Dosimetric measurements and Monte Carlo simulation for achieving uniform surface dose in pulsed electron beam irradiation facility
Dosimetric measurements and Monte Carlo simulation for achieving uniform surface dose in pulsed electron beam irradiation facility
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用于在脉冲电子束辐照设施中实现均匀表面剂量的剂量测量和蒙特卡罗模拟
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发表时间：
2010
期刊：
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通讯作者：
K. Subbaiah
中科院分区：
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作者：
V. Petwal;J. Rao;J. Dwivedi;V. Senecha;K. Subbaiah
我们在印度印多尔的中心正在调试一个用于食品和医疗产品辐射加工的脉冲电子束辐照设施原型。脉冲束装置的表面剂量和均匀性分析是至关重要的，因为它受到各种操作参数的影响，如束流，脉冲重复率（PRR），扫描电流分布和频率，扫描宽度和产品输送速度。需要大量的实验来确定这些操作参数的协调设置，以实现均匀的剂量。由于没有现成的工具来设置这些参数，使用蒙特卡罗方法和计算工具可以证明是最可行和节省时间的技术，以支持剂量分布的评估。在本研究中，蒙特卡罗程序，MCNP，被用来模拟10 MeV的电子束通过各种介质进入束流路径的传输，并产生一个等效剂量分布在一个聚苯乙烯体模稳态。这些结果已与实验测量的剂量分布进行了验证，表明结果在4%以内的良好一致性。蒙特卡罗模拟还被用于优化扫描的连续脉冲之间的重叠，以实现沿扫描方向沿着±5%的剂量均匀性。一个数学模型，它使用的稳态数据，包括输送机速度的影响。讨论了该模型的算法，并将计算结果与实验测量值进行了比较，结果表明，该模型的计算结果与实验测量值的符合率优于15%。最后，协调设置的加速器的操作参数导出提供均匀的表面剂量在1-13 kGy/遍的范围。
A prototype pulsed electron beam irradiation facility for radiation processing of food and medical products is being commissioned at our centre in Indore, India. Analysis of surface dose and uniformity for a pulsed beam facility is of crucial importance because it is influenced by various operating parameters such as beam current, pulse repetition rate (PRR), scanning current profile and frequency, scanning width and product conveying speed. A large number of experiments are required to determine the harmonized setting of these operating parameters for achieving uniform dose. Since there is no readily available tool to set these parameters, use of Monte Carlo methods and computational tools can prove to be the most viable and time saving technique to support the assessment of the dose distribution. In the present study, Monte Carlo code, MCNP, is used to simulate the transport of 10 MeV electron beam through various mediums coming into the beam path and generate an equivalent dose profile in a polystyrene phantom for stationary state. These results have been verified with experimentally measured dose profile, showing that results are in good agreement within 4%. The Monte Carlo simulation further has been used to optimize the overlapping between the successive pulses of a scan to achieve ±5% dose uniformity along the scanning direction. A mathematical model, which uses the stationary state data, is developed to include the effect of conveyor speed. The algorithm of the model is discussed and the results are compared with the experimentally measured values, which show that the agreement is better than 15%. Finally, harmonized setting for operating parameters of the accelerator are derived to deliver uniform surface dose in the range of 1–13 kGy/pass.