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Characterisation of Local Topaz to Develop a Radiation Dosimeter

Thesis Info

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Author

Sardar, Muhammad

Program

PhD

Institute

Pakistan Institute of Engineering and Applied Sciences

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2012

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2758/1/1467S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725670977

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Thermoluminescent dosimeter (TLD) is a device used to evaluate integrated dose of ionizing radiation. Natural mineral topaz as a thermoluminescent (TL) material has been studied for radiation dosimetry. The northern area of Pakistan along with Himalayas, due to its geological settings, is rich in topaz which is found in pegmatite rocks. Four mines namely: Kharguluk, Nyit, Sabser, and Yono in district Skardu were selected for sampling of topaz. Relatively big pieces of topaz were converted into chips and powder of micron size. Pellets of topaz composite with glass 1:2 wt.% and teflon 2:1 wt.% were prepared by compressing and sintering. The mineral was recognized as topaz through phase identification by XRD (X-ray diffraction). The mineral collected from Kharguluk mine was not topaz rather mixed with quartz. The elemental analysis by the XRF (X-ray fluorescence) of topaz of understudy mines resulted about 56.554, 22.030, 11.293, 9.560 and 0.453 at.% of the elements O, Si, Al, F and H. These results confirmed the mineral as topaz. The irradiation of topaz pieces with fast neutrons and thermal treatment produced deep and London blue colours in topaz. The TL response of virgin topaz of understudy mines generated a single huge peak in glow curve at temperature around 250 oC, which is the gesticulation of topaz. The INAA (Instrumental Neutron Activation Analysis) of topaz from the three mines detected the elements Na, Ga and Cs in three mines, while As and Sb were detected in Yono and Nyit mines respectively. The photoinduced emission spectra of topaz powder from three mines at the excitation wavelength 230 nm produced two bands. One band is at 430 nm and other at 470 nm which are the characteristics of topaz. The pellets of the composites were sintered at 400 to1200 oC. The TL response of the composites and [OH]/[F] ratio decreased with increasing sintering temperature. The optimum temperature selected for preparation of topaz composites was 900 oC. The effect of ultraviolet (UV) and visible light on topaz revealed that UV and visible light contribute to phototransference of charge. The TL glow curves of topaz chips, topaz-glass and topaz-teflon composites showed stable peaks (dosimetric peaks) at about 250-260, 250-260 and 257-265 oC respectively. Initially, the fading was maximum (27-30 %) and became 6-9% after few days. Chips and pellets showed the linearity with dose, good reproducibility, independent dose rate, linear dose response and strong energy dependence below 600 keV. The chips and pellets were found suitable for dosimetry for dose greater than 0.01 Gy at high energy beams. Saturation in the TL response was observed above 2000 Gy. The pellets of topaz-glass showed better mechanical stability than topaz chips and topaz-teflon pellets. The cutting of topaz chips was found difficult and time consuming, while the preparation of pellets of topaz-glass and topaz-teflon was relatively easy. Topaz-glass showed better TL dosimetric features as compared to topaz chips and topaz-teflon composites. These are recommended to be used at the facilities where high radiation doses are involved. The TL analysis of the glow curves using IRM (Initial Rise Method), Tm-Tstop, PSM (Peak Shape Method) and VHR (Variable Heating Rate) method showed that topaz and its composites with glass and teflon follow second order kinetics. The thermal activation energies 0.976- 1.576 eV for natural topaz were found to be greater than 0.488-0.627 eV for topaz- glass and 0.447-0.616 eV for topaz-teflon. The thermal activation energy found by VHR was 1.35 times higher than determined by PSM and IRM. The OSL (optical stimulated luminescence) dosimetric characteristics of the pellets of topaz-glass and topaz-teflon composites were studied for various energy beams of photons and particles using CW (continuous wave)-OSL mode. Blue light as a stimulation source for OSL generated a rapid decaying response within 10 s and then a long non-zero tail was observed. The integrated OSL (IOSL) response met the dosimetric requirements for topaz-glass and topaz-teflon at dose greater than 0.01 Gy and 1.0 mGy respectively. The TL response of topaz before and after OSL measurement showed two peaks in the glow curve at the same position. After OSL measurement, decline of about 1.35 times less in intensity of peak 2 was observed. Radiation dose was measured at IPEN, Brazil with the TLDs: LiF, topaz- chips and the composites of topaz-glass and topaz-teflon. Using the respective calibrations curves and applying the fading corrections, the measured dose proved that topaz and its composites are suitable for radiation dosimetry at high radiation areas. The price of topaz based TLDs is less than commercial dosimeters. Topaz-glass and topaz-teflon pellets can be recommended for the measurement of dose greater than 0.01 Gy by the TL method, while topaz-teflon are suitable for dose greater than 1.0 mGy using OSL read out. Further exploration of topaz from other mines of Pakistan, their TL/OSL analysis and applicability at sterilization, irradiation and medical centres is strongly recommended.
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زندگی کی بو قلمونیاں اور رنگا رنگ حقائق

زندگی کی بوقلمونیاں اور رنگارنگ حقائق
نحمدہ ونصلی علی رسولہ الکریم امّا بعد فاعوذ بااللہ من الشیطن الرجیم
بسم اللہ الرحمن الرحیم
صدرِذی وقار!آج مجھے جس موضوع پر اظہار خیال کرنا ہے:’’وہ زندگی کی بوقلمونیاں اور رنگارنگ حقائق کے بارے میں ہے‘‘
جناب!
زندگی ایک ابدی خوشی کا نام ہے۔ زندگی ایک غیر مرئی چاہت کا نام ہے زندگی جگنو کے نور کا نام ہے، زندگی دل کے سرور کا نام ہے۔
جنابِ صدر!
زندگی ایک ایسا پھول ہے جس کی مہک سے گلشنِ حیات کی فضا معطر ہوجاتی ہے۔ زندگی ایک ایسے جذ بے کا نام ہے جو نا امیدی کی دلدل میںکبھی نہیں گرنے دیتا، زندگی ایک ایسی چمک کا نام ہے جس سے مُردنی اور موت کے سائے بھاگ جاتے ہیں۔
صدرِ ذی وقار!
زندگی نے ہی تو مجھے معاشرے میں چلنے کا سلیقہ سکھایا، زندگی نے ہی تو مجھے قبیلے کا ایک اہم رکن بنایا، زندگی نے ہی تو حرارت ِایمانی بخشی، زندگی نے ہی تو مجھے عبادت کا ڈھنگ سکھایا، زندگی ہی نے مجھے خود شناسی کے علاوہ خداشناسی بخشی۔
معزز سامعین!
میرے مخالف نے تو حد کر دی ہے۔ لیکن کیا ہوا مخالفوں نے تو مخالفت تو کرنی ہی ہوتی ہے، زندگی کو ایک مصیبت کے طور پہ پیش کیا ہے، زندگی سے مخاصمانہ رویہ محمودنہیں ہے، زندگی خود اس کی آمد کا سبب ہے، اُس کے والدین کی زندگی اُس کی حیات نو کا سبب ہے۔
جنابِ صدر!
زندگی ہے تو بطخ کا بچہ بھی تالاب میں تیراکی کرتا ہوا اچھا لگتا ہے، زندگی ہے تو فلک کی بلندیوں پرمحو پرواز طائر خوش الحان کی اڑان میں انفرادیت نظر آتی ہے۔ زندگی ہے تو شاخِ مغیلاں پر چہکتی ہوئی کنجشک مادہ اپنے بچوں کو چوگ دیتی ہوئی اچھی لگتی ہے۔
معزز سامعین!
میں یہ...

توبہ و استغفار: قرآن کریم کی تعلیمات کی روشنی میں ذہنی سکون کا منبع

It is evident from the teaching of Quran & Sunna, Allah SWT accepts the repentance of His servants. The concept of repentance is according to synthesis of human nature. As a matter of fact, the commission of sins is deep rooted into the human nature and except the messengers of Allah SWT, who are by their nature immaculate and impeccable, all the human beings commit the sins in one form or the other. However, the countless mercy of Allah SWT is showered upon the servants in the shape of “tauba” or repentance. The concept of repentance infuses a new life into the sinful soul of human being. The tauba or seeking forgiveness of Allah SWT revitalizes the enthusiasm of worship in the Muslim. The concept of the acceptance of tauba provide the peace of mind, consolation and satisfaction of heart to the believers. It enables him to reconnect himself to his Lord. Once a person realizes the forgiveness of Allah SWT, he feels a unique tranquility in his heart. This paper will investigate the multiple verses of Quran and Prophetic Sunna concerning the tauba and istaghfar, and how it helps us to attain the peace of mind and acquire satisfaction of heart.

Analysis of Adoption Gap of Weed Management Practices Among Farmers under Different Cropping Systems in District Khanewal Punjab , Pakistan

Weed management has become a major problem, which needs to be addressed properly by adopting all possible measures to control weeds. Weed infestation is a very serious problem as it can reduce 20-40% yield of wheat, 20-63% of rice, 20-55% of cotton, 10- 18% of potato, and up to 45% of maize by utilizing productivity of land in the form of water and nutrients through root zones. This situation calls for an urgent need to create awareness among the farmers about the recommended weed management practices. There are many extension organizations both public and private working in Pakistan for the introduction of weed management practices among the farmers. However, there are many constraints in the adoption of these practices like shortage of proper facilities available to farmers, high prices of weedicides, adulteration in weedicides, ineffective extension services, and lack of awareness among farmers regarding recommended weed management practices. Keeping in view this situation, present study was designed to analyze the adoption gap of weed management practices by farmers under different cropping systems. The present study was conducted in district Khanewal (Punjab), Pakistan. The most commonly practiced cropping systems in all the four tehsils of district Khanewal are rice-wheat, cotton-wheat, cotton-maize and maize-potato. Total sample size used in this study consisted of 400 farmers (respondents) selected by simple random sampling technique by drawing 100 farmers from each cropping system. A pre-tested, validated and reliable interview schedule was used for data collection. The collected data were analyzed using frequency distributions, weighted scores, standard deviation, mean and LSD values. The Chi-square was used for computing the relationship of socioeconomic characteristics of the respondents with different factors relating to the adoption gap of effective weed management practices. The age, education, farm size, tenancy status, farming experience and annual income of the respondents had shown highly significant association with their awareness regarding weed management practices whereas sources of income had a significant relationship with their awareness about weed management practices in all the cropping systems (C-M, C-W, M-P and R-W). Education, farm size, and annual income of the respondents showed highly significant effects on their adoption. Age and income had a significant association, whereas, tenancy status, farming experience, sources of income had non-significant association with their adoption about weed management practices in all the CSs. Non-availability of labour, lack of time, non-availability of machinery, adulteration and high cost of weedicides were major hindrances in the adoption of recommended weed management practices as reported by the respondents. The high adoption gap of weed management practices in all the CSs was observed. In order to minimize the adoption gap, it was suggested that pure and effective weedicides should be made available at reasonable prices and extension field staff (EFS) should arrange more visits to solve the problems of farmers. Policy makers should take steps to ensure regular checking of rate lists and licenses of herbicide dealers to maintain prices and quality of inputs. It was also suggested by the farmers that there should be good cooperation between farmers and EFS. Furthermore, printed material should be provided to the educated farmers to get deep insight of weed management tactics. It is also proposed that EFS should be equipped with proper training regarding weed management strategies, and their knowledge level and communication skills must be upgraded.