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| Study on the Equivalence of Water Equivalent Materials to Water under High-energy X-ray |
| WANG Zhi-peng1,2,XING Shu-ming1,WANG Kun2,JIN Sun-jun2,FAN Fu-you2,LIU Fu-bin2 |
1. School of Mechanical Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
2. National Institute of Metrology, Beijing 100029, China |
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Abstract The problems in the calibration of accelerator using water equivalent materials were described. Three commonly used water equivalent materials were compared to water phantom in measurements of absorbed dose to water. Two Farmer-type cylindrical chamber, PTW 30013 and IBA FC65-G, were used in measurements. The calibration factors of absolute dose between water phantom and water equivalent materials at two depth, 5cm and 10cm, were listed. Through the results of daily stability nearly seven months, the necessity of daily calibration of the accelerator was explained. The dose drift of accelerator and the possible causes were given. By measuring the output factor of twelve radiation fields, the water equivalent material is consistent with water in the relative measurement. Finally, the suggestions and precautions for the water equivalent material in the calibration of high energy X-ray were given.
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Received: 08 August 2019
Published: 17 February 2020
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2020, Vol. 41 
