Search

The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large gamma-ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23 l and it is filled with the EJ301 liquid scintillator, that presents good neutron-gamma discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the Ni-58 + Fe-56 reaction measured with the Neutron Wall detector array.

A 6LiF target of 26µg/cm2 thickness was bombarded with 250 keV atomic protons with 50 µA beam current intensity for the experiment. The gamma spectrum emerged from the reaction is measured by HpGe detector using a multichannel analyzer in the 0-7 MeV energy range at 3.3 cm away from the target in the proton beam direction. The ground and the first excited states of 7Be and the energy levels of 19F(p,αγ)16O reaction can separately be detected in the resulted spectrum. The cross section of 6Li(p,γ)7Be reaction at 250 keV energy range has been measured.

TENMAK D.N.. 3929 Çevreden gelen doğal gama aktivitesini ≈ 100 misli azaltan kurşun korunak içine alınmış bir 3" x 3" Nal(Tl) dedektörün mutlak foto-pik verimi ölçülmüş ve bu dedektörle, bazı deniz ürünlerinde doğal gama ışınları sayılarak Potasyum miktarı belirlenmiştir. An effective lead shielding around a 3" x 3" Nal(TI) detector has been installed and the general background level for gama rays has been reduced by a factor of ≈ 100 . The photo-peak efficiency of the detector is measured. The potasium concentration in the seaweed and fish determined by measuring the 40K activity.

TENMAK D.N.. 7878 Nötron akışı düşük üreteçlerin ekonomik bir şekilde kullanılmasını sağlayan "Tek Işınlama-Tek Sayım" yöntemiyle, analizi istenen malzeme içindeki bir cok elementin aynı sipekturum içinde belirlenebilmesi, "Aktivasyon Matris Formalizmiyle" mümkündür. Bu çalışmada, özellikle reaktör nötronlarıyla belirlenmesi zor olan elementlerden, Tarım bilimlerinde önemi olan Na, Mg, Al, Si, P, K, gurubunun aktivasyon matris elementlerine gerekli (n,p), (n,α), (n,2n) hızlı nötron tepkileşim kesitleri ölçülmüş ve bu tekniğin bir uygulaması olarak da yerel bir örneğin cok-element analizi gerçekeştirilmiştir. Economical use of a Neutron Generator with low neutron output can be achieved by employing "Single Irradiation-Single Counting" technique. Effective and accurate multi-element analysis utilizing this technique may only be possible by means of the "Activation Matrix Formalism". In this work, (n,p), (n,α), (n,2n) neutron activation cross-sections needed to build the activation matrix for the elements Na,Mg,Al,Si,P,K were measured and applying the technique developed, a local sample was analyzed.

TENMAK D.N.. 8023 3"x3“ kuyu tipi Nal(Tl) dedektör sisteminde Pd Kx-ışınlarının ölçümü yöntemiyle, şimdiye kadar üzerinde durulmamış bir d +d -> α "Soğuk Füzyon” türünün olabilirliği araştırılmıştır. Bu deney, böyle "eksotik" bir tepki leşimin yer almadığını göstermektedir. The plausibility of d + d -> α type "Cold Fusion" which has not been given any attention so far, was investigated by a method based on detection of Pd Kx-rays using a well-type 3"x3" NaI(Tl) detector system. No evidence of this kind of "excotic" reaction was found.

TENMAK D.N.. 7981

TENMAK D.N.. 7869. Bu çalışma III. Ulusal Nükleer Bilimler Kongresinde (İstanbul 1989) bildiri olarak sunulmuştur. TR--2 Reaktör kalbinde, malzeme analizi ve radyoizotop üretimine yönelik çalışmalarda kullanılan ışınlama tüpleri içindeki nötron akı yoğunluk dağılımı nötron aktivasyon yöntemiyle ölçülmüştür. Bu amaçla ışınlanmış Al,Fe,Ni,Zr ve In foillerin gama aktivitesi verim kalibrasyonu yapılmış bir HPGe Sayım Sisteminde ölçülmüş ve 27AI (n,α) , 54Fe(n,p), 58Ni(n,p) ve 90Zr(n,2n) uyarım fonksiyonlarından yararlanılarak Hızlı Nötronların Enerji dağılımı empirik olarak belirlenmiştir. Deneysel değerlere yapılan uyum sonucunda empirik bir akı yoğunluğu bağıntısı elde edilmiştir. 1 MW güç için D-45 ışınlama elemanı içinde ̴ 4 x 10(12) n/s.cm2.MeV lik bir değer bulunmuştur. Neutron flux density inside the irradiation element, which is used for material analysis and radio-isotope production, was measured the by neutron activation method. Al,Fe,Ni,Zr and In foils were irradiated and a HPGe detector system was employed to determine the induced activities. The energy distribution of fast neutrons was determined empirically by utilizing 27Al(n,α), 54Fe(n,p), 58Ni(n,p) and 90Zr(n,2n) excitation functions and fitting the experimentel values measured in the course of this work to an empirical formula. The neuton flux for 1 MW power was found to be ̴ 4 x 10(12) n/s.cm2.MeV.

TENMAK D.N.. 8054 ÇNAEM Fizik Bölümünde oluşturulan Hızlı Nötron Fiziği Laboratuvarının temel cihazı olan SAMES T-400 alçak enerjili iyon hızlandırıcısının geniş bir tanıtımı yapılmıştır. Sistemim güvenli olarak çalışmasını sağlamak için sonradan tasarlanarak sisteme eklenen destek üniteleri ve örnek ışınlamak için yapıları pnömatik transfer sistemi açıklanmıştır. Ayrıca, sistemin döteron huzmesinin hedef üzerindeki yeri tespit edilmiş, d-d tepkileşiminden elde edilen nötronların, akışı ve açısal dağılımı tayin edilmiştir. The Fast Neutron Physics Laboratory, which was recently set up in ÇNAEM Physics Department, is introduced. The Fast Neutron Irradiation System, based on a low energy ion accelerator (SAMES T-400), is described in detail. Additional support units designed for reliable and safe operation of the system and a pneumatic sample transfer system are also described. In addition, the position of the deuteron beam spot on the target, the neutron flux and the angular distribution of neutrons from the 2H(d, n)4He reaction, were determined.

TENMAK D.N.. 7937 ÇNAEM Fizik Bölümünün SAMES T-400 alçak enerjili iyon hızlandırıcısıyla 3H(d, n) 4He tepkileşimi sonucu üretilen nötronların ışınlama bölgesindeki ortalama enerjileri, 90Zr(n, 2n)/93Nb(n, 2n) tepkileşim kesitlerinin oranlanması yöntemiyle ölçüldü. Ek olarak, hızlandırılan döteron huzmesinin atomik ve moleküler bileşenlerden oluşmasını, döteronların Titanyum-Trityum hedef içindeki yavaşlamalarını, döteron huzme kesitini ve ışınlanan örnek boyutlarını içeren basit bir modelle, ortalama nötron enerjisi ve bu enerjideki yayılma hesaplandı. Ölçüm ve hesaplama sonuçlarının tutarlı oldukları görüldü. The method of 90Zr (n , 2n)/93Nb (n ,2n ) cross-section ratio was utilized and the average energy of neutrons -from 3H(d,n) 4He reactions was measured at the sample irradiation position of the ÇNAEM Physics Department SAMES T-400 low-energy ion accelerator. Additionaly, a simple model was utilized and the avarage neutron energy and its spread were calculated. In this model, atomic and molecular composition of the deuteron beam, energy loss of the deuterons in the target material, the deuteron beam size and the irradiated sample geometry were taken into consideration. A good agreement with the measurement was obtained.

WOS: 000372866900001, The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large gamma-ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23 l and it is filled with the EJ301 liquid scintillator, that presents good neutron-gamma discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the Ni-58 + Fe-56 reaction measured with the Neutron Wall detector array., MINECO, Spain [FPA2011-29854-C04, FPA2012-33650, FPA2014-57196-C5]; Generalitat Valenciana, Spain [PROMETEO/2010/101, PROMETEOII/2014/019]; European Regional Development Fund (FEDER) of European Commission; Swedish Research Council; Polish National Science Centre [801/N-COPIN/2010/0, UM0-2014/14/M/ST2/00738, UM0-2013/08/M/ST2/0025]; Scientific and Technological Council of Turkey [106T055, 114F473]; UK STFC [ST/L005727/1]; Science and Technology Facilities Council [ST/L005727/1, ST/L005735/1], This work was partially supported by MINECO, Spain, under the grants FPA2011-29854-C04, FPA2012-33650 and FPA2014-57196-C5, and Generalitat Valenciana, Spain, under the grants PROMETEO/2010/101 and PROMETEOII/2014/019, The European Regional Development Fund (FEDER) of European Commission, the Swedish Research Council, the Polish National Science Centre under contracts: 801/N-COPIN/2010/0 (COPIN/IN2P3 collaboration), UM0-2014/14/M/ST2/00738 (COPIN-INFN collaboration), UM0-2013/08/M/ST2/0025 (LEA-COPIGAL collaboration), the Scientific and Technological Council of Turkey (Proj. no. 106T055 and 114F473), and the UK STFC (ST/L005727/1).