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Rana M.A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2010

Defect structure of latent tracks and their chemical etching are basic issues in solid state nuclear track detection and their advanced understanding helps to extend their applications in different disciplines of science and technology. These fundamental issues are analyzed here using computational and experimental investigations proposing physically appreciable models. A brief description of possible future directions for further extension of nuclear track detection technique is also given. Results, discussion and analysis given here present a comprehensive picture of essential aspects of nuclear track detection. © 2009 Elsevier B.V. All rights reserved. Source


Rana M.A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2010

Systematically planned new experiments were performed on fission fragment and alpha particle tracks in CR-39. In the present experiments, special attention was paid to reduction of spurious variations and fluctuations during exposures, chemical etching and etched track measurements. Measurements of etch induction time (tei) for fission fragment and alpha particle (of energy 4.59-6.11 MeV) tracks were carried out. Potential of tei for alpha particle spectrometry with CR-39 detector is demonstrated. Published results of atomic force microscopy (AFM) and conductometric cell measurements of various charged particle tracks in CR-39 and similar polymers were used as a support of the present results to propose a multiplex mechanism of startup of chemical etching of charged particle tracks. Results are useful for further development in the field of nuclear tracks and technology applications including nanotechnology. © 2010 Elsevier B.V. Source


Abbasi I.A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Medicine and Biology | Year: 2012

Objective: 99mTc-Sn-PYP (Technetium-99m labeled tin pyrophosphate) has been widely used as a radiopharmaceutical for bone scanning as well as in nuclear cardiology. It is also found in the body in trace amounts. 177Lu is presently considered as an excellent radionuclide for developing bone pain palliation agents. PYP is an analogue of MDP and MDP has been labeled with 177Lu. No study on preparing a complex of 177Lu with PYP has been reported yet. Based on these facts, it was hypothesized that a bone-seeking 177Lu-PYP (Lutetium-177 labeled Pyrophosphate) radiopharmaceutical could be developed as an agent for palliative radiotherapy of bone pain due to skeletal metastases. Methods: 177Lu was produced by irradiating lutetium foil (11mg) natural target at a flux ~1.0×1014n/cm2/s for 12h in the swimming pool type reactor. 177Lu in the form of 177LuCl3 was labeled with PYP. The radiochemical purity and labeling efficiencies were determined by paper chromatography. Labeling of 177Lu with PYP was optimized and a labeled sample was subjected to HPLC analysis. To determine the charge on the 177Lu-PYP complex, radio-electrophoresis was conducted for 1 h under a voltage of 300V and 45mA current using 0.025M phosphate buffer (pH 6.9). Bioevaluation studies with rabbit under γ-camera were also performed to verify the skeletal uptake. Results: The quality control using paper radio-chromatography has shown >99% radiochemical purity of 177Lu-PYP complex. Radio-chromatography also showed maximum labeling at ligand/metal ratio=60:1. HPLC analysis showed 1.42±0.01min retention time of 177Lu-PYP complex. No decrease in labeling was observed at higher temperatures. Gamma-camera images of 177Lu-PYP in normal rabbit at 24h post injection also showed high skeletal uptake. Conclusion: The study demonstrated that sodium pyrophosphate could be labeled with 177Lu with high radiochemical yields (>99%). Negatively charged 177Lu-PYP complex retained stability for a day and at high temperatures too. Gamma-camera images of 177Lu-PYP in normal rabbit at 24h post injection showed high skeletal uptake, suggesting that it may be useful as a bone-pain palliation agent for the treatment of bone metastases. © 2012 Elsevier Inc. Source


Matiullah M.,Pakistan Institute of Nuclear Science and Technology
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013

CR-39 based radon detectors are widely used in measuring indoor radon. In this regard, different groups have developed their own systems. However, before using any system for indoor radon measurements, it has, first, to be calibrated with a known source of radon. In the current study, CR-39 based NRPB type radon detector has been calibrated and presented. In this regard, about 200 holders for CR-39 were obtained from the Radiation Protection Division of the Health Protection Agency (former NRPB), UK and several thousand more similar detector holders, hereafter called NRPB type holders, were fabricated locally in Pakistan. Uranium ore samples of known grade were placed into the plastic containers of volume 5.4 × 103 cm3 and CR-39 detectors were placed in the NRPB type holders and were then installed into the containers at a distance of 25 cm from the surface of the known grade ore samples. The containers were hermetically sealed and the detectors were allowed to expose to radon for 3 weeks. After 16 h etching in 25 % NaOH at 80 C, the measured track densities were related to the radon concentration. The calibration factor of 2.563 tracks cm-2 h-1/kBq m -3 was obtained. © 2013 Akadémiai Kiadó, Budapest, Hungary. Source


Mushtaq A.,Pakistan Institute of Nuclear Science and Technology
Nuclear Engineering and Design | Year: 2011

In all probability, the same criteria applied to evaluate the safety of the reactor fuel shall be used to evaluate the safety of the targets used for the production of fission molybdenum-99. Thus, neutronic and thermal hydraulics considerations will dictate the maximum power of the targets, their uranium content, and the uniformity requirements for their loading. Radiography technique is capable of characterizing both meat location and density. Specifically, target plates that meet fuel density specifications can be irradiated with little risk of power peaking and hot spots. An adequate characterization and qualification of target plate cladding is also critical, because cladding breaches will contaminate the reactor coolant. Bend testing is a dependable way of testing bond strength while Ultrasonic Testing (UT) examinations qualify both bonding homogeneity and minimum thickness of that cladding. The bonding quality is inspected by means of a blister test. Lastly, optical microscopy is applied for clad thickness, which further supports the veracity of the UT characterization method. Natural U/Al alloy plate targets have been safely irradiated in the core of Pakistan Research Reactor-1. © 2010 Elsevier B.V. All rights reserved. Source

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