Construction of Sheet Resistance Measurement Setup for Tin Dioxide Film Using Four Probe Method
Rikesh Bhattarai,
Shankar Prasad Shrestha
Issue:
Volume 5, Issue 5, September 2017
Pages:
60-65
Received:
16 January 2017
Accepted:
25 January 2017
Published:
3 August 2017
Abstract: The main purpose of the paper is to construct the four probes to calculate the sheet resistance the thin film. For the thin film this paper presents the experimental preparation of Tin dioxide thin films. A dual voltage power supply and constant current source is developed to study deeply for the constant current output. Electrical properties are measured using constant current source, sheet resistance, four probe), digital multimeter and micro ammeter. The effect of thickness of sheet resistance thin film is carried out by four probe method.
Abstract: The main purpose of the paper is to construct the four probes to calculate the sheet resistance the thin film. For the thin film this paper presents the experimental preparation of Tin dioxide thin films. A dual voltage power supply and constant current source is developed to study deeply for the constant current output. Electrical properties are m...
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Instrumental Quality Control of Therapeutic Linear Accelerator Performance
Issue:
Volume 5, Issue 5, September 2017
Pages:
66-72
Received:
19 July 2017
Accepted:
28 July 2017
Published:
16 August 2017
Abstract: The objective of the article was to assess therapeutic linear accelerator performance. Material & method used were quality control tools, direct measurement & theoretical calculation methods. The analysis of results showed that: shift of machine isocenter was 1 mm then increases up to 2 mm through the gantry angles 0 to 300° and 300 to 360 respectively. The diaphragm rotation isocenter clock & anti-clock wise was 1mm. the light and radiation fields showed concise matching up to 9×9 cm, then for 10×10, 14×14 and 16×16 cm there were incongruence by 0.25, 0.3 and 0.41 cm respectively. The increment of the field sizes (2×2, 4×4 - 20×20) cm following SSD increment fitted with the inverse square law significantly (R2 = 1). The theoretical (calculation method) field size was greater than the measured (practical) field size relative to SSD by 0.2 cm. The system output in Gy/Mu increases significantly (R2 = 0.9) as the field size increases in logarithmic equation; while it decreases as SSD increases. The measured output on phantom surface was greater (0.8Gy/MU) than that calculated theoretically which was (0.5 Gy/MU). A significant (R2 = 0.8) reduction in output reading following the increment of temperature for Linac 10 MV and 6 MV respectively, while the pressure lead to significant (0.6) increment of system output reading. TLD showed narrow penumbra extension as 0.32 and 0.2 cm for lianc 6MV and 10MV respectively compared with 0.5 and 0.3 cm at maximum depth dose when obtained from dose histogram.
Abstract: The objective of the article was to assess therapeutic linear accelerator performance. Material & method used were quality control tools, direct measurement & theoretical calculation methods. The analysis of results showed that: shift of machine isocenter was 1 mm then increases up to 2 mm through the gantry angles 0 to 300° and 300 to 360 respecti...
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, where 
is the total angular momentum) at incident energies between 50 and 1000 keV. Our p-Na results and those determined by previous authors are in reasonable agreement.