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Home > Design and Analysis of Shielding Cerrobend Blocks and Investigation of Performance of Thermoluminesce / Photoluminescence-Based Detectors During In-Vivo Dosimetry

Design and Analysis of Shielding Cerrobend Blocks and Investigation of Performance of Thermoluminesce / Photoluminescence-Based Detectors During In-Vivo Dosimetry

Thesis Info

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Author

Habib Ahmad

Program

PhD

Institute

University of Peshawar

City

Peshawar

Province

KPK

Country

Pakistan

Thesis Completing Year

2017

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/13143/1/Habib_Ahmad_Physics_HSR_2017_UoP_Peshawar_06.02.2018.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725820883

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The actual dose delivery in radiotherapy is of prime importance, which can only be achieved by using an accurate dosimeter. This work reflects the fabrication of three types of dosimeters that can be applied in radiation dose measurement during radiotherapy and other areas of radiation measurements. LiF is a special material, which when doped with some activators produces a single crystal that acts as a highly sensitive nanophosphor. These nanophosphors have several applications, such as, color center laser, integrated optics and radiation dosimetry. It is widely used in personal dosimetry because of its low energy dependence, tissue equivalency, stability and sensitivity. In this work, we have locally fabricated monocrystalline cubes of LiF doped with Mg, Ti, Dy3+ and Eu3+ by simple chemical coprecipitation method. These dosimeters were annealed at two unique temperatures i.e. at 400ºC and at 600ºC. The synthesized samples were characterized by XRD, SEM, and FESEM, EDX, FTIR for structural and morphological studies. XRD showed the phase of LiF and crystallite size was found around 30 nm. SEM studied the surface morphology of the samples as cubic, while EDX indicated the chemical composition of the nanophosphor. FE-SEM was employed to see the grain and grain boundaries more clearly. Furthermore, FTIR spectra were recorded in order to see the different molecular species and functional groups in these nanophosphors. The spectra revealed the presence of hydroxyl group (–O–H) of the metal hydroxide such as Mg (OH)2, stretching vibrations of rare-earth cations (Dy3+ and Eu3+) and metals oxides, Li-O and Mg-O. To study the PL properties of the two dosimeters (LiF: Mg, Dy3+ and LiF: Eu3+), PL spectroscopy was performed, which confirmed the emission spectra in the visible region of 685 nm for Dy3+and 610 nm for Eu3+. Both emissions occurred in the red portion of electromagnetic spectrum. Finally, the core property of these dosimeters i.e. the TL property was studied from their glow curves. All the obligatory parameters for these dosimeters were carried out; for example, dose sensitivity, dose linearity response, dose fading, dose rate dependency, angle dependency, and energy dependency. The fabricated TLDs and commercially available TLDs were compared both in sensitivity and glow curve peak temperatures. The glow peak temperature was 285 °C to 290 °C while the sensitivity of the fabricated TLDs was about 8 times less than that of commercial ones to lower doses and vice versa. In-vivo dosimetry was performed using Rando-phantom in 5 common radiotherapy treatment sights having Organ at Risk. The OARs were shielded with customized blocks. The shielded OAR dose and the in-field target doses were measured, using the TL dosimeters (LiF: Mg, Ti). The measured dose and the Treatment Planning System (eclipse point dose version) results were compared and both were found well correlated in open areas, and shielded regions.
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وفات

۱۵دسمبر ۱۹۹۷ء کو عارضہ قلب اور فالج کے حملے کی وجہ سے امین احسن اصلاحی اس جہاں فانی سے رخصت ہوئے ۔ ان کی نماز جنازہ امیر جماعت اسلامی قاضی حسین احمد نے پڑھائی۔[[1]]



[[1]]       خالد مسعود، علم و عرفان کے ماہ کامل کا غروب، ص ۲۔

The Analytical Study of Medication During Fasting in the Perspective of Shariah Rulings

The beauty of religion Islam is not only to provide the complete life style and charter for one to lead his life smoothly but it flourishes the human life with its eternal directions and commands full of hidden pleasures coupled with physical and spiritual care of human body. In fact, the everlasting religion comprised of such rulings that help individuals in every walk of life until and unless these rulings are implemented and executed in a proper way according to the prescribed codes of Almighty Allah and his Messenger, Prophet Muhammad PBUH. The thorough study of Shariah rulings reveals the fact that to protect the man’s life or even to make it in comfort and ease, the gradual and steady relaxation has been observed like the one unable to perform prayer in standing position, legitimate for him to sit or even through gestures according to the status of his illness and disease. Similarly, the fasting is important part of Worship, obligation upon Muslim to observe fasting during Ramadan with intentions to get Allah’s pleasure and piousness. This research study emphasis on highlighting the shariah rulings about the medication during fasting in order to know the extent of use, specification in drugs like injections and drips along with some relevant discussion about the spirit of medicine permission. The study will be the real addition to the knowledge and will be fine guidance for the Practiced Muslims.

Assessment of Productive Potential of Browse Species and Their Management Strategy in the Degrading Rangelands of Cholistan Desert

The Cholistan rangelands have been on decline due to various stresses and their effects can be visualized on its flora particularly on browse species. Therefore, a baseline study was carried to determine the productivity potential of browses with specific objectives of investigating their floristic composition, vegetation structure, forage productivity, and nutritive evaluation. Total 25 browse species belonging to 12 families and 17 genera were identified whereas Chenopodiaceae, Mimosaceae, and Rhamnaceae were found as dominant families that were mainly contributing to browse cover. In the investigated area two phenological seasons were recorded, first from February to April and second from September to November, whereas December to January and May to August were almost dormant phases. Further, based on economic importance of browses, maximum species were observed to be used as forage/fodder that clearly indicated that this area could serve as potential rangeland. According to phytosociological study, twenty browse communities were documented on the basis of importance value index. Multivariate analysis of twenty stands has delineated three vegetation associations inhabiting the sandunal, interdunal sandy and clayey saline habitats. Soil physio-chemical analysis revealed that texture of sandunal habitat was sandy; interdunal was sandy loam while clayey saline was clayey. Results have exposed that organic matter, and soil nutrients were better at interdunal sandy habitat whereas pH, EC, Na, and soil moisture were high at clayey saline habitat. It was estimated that browse productivity was high (8029.1 kg/ha) in wet season as compare to dry season (5422.9 kg/ha), correspondingly carrying capacity was high during wet season (16 ha/AU/Y) than dry season (24 ha/AU/Y). Moreover, during dry season, mostly stands were observed to be overgrazed while in wet season maximum stands were moderately grazed. High carrying capacity and good grazing status of stands in wet season was due to better forage production. Based on palatability classification, 22 species were found to have palatability to varying degree and 03 species were non-palatable. In palatable species, leaves of 14 species; shoot/stem of 13 species, flower of 04 species, and fruit of 03 species were grazed by livestock, whereas cattle were observed to graze on 07 species; goat and sheep like 10 species each while camel prefer 20 species. Subsequently, nutritive evaluation revealed that browse species were good source of dry matter and protein whereas; concentration of almost all the minerals (micro and macro) was less than required level for ruminants grazing therein. The findings of this study indicate that the browse productivity of Cholistan rangelands was low and fluctuate according to seasons. Therefore, they need proper protection, management, and rehabilitation through ecological approaches. This would be possible with the participation of government and local peoples to make these range resources sustainable. Key words: Cholistan rangelands, Browse species, Floristic composition, Phenology, vegetation structure, Multivariate analysis, Biomass production, Carrying capacity, Palatability, Nutritive evaluation