Photonuclear activation ratios in fluorine compounds; an index of bremsstrahlung quality.
Photonuclear activation ratios in fluorine compounds; an index of bremsstrahlung quality.
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氟化合物中的光核活化率；
DOI：
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发表时间：
1984
期刊：
影响因子：
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通讯作者：
D. W. Anderson
中科院分区：
文献类型：
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作者：
K. L. Prado;D. W. Anderson
用临床用直线电子加速器的韧致辐射束对六氟硅酸钾（K_2SiF_6）和聚四氟乙烯（C_2F_4）_n样品进行了辐照，辐照终点能量的积分值在13 ~ 32 MeV之间。由反应39 K（γ，n）38 K、19 F（γ，n）18F和12 C（γ，n）11 C产生的样品正电子活性通过计数γ辐射来确定。根据这些数据计算每个靶核的饱和活度。对于K2 SiF 6样品，光核活化比（PAR）的7.6分钟39 K饱和活性每个核除以18 F的结果增加了超过20%，每MeV之间的15和21 MeV。对于（C2 F4）n样品，在22和26 MeV之间，每个核的11 C饱和活度与18F饱和活度的比率（PAR）每MeV增加超过24%。使用PAR技术可以很容易地检测到由铅平坦滤波器引起的质量变化。由于对韧致辐射谱变化的高度敏感性，这些PAR值可以作为高能束质量的敏感指标。
Samples of potassium hexafluorosilicate (K2SiF6) and polytetrafluoroethylene (C2F4)n were irradiated in the bremsstrahlung beam from a clinical linear electron accelerator at integral values of endpoint energy between 13 and 32 MeV. Sample positron activities produced by the reactions 39K(gamma, n) 38K, 19F(gamma, n) 18F, and 12C(gamma, n)11C, were determined by counting the gamma radiation. Saturation activities per target nucleus were calculated from these data. For the K2SiF6 samples, the photonuclear activation ratio (PAR) of the 7.6 min 39K saturation activity per nucleus divided by the 18F result increased by more than 20% per MeV between 15 and 21 MeV. For the (C2F4)n samples the ratio (PAR) of the 11C saturation activity per nucleus to that for 18F increased by more than 24% per MeV between 22 and 26 MeV. Quality changes caused by the lead flattening filter were easily detectable using the PAR technique. Because of the high sensitivity to bremsstrahlung spectrum changes these PAR values can serve as sensitive indices of quality for high-energy beams.