac and a 3.56 (4.5) GeV positron ring for linac on ring type electron-positron collider as a charm factory and a few GeV proton linac. Besides the particle factory, it is also planned to produce SASE FEL from electron linac and synchrotron radiation from positron ring. It is planned that the Technical Design Report (TDR) of TAC Project will be completed in 2013. Furthermore, as the first step, an Infrared Free Electron Laser (IR-FEL) facility in oscillator mode will be established in order to become familiar to accelerator technology. This facility is now called Turkish Accelerator and Radiation Laboratory at Ankara (TARLA) since located at Golbasi town 15 km South of Ankara, Turkey. In this study, the status of TAC project is presented and latest considerations are given.

Pion virtual compton scattering ͑VCS͒ via the reaction Ϫ e→ Ϫ e␥ was observed in the Fermilab E781 SELEX experiment.SELEX used a 600 GeV/c Ϫ beam incident on target atomic electrons, detecting the incident Ϫ and the final state Ϫ , electron and ␥.Theoretical predictions based on chiral perturbation theory are incorporated into a Monte Carlo simulation of the experiment and are compared to the data.The number of reconstructed events ͑ϭ9͒ and their distribution with respect to the kinematic variables ͑for the kinematic region studied͒ are in reasonable accord with the predictions.The corresponding Ϫ VCS experimental cross section is ϭ38.8Ϯ13nb, in agreement with the theoretical expectation of ϭ34.7 nb.

Radon, kayaclardaki ve topraktaki Uranyum–238 bozunmasiyla olusan radyoaktif bir asal gazdir. radon hakkindaki ilk calismalar 1956 yilinda Isvicre'de baslamis ve ozellikle 1980 sonrasinda yapilan arastirmalarla radon gazinin cevresel radyasyon uzerindeki katkisi ve ortama yayilma mekanizmasi anlasilmistir. Kayaclardaki 238U bozunmasi sonucu uretilen radon gazi difuzyon yoluyla topraga, oradan da atmosfere veya ortama yayilmaktadir. Gunluk hayatta surekli maruz kaldigimiz radyasyonun %54'nun Radon izotoplarindan, ozellikle de 222Rn'den kaynaklandigi bulunmustur. Turkiye'de, TAEK kritik radon yogunluk degerlerini meskenler icin 400 Bq/m3, sanayi ve isyerleri icin ise 1000 Bq/m3 olarak belirlemistir. Yuksek dozlarda maruz kalindiginda ozellikle akciger kanseri riskini artirdigi ileri surulen radon, yogunlugu fazla olan yerlesme birimlerinde tehlike yaratmaktadir. Bu calismada, Isparta ili sinirlari icinde belirlenen bazi kapali mekanlarda AlphaGUARD radon detektoru kullanilarak radon yogunluklari olculmus ve veriler irdelenmistir.

The synchronization and timing of the hadron calorimeter (HCAL) for the Compact Muon Solenoid has been extensively studied with test beams at CERN during the period 2003-4, including runs with 40 MHz structured beam. The relative phases of the signals from different calorimeter segments are timed to 1 ns accuracy using a laser and equalized using programmable delay settings in the front-end electronics. The beam was used to verify the timing and to map out the entire range of pulse shapes over the 25 ns interval between beam crossings. These data were used to make detailed measurements of energy-dependent time slewing effects and to tune the electronics for optimal performance.

Bu calismada, hizlandirici fizigi ve bu alanla iliskili pek cok bilim dalinda calismalarin yapilabilmesine olanak saglayacak olan, Turk Hizlandirici Merkezi (THM) T.A.R.L.A. (Turkish Acceleration and Radiation Laboratory at Ankara) tesisinin serbest elektron lazeri icin elektron demet parametreleri hesaplamalari yapilmistir. Ayrica, enjektor kismina ait benzetim calismalari gosterilmistir.

The goal of this study is to design a geometry of an electron dump with Simple Geo code which is a freeware product and provides the ability of designing complex geometric systems easily. Also, Simple Geo can output the designed geometry in many different formats. Desired design of the electron dump is to stop the 40 – 42 MeV electron beams. To reach this aim, requested geometric design with the possible material was done with Simple Geo and a FLUKA output format file created to run the simulations in FLUKA code.

Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is an oscillator mode IR-FEL facility which is under construction since 2011. ELBE licensed superconducting modules housing TESLA RF cavities have been manufacturing for one year and the first module will be delivered in 2015. He Cryogenic System has also started to be manufacturing at similar time with the accelerator structures. It will be delivered in 2014. High Power RF amplifiers are started to tender procedures and delivery time is planning as 2015. The installation of high power transmission lines have to be completed at the same time with the delivery date of HPRF amplifiers to test the cavities and amplifiers. In this study, the final structural design of high power RF transmission lines and design parameters of RF amplifiers for TARLA is discussed.

Free Electron Lasers (FELs) ensure superior features such as adjustable wavelength, coherence, mono-chromaticity, and high peak power connected to the high intensity and short pulse length, high flux and brightness values. FELs' wavelength region lies from infrared to X-ray region. A FEL facility, called Turkish Accelerator and Radiation Laboratory at Ankara (TARLA), is under construction with aim to scan wavelength region from 2.5 µm to 250 µm with two undulator lines supplied with 15-40 MeV electron beam out of two superconducting accelerating cavities. Analytical calculations for determination of TARLA FEL undulator and resonator parameters carried out with Mathematica and FELO code used for simulations. In this paper, laser wavelength, beam waist, normalized emittance, Rayleigh length, single-pass gain, ideal gain, mirror radius of resonators, average extracted power, output power and efficiency values for both FEL line for TARLA were presented.

Iyonize olmayan elektromanyetik radyasyonun insan sagligi uzerindeki etkileri, son elli yilda manyetik alanlarin kullanim alaninin genislemesi ile birlikte, buyuk bir arastirma konusu olmustur. Manyetik alanlarin tabiati cok iyi bilinmekle beraber, insan vucudunun karmasik yapisi, bu etkilerin incelenmesini zorlastirmaktadir. Bununla beraber yapilan deneysel ve teorik calismalarin sonucunda, manyetik alanlarin insan sagligi uzerindeki etkileri konusunda kayda deger bulgular elde edilmistir. Ancak, henuz bilinmeyen etkilerinin olabilecegi konusunda da supheler mevcuttur. Bu calisma ile 50 Hz-1mT manyetik alanin izole sican siyatik siniri uzerindeki etkisinin incelenmesi amaclanmistir. Izole sinir 30 saniye 1mT Helmholtz bobini ile manyetik alana maruz birakildiktan sonra 0.1-0.5 msn sureli esik ve supramaksimal pulslarla uyarilmis ve hucre disi izole kayit yontemi kullanilarak degerler kaydedilmistir (n=16). Elde edilen kayitlardan ileti zaman farki, maksimum genlik farki, minimum genlik farki, ortalama depolarizasyon suresi, ortalama repolarizasyon suresi ve ortalama hiperpolarizasyon suresi olculmustur. 50 Hz-1 mT manyetik alan uygulanan sinirlerde, sinir ileti hizinda bir degisme olmamistir. Fakat manyetik alan uygulanan grubun; maksimum genlikler farki (mV) ve ortalama hiperpolarizasyon suresi (msn), kontrol grubuna gore daha dusuktur (p=0,025). Anahtar Kelimeler: Manyetik Alan, Sinir Iletimi, Siyatik Sinir

Gunumuzde, dunyanin bazi ulkelerinde sayilari binlerle ifade edilebilen, hizlandirici merkezleri farkli bilim dallarina (Fizik, Tip, Genetik, Arkeoloji, Ulusal Guvenlik, Enerji Uretimi, Madencilik, vb.) hizmet etmektedir. Hizlandirici merkezleri operasyonlari nedeniyle ani ve dolayli radyolojik kirlenmeye neden olduklarindan, radyasyon ureten bu tesislerde radyasyon guvenligi en onemli unsurlardan birisidir. Bu calismada, TARLA (Ankara Turk Hizlandirici ve Radyasyon Laboratuvari) tesisinin radyasyon guvenligi sisteminde bulunan, radyasyon kapilarinin Arduino teknolojisi ile kontrolu amaclanmaktadir. Tesiste bulunan 3 radyasyon kapisinin kontrolu, 10 arama ve 7 acil durum butonu ile gerceklestirilmistir. Kapilarin acilmasi, kapanmasi icin kullanilan motor surucu devrelerinin kontrolu ile isikli ve sesli uyari panolarinin kontrolunu saglayan program, Arduino IDE kod editorunde yazilarak, Arduino karta yuklenmistir. Arduino Mega 2560 kart ve 4 elektronik kart ile olusturulan sistemin, ayrica C# programiyla yazilan arayuz ile de uzaktan erisimi ve kontrolu saglanmaktadir.

Ozet: Turk Hizlandirici Merkezi'nin (THM) ilk tesisi olarak super iletken elektron hizlandiricisina dayali olarak osilator modda Serbest Elektron Lazeri tesisi kurulmaktadir. Ar-Ge amacli kurulmakta olan bu tesisin laboratuarinin uluslararasi literaturdeki adi “Turkish Accelerator and Radiation Laboratory at Ankara” (TARLA) olarak bilinmektedir. Kurulacak olan SEL tesisinde, super iletken hizlandiricilardan elde edilen 15-40 MeV enerjili elektron demeti iki farkli salindirici hattindan gecirilerek 2,5-250 µm dalga boyu araliginda kizilotesi SEL'in elde edilmesi planlanmaktadir. Elde edilmesi planlanan lazerin istenilen parametrelere sahip olabilmesi icin kullanilacak olan salindiricilarin optimizasyon ve benzetim calismalarinin onceden gerceklestirilmesi gerekmektedir. Bu calismada RADIA ve SPECTRA programlari kullanilarak tesiste kullanilacak olan salindiricilar icin gerekli benzetim calismalari yapilmistir. Salindiricilarin manyetik alan, manyetizasyon degerleri, elektron demetinin hiz ve yorunge degisimleri her iki salindirici icin benzetim calismalari ile belirlenmis ve karsilastirma yapilarak sonuclar verilmistir. Anahtar kelimeler: THM, TARLA, Serbest Elektron Lazeri, optimizasyon, benzetim calismalari Simulation Studies for TARLA IR-FEL Undulator Magnets Abstract: A Free Electron Laser (FEL), which will be run on oscillator mode, constitutes the first facility of Turkish Accelerator Center (TAC). The name of the R&D test laboratory in international literature is known as “Turkish Accelerator and Radiation Laboratory at Ankara (TARLA). In this FEL center, the plan is to obtain infrared FEL within the wavelengths range of 2.5 to 250 micrometer sending electron beam with energy of 15-40 MeV accelerated with superconducting cavities through two undulator lines. Optimization and simulation studies should be completed formerly for undulators in order to obtain desired parameters for the planned laser. In this study, necessary simulation studies were done with RADIA and SPECTRA codes for undulators to be used in this facility. Simulation studies for both undulators carried out to determine the magnetic field of the undulator, magnetization values, changes in speed and trajectory of the electron beam and comparison with the results are given. Key words: Free Electron Laser, optimization and simulation studies

Sinir hucrelerinin fizyolojik yapilarini ve dinamik davranislarini incelemek uzere gelistirilen modellemeler ve simulasyonlar, deneysel calismalarin desteklemesi acisindan onemlidir. Bu calismada uyarilabilir hucrelerde uyari iletiminin elektriksel kurami uzerinde durulmustur. Pasif kablo teorisinin esaslarina yer verilmis ve uyarilabilir hucreler ile ilgili genel diferansiyel denklemlerin turetilmesi yapilmistir. Sinir hucresinin pasif kablo model simulasyonu, MATLAB7.0.4/Simulink programi ile gerceklestirilmistir. Calismanin ana hedeflerinden biri olan gercekci modele erismek icin, basitlestirilmis ve revize edilmis iki model kullanilmistir. Sinir hucresinde yayilan aksiyon potansiyeli dalga sekli olarak, MATLAB7.0.4/Simulink’te gercekci dalga sekli uretilmistir. Basitlestirilmis ve revize edilmis iki modelin simulasyon sonuclari karsilastirildiginda revize edilmis model cikisinda, minimum genligin azaldigi gorulmektedir. Revize edilmis modelde; onerdigimiz olmasi gereken bir kapasite elemani bulunmustur.

In this study, a mechanical system design for a digital optical microscope that capable of electronic circuitry controlled auto-focusing and image-processing software was carried out. Auto focusing of the microscope was achieved by this system based on a multi-point control method for investigation of the objects with nonhomogeneous height. According shape of the object, the most appropriate focus point was determined by means of the eleven-fixed point on the image and motorized unit will adjust the Z-axis location of the microscope accordingly. Studies have shown that the auto focusing system work with 90% accuracy

Ozet: Hizlandirici sistemlerinde Optik Gecis Radyasyonu (OTR), demet profilini belirlemede kullanilir. OTR sistemlerinde goruntuleme ekrani olarak genelde aluminyum ve altin kullanilmaktadir. Bu calismada OTR sistemlerinde Silikon (Si) materyalinin goruntuleme ekrani olarak kullanilabilirligi simulasyon calismasi gerceklestirilmistir. Simulasyon calismalari, 18,5 MeV ve 38,5 MeV farkli iki elektron demet enerjileri ile goruntuleme ekranlari olarak aluminyum, kursun, titanyum, bakir, gumus, altin materyalleri ve silikon uzerinde yapilmistir. Simulasyon sonuclarindan da gorulebilecegi gibi, silikon tabanli goruntuleme ekranlari OTR sistemlerinde iyi bir secenek olabilir. Anahtar kelimeler: Silikon detektorler, OTR goruntuleme sistemi, geant4. Abstract: Optical Transition Radiation (OTR) is used for beam profile measurements in accelerator facilities. In OTR systems generally aluminum and gold are used as view screens. In this work, the simulation studies were carried out on usability of Silicon (Si) material as view screens in OTR systems. The simulations studies were carried out with two different electron beam energies of 18.5 MeV and 38.5 MeV on aluminum, lead, titanium, copper, silver, gold and silicon based view screen materials. It can be seen from the simulation results that silicon based view screens will be a good candidate as view screen in OTR systems. Key words: Particle detectors, silicon detectors, transition radiation, geant4.

Ozet: Bu calismada, elektron spektrometrelerinde (ESM) goruntuleme elemani olarak kullanilan sintilator ekranlarin yuksek cozunurluklu sonuc elde edilmesi amaciyla hassas bir sekilde konumlandirilmalari icin gerekli hesaplama ve benzetim islemleri gerceklestirilmistir. Bu amacla, manyetik alan ile yuklu parcaciklarin bukulmesi sonrasinda sahip olduklari enerji dagiliminin 6 boyutlu uzayda benzetimini yapabilen ve demet karakteristigi hakkinda bilgiler veren General Particle Tracer (GPT) paket programi kullanilmistir. Anahtar kelimeler: Elektron spektrometre (ESM), yuksek cozunurluk, sintilator ekran, konumlandirma. Positioning of Scintillating Screens for High Resolution Electron Spectrometer Abstract: In this study, required calculation and simulation operations were carried out to for precisely positioning the scintillator screens that used in electron spectrometers (ESM) as a viewing element to obtain high resolution results. For this purpose, a package program, General Particle Tracer (GPT) was used which could simulate the energy distribution of the charged particles in 6 dimension space after they bended due to a magnetic field and gives information about the beam characteristic. Key words: Electron spectrometer (ESM), high resolution, scintillator screen, positioning.

In this study the electrical theory of excitation propagation in excitable cell was investigated. The basic principals of linear cable theory were given and general differential equations concerning excitable cells were derived. The passive cable model simulation of axon was made through the programme of MATLAB7.0.4/ Simulink. In order to reach the realistic model, which is one of the main targets of the study, two simplified and revised models were used. A realistic wave shape was produced in MATLAB7.0.4/Simulink as the action potential wave shape spreading in axon. As seen in the results, the more length increases in the values of minimum and maximum amplitude, the weaker. They are as expected in the simplified model. When the simulation results of the two simplified and revised models compared, in the output of the revised model the minimum amplitude is seen to decrease. In the revised model, an ideal capacity element which we recommend was found. However, the most crucial result is that this capacity shortens the hyperpolarization period.

With the increasing use of magnetic fields in recent five decades, the health effects of nonionized electromagnetic radiation is an important investigation subject. While the magnetic field is well known, it is difficult to investigate the health effects of radiation, because of the complex metabolism of human body. However, by the experimental and theorical studies, a lot of significant health effects of magnetic fields have been discovered. But, there are probabilities that can have much more adverse health effects. The purpose of this study is to evaluate the effect of 50 Hz-1 mT magnetic field on human median motor nerve conduction parameters. At this frequency, 1 mT value of magnetic field intensity is known and accepted as the marginal value where biological interaction starts. Standard nerve conduction techniques using constant measured distances were applied to evaluate the median nerve. Consequently in the measures conducted using the device of 4 channel NCS/EMG/ EPS there was a significant decrease in motor distal amplitude after the magnetic field application in comparison to the one during the application (p=0,000573) and also in the motor distal amplitude/ proximal amplitude in comparison to the ones before the application (p=0,037418).

A SASE FEL facility was first proposed in Feasibility Report of the TAC (Turkish Accelerator Center) project in 2000. Conceptual Design Report (CDR) of the project was completed in 2005. Technical Design Report (TDR) studies of TAC were started in 2006 in frame of an inter universities project with support of State Planning Organization (SPO) of Turkey. Main goal of the SASE FEL proposal is to cover VUV and soft X-rays region of the spectrum besides IR-FEL, Bremsstrahlung and Synchrotron Radiation proposals of TAC. Up to now, optimization studies based on a special RF linac or an Energy Recovery Linac (ERL) for the SASE FEL facility, were completed. Today, ERLs provide a powerful broad range of applications like: electron cooling devices, high average brightness, high power FELs, short-pulse radiation sources and high luminosity colliders. In this study, main parameters for two linac options and SASE FEL are given.

The TAC (Turkish Accelerator Center) IR FEL Oscillator facility, which has been supported by Turkish State Planning Organization (SPO) since 2006, will be based on a 15-40 MeV electron linac accompanying two different undulators with 2.5 cm and 9 cm periods in order to obtain IR FEL ranging between 2-250 microns. The electron linac will consist of two sequenced modules, each housing two 9-cell superconducting TESLA cavities for cw operation. It is planned that the TAC IR FEL facility will be completed in 2012 at Golbasi campus of Ankara University. This facility will give an opportunity to the scientists and industry to use FEL in research and development in Turkey and our region. In this study, the results of optimization studies and present plans about construction process of the facility are presented.

Time measurements with sub-nanosecond time resolution (aiming at values of few picoseconds) are of paramount importance for a wide variety of applications. In the field of particle physics, measuring with increasing precision the time taken by a particle to travel between two points (Time-of-Flight, ToF) gives information on the particle’ (relativistic) velocity, contributing to identifying the type of particle (Particle Identification Detectors, PID). Among this category of detectors are also Cherenkov counters, based on the emission of light when a charged particle travels in a transparent medium with a velocity exceeding the light velocity in that medium. Here we discuss a special category of ToF counters using the properties of Cherenkov light to determine the passage of the particles through the detectors with unprecedented precision. Results obtained with test beams are described and analysed, demonstrating the excellent timing resolution that can be obtained. Such detectors may be used to provide a ‘precision time reference’ for calibrating other types of timing detectors. Other applications are, for instance, time-tagging of ‘pile-up’ events in high-luminosity Large Hadron Collider (LHC), and identification of events with anomalous timing properties (for instance, long-lived particles, LLP).

Kozmik ışınlar, oldukça geniş bir enerji aralığına sahip temel yüklü parçacıklardan ve çekirdeklerden oluşur. Bazıları Güneş’ten kaynaklanırken, diğerleri yıldızlararası uzayda süpernova patlamaları ve diğer çok yüksek enerjili olaylar sonucunda bize ulaşır. Bu parçacıklar Dünya’nın üst atmosferiyle etkileşime geçerek ikincil parçacıklara bozunurlar. Burada odaklandığımız ikincil parçacık olan Müon, ömrü 2,5 mikrosaniye kadar kısa olmasına rağmen ışık hızına yakın hızlarda hareket etmesi sebebiyle görelilik etkilerine maruz kalır ve yer tabanlı dedektörler tarafından kolaylıkla tespit edilebilirler. Müon akısındaki değişimlerde Güneş’in rolü son derece önemlidir. Kozmik ışın akısı ile güneş aktivitesi arasında bir ilişki olup olmadığına dair birçok çalışma bulunmaktadır. Bu çalışmalar zaman bağlamında ikiye ayrılabilir; Uzun vadeli değişiklikler olarak Güneş’in 11 yıllık aktivite döngüsü boyunca Kozmik Işın akısının takibi ve kısa vadeli (gün, saat bazında) Kozmik Işın akısının ani düşüşünü gözlemleyerek Güneş aktivitesi ile korelasyonunun takibi (Forbush Azalması) Müon akısının zamanla değişiminin takibi için bu çalışmada sunulan bir kozmik ışın dedektörü kurulup çalıştırılmıştır. Dedektör MIT üniversitesinden S.Axani ve arkadaşları tarafından kurulan CosmicWatch Taşınabilir Kozmik Müon Dedektörü esas alınarak kurulmuştur (Axani et al. 2018). Cosmic Watch dedektörü, Müon dedektasyonu alanına minyatürize edilmiş bir giriş niteliği taşımaktadır. Yapımının kolay ve anlaşılır olması, arka planındaki fiziğin anlaşılır olması esas alınması açısından önemli bir faktördür. Bu çalışmada kurduğumuz dedektörün temel düzeneği ve alınan ilk 41 saatlik veri paylaşılacaktır.

This article presents an overview of the recent RF bioeffects literature dealing with the nervous system. Studies have evaluated the electroencephalography (EEG) of humans and laboratory animals during and after radiofrequency (RF) exposures. Exposure to high levels of RF energy can damage the structure and function of the nervous system. Much research has focused on the neurochemistry of the brain and the reported effects of RF exposure. Studies of individuals who are reported to be sensitive to electric and magnetic fields are discussed. The many exposure parameters such as frequency, orientation, modulation, power density, and duration of exposure make direct comparison of many experiments difficult. At high exposure power densities, thermal effects are prevalent and can lead to adverse consequences. At lower levels of exposure biological effects may still occur but thermal mechanisms are not ruled out. It is concluded that the diverse methods and experimental designs as well as lack of replication of many seemingly important studies prevents formation of definite conclusions concerning hazardous nervous system health effects from RF exposure. The only firm conclusion that may be drawn is the potential for hazardous thermal consequences of high power RF exposure.

Bu calismada, sayisal optik mikroskoplarda otomatik odaklama yapilmasini saglayan elektronik devre kontrollu bir mekanik sistemin tasarimi ve goruntu isleme yazilimi ile birlikte gerceklestirilmistir. Cok noktadan kontrol yontemi temeline dayanan bu sistem ile homojen yukseklige sahip olmayan objelerin incelenmesinde mikroskobun otomatik odaklanmasi saglanmistir. Objelerin sekillerine gore goruntu uzerinde belirlenen sabit on bir nokta araciligi ile objenin sekline en uygun odaklama noktasi belirlenir ve motorlu mekanizma ile mikroskobun Z eksenindeki konumu en uygun noktaya tasinir. Calismalar otomatik odaklama sisteminin %90 dogruluk ile calistigini gostermistir.

well as the study of the di-$$\pi$$ angular correlations in comparison with QCD predictions. Results from the structure of particles produced in association with these $$\pi$$'s are also discussed. A nuclear enhancement of the di-$$\pi$$ events is observed and the results are presented in comparison with the data from other experiments.

A hodoscope system constructed with a scintillating fiber array and a multianode photomultiplier is described. The results of laboratory and beam tests on the hodoscope response, efficiency and spatial resolution are discussed.