Construction and calibration of (Ra-Be) welded standard neutron battery

Bu çalışmada, mutlak nötron akısı bilinen bir standart nötron pili yapılmış ve kalibre edilmiştir. Pilin yapım ve kalibrasyon işlemleri sırasında kullanılan malzemelerin özellikleri ile yöntemler anlatılmıştır. Mukayese yöntemin den yararlanılarak G-M sayma sisteminin verimi belirlenmiştir. Standart pilin herhangi bir noktasındaki termik nötron akısı, nötron aktivasyon yöntemi kullanılarak doğrudan ölçülmüş ve termik nötron akı dağılımları elde edilmiştir.In this study we have constructed and calibrated a standard neutron pile with known absolute neutron flux. We have explained the properties of the materials and techniques which were used during construction and calibration procedures of the pile. We have determined the efficiency of G-M counting system by using comparison method. The neutron flux at an arbitrary point of the standard pile has been measured directly by the activation method and we have obtained thermal flux distribution for the pile

Secondary avalanches in gas mixtures

Avalanche development in gas-based detectors relies not only on direct ionisation but also on excitation of noble gas atoms. Some quencher molecules can be ionised when they collide with excited atoms, a process on which we reported earlier [1]. Alternatively, excited atoms can decay by photon emission. If these photons are insufficiently absorbed by the quencher, yet capable of ionising, then they may escape from the avalanche region and start secondary avalanches. This process, called photon feedback, leads to an over-exponential increase of the gas gain which limits the working range. In this paper, we derive photon feedback parameters from published gain measurements for several gas mixtures and fit these parameters in a model which describes their dependence on the quencher concentration and the pressure

Türk Hızlandırıcı Merkezi Infrared Serbest Elektron Lazer Laboratuarı için Kontrol Sistemi

Özet: Bu çalışmada, Türk Hızlandırıcı Merkezi (THM) infrared serbest elektron lazer (IR-SEL) laboratuarında kullanılması düşünülen EPICS (Experimental Physics and Industrial Control System) kontrol sistemi yazılımı tanıtılmıştır. IR-SEL laboratuarında EPICS yazılımı kullanılarak, SEL' in üretiminden kullanıcı istasyonlarına kadar olan tüm alt birimlerin kontrolü sağlanabilmektedir. THM IR SEL laboratuarı için, doğrusal elektron hızlandırıcı (e-linak) sisteminde demet akımı ve konumu kaynaktan dump edilene kadar çeşitli noktalarda EPICS yazılımı kullanılarak incelenmiştir. Anahtar kelimeler: Laboratuar kontrol sistemi, EPICS, e-linak kontrol Control System for Turkish Accelerator Center Infrared Free Electron Laser Laboratory Abstract: In this work, EPICS (Experimental Physics and Industrial Control System) program chosen for the control system of the Turkish Accelerator Center (TAC) infrared free electron laser (IR-FEL) laboratory has been introduced. By using EPICS program, the control of all sub systems can be provided from SEL production phase to the user stations in IR-FEL laboratories. Beam current and position in a linear electron accelerator (e-linac) system for TAC IR-FEL laboratory have been investigated from source to dump by using EPICS program. Key words: Laboratory control system, EPICS, e-linac contro

Idiopathic focal organizing pneumonia mimicking malignancy

Idiopathic FOP is a rare type of COP. What we know on this subject is made up of a few clinical cases published in recent years. Our patient was admitted to the hospital with an intermittent coughing complaint that worsens over time. Due to a suspicion of malignancy, a radiological evaluation was requested including a PET-CT and a transbronchial biopsy was performed. Until the last part of our algorithm, the patient profile was clinically and radiologically in favor of the diagnosis of malignancy but, in the end, the diagnosis of FOP was fixed with a follow-up decision. In conclusion, FOP is a relatively new entity that should be kept in mind in the differential diagnosis of malignancy

Beam offset impact on the polarization in the CLIC beam delivery system

The baseline configuration of the Compact Linear Collider (CLIC) foresees an electron beam with 80% polarization at the interaction point (IP) to be measured with an accuracy of 0.1%. The propagation of the polarization through the CLIC beam delivery system (BDS) is investigated here using the BMAD code. The impact of offsets applied both to the beam and the different elements in the CLIC BDS on the polarization at the IP is evaluated

Study of Muon Backgrounds in the CLIC Beam Delivery System

We describe the detailed modelling of muon background generation and absorption in the CLIC beam delivery system. The majority of the background muons originates in the first stages of halo collimation. We also discuss options to use magnetised cylindrical iron shields to reduce the muon background flux reaching the detector region

Multipurpose high sensitivity radiation detector: Terradex

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 (222)Rn 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 (222)Rn 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. (C) 2007 Elsevier B.V. All rights reserved

Interaction-Region Design Options for a Linac-Ring LHeC

The interaction-region design for a linac-ring electron-proton collider based on the LHC ('LR-LHeC') poses numerous challenges related to collision scheme, synchrotron radiation, aperture, magnet technology, and optics. We report a first assessment and various options

Determination of the number of ψ(3686)\psi(3686) events at BESIII

The numbers of ψ(3686) events accumulated by the BESIII detector for the data taken during 2009 and 2012 are determined to be and , respectively, by counting inclusive hadronic events, where the uncertainties are systematic and the statistical uncertainties are negligible. The number of events for the sample taken in 2009 is consistent with that of the previous measurement. The total number of ψ(3686) events for the two data taking periods is