http://dspace.zu.edu.ly/xmlui/handle/1/924 2026-04-14T06:44:14Z 2026-04-14T06:44:14Z بلق, سناء محمد النائب عبد الله, كريمة عمر, منال الهادي اغطيسة, سماح أبوبكر http://dspace.zu.edu.ly/xmlui/handle/1/964 2020-12-01T01:00:16Z 2020-08-01T00:00:00Z

التفاعل المتبادل بين إشعاعات جاما والمادة بلق, سناء محمد النائب; عبد الله, كريمة; عمر, منال الهادي; اغطيسة, سماح أبوبكر The aim of this experiment was become familiarized to study the interaction of gamma-rays with matter through three processes, these include photoelectric absorption, Compton scattering, and pair production set-up. This consisted of a high purity germanium (HPGe) detector with energy between [121 keV-1408 keV] rang and a Multichannel Analyzer (MCA) a radioactive source and absorber to calibration. The results of the graph show that an incident photon loses its intensity with every increase in the absorber. The rate at which this happens depends on the absorber material and the atomic number Z. the gamma rays where shown to follow beers law where the mass attenuation coefficient for each peak energy of153 Eu was found to decrease as the peak energy increase. The second part of the experiment was set up by using a Nal (TI) scintillation crystal spectrometer, and 137Cs source to produce γ-ray with energy 662kev. The Compton scattering was investigated the interaction of photon with free electrons. It is deflected through an angle with right direction, as a result the Compton scattering from the aluminium rod was measured by scattered radiation. The relation between the scattered radiations of energy count versus the angle was obtained. It was discovered that low angle the measured value fell below the prediction of klein- Nishina formula but it tend to meet at higher values of the rotation angle. It can be seen clearly from these results that the energy count decrease as the scattering angle increase, by using these data, the graph of 1/Eγ a giant (1-cosθ) was plotted. The result was in straight line with intercept of (1.5114 ±) and gradient of (1.9522±) that were good agreement with theory.

2020-08-01T00:00:00Z المهدي, أسماء سعيد أبوعجيلة http://dspace.zu.edu.ly/xmlui/handle/1/963 2020-12-01T01:00:15Z 2020-08-01T00:00:00Z

دراسة امتصاص الإشعاع (دراسة معامل الامتصاص الخطي والكتلي لأشعة جاما ) المهدي, أسماء سعيد أبوعجيلة Multichannel analyzer (MCA) provides an array of counting channels, or scalars, and systematically stores incoming pulses in these channels according to some prescribed criterion. The criterion defines a mode of operation. MCA can scan a whole energy range and record the number of pulses they count in each of the channels. A full width at half maximum (FWHM) is an expression of the extent of a function, given by the difference between the two extreme values of the independent variable at which the dependent variable is equal to half of its maximum value. Gamma rays are photons (quanta of light) and have no electric charge and no rest mass. Therefore, the interaction of gamma rays with matter is weak. There are 3 mechanisms that are important from the point of view of radiation protection such as (i) photoelectric effect (ii) Compton scattering (iii) pair production. This work will focus to photoelectric effect. The idea of the experiment is when the photons emitted from the source and strike the detector,The PMT consists of a photocathode, a focusing electrode, and 10 or more dynodes that multiply the number of electrons striking at each dynode. A chain of resistors typically located in a plug-in tube base assembly biases the anode and dynodes. Complete assemblies including the scintillator and PMT are available. The properties of a scintillation material required to produce a good detector are transparency, availability in large size, and large light output proportional to gamma-ray energy. Sodium iodide [NaI(Tl)] crystals are commonly used. The high Z of iodine in NaI(Tl) crystals result in high efficiency for gamma-ray detection. Resolution for a 2inch diameter by 2 inch length crystal. The light decay time constant for a NaI(Tl) crystal is about 0.23 µs. Typical charge-sensitive preamplifiers translate this into an output voltage pulse with a risetime of about 0.5 µs. Fast coincidence measurements cannot achieve the very short resolving times that are possible for plastic scintillators, especially at low gamma-ray energies. So a good signal will appeared from the MCA represented by peaks we take the bigger one to get the results . And before we start the details of our experiment we’d like to going into some properties of gamma ray and its interactions with matter according to the probability of its interactions and the attenuation of its intensity during the interaction with different types and thicknesses of materials, as we used the (AM-241) source of gamma.

2020-08-01T00:00:00Z دلالة, جمال أبوعجيلة http://dspace.zu.edu.ly/xmlui/handle/1/962 2020-12-01T01:00:15Z 2020-08-01T00:00:00Z

التعرف على مفاهيم أساتذة الجامعات حول التقويم التكويني الهادف في تدريس اللغة الإنجليزية كلغة أجنبية دلالة, جمال أبوعجيلة Having positive attitudes towards formative assessment in the classroom is unquestionably of paramount importance in teaching and learning English as a foreign language. Investigating teachers’ conceptions towards formative assessment would be more useful for supporting students ‘learning. This study investigates the Libyan university teachers ‘views about formative assessment in the classroom. Based on this, the following research question was formulated to guide the current study: What teaching conceptions do Libyan university teachers hold towards formative assessment in teaching and learning English as a foreign language? Data were collected through self-completed questionnaires answered by 30 EFL teachers at the public University of Zawia. The teachers were invited to give their opinions about formative assessment role in improving student learning. The data were analyzed through a calculation of the percentage in descriptive statistics. Very strong opinions were expressed about formative assessment as a powerful strategy to supports student learning. Formative assessment involves students in the learning process through identifying the gap in student learning, providing constructive feedback and providing clear learning progressions. And new evidence may lead to the conclusion that there is a strong link between formative assessment and Learning development

2020-08-01T00:00:00Z حسن, طارق مفتاح أبومهدي, عفاف عامر حسن http://dspace.zu.edu.ly/xmlui/handle/1/961 2020-12-01T01:00:13Z 2020-08-01T00:00:00Z

تقدير الفلوريد في بعض الانواع من الشاي في السوق الليبي حسن, طارق مفتاح; أبومهدي, عفاف عامر حسن

2020-08-01T00:00:00Z