Development of a Survey to Assess Conceptual Understanding of Quantum Mechanics among Moroccan Undergraduates

We developed a Quantum Mechanics Conceptual Understanding Survey (QMCUS) in this study. The survey was conducted using a quantitative methodology. A multiple-choice survey of 35 questions was administered to 338 undergraduate students. Three experienced quantum mechanics instructors examined the validity of the survey. The reliability of our survey was measured using Cronbach's alpha, the Fergusson delta index, the discrimination index, and the point biserial correlation coefficient. These indices showed that the developed survey is reliable. The statistical analysis of the students' results using SPSS shows that the scores obtained by the students have a normal distribution, around the score of 7.14. The results of the t-test show that the students' scores are below the required threshold, which means that it is still difficult for the students to understand the concepts of quantum mechanics. The obtained results allow us to draw some conclusions. The students' difficulties in understanding the quantum concepts are due to the nature of these concepts; they are abstract and counterintuitive. In addition, the learners did not have frequent contact with the subatomic world, which led them to adopt misconceptions. Moreover, students find it difficult to imagine and conceptualize quantum concepts. Therefore, subatomic phenomena are still explained with classical paradigms. Another difficulty is the lack of prerequisites and the difficulties in using the mathematical formalism and its translation into Dirac notation

Determination of correction factor of self-absorption for lead-210 in environment samples using spike method

In environment radiation measurement, calculation the correction factors are critical, especially for low energy measurement because of self-absorption phenomena. In this work the main purpose is to determination the self-absorption correction factors of lead-210 (210Pb) energy (46.5keV) in various environment samples (7 sediments, 5 soil) using an experimental method called Spike Method. The samples were collecting from different places in Syrian. They were prepared according to the laboratory producers starting from collecting, cleaning, drying, grounding, hemogenic and calculating the appearance density. Low-energy gamma spectroscopy HPGe was used for radiation analysis which available at the laboratories of the Protection and Safety Department - Syrian Atomic Energy Commission – Syria. The spike method depends on adding a quantity of a standard solution with a known activity which contains lead isotope 210Pb and added to the studied samples. Self-absorption correction factors (CF) calculated by the ratio of the count rate or activity of spiked and unspiked samples. The CF for sediment samples were between 29% to 54% and for soil samples, the CFs were between 38% to 56% recording correction higher than sediment samples. The results showed a relatively high self-absorption and CFs values because of the chemical composition changeable between the spiked and unspiked samples. For that, it is better to adopt other methods less expensive, give results faster, higher accuracy and do not make change in the chemical composition. The results were also showed the density factor is the most influential factor in self-absorption phenomena