Evaluation of water decomposition by irradiation of heavy ion beam and development of the visualization of the ion track in matter

Water radiolysis has been investigated with heavy ions？ing energies up to 28 GeV produced from the Heavy Ion Medical Accelerator in Chiba （HIMAC） at the National Institute of Radiological Sciences （NIR）。^4 He ^&lt;2+&gt;、^<12>C^&lt;6+&gt;、^<20>Ne^&lt;10+&gt;、^<28>Si^&lt;14+&gt;、^<40>M^&lt;18+&gt;和^<56>Fe^&lt;26+&gt;的相应能量为150、400、300、490、500和500 MeV/u，对应于2.2、13、30、54、92和183 eV/nm的光束，对辐射的值是正确的，是对辐射的。在样本解决方案中的变化可能是消极的，因为它们对1厘米细胞的辐射产生了高能量。主要g值被确定为三种重要产品、氢化电子（e^-_<aq>）、羟基基（●OH）和羟基过氧化物（H2 O2），如轨道段yields （差异yields）下的中性pH条件下的G值，如LET，E^-_<aq>和 * OH在2.4和2.6中的G值在^He ^&lt;2+&gt;放射性为0.9和1.1数字/100 eV在<56>^&lt;26+&gt;放射性，对此表示赞赏。It wa（It wa） ... More s also found that the primary g value of _&lt;e-\&gt; is smaller that of任何类型的ion beam.对于^<12>C^&lt;6+&gt;光束，其他能量如290， 220，135 MeV/u被用于调查辐照对测量年份的类型或原子数目的影响。进一步研究，溶解氧对H_2O_2生产增强的影响也已通过空气化NaNO_3解决方案进行了调查。在H_2O_2年中，溶解氧在所有光束中的含量增加了15- 35%。作为第二个化学系统，我们选择甲基紫罗兰（MV^&lt;2+&gt;），在各种形式和测量了甲基紫罗兰基化（MV^&lt;●+&gt;）的浓度下存在。G（MV^\\+\） increases with increasing formate concentration。在^4 He ^&lt;2+&gt;放射性， G（MV^&lt;●+&gt;）从5.7到7.1增加，而格式的集中从10 mM到2 M增加，同时在^<56>Fe^&lt;26+&gt;放射性，MV^&lt;●+&gt;从2.2到4.1的yield变化。Other values lie between these ^4 He ^&lt;2+&gt; and ^<56>Fe^&lt;26+&gt; data。G（MV^\\+\） decreases with increasing LET。在C^&lt;6+&gt;放射性、G（MV^&lt;●+&gt;）的情况下，碳离子的能量从135至400 MeV/u增加到21至11 eV/nm的减少，在并行测量上，蒙特卡洛模拟MV^&lt;2+&gt;/格式的解决方案已得到执行。离子强度对充电品种之间的反应的影响将被纳入帐户。要生产实验结果，未报告的反应如MV^&lt;·+&gt; + ●OH和COO^&lt;·-&gt; + ●OH在反应方案中引入。在优化后，反应速率常数已确定为3 × 10 ^<10>和5 × 10 ^<10>M^&lt;-1&gt;s^&lt;-1&gt;，响应。在e^-_<aq>和MV^&lt;·+&gt;之间的对比下，反应对G（MV^&lt;·+&gt;）的影响太慢了。Furthermore，蒙特卡罗和马刺扩散计算的可复制性比较了。Less（低）

Water radiolysis has been investigated with heavy ions having energies up to 28GeV produced from the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIR). Beams of ^4He^<2+>, ^<12>C^<6+>, ^<20>Ne^<10+>, ^<28>Si^<14+>, ^<40>M^<18+> and ^<56>Fe^<26+> with respective energies of 150, 400, 300, 490, 500 and 500MeV/u corresponding LET values of 2.2, 13, 30, 54, 92 and 183eV/nm, respectively, were taken for the irradiation. The LET changes in sample solutions can be neglected due to their high energies for the irradiation of 1 cm cells. Primary g values have been determined for three important products, hydrated electron (e^-_<aq>), hydroxyl radical (●OH) and hydrogen peroxide (H2O2) as track segment yields (Differential yields) under the condition of neutral pH.With increasing LET, the g values of e^-_<aq> and ●OH decrease from 2.4 and 2.6 in ^4He^<2+> radiolysis to 0.9 and 1.1 numbers/100 eV in ^<56>Fe^<26+> radiolysis, respectively. It wa … More s also found that the primary g value of _<e-aq> is smaller than that of ●OH for any type of ion beam. For the ^<12>C^<6+> beam, other energies such as 290, 220, 135MeV/u were taken for the irradiation to investigate the effects of type or atomic number of ions on the measurement yields. Furthermore, effects of dissolved oxygen on enhancement of H_2O_2 production have also been investigated with aerated NaNO_3 solutions. The presence of dissolved oxygen caused 15-35% enhancement in H_2O_2 yields for all beams.As a second chemical system, we chose methyl viologen (MV^<2+>) solution in the presence of various concentration of formate and measured the yield of methyl viologen radical cation (MV^<●+>). The G(MV^<●+>) increases with increasing formate concentration. In ^4He^<2+> radiolysis, G(MV^<●+>) increases from 5.7 to 7.1 as the concentration of formate is increases from 10mM to 2M, while in ^<56>Fe^<26+> radiolysis, the MV^<●+> yield changes from 2.2 to 4.1. Other values lie between these ^4He^<2+> and ^<56>Fe^<26+> data. G(MV^<●+>) decreases with increasing LET. In the case of C^<6+> radiolysis, G(MV^<●+>) increases with increasing energy of the carbon ion from 135 to 400 MeV/u corresponding to the decrease of the LET of 21 to 11 eV/nm.In parallel to above measurement, Monte-Carlo simulations of the radiolysis of MV^<2+>/formate solutions have been performed. Ionic strength effects on reactions between charged species are taken into account. To reproduce the experimental results, unreported reactions such as MV^<・+> + ●OH and COO^<・-> + ●OH were introduced in the reaction scheme. After optimization, the rate constants of the reactions have been determined to be 3x10^<10> and 5x10^<10>M^<-1>s^<-1>, respectively. On the contrary, reaction between e^-_<aq> and MV^<・+> is too slow to affect G(MV^<・+>).Furthermore, reproducibility of the Monte Carlo and Spur diffusion calculations was compared. Less