Addition of luminescence process in Monte Carlo simulation to precisely estimate the light emitted from water during proton and carbon-ion irradiation
Addition of luminescence process in Monte Carlo simulation to precisely estimate the light emitted from water during proton and carbon-ion irradiation
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DOI：
10.1088/1361-6560/aac74b
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发表时间：
2018-06-01
影响因子：
3.5
通讯作者：
Yamamoto, Seiichi
中科院分区：
文献类型：
--
作者：
Yabe, Takuya;Sasano, Makoto;Yamamoto, Seiichi
虽然在质子和碳离子照射过程中发现了能量低于切伦科夫光阈值的水的发光，但这种现象尚未被用于蒙特卡罗模拟。由模拟提供的结果导致的物理现象的误解，在质子和碳离子辐照期间的水的光学成像。为了解决这些问题，以及澄清发光的水的光产生，我们修改了Monte Carlo模拟代码，包括发光的水的光产生，并将它们与发光成像的水的实验结果进行比较。我们使用GEANT 4模拟质子和碳离子辐照期间水的发射光。我们在GEANT 4中使用了来自水的发光的光产生，而来自水中的二次电子和即时伽马光子的切伦科夫光也被包括在模拟中。修正后的模拟结果表明，质子和碳离子的深度分布与实测数据相似。当0.1光子/MeV的光产生用于模拟中的水的发光时，与用于较小和较大数量的光子/MeV的那些相比，模拟的深度剖面显示出与质子和碳离子的测量结果的最佳匹配。在假定水的发光产生光的情况下，利用GEANT 4软件可以连续得到与实验数据基本一致的模拟深度剖面。我们的结果证实了在Monte Carlo模拟中加入水的发光对于精确计算质子和碳离子辐照时水中的光分布是必不可少的。
Although luminescence of water lower in energy than the Cerenkov-light threshold during proton and carbon-ion irradiation has been found, the phenomenon has not yet been implemented for Monte Carlo simulations. The results provided by the simulations lead to misunderstandings of the physical phenomenon in optical imaging of water during proton and carbon-ion irradiation. To solve the problems, as well as to clarify the light production of the luminescence of water, we modified a Monte Carlo simulation code to include the light production from the luminescence of water and compared them with the experimental results of luminescence imaging of water. We used GEANT4 for the simulation of emitted light from water during proton and carbon-ion irradiation. We used the light production from the luminescence of water using the scintillation process in GEANT4 while those of Cerenkov light from the secondary electrons and prompt gamma photons in water were also included in the simulation. The modified simulation results showed similar depth profiles to those of the measured data for both proton and carbon-ion. When the light production of 0.1 photons/MeV was used for the luminescence of water in the simulation, the simulated depth profiles showed the best match to those of the measured results for both the proton and carbon-ion compared with those used for smaller and larger numbers of photons/MeV. We could successively obtain the simulated depth profiles that were basically the same as the experimental data by using GEANT4 when we assumed the light production by the luminescence of water. Our results confirmed that the inclusion of the luminescence of water in Monte Carlo simulation is indispensable to calculate the precise light distribution in water during irradiation of proton and carbon-ion.